BINARY COPOLYMER REACTIVITY OF SOLKETAL
METHACRYLATE, TERTBUTYL METHACRYLATE,
AND 2BROMOETHYL METHACRYLATE
By
Larissa Nita Miranda
Bachelor of Science
University of Bombay
Bombay, India
1992
Submitted to the Faculty of the
Graduate College of the
Oklahoma State University
in partial fulfillment of
the requirements for
the degree of
MASTER OF SCIENCE
December, 2003
BINARY COrOLYMER REACTIVITY OF SOLKETAL
METHACRYLATE, TERTBUTYL METHACRYLATE,
AND 2BROMOETHYL METHACRYLATE
Thesis Approved"
Thesis Adviser
~~V{0@s· _
_ 1_~W/2~ . _
11
PREFACE
Polymers are long chain molecules 'hat are IXlllt up of smaller molecules called monomers. A
copolymer is composed of lWo or more mOnomers. Polymer chains lhat contain hOlh positively and
negatively charged units are called polyampholytes. The introduction of charged groups along lhe
polymer backbone leads 10 a complex solution behavIOr thai is essentially controlled by elew'ostatic
atlraction~ and repulsions. Proteins and DNA are examples of pol ymers whose struclures anJ functions
are tnfluenced by their electrical charges. Synthetic polymers have molecules of one or mme repeating
Slruclures and a wide range of chain lengths. The goal of this research was to determine (he amounLs
and sequences of the monomer units in copulymers made from three cambi nations of three different
monom.ers. From (he experiments conduCled using binary combJnalions of the three monomers we
were able to determine the order of reactivity of the three monomers
Our future goal is to synthesize watersoluble polyampholytes using three monomers. Based on
the results obtained in this research work, we will design experiments to syl1Lhcsizc ternary copolymers
WIth a range of chain lengths and latcr COil vert them inl0 polyampholylcs hy con vening the rC<Jctive
groups in the copolymers (0 positively and negatively chnrged units on the ~ame copolymer chain. The
ternary copolymers will be prepared by new methods tllal produce ntlrrower distrihutions of chain
lengths than conventional methods of copolyrnerizilLion.
III
ACKNOWLEDGEMENTS
I wish to express my gratitude to my research advisor, Dr. Warren T. Ford, for his understanding,
encouragement, guidance and support. I also wish to express my appreciation to my colleagues in the lab
for their assistance and encouragement. ] am very grateful to Dr. Darrell Berlin and Dr. Ziad 1:1 Rassi, for
serving on my advisory committee.
To my parents,] thank you for your encouragement, love and support, throughout my life. ] also
wish to thank my sisters, Glynis and Anthea, and my brotherinlaw, Nitin, for their inspiration and love
through all my education No words can express my gratitude and affection to my husband, Frank
D'Souza, for his never ceasing encouragement, love and support. Finally,] would like to thank the
Department of Chemistry for their financial support, during my graduate study at Oklahoma State
University.
IV
TABLE OF CONTENTS
Chapter
I. fNTRODUCTION
Objective oftlis Research
2. LITERATURE REVIEW
Kinetics of Free Radica 1Polymerization
Copolymerization
Chain Growth Copolymerization
The Terminal Model
Types of Copolymerization I3ehavior
Determination of Reactivity Ratios
3. EXPERIME~T AL
Chemicals
Measurements
Synthesis of Solketal Methacrylate
Procedure for Synthesis of Poly(tertbutyl methacrylate
Procedure for Synthesis of Poly(2bromoethyl methacrylate)
Procedure for Synthesis ofPoly(solketal methacrylate)
Procedure for Synthesis of Poly(terlbutyl methacrylateco
2bromoethyl methacrylate)
Procedure for Synthesis of Poly(tertbutyl methacrylateco
solketnl methacrylate)
Procedure for Synthesis of Poly(2bromoethyl methacryJateco
solketa\ methacrylate)
Analysis of Monomer Compositions
4. RESULTS AND DISCUSSION
Homopolymers
Analysis of Compositions of Monomer /
Polymer Mixtures
Monomer Reactivity Ratios
Variation of Copolymer Composilion
with Conversion
Monomer Sequence Distributions
Page
3
IJ
10
II
15
16
20
20
20
20
21
21
21
21
22
22
23
25
25
26
29
37
37
Cbapter
5. CONCLUSIONS
SUGGESTED FUTURE RESEARCH
REFERENCES
APPENDICES
VI
Page
41
42
44
4."
LIST OF TABLES
Table
1. Test of Solubility of Homopolymers
2. Data for Copolymerization of tertButyl Methacrylate
and 2Bromoethyl Methacrylate
3. Data for Copolymerization of tertButyl Methacrylate
and Solketal Methacrylate
4. Data for Copolymerization of2Bromoethyl Methacrylate
and Solketal Methacrylate
5. Reactivity Ratios for BEMA (M l ) and lEMA (M2)
6. Reactivity Ratios for IBMA (M,) and SMA (M2)
7. Reactivity Ratios for BEMA (M1) and SMA (M2)
8. 95 % Confidence Interval for Poly(BEMAcotBMA)
9. 95 % Confidence Interval for Poly(tBMAcoSMA)
10.95 % Confidence Interval forPoly(BEMAcoSMA)
11. Summary of 8 inary Copolymer Reactivity Ratios
Determined by the TM Method
12. Comparison of the Copolymer Composition F,
in Poly(BEMAcotBMA)
13. Comparison of the Copolymer Composition F1
in Poly(tBMAcoSMA)
J4. Comparison of the Copolymer Composition FI
in Poly(BEMAcoSMA)
15. Buildup ofa Sequence ofM1 units
16. Average Sequence Lengths oftBMA (M1)and
SMA (M2) in Poly(IBMAcoSMA)
17. Average Sequence Lengths of BEMA (M,) and
tSMA (M2) in Poly(BEMAcotBMA)
18. Average Sequence Lengths of BE.t\1A (M I) and
SMA (M2) in Poly(BEMAcoSMA)
Vll
Page
26
27
28
29
32
32
32
33
33
34
35
36
36
36
38
39
40
40
LIST OF FIGURES
Figure
I. Structures of solketal (l), solketal methacrylate (2), tellbutyl
methacrylate (3) and 2bromoethyl methacrylate (4)
2. Thennal decomposition of benzoyl peroxide
3. Thermal decomposition of azobisisobutyronitrile
4. Termination by combination
5. Termination by disproportionation
Vlll
Page
3
4
5
LIST OF SCHEMES
Scheme
I. Synthesis of solketal methacrylate
2. Copolymerization of 2bromoethyl methacrylate
and tertbutyl methacrylate
3. Copolymerization of tertbutyl methacrylate
and solketal methacrylate
4. Copolymerization of 2bromoethyl methacrylate
and solketal methacrylate
5. Synthesis of polyampholytes
IX
Page
25
27
28
29
43
APPENDICES
Figure
1. 'H NMR spectrum of solketal methacrylate
2. 'H NMR spectrum ofa mixture ofBEMA
and tBMA at room temperature
3. 'H NMR spectrum ofa mixture oftBMA
and SMA at room temperature
4. JH NMR spectrum ofa mixture of BEMA
and SMA at room temperature
x
Page
46
47
48
49

1
CHAPTER I
INTRODUCTION
Copolymerization allows the synthesis of an unlimited number of differenr products, by variations
in the nature and relative amounts of the two monomer units in the copolymer. I The behavior of monomers
in copolymerization reactions is useful for studying the effect of chemical structure on reactivity.' The
accurate estimation of the copolymer compositions and detennination of monomer reactivity ratios is
significant for producing tailormade copolymers. Binary copolymerization is defined by the inclusion
within a copolymer of two comonomers." The copolymer structure throughout the polymerization reaction,
depends (among other things) on the relative comonomer concentrations and on their reactivi ty 2 The
conversion factor is also important. A number of methods can be found in the copolymer literature for
calculating reactivity ratios from copolymer composition and initial comonomer feed compositions."
Reliable monomer reactivity ratios are needed primarily to predict the copolymer compositions for any
starting mixture as well as to classify the reactivities of the reacting comonomers in the copolymer. For
any experimental investigation, an optimal experimental design is of great importance, since it enables one
to perform the minimum number of experiments and obtain the most precise parameter estimates.! The aim
of this research is 10 detennine binary copolymer reactivity ratios of solkelal methacrylate [(2,2'dimethyl
1,3dioxotan4yl)methyl methacrylate] (SMA) (2) synthesized from solketal (1), fer/butyl methacrylate
(tBMA) (3) and 2bromoelhyl methacrylate (BEMA) (4). The structures of the three monomers are as
shown in Figure I.
solketal (1) SMA (2) tBMA (3) BEMA (4)
Figure]. Structures of solkelal (1), solketal methacrylate (2), terfbutyl methacrylate (3) and
2bromoethyl methacrylate (4)
2
Our future goal is to synthesize polyampholytes that are watersoluble, using solketal methaclylate (SMA),
ter/butyl methacrylate (IBMA) and 2bromoethyJ methacrylate (BEMA). Polyampholytes (PA) contain
both positively and negatively charged units on the same polymer chain.4 The introduction of ionic groups
of opposite charges along the backbone leads to a complex solution behavior, that is essentially controlled
by electrostatic interaction. We tried to polymerize tBMA, SMA and BEMA via the RAFT (reversible
additionfragmentation chaintransfer) method. The polymerizations ofBEMA via RAFT gave less than
10 % conversion, under the same experimental conditions that worked for tBMA and SMA. Our revised
approach will be to synthesize polyampholytes via ternary copolymers of solketal methacrylate, tertbutyl
methacrylate and N,Ndimethylaminoethyl metbacrylate (DMAEMA). The ternary copolymers will be
transfonned into polyampholyLes by functional group conversions. The positively charged units will be
provided by quatemizing DMAEMA with methyl iodide, while the acidcatalyzed elimination of tertbutyl
ester will provide the negatively charged carboxylate end units. Solketal methacrylate on hydrolysis, in an
aqueous medium will be converted to the diol that is, glyceryl methacrylate, which will make the
polyampholytes watersoluble.
