Copolymerization of glycidyl methacrylate with alkyl acrylate monomers

A newer approach to obtaining acrylic thermoset polymers with adequate hydrophilicity required for various specific end uses is reported. Glycidyl methacrylate (GMA) was copolymerized with n-butyl acrylate (n-BA), isobutyl acrylate (i-BA), and 2-ethylhexyl acrylate (2-EHA) in bulk at 60°C. with benzoyl peroxide as free radical initiator. The copolymer composition was determined from the estimation of epoxy group. Reactivity ratios were calculated by the Yezrielev, Brokhina, and Roskin method. For copolymerization of GMA (M₁) with n-BA (M₂) the reactivity ratios were r₁ = 2.15 ± 0.14, r₂ = 0.12 ± 0.03; with i-BA (M₂) they were r₁ = 1.27 ± 0.06, r₂ = 0.33 ± 0.031; and with 2-EHA (M₂) they were r₁ = 2.32 ± 0.14, r₂ = 0.13 ± 0.009. The reactivity ratios were the measure of distribution of monomer units in a copolymer chain; the values obtained are compared and discussed.     

Copolymerization of 2-Hydroxypropyl Methacrylate with Alkyl Met hacrylates

2-Hydroxypropyl methacrylate (2-HPMA) has been copolym-erized with ethyl methacrylate (EMA), n-butyl methacrylate (BMA), and 2-ethylhexyl methacrylate (EHMA) in bulk at 60°C using benzoyl peroxide as initiator. The copolymer composition has been determined from the hydroxyl content. The reactivity ratios have been calculated by the Yezrielev, Brokhina, and Raskin method. For copolymerization of 2-HPMA (M₁) with EMA (M₂), the reactivity ratios are r₁ = 1.807 ± 0.032 and r₂ = 0.245 ± 0.021; with BMA (M₂) they are n = 2.378 ± 0.001 and r₂ = 0.19 ± 0.01; and with EHMA the values are r₁ = 4.370 ± 0.048 and r₂ = 0.103 ± 0.006. Since reactivity ratios are the measure of distribution of monomer units in copolymer chain, the values obtained are compared and discussed. This enables us to choose a suitable copolymer for synthesizing thermoset acrylic polymers, which are obtained from cross-linking of hydroxy functional groups of HPMA units, for specific end-uses.     

Copolymerization of 2-Hydtoxypropyl Methacrylate with Alkyl Methacrylates

2-Hydroxypropyl methacrylate (2 HPMA) has been copolym-erized with ethyl methacrylate (EMA), n-butyl methacrylate (BMA), and 2-ethylhexyl methacrylate (EHMA) in bulk at 60°C using benzoyl peroxide as initiator. The copolymer composition has been determined from the hydroxyl content. The reactivity ratios have been calculated by the YBR method. For copolymerization of 2-HPMA (M₁) with EMA (M₂), the reactivity ratios are: r₁=1.807 ± 0.032, r₂=0.245 ± 0.021; with BMA (M₂) they are r₁=2.378 ± 0.001, r₂=0.19 ± 0.01; and with EHMA the values are r₁=4.370 ± 0.048, r₂=0.103 ± 0.006. Since the reactivity ratios are the measure of distribution of monomer units in a copolymer chain, the values obtained are compared and discussed. This enables us to choose a suitable copolymer for synthesizing thermoset acrylic polymers, which are obtained from cross-linking of hydroxy functional groups of HPMA units, for specific end uses.     

Polymerization of aromatic aldehydes. IV. Cationic copolymerization of phthalaldehyde isomers and styrene

Copolymerizations of three phthalaldehyde isomers (M₂) with styrene (M₁) were carried out in methylene chloride or in toluene with BF₃OEt₂ catalyst. The monomer reactivity ratios were r₁ = 0.77, r₂ = 0 for the meta isomer and r₁ = 0.60, r₂ = 0 for the para isomer. The second aldehyde group of both isomers did not participate in polymerization and acted simply as the electron-withdrawing group, thus reducing the cationic reactivity of these monomers. Copolymerization behaviors of the ortho isomer (o-PhA) were quite different between 0°C and ?78°C. At ?78°C, o-PhA preferentially polymerized to yield “living” cyclopolymers, until an equilibrium concentration of o-PhA monomer was reached. Then, styrene propagated from the living terminal rather slowly. The block structure of the copolymer was confirmed by the chemical and spectroscopic means. In the copolymerization at 0°C, the o-PhA unit in copolymer consisted both of cyclized and uncyclized units. This copolymer seemed to contain short o-PhA sequences. The variation of the o-PhA-St copolymer structure with the polymerization temperature was explained on the basis of whether the polymerization was carried out above or below the ceiling temperature (?43°C) of the homopolymerization of o-PhA.     

