Radical polymerization of vinyl monomer having diacylurea moiety

N-acryloyl-N′-benzoylurea ( 1 ) was prepared and its radical homopolymerization and copolymerization with styrene were carried out. 1 was synthesized yield by the reaction of benzoylisocyanate and acrylamide in tetrahydrofuran in 78%. Radical polymerization of 1 was carried out at 60 or 80°C in DMF (0.1-2.5M) for 5 h in a sealed tube using AIBN (3 mol %) or BPO (3 mol %) as initiators to obtain poly(N′-acryloyl-N′-benzoylurea) ( 2 ) as a methanol-insoluble part in good yield (75–82%) independent of concentration. Number-average molecular weights of 2 were 2700–91,900. Furthermore, copolymerization of 1 with styrene was carried out in various feed ratios to confirm the alternating character in the copolymerization (r₁r₂ = 0.21) and Q, e values of 1 were evaluated as 0.52, 1.16, respectively. © 1995 John Wiley & Sons, Inc.     

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     

Free-radical homopolymerization and copolymerization of vinylferrocene

The benzene solution homopolymerization of vinylferrocene, initiated by azobisisobutyronitrile, gave a series of benzene-soluble homopolymers. Thus, free-radical copolymerization studies were performed with styrene, methyl acrylate, methyl methacrylate, acrylonitrile, vinyl acetate, and isoprene in benzene. With the exception of vinyl acetate and isoprene, which did not give copolymers with vinylferrocene under these conditions, smooth production of copolymers occurred. The relative reactivity ratios, r₁ and r₂, were obtained for vinylferrocene–styrene copolymerizations by using the curve-fitting method for the differential form of the copolymer equation, by the Fineman-Ross technique, and by computer fitting of the integrated form of the copolymer equations applied to higher conversion copolymerizations. In styrene (M₂) copolymerizations, the curve-fitting and Fineman-Ross methods both gave r₁ = 0.08, r₂ = 2.50, while the integration method gave r₁ = 0.097, r₂ = 2.91. Application of the integration method to methyl acrylate and methyl methacrylate (M₂) gave values of r₁ = 0.82, r₂ = 0.63; r₁ = 0.52, r₂ = 1.22, respectively. The curve-fitting method gave r₁ = 0.15, r₂ = 0.16 for acrylonitrile (M₂) copolymerizations. From styrene copolymerizations, vinylferrocene exhibited values of Q = 0.145 and e = 0.47.     

Homo- and copolymerization of N-(2-thiazolyl)methacrylamide with different vinyl monomers: Synthesis,characterization, determination of monomer reactivity ratios and biological activity

N-(2-thiazolyl)methacrylamide (TMA) monomer was synthesized from 2-aminothiazole by two different methods. The homo- and copolymerization of this monomer with methyl methacrylate (MMA), styrene (St), acrylonitrile (AN), and vinyl acetate (VA) were performed in dimethyl formamide using 1 mol% AIBN at 70°C. The copolymerization behavior was studied in a wide composition interval with the mole fractions of TMA ranging from 0.1 to 0.7 in the feed. Characterization using FTIR and 1HNMR techniques confirmed the structure of the monomer and the prepared homo- and copolymers, but the copolymers compositions were determined from sulphur analysis. The monomer reactivity ratios were computed using Fineman and Ross and Kelen and Tüdös methods for the systems TMA-MMA, TMA-St, TMA-AN and TMA-VA and were found to be r ₁ = 0.59 ± 0.05, r ₂ = 2.72 ± 0.03; r ₁ = 0.39 ± 0.02, r ₂ = 0.90 ± 0.01; r ₁ = 0.77 ± 0.06, r ₂ = 1.99 ± 0.04 and r ₁ = 0.80 ± 0.08, r ₂ = 0.40 ± 0.05 respectively (r ₁ corresponds to monomer reactivity ratio of TMA). The Q and e values for TMA monomer were found to be 1.079 and ?0.054. The synthesized monomer and polymers were tested in vitro for biological activity against some microorganisms, using the disk diffusion technique. Generally, all the polymers were effective against the tested microorganisms, but their growth-inhibition effects varied.     