3
CHAPTER II
LITERATURE REVIEW
Kinetics of Free Radical Polymerization. Free radical polymerizations are chain reactions.
Radical chain polymerization consists of a sequence of three steps:
(I) Chain initiation  a process in which highly reactive free radicals are formed.
(2) Chain propagation  the addition of monomer molecules to the active chain end, accompanied by
regeneration of the terminal active site.
(3) Chain termination  a reaction in which the active chain centers are destroyed.
Free radicals must be introduced into the system to start the reaction. 5 A large number of free radic.al
initiators are available; they may be c1a'lSified into four major categories: peroxides and hydroperoxides,
azo compounds, redox initiators, and cerlain compounds that form radicals under the influence of light
(photoinitiators).5 Highenergy radiation (y and Xrays) can also promote free radical polymerization,
although such radiation is less commonly used.
Of the various types of initiators, peroxides and hydroperoxides are most widely used. The most
commonly used peroxide is benzoyl peroxide (BPO), which undergoes them1al homolysis to form
benzoyloxy radicals. 5 Compounds like benzoyl peroxide are reactive, because the bond between the two
oxygen atoms is weak and can split homolytically to give two free radicals, as shown in Figure 2.
Figure 2. Thermal decomposition of benzoyl peroxide. s
The most commonly used azo compounds are those having cyano groups on the carbons attached to the
azo linkage. 5For example, azobisisobutyronitrile (AlBN) is the most commonly used azo initiator.
fH3 fH3
CH3CN=N CCH3 I I
eN CN
+ NZ
4
Figure 3. Decomposition of AIBN to form free radicals.6
Figure 3 represents the decomposition of AIBN to form two cyanopropyl radicals.
The initiation step is considered to involve two reactions. 5 The first is the production of free
radicals.
(1)
Here the initiator 1, decomposes to yield two free radicals R" and kd is the decomposition rate constant for
the reaction. The second part of the initiation involves the addition of this radical to the first monomer
molecule to produce the chain initiating species R;;
R" +M _k_,) R'
I
(2)
where M represents a monomer molecule, R: represents a monomerended radical, and ki is the rate
constant for the initiation step (equation 2).
In the initial propagation step, R; adds to another monomer molecule to form a new radical, R;,
which in tum, adds to M to form R;, and so 00:
5
R" +M _k_p_~R'
" n+1
(3)
(4)
(5)
where k is the rate constanl for propagation. Each reaction in the sequence involves the addition of a
p
monomer to a monomerended radical, and each is assigned the same rate constant, k}J , on the reasonable
assumption that the rate of addition reaction does not depend on the size of the propagating radicaL
6
The two principal ways in which termination may OCcur in free radical polymerization are radical
coupling, or combination and disproportionation. S In tennination by combination of the growing free
radical chains, the two macroradicals couple to fonn a paired electron bond.6
5
~~CH CH' 2 .IY
+ i~~ /VVV"VV'CH CH~~
I I Y y
Figure 4. Tennination by combination. s
Alternatively, the two radical chains can form two new molecules by a disproportionation reaction. In this
reaction, a hydrogen atom is transferred from one chain to the other$
~~CH CH'
2 Iy
+
,. NVV"VV'CH=CH
IY
+
Figure 5. Termination by disproportionation. 5
The following are the approximations made to derive the kinetic equations for free radical
polymerization:
1. The kinetic chain length is long, that is, the propagation steps are much faster than the initiation step.
This means that all the monomer is consumed by propagation.
2. Assume that k does not depend on the length of the polymer radical, that is, it doesn't mailer if yOll
p
have one or ten repeat units in the polymer.
3. The rate constants for tennination by combination, k/c and for termination by disproportionation, ku"
do not depend on the length of the polymer radicals.
4. When a free radical polymerization first starts, the number of free radicals in the system will increase
gradually as tbe initiator begins to decompose, according to equation (1)6 As a resull, the frequency of
termination reactions wilJ also increase gradually, since the rates of these reactions are proportional to the
6
concentration of radicals in the system. Eventually the rate of generation of radicals will be balanced by
tbe rate of termination of radicals, and the concentration of radicals in the system will reach a steady value.6
The assumption 1hat the rate of initiation (R;) equals the rate oftennination (R,) is called the steadystate
assumption. It is equivalent 10 the following two statements:
R; = R, at steady state
and
d[R' ] =0 at steady state
dt
This assumption is mandatory for the establishment of a constant freeradical concentration.
The rate of radical production from equation (1) is given by:6
d[R'] = 2k [1]
dl d
(6)
(7)
(8)
Since each molecular decomposition produces two radicals. The rate of initiation, Rj is the rate of reaction
(equation (2». This can be expressed as the rate of radical production as:
R; = 2fkdf1]
where [I] is the molar concentration of the initiator and f is the initiator efficiency factor,
(9)
that is, the fraction of initiator radicals that actually start a chain reaction 6 The factor 2 arises from the fact
t11at two initiator radicals are generated from each decomposi tion.
The two termination reactions can be represented in general terms as follows:
, • XI M M
M" +lvlm ~ m+ "
(0)
(II)
where k is the rate constant for termination by combination, and k is the rale constant for termination by
k d
disproportionation. One can also express the termination step as follows:
M' +M· _X_,) dead polymer
" m
(2)
where the particular mode of termination is not speci fied and the overall rate constant k is giv b'
I en y.
7
(13)
The termination rates RI ' corresponding to the different modes of termination are:
The overall expression for the rate of termination is given by:
R, = 2k, [Ro]'
The factor 2 takes into account that two radicals are consumed in any termination reaction. s
(14)
(15)
(16)
From the steady state assull1ption, which assumes that the rale of initiation equals the rate of
tenrunalion, which is equivalent to R, = RI
, at steady state one obtains the following expression after
equating equations (9) and (16):
Thus,
fRO ]=(fkA!]J'12
k,
(17)
(l X)
This :s an expression for tbe total concentration of monomerended radicals in terms of experimentally
accessible quantities.~
The rate of polymerization is taken to be the rate of Jisappearance of monomer, which is
dfM]/dt 6 Since the concentration of monomer decreases with time, so d[M]jdt is negative. The two
reactions that consume monomer are equation (2), that is initiation, and equation (5), that is propagation.'
Therefore,
d[M] =R + R
dt I P
( 19)
Because propagation invol ves a large number of monomer molecules per chain, whereas initiation
consumes only one. the rate of polymerization, is for all practical purposes, equivalent to the rate of
. s
propagatIOn.

8
Thus,
The rate of polymerization, is therefore proportional to the square root of the initiator concentration, and to
the first power of the monomer concentration,5
d[M] =R =k [M'I[R"]
dt P P ,
where [R'] stands for sum of the concentrations of all monomerended radicals in the system,(,
Substituting the expression for [R'], from equation (18) above, we obtain:
k
R =_P[M(lk [/])1/2
{J kl,2 V'rl
I
The rate of initiator disappearance is given by;6
 d(l] = k [I]
dt d
integrating equation (22) between [I] = [1]0 at time t = 0 and [I] at t gives:
where [1)0 is the initiator concentration at the start of polymerization.
Substituting equation (23) into equation (21) yields:
d[M] =(~J(jk [I] )ll2 ekJ
j{dt
[M] k,lil . d 11
(20)
(21 )
(22)
(23)
(24)
The third term indicates that the polymerization slows down in an exponential manner with respect
to time, as more initiator gets consumed. The poJymerizability of a monomer in a free radical reaction is
related to k /k"', rather than to k alone, as seen in the first term, On integrating equation (24) between p r p
[M] =[MJoat t = Oand [M] at I:
(25)
Th.is expression gives the amount of polymer (in terms of moles of monomer converted) produced in lime l.
The rate constants depend on lemperature6
The average kinetic chain length (U) is defined as the average number of monomer molecules
polymerized per chain initiated, or equivalently, as the rate of polymerization per unit rate of initiation.'
Under steady state conditions. where Ri =R, :
9
from equation~ (8), (15) and (18). Therefore,
Substituting the expression for [K] from equation (18), we get:
k [M]
U= '1'_,,:
2(jk1kd [I])' 2
It can be seen from equation (29) that the kinetic chain length will decrease, as both the initiator
(26)
(27)
(28)
(29)
concentration and initiator efficiency increases The number average degree of polymerization, DP ,
"
defined as the average number of monomer molecules contained in n polymer molecule is related to the
kinetic chain length, according to the mode of teonination. 5 1f teonination occurs exclusively by
disproportionation, then every radical chain leads 10 one polymer molecule.
Dp', = U
If teonination occurs by combination then it takes two radicais to give one polymer molecule.
Dp', = 2u
If both tennination by combination and disproportionalion, occur at the same time,
(30)
0\ )
(2)
10
Copolymerization. Copolymerization allows the synthesis of a large number of different polymers
by varying the sequence and the amounts of the two monomer units in the copolymer product.2 A
description of the copolymer structure requires the specification ofIhe relative compositions of the comonomers
and their sequence distribution.? Copolymers are most often classified into the follo\\ring
categories:7 Statistical (random) copolymers, in which comonomers appear in irregular, unspecified
sequences, along the chain:
Alternating copolymers, in which the comonomers occur in alternation:
Block copolymers, in which long linear sequences of comonomer A arej0ined to long linear sequence" of
Graft copolymers, in which chains of one comonomer are pendant from a backbone of the other:
comonomer B:
A
A
A
A
+
+
+
+
B
B
B
B
..