On the copolymerization model and microstructure of methyl acrylate - styrene radical copolymer. Influence of ZnCl2

Bulk radical copolymerization of methyl acrylate (MeA, M₁) with styrene (St, M₂) in presence and absence of ZnCl₂ as complexing agent was studied. ¹H-NMR spectra were used to establish copolymer composition and sequence distribution. The methoxy group signal was observed to be split due to pentads, but the analysis of sequence distribution is possible only at triad level. Both composition and sequence distribution data confirmed that bulk radical copolymerization respects quite well the terminal addition model; the values of r₁ = 0.14 ± 0.02 (from composition data) and r₁ = 0.25 ± 0.03 (from sequence distribution data) and r₂ = 0.83 ± 0.10 (from composition data) were found. The presence of ZnCl₂ increases the probability of alternating addition, e.g., for [ZnCl₂]/[MeA] = 0.2, r₁ = 0.03 ± 0.02 and r₂ = 0.17 ± 0.03. The radical copolymer obtained in bulk in the absence of ZnCl₂ presents a coisotactic configuration with σ = 0.75 ± 0.03, but the presence of the complexing agent reduces the probability of coisotactic addition, e.g., for [ZnCl₂]/[MeA] = 0.2, σ = 0.52 ± 0.03.     

Alternating copolymerization of bis(hexafluoroisopropyl) fumarate with styrene and vinyl pentafluorobenzoate: Transparent and low refractive index polymers

Bis(hexafluoroisopropyl) fumarate (BHFIPF) did not homopolymerize with free radical initiators. However, BHFIPF yielded alternating copolymers with styrene in bulk with Azobisisobutyronitrile (AIBN) as a radical initiator. The monomer reactivity ratios of BHFIPF (M₁) and styrene (M₂) were calculated as r₁ = 0.00 and r₂ = 0.02. BHFIPF also copolymerized with vinyl pentafluorobenzoate (VPFB) in bulk and in pentafluoroisopropanol solution to produce an alternating copolymer. The reactivity ratios of BHFIPF (M₁) with VPFB (M₂) were r₁ = 0.00 and r₂ = 0.05 in bulk and r₁ = 0.01 and r₂ = 0.11 in pentafluoroisopropanol, respectively. The glass transition temperatures (T_g) of the BHFIPF‐styrene and BHFIPF‐VPFB copolymers were 107 and 86 °C, respectively. The BHFIPF‐styrene copolymer was thermally stable, and the thermal degradation temperature (T_d) was 400 °C, whereas the T_d of BHFIPF‐VPFB copolymer was 240 °C. The films obtained by casting from tetrahydrofuran (THF) solutions of these copolymers were flexible and transparent. Their refractive indices were 1.4048 for the BHFIPF‐styrene copolymer, and 1.3980 for the BHFIPF‐VPFB copolymer at 633 nm, respectively. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Aminimides. IV. Homo- and copolymerization studies on trimethylamine methacrylimide

Trimethylamine methacrylimide (TAMI) has been homo- and copolymerized with methyl methacrylate, vinyl acetate, vinyl chloride, hydroxypropyl methacrylate, and acrylonitrile by free-radical initiators to soluble, low molecular weight polymers containing pendant aminimide groups along the backbone of the polymer chains. The reactivity ratios in the copolymerization of TAMI (M₁) with acrylonitrile (M₂) were determined: r₁ = 0.10 ± 0.01, r₂ = 0.37 ± 0.04. The Alfrey-Price Q and e values for TAMI were also calculated: Q = 0.18, e = ?0.60. This preliminary work indicates that TAMI has potential for the preparation of reactive polymers.     