Polymerization behavior of 2,2,6,6-tetramethylpiperidinyl methacrylate: A monomer carrying a hindered amine group

Copolymers of 2,2,6,6-tetramethylpiperidinyl methacrylate (TPMA) with styrene (S) and with methyl methacrylate (MMA) were synthesized using AIBN as initiator. S–TPMA copolymers from feed ranging from 0.10–0.80 mole fractions TPMA and MMA-TPMA copolymers from feed of 0.04–0.85 mole fractions TPMA were used in the determination of monomer reactivity ratios r₁, r₂. Four different methods were employed in the calculations of r₁ and r₂ and all calculated results were in good agreement with each other. The structure of S–TPMA copolymers was inferred to be of an alternating nature while that of MMA–TPMA copolymers was random. Both copolymers are potential hindered amine light stabilizers (HALS) and are expected to be less extractable from, and more compatible with, polystyrene and poly(methyl methacrylate) base polymers.     

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.     

Silyl enol ethers as monomer. III. Radical polymerization and copolymerizations of 2-trimethylsilyloxy-1,3-butadiene and desilylation of the resulting polymers

2-Trimethylsilyloxy-1,3-butadiene (TMSBD), the silyl enol ether of methyl vinyl ketone, was homopolymerized with a radical initiator to afford polymers with a molecular weight of ca. 10⁴. Radical copolymerizations of TMSBD with styrene (ST) and acrylonitrile (AN) in bulk or dioxane at 60°C gave the following monomer reactivity ratios: r₁ = 0.64 and r₂ = 1.20 for the ST (M₁)–TMSBD (M₂) system and r₁ = 0.036 and r₂ = 0.065 for the AN (M₁)–TMSBD (M₂) system. The Q and e values of TMSBD determined from the reactivity ratios for the former copolymerization system were 2.34 and ?1.31, respectively. The resulting polymer and copolymers were readily desilylated with hydrochloric acid or tetrabutylammonium fluoride as catalyst to yield analogous polymers having carbonyl groups in the polymer chains.     

Ferrocene-containing polymers. II. Radiation-induced copolymerizations of ferrocenylmethyl methacrylate with styrene,methyl methacrylate,and ethyl acrylate

Ferrocenylmethyl methacrylate (FMMA) was copolymerized with styrene (St), methyl methacrylate (MMA), and ethyl acrylate (EA) in benzene solution at 25°C by γ radiation. The reactions proceeded by a free radical mechanism, and monomer reactivity ratios were derived by the Tidwell–Mortimer method for St(M₁)–FMMA(M₂), r₁ = 0.35 and r₂ = 0.46; for MMA(M₁–FMMA)(M₂), r₁ = 0.85 and r₂ = 1.36; for EA(M₁)–FMMA(M₂), r₁ = 0.36 and r₂ = 3.03. The Q and e values of FMMA determined from copolymerization with St were 0.97 and 0.55, respectively. Terpolymerization of a MMA–FMMA–EA system based on the Alfrey–Goldfinger equations was studied. This is a typical terpolymerization system in which reactivities of the monomers obey the Q–e scheme. Comparing the results obtained here with those previously reported for other monomers, we concluded that FMMA is one of the most highly reactive monomers among alkyl methacrylates.     

Monomer Reactivity Ratios for the Copolymerization of Styrene with Pure Meta-and Pure Para-Divinylbenzenes

Reactivity ratios for the copolymerization of styrene (r ₁) meta-divinylben-zene (r ₂–m) and with para-divinylbenzene (r ₂–p) have been redetermined under different reaction conditions and with different radioactivity assay techniques. The copolymers were prepared at two conversion levels [0.55 to 3.7% and 2.7 to 7.5% and at 80° (rather than 100°)] with benzoyl peroxide (in place of τ-butylhydroperoxide) initiator. The ionization chamber-vibrating reed electrometer radioactivity assay technique developed for other copolymerization studies was used in place of the direct counting technique previously used for the styrene/divinylbenzene systems. The new values are r ₁ = 0.605/r ₂-m = 0.88: r ₁ = 0.77/r ₂-p = 2.08 at 0.55 to 3.7% conversion and r ₁ = 1.27; r ₂–m = 1.08 at 2.7 to 7.5% conversion. These are not in close agreement with previous values partly because of the difference in conditions of copolymerization (temperature, per cent conversion, initiator) and in the improved analytical precision. Also the high-DVB-content (80%) para copolymer data are not assumed to be invalid and are not omitted (as they were before) from selection of the r ₂–p values.     