~~ABBABAAABAB~~
~~ABABABABABA~~
~~AAAAAABBBBBB .rvvv.A/VV
For our discussion, we will focus mainly on statistical or random copolymers. The term statistical
copolymer is preferable in describing copolymers, in which the distribution of sequences of monomer units
obeys known statisticallaws.7 Such copolymers are frequently called random copolymers in the literature.
Random copolymers are actually a special class of statistical copolymers, in which the probability of
finding a given monomeric unit. at any given site in the chain, is independent of the nature of the
neighboring units at that position, that is, the sequence may be described by Bemoul1ian statistics 7
Chain Growth Copolymerization. In chaingrowth processes, the copolymer grows via
successive additions of the comonomers to an active center that is either radical or ionic. 7
~ABAABBA*
A
B
~ABAABBAA"
~ABAABBAB"
11
Of primary concern are copolymer composition and sequence and copolymerization rate. The
relative rates of incorporation of comonomers A and B are not, in general, equal to their relative
concentrations in the initial reaction mixture.7 Thus the copolymer formed at any instant, differs in
composition from the feed mixture, and the feed composition changes continuously, from the begilming of
tbe reaction to the end 7 The products of copolymerization, like any chemical reaction, may be dictated by
the kinetics or thermodynamics of the reaction. With a few exceptions, chaingrowth copolymerization
products are kinetically determined, so instantaneous copolymer composition can be predicted by a set of
differential equations, that describe the rates of monomer consumption, Developing these equations,
requires an appropriate kinetic model of the copolymerization process. 7
The Terminal Model. The composition of a copolymer is usually different from the composition
of the comonomer feed, from which it is produced. In other words, different monomers have differing
tendencies to undergo copolymerization. It was observed eelrly that the relative copolymerization
tendencies of monomers usually bore little resemblance to their relative rates of homopoJymerization,I
Further a few monomers such as maleic anhydride and stilbene undergo facile copolymerization with
radical initiation, although they have very liltle or no tendency 10 undergo homopolymerization. The
composition of a copolymer thus caJUlot be determined simply from a knowledge of the
homopolymerization rates of the two monomers,
Consider the case where two monomers, M, and M2
• copolymerize. Copolymerization of the
two monomers leads to two ~ypes of propagating species, one with M 1 at the propagating end elnd the other
with M 2 at the propagating end. These can be repre,;enled by M; and M; where • represents a radica I as
the propagating species. If it is assumed that the reactivity of the propagating species is dependent only on
the monomer unit at the end of the chain, four propagation reactions are then possible:
M o M k" M" 1+ I~ I
Af; +M2 __k, _,_) M;
M; +M, _k~~M;
M; +M2
~M;
(33)
(34)
(35)
(36)
12
where k
"
is the rate constant for a propagating chain end ending in M" adding to monomer M, ' k is that
12
for a propagating chain ending in M, ' adding to monomer M 2' and so on. The propagatio11 of a reactive
center, by addition of the same monomer (that is equations (33) and (36), is often referred to as
homopropagation or selfpropagation, whereas propagation of a reactive center by addition of the other
monomer [equations (34) and (35)], is referred to as crosspropagation.' Monomer M, disappears by
reactions represented by equations (33) and (35), while monomer M 2 disappears by reactions represented
by equations (34) and (36). The rates of disappearance of the two monomers, which are synonymous with
their rates of entry into the copolymer are given by:
(37)
(38)
where [Mil and [M2 l are the monornerfeedcol1centrations, and [M:J and (M;J are the concentrations
of the growing chains, with terminal residues derived from M I and M 2' respectively.
Since it is experimentally observed that the number of growing chains remains approximately
constant, throughout the duration of most copolymerizations, in order to remove the concentration terms in
M: and M; ,a steady state concentration is assumed for each of the reactive species M: and
M; separately. r For the concentration of M: and M; to remain constant, their rates of interconversion
must be equal.
.
Assumption of the steady state concentrations of MI and M 2 takes the foml:
Solving for [M;J gives:
(40)
The ratio of disappearance of monomers MilM2 is obtained by dividing equation (37) by equation (38):
13
d[M j ] = k"lM;][Mj]+k21[M;][M,]
d[M2 J k12 [M;][M 2 ]+kn [M;][M 2 }
Substitution of [M; ] into equation (41) gives:
Dividing by k 2 and cancellation of the appropriate k's gives:
(41)
(42)
(43)
Substitution of ~ = r,
kl2
(44)
and cancellation of [M;] gives:
(45)
We derive the copolymer composition equation (46), by multiplication of equation (45) by [M2] a'):
(46)
The copolymer composition equation defines the molar ratio of the two monomers that are incorporated
into the copolymer, d{M, J/d[M2].' df.M ,l/d[M2] is expressed by equation (46) as being related to the
concentrations of the two monomers in the feed, [M,] and [M2] and the parameters IJ and /2. The
parameters rand,., are tenned monomer reactivity ratios I Each r is the ratio of the rate constant for a I _
14
reactive propagating species adding to ils own type ofmOnomer to the rate constant for its addition of the
other monomer. I
The copolymer equation can also be expressed in terms of mole fractions. I Thus if .f., and f~ are
the mole fractions of the monomers M 1 and M 2 in the feed, respectively, and F, and F
2
are the mole
fractions of the monomers M I and M 2 in the copolymer, then
(47)
and
(48)
Combining equations (47) and (48) with equation (46) yields the copolymer equation, which may be
written as:
(49)
Equation (49) gives the copolymer composition as the mole fraction of monomer M 1
. The quantities F2
and /2' are given by 1 F1 and 1 f ' respectively. The monomer reactivity ralios 1'1 and r 2 are extremely
important quantities 8 First, they are a measure of the relative preference of a radical species for the
monomers. Second, these two quantities, 1'1 and r 2' represent the only two independent rate variables that
we need to know, rather than the four individual rale constants, /ell elc. Finally, experimental methods for
the measurements of 1'1 and r 2' have been established, so that in principle, we should be <.lble to calculate
copolymer composition from monomer composition and I' values.
The relative proportions ofunreacted monomer after polymerization has proceeded for a while, may
be very different from the proportions at the very start of the polymerization (for example one monomer
could react far more quickly than the other and is therefore used up much faster). This means thaI we have
15
a composition drift. The copolymer composition usually varies throughout the polymerization, (except for
a special case we will consider below) and differs from the monomer "feed" concentration.8
Types of Copolymerization Behavior. Different types of copolymerization behavior are observed
depending on the values of the monomer reactivity ratios.
Case I. Ideal copolymerization. A copolymerization is termed ideal when the r,l", product is
unity. Ideal copolymerizations occur when two types of propagating species M; and M; show the same
preference for adding one or Ihe other of the two monomers.' Under these conditions,
len kll
/e" /ell I"I
(50)
For an ideal copolymerization, equation (50) is combined with equation (46) or (49) to yield the
copolymerization equation as:
(51 )
(52)
When rl = f"l =I, the two monomers show equal reactivlties towards both propagating species. The
copolymer composition is the same as the comonomer feed, with a random placement of the two
monomers along the copolymer chain. Such behavior is referred to as random.'
Case II. Alternating copolymerization. When 1", :; 1", =0 (and r,rl =0), tile two monomers enter
into the copolymer in equimolar amounts, in an alternating anangement along the copolymer chain. This
type of copolymerization is referred to as alternating copolymerization. Each of the two types of
propagating species preferentially adds to the olher monomer, that is AI" adds only M 2' and M; adds only
MI' The copolymer equation reduces to:
(53)
The tendency to alternate increases, as the rlr2 product nears zero, as long as both r l and r2 are both less
than unily. I
16
Case Ill. fl >1 and f2 < I or f, < land f~ > 1. In these cases, one of the monomers is more
reactive than the other toward both propagating species. The copolymer will contain a larger proportion of
the more reactive monomer, in statistical placement. 1
Case IV. Block Copolymerization. Ifboth 1'1 and 1"2 are greater than unity (and therefore also
Ijr2 > I), there is a tendency to fonn a block copolymer, in which there are blocks of both monomers in the
chain. 1
Determination of Reactivity Ratios. A number of methods can be found in the copolymer
literature for calculating reactivity ratios from copolymer composition and initial comonomer
concentrations2 The estimation methods developed to determine reactivity ratios are based on the
copolymer composition equation (46) in various differential and integral forms.
The FinemanRoss (FR) Method. 9 The first method to balance successfully the entire experiment
and estimate the experimental errors was thai developed by Fineman and Ross in 1950.2
.
9 The copolymer
equation, which relates the polymer composition to Ihe monomer composition is given by:
d[MJJ == [M1J( r,[Md+[M 2 JJ
d[M1J [M2JUM1J+ r1[M 2 J
The FR method pennits the use of uata in the intemlediate concentration regions and reduces the
uncertainties in the I" values 9 The FinemanRoss equation can be deduced as follows:
Then equation (54) can be rewritten as:
By rearranging lerms one obtains:
/ (F 1) == I' I'"  1", F I F 
(54)
(55)
(56)
(57)
A plot of / (F l)as ordinate and /" as abscissa is a straight line whose slope is 1'1 and whose intercept
F F
is  1',.
Introducing (58)
17
and II == [?
F
Equation (57) can be rewrillen as:
Equation (57) can also be rearranged as:
FJ F
 == I', +1' [  [2 1
(59)
(60)
(61 )
In this case the slope is  1'2 and the intercept is 1'1' In addition to simplifying the calculations, the use of
equations (57) and (61) offers the considerable advantage that they permit Lhe facile use of the method of
least squares to get the best fit to Lhe experimental data 9
The following assumptions are made by the FinemanRoss method: 2
J. The random elTors in the dependent variable are statistically independent from experiment to experiment,
and exhibit a constant variance.