Copolymerization of 4-cyclopentene-1,3-dione with p-chlorostyrene and vinylidene chloride

The copolymerization of 4-cyclopentene-1,3-dione (M₂) with p-chlorostyrene and vinylidene chloride is reported. The copolymers were prepared in sealed tubes under nitrogen with azobisisobutyronitrile initiator. Infrared absorption bands at 1580 cm.^?1 revealed the presence of a highly enolic β-diketone and indicated that copolymerization had occurred. The copolymer compositions were determined from the chlorine analyses and the reactivity ratios were evaluated. The copolymerization with p-chlorostyrene (M₁) was highly alternating and provided the reactivity ratios r₁ = 0.32 ± 0.06, r₂ = 0.02 ± 0.01. Copolymerization with vinylidene chloride (M₁) afforded the reactivity ratios r₁ = 2.4 ± 0.6, r₂ = 0.15 ± 0.05. The Q and e values for the dione (Q = 0.13, e = 1.37), as evaluated from the results of the vinylidene chloride case, agree closely with the previously reported results of copolymerization with methyl methacrylate and acrylonitrile and confirm the general low reactivity of 4-cyclopentene-1,3-dione in nonalternating systems.     

Self-crosslinkable polymers. I. Copolymerization of glycidyl methacrylate with 2-vinylpyridine and 2-vinyl-5-ethylpyridine

A soluble and self-crosslinkable linear copolymer with pendant epoxy and pyridyl groups was obtained from glycidyl methacrylate (M₁) and 2-vinylpyridine (M₂) or 2-vinyl-5-ethylpyridine (M₂) by the action of azobisisobutyronitrile. The monomer reactivity ratios were determined in tetrahydrofuran at 60°C: r₁ = 0.510, r₂ = 0.620 with 2-vinylpyridine and r₁ = 0.57, r₂ = 0.62 with 2-vinyl-5-ethylpyridine. These were consistent with the calculated values with the reported Q and e values for these monomers. The intrinsic viscosities of the copolymers with 2-vinylpyridine and with 2-vinyl-5-ethylpyridine were found to be 0.17–0.19 and 0.26–0.38, respectively, in tetrahydrofuran at 30°C; they were independent of the copolymer composition. The copolymers were amorphous, had no clear melting points, and became insoluble crosslinked polymers under heating without further addition of any curing agents.     

Monomer reactivity ratio and Q–e values for copolymerization of hydroxyalkyl acrylates and 2-(1-aziridinyl)ethyl methacrylate with styrene

Copolymers of 2-hydroxyethyl acrylate, hydroxypropyl acrylate, and 2(1-aziridinyl)-ethyl methacrylate (M₂) with styrene (M₁) were prepared in benzene solution at 60°C. Benzoyl peroxide, 0.1–0.2 mole-%, was used as initiator. Copolymer samples with the molar concentrations of M₂ feed ranging from 0.10 to 0.85 were used to determine the reactivity ratios. Elemental analysis and nuclear magnetic resonance spectroscopy (NMR) were used to determine copolymer compositions. There was a solubility problem when the latter technique was applied. When samples which were completely soluble were analyzed, the results obtained from NMR and elemental analysis were in excellent agreement. The monomer reactivity ratios and the corresponding parameters for the copolymerization of (M₁) with 2-hydroxyethyl acrylate are: r₁ = 0.38 ± 0.02, r₂ = 0.34 ± 0.03; Q₂ = 0.85, e₂ = 0.64; with hydroxypropyl acrylate are: r₁ = 0.45 ± 0.03, r₂ = 0.36 ± 0.03; Q₂ = 0.75, e₂ = 0.56; with 2(1-aziridinyl)ethyl methacrylate are: r₁ = 0.53 ± 0.02, r₂ = 0.63 ± 0.04; Q₂ = 0.82, e₂ = 0.25.     

Copolymerization of Tri-n-butyltin Acrylate and Tri-n-butyltin Methacrylate Monomers with Vinyl Monomers Containing Functional Groups