Facile synthesis of blocky styrene(1,3)‐butadiene copolymers having stereoregular monomeric sequences

Half titanocenes (CpCH₂CH₂O)TiCl₂ 1 and (CpCH₂CH₂ OCH₃)TiCl₃ 2 , activated by methylaluminoxane are tested in styrene–1,3‐butadiene copolymerization. The titanocene 1 is able to copolymerize styrene and 1,3‐butadiene, with a facile procedure, to give products with high molecular weight. The analysis of microstructure by ¹³C‐NMR reveals that the styrene homosequences in copolymers are in syndiotactic arrangement, while the butadiene homosequences are, prevailingly, in 1,4‐cis configuration, according with behavior of 1 in the homopolymerizations of styrene and 1,3‐butadiene, respectively. The reactivity ratios of copolymerization are estimated by diad composition analysis. All obtained copolymers have r₁ × r₂ values much larger than 1, indicating blocky nature of homosequences. The structural characterization by wide‐angle X‐ray powder diffraction and differential scanning calorimetry indicates that all copolymers are crystalline, with T_m varying from 171 to 239 °C, depending on the styrene content. The titanocene 2 did not succeed in styrene–1,3‐butadiene copolymerization, giving rise to a blend of homopolymers. Compounds 1 and 2 were also tested in the polymerization of several conjugated dienes, and the obtained results were very useful to rationalize the behavior of both catalysts in the copolymerization of styrene and butadiene. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 815–822, 2010     

Catalytic systems Me2SiCp*NtBuMX2/(CPh3)(B(C6F5)4) (MTi,XCH3, MZr,XiBu) in copolymerization of ethylene with styrene

Catalytic activity of Me₂SiCp*N^tBuMX₂/(CPh₃)(B(C₆F₅)₄) [MTi, XCH₃ (1); MZr, X=ⁱBu (2)] systems in the ethylene/styrene (E/S) feed was examined. Experimental data revealed high activity for the catalytic system (1) for copolymerization ethylene with styrene, whereas the system with enhanced catalytic activity for ethylene homopolymerization (2) was temporarily blocked in the styrene presence yielding, even at high styrene content, homopolyethylene as the final product. Properties of thus obtained polymers were analyzed. Catalytic system (1) occurred very sensitive to S/E ratio in the comonomers feed. The 10‐fold acceleration for ethylene consumption was shown in two experimental sets conducted at S/E = 1.3 ratio, 1 bar, and 7.5 bar ethylene pressure, respectively. The consequent enhancement in S/E ratio resulted in slowing down both ethylene consumption and catalyst deactivation rates. Atactic polystyrene was formed at high styrene content with the catalyst (1). Catalytic system (1) allowed design of products with the highest styrene content (20 mol %) at low ethylene pressure, moderate temperature, and high S/E ratio. The apparent activation energy estimated from the initial rates of ethylene consumption was 54.6 kJ/mol. Analysis of apparent reactivity factors (r_E = 9 and r_S = 0.04; r_E × r_S = 0.4) and ¹³C‐NMR copolymer spectra revealed an alternating tendency of the comonomers for active center incorporation. DSC measurements showed considerable decrease of melting points and crystallinity even for copolymers with low styrene content. The catalyst produced relatively high–molecular weight copolymers (140–150 kg/mol) even at 80°C. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1083–1093, 1999     

Polymerization behavior of 1,2,2,6,6-pentamethyl-4-piperidinyl m-isopropenyl-α,α-dimethylbenzyl carbamate

Copolymers of 1,2,2,6,6-pentamethyl-4-piperidinyl m-isopropenyl-α,α-dimethylbenzyl carbamate (CB) with styrene (S) and with methyl methacrylate (MMA) were synthesized using AIBN as initiator. S–CB copolymers made from feed ranging from 0.45–0.94 mole fractions S and MMA-CB copolymers made from feed of 0.34–0.88 mole fractions MMA were used to determine the monomer reactivity ratios r₁ and r₂. The structure of S–CB copolymers was inferred to be mainly of a random nature and in the MMA–CB copolymerization system there is a stronger tendency to form alternating copolymers. © 1993 John Wiley & Sons, Inc.     