2. The random en"orS in the dependent variable are normally distributed.
3. The independent variable, that is, the comonomer feed composition, is assumed to be errorless.
This method employs a linear least squares analysis. 2 Different values of ,.. and 1'2 can be produced,
depending all which monomer is sekcted as monomer I or M 1
2 The effect of switching indexes is brought
about by the lack of symmetry in equation (57). Two pairs of reactivity ratios can be obtained by using just
one estimation method.2 Fineman and Ross did not underline the hazards of switching the indexes on M .2
YezrielcvBrokhinaRoskin (YBR) Method. In order to write equation (57) in a symmetric form,
YezneJev et al. suggested a division of all the lenns in equation (57) by M, mz .
M 2 111 1
(62)
The results obtained via the symmetric equation (62) are not speclacular, bUI they allow for a less
ambiguous solution, than tllat provided by the FinemanRoss method.2 The YBR and the FinemanRoss
methods are linear methods and use the differential form of the copolymerization equation (46)2
18
However, the YBR method doesn't always yield better results than those obtained with the FR method. 2
The values found via the YBR method lie between the F values detennined for the two variants of the FR
method, namely FRI and FR2, obtained after switching indexes. This shows that the YBR method,
despite its methodological advances, does not fully improve the processing of the experimental dat.a 2 Even
if the effects of switching indexes are removed, a better fit of experimental data is not guaranteed.
The KelenTudos (KT) l\tlethod. 1o The refined Conn of the copolymer composition equation (46),
as put forward by Kelen and Tudo~ is:
(63)
where TJ and ~ are functions of the monomer mole fraction, in the copolymer and the feed respectively.
and/or
where G
TJ == ,....,.
(a + H)
and ~ == H
(a+H)
(64)
((5)
(66)
Kelen and Tudos transformed the FinemanRoss equation, by introducing an arbitary positive constant a
into equation (57) to spread the data more evenly, so as to give equal weighting [0 all the data points. The
term a is a parameter of symmetrization, tbe optimal value of which, ror a given series of measurements
being a == JH rna.' . H min (where Hmo' and Hmill are the lowest and highest H values of the set of
experimental points, respectively).2 By plotting 17 versuS 4, a straight line is obtained, which gives  r 2 as
a
the intercept, and ~ + 1'1 as the slope.2
I a
The TidwellMortimer (TM) Method. 11 In a critical review of the methods used to determine
reactivity ratios, for the terminal model, Tidwell and Mortimer' II pointed out the defects of the different
linear methods and suggested the use of nonlinear least squares (Ni.LS) procedure.? This method uses a
nonlinear least squares approach for determining reactivity ratios. This method provides a means of
19
evaluating how well the reactivity ratios have been estimated, as well as a means of determining if the data
are consistent with the assumption, that the copolymerization equation describes the relationship between
monomer and polymer composition. I I Briefly the method consists of the following: given initial estimates
of rl and '"2' several sets of computations are perfonned which rapidly leads to a pair of values of the
reactivity ratios, which yields the minimum value of the sum of the squares of the differences between the
observed and the computed copolymer composition. I I One of the shortcomings of the TM method is in
order to start the calculation, the reactivity ratios are chosen directly from the experimental data under
study or by using the FR or the KT method? The TM method presumes ·that there is no possible
experimental error in the independent variable, that is, rn z or the composition of the monomer in the feed,
and that the absolute error, in the copolymer composition, that is M 2 is independent of its value or
constant. l ? Thus it follows that the differences in the comonomer [Taction values incorporated into the
copolymer, during the respective time intervals, are evenly distributed with constant variances.
20
CHAPTER III
EXPERIMENTAL
Materials. Solketal (Aldrich, 98%) and methacryloyl chloride (Aldrich, 97%) were used without
further purification. tertButyl methacrylate (Aldrich) and 2bromoethyl methacrylate (MonomerPolymer
Dajac Labs Inc.) were purified by passing through a shon colunm of basic alumina to remove any phenolic
inhibitors. The purified monomers were stored in the refrigerator to prevent any polymerization. AlBN
(Aldrich, 98%) was recrystallized from ethanol. CDCI] (Aldrich, 99.9 % D) was used as received.
Spectroscopic Analysis. The 'H NMR spectra of the monomers, homopolymers and copolymers
were recorded a1399.905 MHz, using CDCI] as the NMR lock solvent. The spectra oftbe copolymers were
recorded on a Quad probe using the following conditions: 44 K data points, flip angle of 20 0 and a
relaxation delay of 5 S.13 Thirty two scans were accumulated for each spectrum. The temperature of the
sample was maintained at 50.0:±:. 0.1 uC during polymerizations. The signals assigned to the vinyl protons
of the comonomers were integrated after Fourier transfonning the free induction decays (FIDs).
Solketal metbacrylate. Solketal methacrylate was synthesized according to the literature
procedure, I~ except the solvent used in the literature procedure was benzene (400 mL). Toluene (200 mL)
was added to a threeneck 500 rnL round bottom flask. Solketal (I) (0.44 mol, 54.5 mL) was added next,
and finally triethylamine (0.44 mol, 61.8 mL) was added. N z gas was bubbled through the solution. The
round bottom flask was chilled in an ice bath to 0 0c. Methacryloyl chloride (0.33 mol, 32.2 mI.) wa~
added through a pressure equalizing addition funnel drop wise over 45 minutes with stirring. Since
methacryloyl chloride is toxic, corrosive and a strong lachrymator, it should be handled wilh caution, by
working inside the fume hood and wearing a protective face mask and safety goggles. The flask was left to
wann to room temperature and lhe contents were stirred overnight for 24 h. The triethylammonium sail
formed was filtered off, and an integrated'H NMR spectrum of the filtrate in CDCI] was obtained. From
the analysis oCthe integrated IH NMR spectrum, the amount of sol ketal remaining unreacted in the filtrate
was calculated to be 39%. The filtrate was washed thrice with deionized water (30 rnL), and the organic
phase was dried over anhydrous sodium carbonate (35 g) and filtered.
21
CuCI:!.2H20 (17 mg) was added as an inhibitor prior to rotary evaporating toluene. The crude sol ketal
methacrylate was purified by vacuum distillation at a reduced pressure (2.32.4 mm Hg), recorded on a
McLeod Gauge. The temperature of the distillate in the round bottom flask was 76 80°C, when the liquid
started to distill, and stayed constant at 78 Dc. The rate of distillation was about I drop per second, with nu
bumping. The boihng point reported in the /.iterature procedure was 5355°C (1.5 nun Hg pressure). The
distillate (a coJorless liquid) was stored in the freezer. Solketal methacrylate (2) was obtained in 89% yield,
as compared to 50% yieJd, reported ill the Jiterature. 14 From the integrated 'H NMR spectrum ofpurificd
solketal methacrylate, the amount of unreacted solketal was calculated to be 12 % based on the difference
between the peak areas under the vinyl hydrogens (6.10 and 5.59 ppm) and the area under the peaks from
3.6 to 4.4 ppm, which accounts for the 5 protons of soJketal and solketal methacrylate. 'H NMR (CDC)3) 8:
6.10 and 5.59 (m, =CH2), [4.34 (m, CR), 4.20 (m, CH2), 4.06 (m, CH) from soJketaJ methacrylate], 1.9
(s, CH), 1.3 and J.5 (s, 2 ClI).
Poly(tertButyJ methacrylate). tBMA (1.000 g) and AlBN (2,2'azobisisobutyronitrile)
(0.164 g, 0.001 mol) in dimethyl sulfoxide (5 mL) were heated at 70°C for 24 h. The soJution was added
dropwise to a solution of methanol (l00 mL) with vigorous stirring. A white solid precipitated. The solid
was filtered and dried (yield = 0.892 g). IH NMR (CDCL3) 8: L,69  1.7R (m, CH2), 1.38 lAO (m, qCH)))
due to different tacticities}, 0.99  1.19 (m, CH).
Poly(2bromoethyl methacrylate). The homopolymer of BEMA was synthesized in a manner
similar to tBMA homopolymer, (yield = 0.847 g). IH NMR (CDCI3) 8: 4.25 and 3.53 (s, 2 ·CH2), 1.88
196 (m, CH2), 1.08  0.93(m, Cll" due to different tacticities).
Poly(solketal methacrylate). Poly(solketaJ methacrylate) was synthesized by heating solketal
methacrylate (1.000 g) in toluene (3 mL) and AlBN (0.164 g. 0.001 mol) at 70°C for 24 h. The solution
was added dropwise La nhexane (50 mL). A white sticky and strctchy precipitate fonned, which was
tiltered and dried (yield = 0.650 g). IH NMR (CDCh) 8: 4.29  3.72 (m, CH2CHCH2, 5 H from solketal
methacrylate), 1.93  1.81 (m, CH2), 1.31 and 1.40 (s, 2 Cll,,), 0.86  0.95 (m, CH) due to different
tacticities).
Poly(BEMAcotBMA). These copolymers were synthesized using a literature procedure. 13
Different mole fractions of 2bromoethyl methacrylate/tertbutyl methacrylate in the feed were used to
22
!':ynthesize copolymers ofBEMA and tBMA directly in the NMR tube. In an example preparation, BEMA
(0.610 mmol, 0.09 mL) and tBMA (0.390 mmol, 0.05 ml) were measured using I mL disposable syringes
and transferred to a scintillation vial. An internal standard, pxylene (0.5 lTunol, 0.06 ml) was measured
and transferred to the vial. AIBN (0.125 mmol, 0.020 g) was added followed by CDCI~ (0.50 mL). The
amount of AlBN used in all the copolymerization experiments was held constant (0.125 mmol, 0.020 g).