A new approach to obtaining thermoset organotin polymers, which permits control of crosslinking site distribution and, through it, a better control of properties of organotin antifouling polymers, is reported. Tri-n-butyltin acrylate and tri-n-butyltin methacrylate monomers were prepared and copolymerized, by the solution polymerization method with the use of free-radical initiators, with several vinyl monomers containing either an epoxy or a hydroxyl functional group. The reactivity ratios were determined for six pairs of monomers by using the analytical YBR method to solve the differential form of the copolymer equation. For copolymerization of tri-n-butyltin acrylate (M₁) with glycidyl acrylate (M₂), these reactivity ratios were n = 0.295 ± 0.053, r₂ = 1.409 ± 0.103; with glycidyl methacrylate (M₂) they were r₁ = 0.344 ± 0.201, r₂ = 4.290 ± 0.273; and with N-methylolacrylamide (M₂) they were r₁ = 0.977 ± 0.087, r₂ = 1.258 ± 0.038. Similarly, for the copolymerization of tri-n-butyltin methacrylate (Mi) with glycidyl aery late (M₂) these reactivity ratios were r₁ = 1.356 ± 0.157, r₂ = 0.367 ± 0.086; with glycidyl methacrylate (M₂) they were r₁ = 0.754 ± 0.128, r₂ = 0.794 ± 0.135; and with N-methylolacrylamide (M₂) they were r₁ ?4.230 ± 0.658, r₂ = 0.381 ± 0.074. Even though the magnitude of error in determination of reactivity ratios was small, it was not found possible to assign consistent Q,e values to either of the organotin monomers for all of its copolymerizations. Therefore, Q,e values were obtained by averaging all Q,e values found for the particular monomer, and these were Q = 0.852, e = 0.197 for the tri-n-butyltin methacrylate monomer; and Q = 0.235, e = 0.401 for the tri-n-butyltin acrylate monomer. Since the reactivity ratios indicate the distribution of the units of a particular monomer in the polymer chain, the measured values are discussed in relation to the selection of a suitable copolymer which, when cross-linked with appropriate crosslinking agents through functional groups, would give thermoset organotin coatings with an optimal balance of mechanical and antifouling properties.     

Copolymerization of isopropenyl and isopropylidene oxazolones with styrene

2-Isopropenyl-4-isopropyl-2-oxazolin-5-one (M₂), was copolymerized with styrene (M₁), and the monomer reactivity ratios were determined to be r₁ = 0.31 ± 0.03, r₂ = 1.12 ± 0.10. New isomerized oxazolones (M₂), 2-isopropylidene-4-methyl-3-oxazolin-5-one, 2-isopropylidene-4-isopropyl-3-oxazolin-5-one, and 2-isopropylidene-4-isobutyl-3-oxazolin-5-one were prepared and copolymerized with styrene. The monomer reactivity ratios were: r₁ = 0.36 = 0.07, r₂ = 0.0; r₁ = 0.39 ± 0.06, r₂ = 0.00 ± 0.10; r₁ = 0.39 ± 0.10, r₂ = 0.0, respectively. The isomerized oxazolones showed no tendency towards homopolymerization by radical initiator. From the results of infrared and NMR spectra and hydrolysis of the copolymer, it was indicated that the isomerized oxazolones participated in copolymerization in the form of 1–4 polymerization of the conjugated dienes (exo double bond at C₂ and the C?N in the ring). Copolymers reacted with nucleophilic reagents such as amines and alcohols.     

Sulfur-Containing Vinyl Monomers. XIV. Radical Polymerizations and Copolymerizations of Vinyl Mercaptobenzazoles

Vinyl mercaptobenzazoles [thiazole (VMBT), oxazole (VMBO), and imidazole (VMBI)] were prepared through dehydrochlorination of the respective β-chloroethyl mercaptobenzazoles. These monomers were found to undergo vinyl polymerization in the presence of light or radical initiator, α,α'-azobisisobutyonitrile, to give relatively high molecular weight homopolymers. From the results of radical copolymerizations of these monomers with various monomers, the copolymerization parameters were determined as follows: VMBT(M₂): r₁ styrene(M₁): r₁ = 2.12 ± 0.09, r₂ = 0.336 ± 0.028, Q₂ = 0.75, e_z = ?1.38; VMBO(M₂)-styrene(M₁): r₁ = 2.61 ± 0.13, r₂ = 0.274 ± 0.03, Q₂ = 0.61, e₂ = ?1.38; VBMI(M₂)-styrene(M₁) r₁ =4.0, r₂ = 0.2, Q₂ = 0.37, e₂ = ?1.17. The polymerization reactivities of these monomers obtained from these parameters were compared with those of other vinyl sulfide monomers and discussed.     