Studies on Synthesis and Characterization of Charge Transfer Polymerization of Styrene and Alkyl Methacrylates

Abstract

Copolymers involving styrene and homologues of alkyl methacrylates (viz., methyl, ethyl, and butyl methacrylates) were synthesized at 60°C by employing a mixture of n‐butylamine and carbontetrachloride as charge transfer (CT) initiators in dimethyl sulphoxide medium. The CT complex was characterized by UV spectroscopy while the respective copolymers were characterized by employing infrared (IR) and ¹H NMR spectroscopy. The copolymer compositions were determined by using ¹H NMR spectroscopy and the reactivity ratios were computed by Fineman–Ross (F–R) and Kelen–Tudos (K–T) methods. The reactivity ratios of Sty‐MMA and Sty‐EMA copolymers indicate that higher level of styrene is incorporated in the copolymer. On the other hand the Sty‐BMA system exhibits different behavior. The higher value of r ₂ is obtained denoting that BMA is more active than styrene and hence, more BMA is present in the copolymer chain. In Sty‐MMA and Sty‐BMA systems, the product of r ₁ and r ₂ is greater than 1, representing the formation of high degree of random copolymers. However, in the case of Sty‐EMA, the product of r ₁ and r ₂ is less than 1 indicating the formation of alternating copolymer.     

The introduction of hydroxyl functionality into polymers: The synthesis,polymerization, and hydrolysis of vinylbenzyl acetate

Vinylbenzyl acetate was synthesized in yields greater than 80% via the reaction of vinylbenzyl chloride with potassium acetate. Radical copolymerization of the monomer with styrene and methylmethacrylate were studied at 60°C. Reactivity ratios determined from FT-IR analysis of low conversion copolymerizations with styrene (M₁) were r₁ = 0.78 ± 0.07 and r₂ = 1.33 ± 0.13. Polymers and copolymers of vinylbenzyl acetate were found to completely hydrolyze in dioxane/water/base solution to yield hydroxymethyl functionality. Size exclusion chromatography studies indicated that the hydrolysis proceeded without crosslinking. This procedure is a useful method for the introduction of hydroxyl functionality on polymers and avoids crosslinking problems common in previously reported methods.     

The structure of copolymers of vinyl cyclohexane with styrene

Copolymerization of vinyl cyclohexane (monomer-1) with styrene was investigated in the presence of the stereospecific complex catalyst TiCl₃ + Al(iso-C₄H₉)₃. Monomer reactivity ratios were r₁ = 0·177 ± 0·051 and r₂ = 2·117 ± 0·370. The monomer unit distributions in the copolymers were estimated by comparison of the i.r.-spectra of copolymers and the isotactic homopolymers using absorption bands at 565 and 1084 cm^?1 which correspond to the vibrations of styrene blocks containing ? 5 styrene units and the band at 985 cm^?1 characterizing polystyrene crystallinity. The data indicate the tendency towards alternation in the copolymerization. Analysis of the experimental and literature data led to the conclusion that distribution of the units in copolymers of vinyl cyclohexane with α-olefins is determined by the nature of the α-olefin. The following activity series is proposed for α-olefins in their copolymerization with vinyl cyclohexane in the presence of catalytic systems based on titanium salts and organo-aluminium compounds: propylene >; 4-methylpentene-1 >; styrene >; 3-methylbutene-1 ～ vinyl cyclohexane.     