The homogenous solution was transferred to an NMR tube and N2 gas was passed over the solution in a
gentle stream, through a syringe needle. The NMR tube was firmly capped with a plastic cap and the
contents in the tube were mixed by gently tilting the tube several times. pXylene was used as an intemal
standard in order to be able to compare the integrated peak areas of the singlet from pxylene at 6.98 ppm
with those of the vinyl protons of BEMA and tBMA, which decreased as the polymerization progressed.
The NNfR tube was placed in the 'H NMR Quad probe at room temperature, and the room temperature
spectrum was obtained. The integrated peak areas of the vinyl protons and pxylene, from this spectrum,
were used to calculate the compositions of the comonomers in the feed, prior to any polymerization. The
temperature of the probe was equilibrated to 50.0 :.!:. 0.1 fie and the probe was shimmed and locked at the
temperature setting of the probe. The I H NMR spectra were time arrayed to collect the free induction
decays (FlO's) after 10 minute intervals. The copolymerizations were run lip to about 20 % conversion.
The NMR spectra thus obtained, were integrated [or further calculations.
POly(tBMAcoSMA) and Poly(BEIVIAcoSMA). These copolymerization experiments were
carried out in a manner similar to the above, except in poly(BEMAcoSMA), the monomers were
measured by weight and transferred to a scintillation vial. The mole fractions of the two monomers in
poly(BEMAcoSMA) determined from the integrated peak areas and the mole fractions measured by
weight differed in the range from 0.0 I to 0.03.
'H NMR Spectra of MonoIner Mixtures_ BEMA and tBMA. 'H NMR (CDCI) 0: 6.98 (s, 4 H
frompxylene), 6.11 and 5.54 (m, =CHz from BEMA), 5.94 and 5.39 (m, =CHz from ISMA), 4.35 (I, C0
2CH2 of BEMA), 3.45 (t, CH2Br of BEMA), 2.2 (s, CH3 from pxylene), 1.9 (s, CH.l from tBMA),
1.85 (s, CH3 from BEMA), L.4 (s, .C(CH3h from tBMA).
tRIVIA and SMA. 'H NMR (CDCI) 8: 6.98 (s, 4 H from pxyJcne), 6.08 and 5.50 (m, =CH2 from
SMA), 5.94 and 5.39 (m, =CHz from tBMA), 3.7  4.4 (m, CHzCHCHz, 5 H from solketal methacrylate),
23
2.2 (5, CH,1 from pxylcne), 1.8R (s, CH] from SMA), 1.83 (s, CH] from tBMA), 1.42 (s, C(CH])] from
LBMA), 1.35 and L29 (s, 2 CH., from SMA).
BEMA and SMA. 'H NMR (CDCl,) 8: 6.98 (s, 4 H from pxylene), 6.11 and 5.54 (m, =CH2
from BEMA). 6.09 and 5.52 (m, =CHz from SMA), 3.7  4.4 (m, CHzCHCHz, 5 H from solketal
methacrylate), 4.35 (t, CO]CHz of BEMA), 3.45 (t, CHzBr of BEMA), 2.2 (s, CH] from pxyJene), 1.90
(s, CH] from BEMA), 1.88 (s, CH] from SMA), 1.30 and 1.37 (s, 2 CH,1 from SMA)
Analysis of Monomer Compositions. An Excel spreadsheet was developed to calculate the
values of the composition of the comonomers in the copolymer (F; and F] ), after integrating Lhe spectra
of each of the binary copolymer reaction mixtures. To illustrate this, consider the synthesis of poly(tBMAco
SMA). From the room temperature spectrum of the copolymer mixture, the values of the areas unde: the
integrals for the vinyl hydrogens of tBMA were assigned as a and b, and tor SMA assigned as c a od d and
the area under the singlet (for the proLons attached to the aromatic ring in pxylene) was denoted by z. The
ratios were calculated by dividing the sum of the areas for the two vinyl hydrogens, belonging to LBMA
(denoted by A) and SMA (denoted by B), respectively, by Lhe area ofpxylene (z).
tBMA ratio(A) = a + b
z
SMA ratio (B) ::: c + d
z
The feed compositions,;; of lBM!\. and /2 for SMA were calculated as follows:
A
r; = A+B
(67)
(68)
(69)
and (70)
In a manner similar to the above, from the IH NMR integrated spectnlm of a mixture of tBMA and SMA
obtained after partial conversion, ratios for the two monomers were calculated, denoted by C for IBMA and
D for SMA respectively. The percent conversions for each monomer was determined as follows:
% tBMA leh(P) = (~)x 100
% tBMA consumed (Q) ::: 100  P
(71 )
(72)
% SMA left (R) == (~)x 100
% SMA consumed (S) == 100  R
(73)
(74)
24
The composition of the comonomers incorporated into the copolymer is then calculated as follows:
and
Amount oftBMA consumed (X) == r x (JL) JI lOa
Amount of SMA consumed (Y) = f x (~)
2 100
F=~
J X+Y
(75)
(76)
(77)
(78)
25
Chapter IV
RESULTS AND DISCUSSION
Sol ketal methacrylate. For our target polyampholytes, we need a monomer with uncharged
repeat units that can give high solubility in water. We chose solketal methacrylate since it could be
converted to the diol, that is glyceryl methacrylate, on hydrolysis in an aqueous medium. The synthesis of
solketal methacrylate was accomplished using the literature procedure ofMori and coworkers. 14 The
scheme for the synthesis of solketal methacrylate (2) from solketal (l) is represented in Scheme J U The
'H NMR spectrum of solketal methacrylate in CDCI] is Figure 1 of Appendices.
sol ketal (1)
+ ~COCI
I Toluene
~ 025 0 C
+
SMA (2)
+
Scheme 1. Synthesis ofsoJketal methacrylate
Homopolymers. The bomopolymcrs of solketal methacrylate (SMA), tertbutyl methacrylate
(tRMA) and 2bromoethyl methacrylate (BEMA) were synthesized by free radical polymerization using
dimethyl sulfoxide as the solvent fOT poly(tBMA) and poly(BEMA) and toluene for poly(SMA) and AIBN
as initiator. The solubility of the homopolyrners is represented in Table 1. These homopolymers were
26
synthesized and characterized by 'H NMR spectroscopy. The spectra of the homopolymers will help us in
the analysis of ternary copolymers and to measure sequence distributions in the copolymers at a later stage.
Table 1. Test of Solubility of Homopolymers
solvents poly(tBMA) poly(SMA) poJy(BEMA)
chlorofonn + +
cWorobenzene + + +
odichlorobenzene +
N,N'DMF + +
1,4dioxane
THF + + +
+ = soluble,  ~ insoluble
Analysis of Compositions of MonomerlPolymer Mixtures. Many different J:lethods have been
used by polymer scientists to monitor the disappearance of the comonomers, and the formation of
copolymer during a free radical copolymerization reaction. The IH NMR experiments produced wellresolved
peaks that corresponded to the two pairs o[viny] hydrogens from the comonomers in the reaction
system, for poly(BEMAcotBMA) and poly(tBMAcoSMA). However in the case of BEMA and SMA
copolymer mixture, since the chemical shifts of the vinyl protons from 8EMA and SMA overlapped with
each other, only one pair of vinyl proton peaks was wellresolved and thus, this pair of viny I proton peaks
was integrated and used for further calculations. The I Jl NMR spectrometer monitors the decreasing
intensity of the vinyl proton peaks in lhe respective copolymer system. The decrease in the peak intensity
of the vinyl protons corresponds directly to the formation of copolymer in the reaction mixture. An
advantage of doing the copolymerization experiments, directly in the NMR tube, was that the copolymers
did not need to be isolated.
Poly(BEMAcotBMA). The reaction scheme for the copolymerization of2bromoethyl
methacrylate and tertbutyl methacrylate is outlined in Scheme 2. The copolymer composition data of the
monomers in the feed and copolymers are presented in Table 2. The l}i NMR spectrum of a mixture of
27
BEMA and tBMA (Entry 1, Table 2) at room temperature, and the assigned peaks that were used in the
calculations to determine the amount of eae h comonomer is shown in Figure 2 of Appendices.
CH3
x H2CAC02CH2CH2Br
BEMA
+ y l H3
H2C C02C(CH3b
IBMA
jAIBN
CDCI3. 50 DC
pxylene
Scheme 2. Copolymerization of 2bromoethyl methacrylate and fer/butyl methacrylate
Table 2. Data for Copolymerization of 2Bromoethyl Methacrylate with tertButyl Methacrylate
experiment feed composition conv% copolymer composition
J, 12 BEMA F; F2
1 0.395 0.fi05 13.5 OA21 0.579
2 0.610 0.390 10.7 0694 0.306
3 0.306 0.694 12.5 0.313 0.687
4 0.658 0.342 14.6 0.702 0.298
5 OA08 0.592 11.4 0.441 0.559
6 OAR2 0.518 11.9 0.488 0.512
7 0.363 0.637 14.5 0.399 0.601
Poly(tBMAcoSMA). The reaction scheme for the polymerization of fer/butyl methacrylate and
solketal methacrylate is shown Scheme 3. The composition data of the monomers in the feed and
copolymers are presented in Table 3. The I H NMR spectrum of a mixture of tBMA and SMA at room
temperature (Entry 1, Table 3) is shown in Figure 3 of Appendices.
x.JC..H3
H2C C02C(CH3h
tBMA
+
SMA
jAIBN
CDCI3, 50°C
pxylene
28
Scheme 3. Copolymerization of terlbutyl methacrylate and solketal methacrylate
Table 3. Data for Copolymerization of tertButyl methacrylate and Solketal Methacrylate
experiment feed composition conv% copolymer composition
;; 12 tBMA F; F,
I 0.623 0.377 5A 0.692 0.308
2 0.345 0.655 9.8 OAO 1 0.599
3 0.690 0.310 R.5 0.740 0.260
4 0.326 0.674 10.1 0.384 0.616
5 0.733 0.267 7.6 0.796 0.204
6 0.431 0.569 lOA 0.520 0.480
Poly(BEMAcoSMA). The procedure is outlined in Scheme 4. The copolymer composition data
of the monomers in the feed and copolymers arc presented in Table 4. The I H NMR spectrum of a mixlure
of BEMA and SMA at room temperature (Entry I, TClbie 4) is shown in Figure 4 of Appendices.