Anionic copolymerization of optically active α-methylbenzyl methacrylate and trityl methacrylate. I. Reactivity of monomers

The monomer reactivity ratios were determined in the anionic copolymerization of (S)- or (RS)-α-methylbenzyl methacrylate (MBMA) and trityl methacrylate (TrMA) with butyllithium at ?78°C, and the stereoregularity of the yielded copolymer was investigated. In the copolymerization of (S)-MBMA (M₁) and TrMA (M₂) in toluene the monomer reactivity ratios were r₁ = 8.55 and r₂ = 0.005. On the other hand, those in the copolymerization of (RS)-MBMA with TrMA were r₁ = 4.30 and r₂ = 0.03. The copolymer of (S)-MBMA and TrMA prepared in toluene was a mixture of two types of copolymer: one consisted mainly of the (S)-MBMA unit and was highly isotactic and the other contained both monomers copiously. The same monomer reactivity ratios, r₁ = 0.39 and r₂ = 0.33, were obtained in the copolymerizations of the (S)-MBMA–TrMA and (RS)-MBMA–TrMA systems in tetrahydrofuran (THF). The microstructures of poly[(S)-MBMA-co-TrMA] and poly-[(RS)-MBMA-co-TrMA] produced in THF were similar where the isotacticity increased with an increase in the content of the TrMA unit.     

Structure and reactivity of α,β-unsaturated ethers. VIII. Cationic copolymerizations and acetal additions of propenyl and isobutenyl ethyl ethers

Cationic copolymerizations of cis- and trans-propenyl ethyl ethers (PEE) with isobutenyl ethyl ether (IBEE) were carried out in methylene chloride at ?78°C with the use of boron trifluoride etherate as catalyst. Monomer reactivity ratios were r₁ = 24.0 ± 2.4 and r₂ = 0.02 ± 0.02 for the cis-PEE (M₁)–IBEE (M₂) system and r₁ = 19.1 ± 1.8 and r₂ = 0.04 ± 0.02 for the trans-PEE (M₁)–IBEE (M₂) system, indicative of the reactivity order: cis-PEE > trans-PEE ? IBEE. In separate experiments, these β-methyl-substituted vinyl ethers were allowed to react with various acetals in the presence of boron trifluoride etherate. The relative reactivities of these ethers were generally found to decrease in the order: cis-β-monomethylvinyl > vinyl > trans-β-monomethylvinyl > β,β-dimethylvinyl. Comparisons of these results with previously published copolymerization data have permitted the conclusion that, in both the copolymerizations and acetal additions, the single β-methyl substitution on vinyl ethers exerts little steric effect against their additions toward any alkoxycarbonium ion, whereas the β,β-dimethyl substitution results in a large adverse steric effect toward both β-monomethyl- and β,β-dimethyl-substituted alkoxycarbonium ions.     

Copolymerization parameters of acrolein and acidic vinyl monomers

Acrolein was copolymerized by radical initiation in aqueous solutions with sodium p-styrenesulfonate and acrylic acid, respectively, in the pH range of 3–7. The reactivities were shown to be pH-dependent. For the acrolein (M₁)–sodium p-styrenesulfonate (M₂) pair, r₁ = 0.33 ± 0.15 and r₂ = 0.32 ± 0.05 at pH 3; r₁ = 0.23 ± 0.12 and r₂ = 0.05 ± 0.03 at pH 5; r₁ = 0.26 ± 0.03 and r₂ = 0.025 ± 0.025 at pH 7. For the acrolein (M₁)–acrylic acid (M₂) pair, r₁ = 0.50 ± 0.30 and r₂ = 1.15 ± 0.2 at pH 3; r₁ = 2.40 ± 0.50 and r₂ = 0.05 ± 0.05 at pH 5; r₁ = 6.70 ± 3.00 and r₂ = 0.00 at pH 7. For acrolein, the new values of Q = 1.6 and e = 1.2 have been calculated. For sodium p-styrenesulfonate, the values Q = 0.76 and e = ?0.26 at pH 3, Q = 0.51 and e = ?0.87 at pH 5, Q = 0.39 and e = ?1.00 at pH 7 were obtained; and for acrylic acid, the values Q = 1.27 and e = 0.50 at pH 3, Q = 0.11 and e = ?0.22 at pH 5 were derived. The changes in reactivity are explained on the basis of inductive and resonance effects.     

