Oxidation of Stereo‐regular Poly(styrene‐co‐4‐methylstyrene) by Cobalt(II) Acetate Tetrahydrate/Sodium Bromide Catalyst

Chemical modification on the stereo‐regular poly(styrene‐co‐4‐methylstyrene) (sPS‐PMS) was attempted in this study. Metallocene copolymerization of styrene (St) and 4‐methylstyrene (MSt) was performed by using η⁵‐pentamethylcyclopentadienyl‐titanium(IV)tributoxide (Cp*Ti(OBu)₃)/methylaluminoxane (MAO)/tri‐iso‐butylaluminum (TIBA) catalyst in the bulk state. Cobalt(II) catalyst was then applied to oxidize the benzylic methyl group on the MSt units of the resulting sPS‐PMS copolymer. Both aldehyde and carboxylic acid in the oxidized products were resolved by the FTIR and ¹H NMR. The oxidized sPS‐PMSs exhibit a low and a high‐temperature T_g and T_m corresponding to the transitions in the amorphous and the crystalline regions. Hydrogen‐bond and polar interactions between the aldehyde and carboxylic acids tend to interrupt the regular chain packing of the oxidized sPS‐PMS, resulting in the lowering of T_m with oxidation level. The oxidized sPS‐PMS showed better adhesion to glass fiber than pure sPS‐PMS copolymer as evaluated from the respective SEM fractured micrographs.     

Adsorption-desorption behavior of phenols on novel polymers containing the pyrrolidinone moiety

Crosslinked polymers having a pyrrolidinone moiety (CPS, CPES, and CVP) were synthesized by radical copolymerization of 4-(2-oxo-1-pyrrolidinyl)methylstyrene, 4-[2-(2-oxo-1-pyrrolidinyl)ethoxy]methylstyrene, or 2-vinylpyrrolidinone with divinylbenzene in the presence of AIBN as a radical initiator. The adsorption-desorption behavior of phenols on these polymers was investigated. The polymers with spacers between the polymer main chain and pyrrolidinone moiety appeared to have a superior adsorption capability to those without such spacers. The amount of phenol adsorbed on the polymers in a solvent decreased in the following order: water > chloroform > methanol. In methanol, the interaction between the polymers and phenol was suggested to come only from charge-transfer stacking (C–T stacking), whereas in chloroform the interaction was caused mainly by both hydrogen bonding and C–T stacking. The interaction in water was attributed not only to both hydrogen bonding and C–T stacking, but also to a hydrophobic interaction. Characterization of polymers (CVP) containing adsorbed phenol was carried out by thermogravimetric analysis (TGA). The TGA curves indicated a two step weight-decrease, namely the first step in the temperature ranging from ca. 100-200°C was attributed to the desorption of phenol while the second step in the temperature ranging from ca. 350-500°C was based on thermal decomposition of the polymers. The desorption of phenol adsorbed on the polymers in water indicated an inverse tendency to the adsorption; that is, the amount of phenol desorbed from the polymers without a spacer was more than those from the polymers with spacers. © 1994 John Wiley & Sons, Inc.     

Studies of the polymerization of diallyl compounds. XXVII. Copolymerization of diallyl tartrate with several vinyl monomers

The radical copolymerization of diallyl tartrate (DATa) (M₁) with diallyl succinate (DASu), diallyl phthalate (DAP), allyl benzoate (ABz), vinyl acetate (VAc), or styrene (St) was investigated in order to disclose in more detail the characteristic hydroxyl group's effect observed in the homopolymerization of DATa. In the copolymerization with DASu or DAP as a typical diallyldicarboxylate, the dependence of the rate of copolymerization on monomer composition was different for different copolymerization systems and unusual values larger than unity for the product of monomer reactivity ratios, r₁r₂, were obtained. In the copolymerization with ABz or VAc (M₂), the r₁ and r₂ values were estimated to be 1.50 and 0.64 for the DATa/ABz system and 0.76 and 2.34 for the DATa/VAc system, respectively; the product r₁r₂ for the latter copolymerization system was found again to be larger than unity. In the copolymerization with St, the largest effect due to DATa monomer of high polarity was observed. Solvent effects were tentatively examined to improve the copolymerizability of DATa. These results are discussed in terms of hydrogen-bonding ability of DATa.     

N-(monohalogenphenyl) maleimides and their copolymers with styrene and butadiene

N-(Monohalogenphenyl)maleamic acids (I) and N-(monohalogenphenyl) maleimides (II) which contained bromide or chlorine atoms in the 2-, 3-, or 4-position of the phenyl ring and their respective isoimides (III) were prepared. The radical copolymerization of Pairs II + styrene and II + butadiene in benzene solution initiated with 2,2′-azobisisobutyronitrile at 50°C was used to determine the monomer reactivity ratios of II. Their values, which are close to zero, indicated an alternating addition of the two monomers on the polymer radical. The thermal stability of the copolymers was characterized by thermogravimetric analysis; their flammability was determined by the method of limiting oxygen index. The copolymerizability of III with styrene and isobutylene was verified at 30°C.     