29
SMA jAIBN
CDCI3• 50 °C
pxylene
Scheme 4. Copolymerization of 2bromoethyl methacrylate and sol ketal methacrylate
Table 4. Data for Copolymerization of 2Bromoethyl Methacrylate with Sol ketal Methacrylate
experiment feed composition conv% copolymer composition
J; I, BEMA F; F2
I 0.695 0.305 8.3 0.798 0.202
2 0.375 0.625 9.8 0.449 0.551
3 0.627 0.373 8.6 0.756 0.244
4 0.371 0.629 6.0 0.543 0.457
5 0.400 0.600 R.O 0.497 0.503
6 0.715 0.285 10.6 0.805 0.195
Monomer Reactivity Ratios. Many different methods have been used to compute reactivity
ratios. The computer program, Procop, developed by Octavian Frangu and Cornel Hagiopol. allows fur a
quick analysis of the data via four different methods, namely, FinemanRoss, KelenTudos, YezrieJiev
BrokhinaRoskin and TidwellMortimer methods.2 The computer program employs [he mole fraction of
monomer 1 in the feed, ~, the mole fraction of monomer I formed, f;, formed. in the copolymer. and the
value of percent conversion for monomer 1.3 The compositions of the three binary copolymer mixtures
were detennined by carrying out the experiments directly in an NMR tube and monitoring the
30
disappearance of the vinyl prolon peaks of the comonomers as polymerization progressed. The following
were the steps involved in the detemlination of reactivity ratios.
I. A room temperature 111 NMR spectrum was obtained, which was integrated to determine the feed
compositions of the comonomers.
2. A IH NMR spectrum of the mixture of the two monomers after partial conversion was integrated, and the
the ratios of the vinyl hydrogen peaks in the comonomers were then compared with that of the internal
standard, pxylene, to deteonine the copolymer compositions.
3. The monomer feed and copolymer compositions along with the monomer percent conversions were fed
into the Procop program to calculate the reactivity ralio values.
The reactivity ratios values obtained from the Pracop program for each binary copolymer pair and
the feed compositions of the two monomers in that binary copolymer system were used in the copolymer
composition equation expressed in terms of mole fractions (equation (49» to obtain the expected
copolymer composition value. Tills was done in order to compare the differences between the expected
and actual copolymer compositions.
For any experimental investigation, an optimal experimental design is of great imporlance since it
enables one to perform the minimum number of experiments and obtain precise parameter estimates.) In
copolymerizations, such a design is that using the TidwellMortimer criterion. l
.
11 Tidwell and Mortimerll
recommended running several replicates al two different monomer feed compositions. Since we did not
have preliminary estimates of reacti vity ratios for the monomers under study we started the
copolymerization experiments with a 2: 1 mol ratio of comonomers and viceversa in the respective binary
copolymer pair. The following two equations were then used to obtain monomer compositions to carry out
further copolymerization experiments.
. 2
.flO =2+
rl
.. r2 flU = 2+
r2
f,~ and .fl~ are the mole fractions of the two different monomers in the feed.
(79)
(RO)
The Procop computer program involves inputting not only the experimental data (monomer and
copolymer compositions), but also the conversion values, for each experiment. 2 As a result, no infonnation
31
provided by the experimental data is left aside by the program, which increases the reliability of the fmal
reactivity ratio values.
The Fcriterion. Joshil 2 compared several calculation methods with the following sum of squares
(SS) criterion for the suitability of a set ofreactivity ratios to fit an experiment with n points:
(R 1)
where mr'p stands for the copolymer composition determined for experiment i, and m;n' stands for the
copolymer composition calculated with the estimated reactivity ratios at comonomer feed compositions
(::) for experiment i .2 The Procop program examines the experimental data, via a nonlinear methodlS
,
•
and characterizes the estimation procedures with the same method.2The program considers the random
errors in the copolymer composition to be nonnally distributed and statistically independent from run to
run. The independent variable, that is the comonomer feed composition, is assumed to be elToriess. Bya
simplextype optimization method, the computer program searches for the pair of reactivity ratios for which
the standard deviation is minimized. The F value is given by:
F=
~ (exp cal ')2 L 111; nl,
/,1
/1 P
(82)
where n stands for the number of data points and p stands for the number of reactivity ratios in the given
kinetic model.2 The F value is both a criterion for discriminating among calculation methods and an
indicator of the quality of the experimental data, The smaller the F value, the closer the respective point is
to the pair of reactivity ratios that best fits the experimental data as a whole. 2The terms f~ and Fo as
shown in Tables 5, 6 and 7 are related to the calculations performed with and without inpulling the percent
conversion values (as detemlined by NMR)2
The reactivity ratios obtained for poly(BEMAcotBMA), poly(tBMAcoSMA), and
poly(BEMAcoSMA) are represented in Tables 5, 6 and 7, The Procop software calculates the reactivity
ratio values without considering monomer conversion and with monomer conversion denoted as Fa and
Fe respectively in Tables 57.
32
Table 5. Reactivity Ratios for BEMA (MI) and tBMA (Mz)
rl r~ r,,·, Fo F, Meth.od
1.46 1.07 1.56 0.022 0.023 FinemanRoss (FRl)
1.49 1.11 1.65 0.022 0.023 FinemanRoss (FR2)
1.48 1.09 1.61 0.022 0.023 KelenTUdos (KT)
1.48 1.09 1.61 0.022 0.023 YBR
1.55 1.16 1.79 0.022 0.023 TidwellMortimer (TM)
Table 6. Reactivity Ratios fOl" tBMA (M.) and SMA (Mz) r l r, r,'i Fo F, Method
1.39 0.78 1.08 0.012 0.013 FinemanRoss (FRl)
1.42 0.81 1.15 0.Ol2 0.013 FinemanRoss (FR2)
1.39 0.79 1.09 0.012 0.013 KelenTudos (KT)
1.39 0.79 1.09 0.012 0.013 YBR
1.40 0.79 1.10 0.012 0.013 TidwellMortimer (TM)
Table 7. Reactivity Ratios for BEMA (Ml) and SMA (Mz)
r r r,T, Fo F Method I , (
1.74 0.65 1.13 0.038 0.037 FinemanRoss (FRl)
1.53 0.52 0.80 0.042 0.040 FinemanRoss (FR2)
1.72 0.63 1.08 0.038 0.03R KelenTudos (KT)
1.70 0.62 1.05 0.039 0.038 YBR
1.84 0.71 1.3 J 0.038 0.037 TidwellMortimer (TM)
The 95 % confidence intervals of the reactivity ratios for BEMAIBMA, IBMASMA and BEMASMA
copolymer pairs are shown in Tables 8, 9 and 10 respectively. Ii>
Table 8. 95 % Confidence Interval for Poly(BE1\1AcotBMA)'c,
Method r l r2
(FRI )c 1.46 ±0.04 1.07 ±0.04
(FRl )0 1.46 ±0.05 1.07 ± 0.05
(FR2)c 1.49 ±0.04 1.]] ±0.04
(FR2)0 1.49 ±0.05 1.11 :t005
(KT)c 1.48 ±0.04 1.09 ±0.04
(KT)o 1.48 ±0.05 1.09 ±0.05
(YBR)c lA8 ±0.04 1.09 ±0.04
(YBR)o 1.48 ± 0.05 1.09 ±0.05
(TM)c 1.55 ± 0.04 1.10 ±0.04
(TM)o 1.55 ±0.05 1.16 ±0.05
where c means conversion and 0 means without conversionJ
Table 9. 95 % Confidence Interval for Poly(tBMAcoSMA)If,
Method r l r2
(FRl )c 1.39:!:: 0.03 0.78 ±0.03
(FRI )0 1.39 ±0.02 0.78 :!:. 0.02
(FR2)c 1.42 ±0.03 0.81 ±0.03
(FR2)0 1.42 ±0.02 0.81 ±0.02
(KT)c 1.39 ±0.03 0.79 ±0.03
(KT)o 1.39 ±002 0.79 ±0.02
(YBR)c 1.39 ±0.03 0.79 ±0.03
(YBR)o 1.39 ±0.02 0.79 ±0.02
(TM)c lAO ±0.02 0.79 ±0.02
(TM)o 1.40 ±0.02 0.79 ±0.02
. . I where c stands for conversion, and 0 means WIthOut conversion:
33
34
Table 10. 95 % Confidence Interval for Poly(BEMAcoSMA)'U
Method r I r,
(FR1)c 1.74:.:: 0.07 0.65:±, 0.07
(FR1)o 1.74 ± 0.07 0.65 ± 0.07
(FR2)c 1.53:±. 0.07 0.52:±, 0.07
(FR2)o 1.53 ±0.07 0.52 ± 0.07
(KT)c 1.72:±. 0.07 O.631~ 0.07 (KT)o 1.72 ± 007 0.63:'.: 0.07
(YBR)" 1.70 ± 0.07 0.62 ±0.07
(YBR)o 1.70 ±0.07 0.62 ± 0.07
(TM)c 1.84 ± 0.07 0.71 :!.. 0.07
(TM)o 1.84 ± 0.07 0.71 ± 0.07
where c stands for conversion, and 0 means without conversion."