Synthesis, reactivity ratios and characterization of hydroquinone promoted CT co-polymerization of styrene and methyl methacrylate in a room temperature ionic liquid

For the first time, charge transfer (CT) co-polymerization of styrene and methyl methacrylate, promoted by hydroquinone (HQ) at various feed compositions, has been achieved in a hydrophobic ionic liquid. The co-polymers have been characterized for thermal and molecular weight properties. The molecular weights obtained for the co-polymers made in ionic liquid were found to be slightly lower than the corresponding polymers synthesized in conventional solvent. The reactivity ratios of the co-polymers have been computed and compared with conventional CT polymerization. The reactivity ratios of Sty-MMA indicate that the co-polymerization has a tendency to alternate and to produce a higher styrene content in the co-polymers. The numerical values of the inverse of r₁ and r₂ indicate that both monomer radicals have a distinct cross propagation tendency.     

Radical polymerization of butadiene-1-carboxylic acid

The homopolymerization and copolymerization of butadiene-1-carboxylic acid (Bu-1-Acid) (M₁) were studied in tetrahydrofuran at 50°C with azobisisobutyronitrile as an initiator. The initial rate of polymerization was proportional to [AIBN]^1/2 and [Bu-1-Acid]¹. The overall activation energy for the polymerization was 22.87 kcal/mole. For copolymerization with styrene (M₂) and acrylonitrile (M₂), the monomer reactivity ratios r₁, r₂ were determined by the Fineman-Ross method, as follows; r₁ = 5.55, r₂ = 0.08 (M₂ = styrene); r₁ = 11.0, r₂ = 0.03 (M₂ = acrylonitrile). Alfrey-Price Q-e values calculated from these values were 6.0 and +0.11, respectively. The Bu-1-Acid unit in the copolymer as well as the homopolymer was found from infrared and NMR spectral analyses to be composed of a trans-1,4 bond. The hydrogen-transfer polymerization of Bu-1-Acid leading to polyester was attempted with triphenylphosphine as initiator, but did not occur.     

Organotin polymers—VIII. Binary and ternary copolymerizations of triphenyltin methacrylate with arylonitrile,styrene, N-vinyl pyrrolidone and n-butyl methacrylate

Copolymerizations involving triphenyltin methacrylate (PTMA) were carried out in solution at 70° in the presence of a free radical initiator; the copolymer compositions were determined from tin analyses. The monomer reactivity ratios for the copolymerizations of PTMA with acrylonitrile, styrene, and N-vinyl pyrrolidone were: r₁ = 0.69, r₂ = 0.16; r₁ = 0.76, r₂ = 0.47, and r₁ = 1.22, r₂ = 0.36, respectively. The sequence distribution of the alternation diads for the systems were calculated at various feed compositions. Ternary copolymerization of PTMA-acrylonitrile-butyl methacrylate was studied; the variation of terpolymer composition with conversion fit satisfactorily the experimental results. Ternary azeotropy for PTMA-acrylonitrile-styrene system was verified experimentally.     

Copolymerization of styrene and methyl methacrylate. Reactivity ratios from conversion–composition data

A method for the determination of reactivity ratios from conversion–composition data has been outlined. The conversion–composition changes during the copolymerization of styrene (M₁) and methyl methacrylate (M₂) have been studied at 60°C. By a method of graphical intersection, the integrated form of Skeist's equation has been used to determine the reactivity ratios (r₁ = 0.54 ± 0.02 and r₂ = 0.50 ± 0.06) in reasonably good agreement with values reported in the literature. The area of intersection was used as a measure of the precision of the data.     

Applicability of the Mayo–Lewis equation to high conversion copolymerization of styrene and methylmethacrylate

In contradiction to reports from this and other laboratories, this study reports that the integrated Mayo–Lewis equation, or Meyer–Lowery equation, adequately describes the high-conversion free radical copolymerization of styrene and methylmethacrylate. The copolymerization was monitored by following the changes in the feed composition using NMR, as well as determination of the resulting copolymer compositions by NMR and UV. “Error in all Variables” statistical techniques were used to produce estimates of the reactivity ratios. The reactivity ratios estimated were, from feed composition, NMR, r₁ (styrene) = 0.472, r₂ = 0.454, from copolymer composition, UV, r₁ = 0.497, r₂ = 0.464, and NMR, r₁ = 0.432, r₂ = 0.422.