Silyl enol ethers as monomer. I. Radical copolymerizability of α-trimethylsilyloxystyrene

α-Trimethylsilyloxystyrene (TMSST), the silyl enol ether of acetophenone, was not homopolymerized either by a radical or a cationic initiator. Radical copolymerization of TMSST with styrene (ST) and acrylonitrile (AN) in bulk and the terpolymerization of TMSST, ST, and maleic anhydride (MA) in dioxane were studied at 60°C and the polymerization parameters of TMSST were estimated. The rate of copolymerization decreased with increased amounts of TMSST for both systems. Monomer reactivity ratios were found as follows: r₁ = 1.48 and r₂ = 0 for the ST (M₁)–TMSST (M₂) system and r₁ = 0.050 and r₂ = 0 for the AN (M₁)–TMSST (M₂) system. The terpolymerization of ST (M₁), TMSST (M₂), and MA (M₃) gave a terpolymer containing ca. 50 mol % of MA units with a varying ratio of TMSST to ST units and the ratio of rate constants of propagation, k₃₂/k₃₁, was found to be 0.39. Q and e values of TMSST were determined using the values shown above to be 0.88 and ?1.13, respectively. Attempted desilylation by an acid catalyst for the copolymer of TMSST with ST afforded polystyrene partially substituted with hydroxyl groups at the α-position.     

Spontaneous alternating copolymerization of N-phenylmaleimide with ethyl α-phenylacrylate

The spontaneous copolymerization of N-phenylmaleimide (NPMI) (M₁) with ethyl α-phenylacrylate (EPA)(M₂) were carried out in dioxane at 85°C. A high alternating tendency was observed. The monomer reactivity ratios were r₁ = 0.07 ±0.01 and r₂ = 0.09 ± 0.02. The maximum copolymerization rate and molecular weight occurs at 70–80 mol% (M₁) in feed ratio. The spontaneous alternating copolymerization is considered to be carried out via a contact-type charge transfer complex (CTC) formed between the monomers. Thermogravimetric analyses (TGA) indicate the resulting copolymers have high thermal stability. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 2927–2931, 1998     

Living Carbocationic Copolymerizations. V. Synthesis of Isobutylene/p-Methylstyrene Copolymers with the Constant Copolymer Composition Technique in the Leidenfrost Reactor

Abstract

Living copolymerization of the isobutylene (IB)-p-methylstyrene (pMeSt) monomer pair in combination with the constant copolymer composition (CCC) technique produces high molecular weight ( M _n ≈ 100,000 g·mol^?1) and narrow molecular weight distribution ( M _w/ M _n ≈ 1.45) compositionally uniform IB/pMeSt copolymer molecules in the industrially important IB/pMeSt = 97–99/3–1 mol% composition range. Syntheses were carried out with TiCl₄ coinitiator in n-butyl chloride homogeneous solution at ?85°C by the use of the Leidenfrost reactor (i.e., by direct cooling of the charge with liquid nitrogen). In order to carry out the CCC technique it was necessary to obtain reliable copolymerization reactivity ratios. These investigations led to r_IB = 0.5 ± 0.1 and r _pMeSt = 10 ± 4. The attainment of CCC and living copolymerization conditions has been quantitatively demonstrated by dedicated diagnostic plots. Specifically, the attainment of CCC conditions was proven by the analysis of composite rate plots (comonomers input and corresponding copolymer formed versus time) and composition plots (comonomer composition in feed and copolymer formed versus weight of copolymer formed, W _p), and living copolymerization was proven by linearly ascending number-average molecular weight of copolymer ( M _n) versus W _p plots starting at the origin.     

Photosensitized copolymerization of optically active N-l-menthylmaleimide with styrene and methyl methacrylate

Photosensitized copolymerization of optically active N-l-menthylmaleimide (NMMI) with styrene (Sty) and methyl methacrylate (MMA) was carried out in tetrahydrofuran (THF) at 30°C with benzoyl peroxide (BPO). The monomer reactivity ratios for the copolymerization of NMMI (M₂) with Sty (M₁) and MMA (M₁) were r₁ = 0.08 ± 0.10, r₂ = 0.20 ± 0.05 and r₁ = 2.85 ± 0.06, r₂ = 0.07 ± 0.06, respectively. Copoly-MMA–NMMI and poly-NMMI showed positive circular dichroism(CD) curves of equal intensity and shape over the wavelength region from 230 to 270 nm; copoly-Sty–NMMI also showed a positive CD curve which was similar in shape but was different in intensity from that of poly-NMMI. The correlation between monomer unit ellipticity of the copolymers and their composition would suggest the alternating and stereoregular copolymerization of NMMI with Sty.