We chose to report the reactivity ratio values for the three binary copolymer pairs obtained via the
TidweJlMortimer nonlinear least squares method because i.t is considered to be the only statistically
accurate means of determining reactivity ratios from data obtained at low conversi.on. 2 The reactivity ratios
so detennil1ed are the most probable values of the system, and the TM joint confidence interval is the
statistically correct one.2
The rcsults of reactivity ralio values obtained for the three binary copolymer" systems, namely,
poly(BEMAcotBMA), poly(tBMAcoSMA) and poly(BEMAcoSMA) via the TidwellMortimer
method are shown in Table II. The values of the reactivity ratios for 2bromoethyl methacrylate and ler!
butyl methacrylate in poly(BEMAcotBMA) are both greater than unity. This reflects Case IV, where
rl and r2 are greater than unity and r,r2 > 1. However the values of reactivity ratioS determined via the TM
method for BEMAtBMA copolymer pair may not be as reliable as the reactivity ratio values of the other
monomer pairs, since the reactivity ratios have been calculated [rom experimental data at high conversions
(1015%). At higher conversions the errors due to composition drift become significant. The reactivity
ratio values for BEMAtBMA copolymer pair were also determined by using experimental data obtained at
lower conversions (511 %). The results obtained by the TidwellMortimer method ( r l == 4.70 and "2 =2.54)
35
were nol in good agreement with the results oblained from Ihe linear FR, KT and YBR methods and
moreover were unreasonably large in view of alllhe other results.
Table 11. Summary of Binary Copolymer Reactivity Ratios Determined by the TM Method
Copolymer ,I I' r, r~ ,
poly(BEMAcoIBMA) 1.55 1.16 l.79
poly(tBMAcoSMA) 1.40 0.79 1.10 poly(BEMAcoSMA) 1.84 0.71 1.30
1n poly(tBMAcoSMA) the values of reactivity ralios ('tBMII = 1.40 , and 'SMII ,= 0.79) reflect
Case Ill, where 1", > 1and 1'2 < 1. This means that tBMA is more reactive towards both IBMA and SMA
propagating chain ends, as compared to SMA. As a result the copolymer formed will be richer in more
reactive tertbutyl methacrylate monomer unils rather than solketal methacrylate monomer units. By
analogy, we can pred.icI from the values of 1'1 (1.84 for BEMA) and 1'2 (0.71 for SMA) that poly(BEMAco
SMA) contains a larger proportion ofBEMA monomer units, as opposed 10 IBMA.
In poly(BEMAcotBMA) since 1', r~ > I suggests Ihal there is a tendency to form block
copolymers. In poly(tBMAcoSMA) and poly(BEMAcoSMA) the product oflhe reactIvity ratios orthe
two monomers closely approaches unily. This means Ihat the composilions of IBMA and SMA monomer
unils in tBMASMA binary copolymer pair and BEMA and SMA monomer units in BEMASMA binary
copolymer pair are approximately ideal during the course of polymerization.
For each of (he binary copolymer reaction mixtures, the values of the copolymer composition, F;,
obtained experimentally were compared witb the values obtained by inpulling the renctivity ratio values 1'"
r
2
delermined by the TidwellMortimer method and the feed compositions;; and f~ , of the comonomers,
in terms of mole fractions from Tables 24, into the copolymer composition equation (49). This
was done in order to verify the values of the copolymer compositions determined experimentally. The
differences in F; for poly(BEMAcOIBMA), poly(tBMAcoSMA) and poly(BEMAcoSMA) are as
shown in Tables 1214. The calculated values of cop01ymer composition (F.) are determined u~ing the
reactivity ratio values obtained from the TM method in Table II.
Table 12. Comparison of the Copolymer Composition F.. in Poly(BEMAcotBMA)
36
F. (experimental) F.. (calculated) difference
0.421 0.420 0.001 0.694 0.663 0.031
0.313 0.316 0.003
0.702 0.713 0.01l
0,441 0,435 0.006
0.488 0.521 0.033
0.399 0.383 0.016
Table 13. Comparison of the Copolymer Composition F. in Poly(tBMAcoSMA)
F.. (experimental) F; (calculated) difference
0.692 0.690 0.002
0,401 0.409 0.008
0.740 0.751 0.011
0.384 0.388 0.004
0.796 0.789 0.007
0.520 0.501 0.019
Table 14. Comparison of the Copolymer Composition J'~ in Poly(BEMAcoSMA)
F.. (experimental)
0.798
0.449
0.756
0.543
0.497
0.805
FI (calculated)
0.798
0.497
0.742
0.486
0.518
0.814
difference
0.000
0.041
0.013
0.056
0.021
0.009
37
Variation of Copolymer Composition with Conversion. The degree of conversion is equal to
the fraction 0 f the monomer that has been reacted and is given by:
[Mt  [M] = 1_ [M]
[ML [M].
(83)
where [M]. is the initial monomer concentration and [M] is Lhe concentration that is left umeacted, so that
[M]o  [M] is the concentration of the monomer that has reacted. For all copolymerizations, except
azeotropic copolymerizations, the comonomer feed and copolymer composition are different. The
monomer composition changes during the course of polymerization, and the copolymer composition at
each point in time is a function of monomer conversion. As the polymerization progresses, the monomer
that has a higher reactivity in the binary copolymer, for example, monomer I will react more rapidly tban
monomer 2. The comonomer feed changes in composition, as monomer I, preferentially enters the
copolymer. Thus, there is a drift in the comonomer composition, toward the less reactive monomer 2, as
the degree of conversion increases. Therefore late in the polymerization, the copolymer formed will be
more enriched in the less reactive comonomer 2, because the more reactive comonomer I has been
largely consumed.
Monomer Sequence DistributioIlS.I,2·17 The microstructure of a copolymer is delined by the
distribution of the various lengths of iVI I and M~ sequences, that is, the sequence length distrihutiol1.
According to the reaction scheme, M , M, bonds are formed only by equation (33). The probability that a
radical ending in anM
I
unit adds an M, unit is equal to the rate of the reaction given by equation (33),
divided by the sum of the rates of all reactions available to this radical. This is the probability ~, that a
growing radical chain M; will add to monomer M,. To a good approximation, the only two possible fales
of the growing chain M; are addition of M
I
or addition of M z' We can write this probability as follovvs:
(84)
or (85)
38
where P'2 is the probability that the growing chain M; will react with M,. Given a radical site of type
MI" in the copolymer, consider now the probability of forming a sequence of exactly m units of monomer
M Iand denote this probability as P'11, (m).17 Table 15 shows the buildup of a sequence of M I units.
Table 15. Buildup of a Sequence of M, Units. '7
Reaction Sequence Length
M; +M, ~M,M; 2
M,M; +/vl 1 ) (M I ), M; 3
Probabilty
(M \ __1.1' M (.~ M' 1~11 + I ~ 'V~_l I m p./UI
I:
To fonn a sequence of exactly munits, the sequence must end with the last entry in Table 15. This means
that the last growing radical in the table must react with M z'
Thus, (86)
Similarly a probability tbat a sequence of In units of M z will be fomled, given a radical sile, derived from
M 2' is given by:
(87)
The average sequence lengths ;M, and ;M, ' may now be detennined from equations (86) and (87), using
the definition of an ari thmetic mean. Thus,
T "
'LmFM, (m) 'L r,1 In II (88)
m! m=1
mu, == IP,w, (m)
7. 'LP'>n' II
m·j m....:)
r.
39
The numerator is given by (_1_):and the denominator by l/_I). Therefore we get the expression
IF., IF.I
for ;.\1, as:
(89)
From equation (85), ~ I is related to 1'1 and we get equation (90) for the average sequence length of
M,units:
(90)
Similarly, the average sequence length of M ~ units is given by:
(91 )
Tables 16, 17 and 18 show the average sequence length of the two monomers in poly(tBMAcoSMA),
poly{BEMAcotBMA) and poly(BEMAcoSMA) respectively. The run number, R , of the copolymer is
defIned as the average number ofsequences of either type per lao monomer units. The run number is
expressed by the following equation: 17
R=_ 20~
m,11) +mJ/2
Table 16. Average Sequence Lengths of tBMA (MI) and SMA (M1) in Poly(tBMAcoSMA)
(92)
0.623
0.345
0.690
0.326
0.733
0.431
0.377
0.655
0.310
0.674
0.267
0.569
mM,
3.297
1.732
4.094
1.672
4.816
2053
1.478
2.500
1.355
2.633
J.28R
2.043
Run number (R)
4\.88
47.26
36.71
46.45
32.77
48.83
Table 17. Average Sequence Lengths of BEMA (M 1) and tBMA (M2) in Poly(BEMAcotBMA)
40
0.395
0.610
0.306
0,684
0.408
0.482
0.366
0.605
0,390
0,694
0,316
0,592
0.518
0.634
111M,
2.064
3.549
1.719
4,528
2.123
2.517
1.941
m,lf,
1.980
J .409
2.452
1,296
1.929
[,688
2.109
Run number (R)
49.45
40.33
47.96
34,34
49,36
47.57
49.39
Table ]8. Average Sequence Lengths of BEMA (M)) and SMA (Mz) in Poly(BEMAcoSMA)
0,695
0.375
0.627
0,371
OAOO
0.715
0.305
0.625
0.373
0,629
0.600
0,285
m,l"/.
4.919
2.032
3.891
2.014
2.147
5.315
/nM:
1.276
2.050
1.375
2.068
1.945
1.251
Run number (R)
32.28
49.00
37.98
4R.99
4R.88
30.46
41
CONCLUSIONS
The monomer solketal methacrylate was synthesized in 89 % yield and characterized by IH NMR
spectroscopy. HomopoJymers oftBMA, BEMA and SMA have been synthesized and characterized by IH
NMR spectroscopy. Binary copolymers ofBEMA and tBMA tBMA and SMA, and BEMA and SMA
having different feed compositions were synthesized in solution by free radical polymerization and
characterized by IH NMR spectroscopy. The copolymer compositions and percent conversions of the
monomers were calculated by 'H NMR analysis of the umeacted monomers. The reactivity ratios were
detennined using the cOl1ventionallinear FinemanRoss, KelenTudos and YBR methods and the nonlinear
TidwellMortimer method using the Pracop software. 2 The values of the reactivity ratios for BEMA
and tBMA in poly(BEMAcotBMA) were determjned to be rBEMA = 1.55 and rtl3MA 1.16. In poly(tBMAco
SMA), r,SMA = lAO and rSMA = 0.79 and in poly(BEMAcoSMA), r[lE,VlA C~ 1.84 and rS'vI/I' 0.71.
The product of the reactivity ratios, 1', r1 > I in poly(BEMAcotBMA) suggests thaI there is a tendency to
form a block copolymer. The product 1'11'2"" I in poly(tBMAeoSMA) and poly(BFMAcoSMA)suggests
that these binary copolymer systems have an ideal distribution of the comonomers along the copolymer
chain. The values of reactivity ratios obtained for the three monomers prove Ihat the order of reactivity is
2bromoethyl methacrylate> lalbutyl methacrylate> solketal methacrylate.
•
42
SUGGESTED FUTURE RESEARCH
For our target polyampholytes, we tried to synthesize homopolymers oftBMA, SMA and BEMA
via the RAfT (reversible additionfragmentation chain transfer) method. The RAFT method is a controlled
living radical polymerization method that offers better control over the molecular weight distributions of
the polymers as opposed to conventional free radical polymerization method. This is due to the RAFT
chain transfer agent that serves to maintain living character between the active and donnant chain ends. The
polymerization of BEMA via RAFT gave less than 10 % conversion under the same experimental
conditions that worked for tBMA and SMA. Moreover, there is no precedent in literature of polymerization
of monomers containing a primary alkyl halide group by the ATRP (atom transfer radical polymerization)
method. Therefore BEMA cannot be used for the polyampholyte syntheses.
For the synthesis of ternary copolymers we will replace BEMA with N,Ndimethylaminoethyl
methacrylate (DMAEMA). Synthesis of homopolymers of DMAEMA via the RAFT (Reversible AdditionFragmentation
Chain Transfer) method is in progress. We will now need to determine reactivity ratios k,r
binary copolymers containing SMA and DMAEMA and lEMA and DMAEMA, Lo be able to detenlline the
compositions of the feed mixture in order to synthesize t~rnary copolymers. The compositions of the
ternary copolymers, as a function of conversion, will be determined by I IJ NM R spectroscopy. The
numberaverage molecular wcighL'i and the polydispersities of these cupolymers will be measured relative
to polystyrene standards using size exclusion chromatography. The goal is to synthesize statistical tertiary
copolymers of narrow molecular weight distributions (Mw/Mn < 1.5), and then transform them to
polyampholytes by functional group conversions as shown in Scheme 5.
CH3 +
H2C~~lC02CH2CH2N(CH3h
DMAEMA
CH3
H2C~C02C(CH3h
tBMA
43
RAFT method
S CH3
" t CsHsCSCCN
I
CH3
2Cyanoprop2yl Oithiobenzoate
"C,LO::::.2CH2CH(OH}CH20Htxl...........Itit:r
Scheme 5. Synthesis ofpolyampholyles

44
REFERENCES
(I) Odian, G. Principles ofPolymerization, Third Ed., McGrawHili, Inc: New York, 1991, pp 452531.
(2) Hagiopol. C. Copolymerization: toward a svstematic approach, Kluwer Academic: New York, 1999,
pp 147.
(3) Dube, M.; Sanayei, R. A.; Penlidis, A; O'Driscoll, K. F.; Reilly, P. M. J. Polym. Sci., Part A:
Polym. Chem. 1991,29, 703708.
(4) Candau, F.; Joanny, JF. Polyampholytes; In Polymeric Materials Encyclopedia; Salamone, J.c.
Salamone, J.c.s, Ed.; CRC Press: Boca Raton, 1996; pp 54765488.
(5) Stevens, M. Polymer Chemistry An Introduction, Third Ed., Oxford University Press: New York,
1999, pp 194196.
(6) Rudin, A The Elements ofPolymer Science and Engineering, Second Ed., Academic Press: London,
1999, pp 189260.
(7) Mark, H.; BikaJes. N. M.; Overberger, CG. Encyclopedia ofPolymer Science and Engineering,
Second Edition, 4, pp 192233.
(R) Painter, pc.; Coleman, M.M. Fundamentals ofPolymer Science, An Introductory Text, Second
Edition, Technomic Publishing Co. Jnc.: Pennsylvania, 1997.
(9) Fineman, M.; Ross, S. D. J. Polym. Sci., ]950,5(2),259262.
(10) KeJen, T.; Tudos, F. J. Macromol Sci. Chem, 1975. A 9(1), l27.
(l!) Tidwell, P.W.; Mortimer, G.A.; J. Polym. Sci. Part A Po/ym. Chern Vol. 3, 1965,369387.
(12) Joshi, R.M. J. Macromof. Sci. Chern. ] 973, A 7(6), 12311245.
(l3) Belleney 1.; Helary, G.; Migonney, V. Eur Po/ym. J., 2002, 38,439444.
(14) Mori, H.; Hirao, A; Nakahama, S. Macromolecules 1994,27,3539
(J 5) Hagiopol, c.; Frangu, 0; Dumitru, J. J Macromol. Sci. Chun., 1989, A 26(10), 13631379.
(16) Moore, D.S. The Basic Pracli.~·e o/Statistics, W. H. Freeman and Company, New York, J995.
(17) Allcock,H. R.; Lampe, F.W.; Mark J. E. Contemporary Polymer Chemistry, Third Ed., Prentice
Halt: Upper Saddle River, New Jersey, 2003, pp 3333n8.
APPENDICES
45
Figure 1. IH NMR spectrum of solketal methacrylate
9
f
CH3 C
A /CH2~e
H2C cO2 / \
a,b 0XO
H3C CH3
9 h
c:..d,e
b
a
CDCI) ~ ~ ~ )11 l j
J II:: 'i. ~ I __ ._._~ I~'. . ,..," __J"","
h
~IIi'
I!I
II
I I :: ! !~I ;:_l...._.~~......, ...... ' ILo
ppm
+:0Q\
Figure 2. lH NMR spectrum of a mixture of BEMA. and tBMA. at room temperature
e
e
b CH3 P q
H ).C~OCH2CH2sr +
1~ II f1 0
a BEMA
f
d CH3 9
HJ :)'.COC(CH3b II f1 0
C tSMA
1.
c
mzozm H3C If_ ~ CH3
Z Z
d
p
q
9
rn
b I1
Il i ! I ! __J.11jJ L  ,   . .> ......
l2.13
a
l.".
J.52
2.21!1
L
3. ,2
l. 31 4.4S
,
a
l.U
I
3 2
l1.S!
ll!!.21 '1. SS
ppm
.j:>.
.J
Figu re 3. IH NMR spectrum of a mixture of tBMA and SMA at room temperature
h
g'
g
e
f k j
d CH3 i f,j hi
H~ )~OCH2++Hj
T ° °XO
c SMA H3C CH3
9 g'
+
z z
m~ m
H3CUCH3
z Z
e
b CH3
H )COC(C~3l3
l"~ II
f1 0
8 tBMA
i, j, k
m
a b
d
c r
11.1 lJWU~
6 4
~~""~_·~ll~ I
,~~,~~1, ., ~ I~ ~ 2 1 pplll
_~'"'1)LUJUl JUU~
U.11 Z.79
1. ,.!
1") • .",
2.'11
1. 'a ,. ..., 1. !S
18_1'
13.5'
37. 'S
.+::000
Figure 4. lH NMR spectrUm of a mixture ofBEMA and SMA at room temperature
/I
mzozm H3C f_ ~ CH3
Z Z
e
b CH3 P q
H1 )/CoCH2CH28r + II
f'l ° a BEMA
f k j
d CH3 i Irl I;j
H~~OCH2++Hj
R ° 0Xo
c SMA H3C CH3
g g'
a
z
~
',,_) \,L~_.__.
.~ c
6.9 6.8 6. 7 6.6
I ~.r,iIi 1 I ~Ii' t
7.1 7.0 6.5 6.11 6.3 6.2 6.1 ppm
!Ll'
'r~"''
e.•'
II.H
.p.
'C>
VlTA
Larissa Nita Miranda
Candidate for the Degree of
Master of Science
Thesis: BINJ\RY COPOLYMER REACTIVITY OF SOLKETAL METHACR YLATE,
TERTBUTYL METHACRYLATE, AND 2BROMOETHYL METHACRYLATE
Major Field: Chemistry
Biographical:
Personal Data: Born in Bomhay, lnd ia, on November 30, 197 L the daughter of (late) Jeanelle and
Louis Miranda. Married to Frank D'SulIZ.a in December 2002.
Education: Received Bachelor of Science Degree in Chemistry from the University of Bombay, in
April 1992 (Gold Medallist). Compktl:t.I requirements for the Master of Science degree,
with a major in Chemistry, at Oklahoma Slate University in December, 2003.
Experience: Employed by Oklahoma Sltlte University, Department of Chemistry, as a graduate
teaching assistant; Oklahoma State University, Department of Chern istry, 2000 to
present.
Professional Membership: American Chemical Society, Phi Lambda llpsi Ion Honorary Chemical
Society, National Collegiate HOllars Society.