Alternating copolymerization of benzofuran with crotononitrile and α-chloroacrylonitrile

The copolymerizations of benzofuran with α,α- or α,β-disubstituted acrylic monomers were studied. The alternating copolymer of benzofuran and crotononitrile was prepared in the presence of an excess amount of crotononitrile with respect to benzofuran, ethylaluminum dichloride, and azobisisobutyronitrile. The intrinsic viscosity of copolymers was 0.1–0.2 dl/g. Crotononitrile is known to possess a polar carbon–carbon double bond from ¹³C-NMR spectroscopy but the alternating copolymerizability with benzofuran is low. It was found that the order of alternating copolymerizability of acrylic monomers is as follows: This fact may be attributed to the steric hindrance of the β-methyl of crotononitrile. The induced shifts by complexation with ethylaluminum dichloride on ¹³C-NMR spectra of the two isomers of crotononitrile are almost same but the copolymerizability of cis isomer is higher than that of trans isomer. α-Chloroacrylonitrile shows the highest alternating copolymerizability with benzofuran in the presence of weak Lewis acid such as ethoxyaluminum chloride. Alternating copolymerizability of acrylic monomers seems to be in proportion to their e value. The reactivity of cis- and trans-crotononitrile may depend on the nature of a ternary complex composed of aluminum compound, crotononitrile, and benzofuran.     

Studies on pyrrolidinones. A convenient synthesis of 2-methyl-5-(5-oxo-1-benzyl-2-pyrrolidinyl)-1,3,4-oxadiazole

2-Methyl-5-(5-oxo-1-benzyl-2-pyrrolidinyl)-1,3,4-oxadiazole is easily obtained by dehydration of N-acetyl-1-benzylpyroglutamic acid hydrazide with a methanesulfonic acid/phosphoric anhydride mixture.     

Free-Radical-Initiated Polymerization of N(p-Phenoxy-phenyl)maleimide and Copolymerization with Styrene, α-Methylstyrene and β–Methylstyrene

Abstract

Synthesis and free-radical-initiated homopolymerization of phenoxy-phenylmaleimide (PhOPhMI) and copolymerization with styrene (St), (α-methylstyrene (αMeSt) and β–methylstyrene (β-MeSt) are described. It was found that alternating copolymers are formed under different monomer-to-monomer ratios in the feed and that the mechanism based on the participation of CT-complex best explains the formation of alternating copolymers. Equilibrium constants of CT-complexes are: K _PhOPhMI/St = 0.20 Lmol^?1; K_{PhOPhMI/αMeSt} = 0.05 Lmol^?1; K_{PhOPhMI/βMeSt} = 0.02 Lmol^?1. Homopolymer and co-polymers are film-forming materials, stable up to 350°C under TGA conditions. T_g s and higher transition temperatures are within the thermally stable region.     

Free-radical copolymerization of styrene with N-phenyl maleimide initiated by thiol

2-Methyl–2-undecanethiol was found efficient to initiate the free-radical copolymerization of styrene (St) with N-phenyl maleimide (NPMI) at 40°C. The initial copolymerization rate increases with the increasing of thiol concentration at first, then keeps constant with the further increasing of the thiol concentration. The charge-transfer complex (CTC) formed between St and NPMI was investigated in different solvents by using ¹H-NMR. There is no definite correlation between CTC equilibrium constant, K, and the polarity of the solvent. With the increasing of CTC concentration, both the copolymerization rate and NPMI content in copolymer enhances, indicating the participation of CTC in both initiation and propagation. The monomer reactivity ratios were calculated to be r_NPMI = 0.052 and r_St ? 0.166, showing an alternating tendency for the copolymerization of St with NPMI. The molecular weight approach has shown again the effect of CTC. The function of thiol as a regulator is mitigated due to the involvement of CTC. © 1992 John Wiley & Sons, Inc.     

Influence of the catalyst on monomer insertion in the syndiospecific copolymerization of styrene and para‐methylstyrene

The effect of the kind of transition‐metal catalyst on the extent of comonomer insertion in the syndiospecific complex‐coordinative copolymerization of styrene and para‐methylstyrene has been investigated. The results for the influence of the polymerization conditions have shown that there is no real difference between solution copolymerization in toluene and solvent‐free styrene copolymerization in bulk, with respect to the reactivity ratio for para‐methylstyrene (r₂), under comparable conditions in the presence of methylaluminoxane and triisobutylaluminum and at low polymerization conversions. All the investigated catalysts lead to a preferred incorporation of para‐methylstyrene into the polymer chain in comparison with styrene and over the whole range of monomer compositions. The increasing capability of the different catalysts to provide copolymers with enhanced para‐methylstyrene concentrations can be summarized by the increasing r₂ values for the copolymerization in bulk as follows: η⁵‐pentamethylcyclopentadienyl titanium trichloride < η⁵‐octahydrofluorenyl titanium trimethoxide < η⁵‐octahydrofluorenyl titanium tristrifluoroacetate < η⁵‐cyclopentadienyl titanium(N,N‐dicyclohexylamido)dichloride < η⁵‐cyclopentadienyl titanium trichloride. For a correlation between the catalyst structure and the comonomer insertion, the catalysts can be described by electronic effects (electrostatic charge of the transition‐metal atom) and steric effects (minimum structural cone angle). The results show that the steric properties of the transition‐metal complexes have the most important effect on the insertion of para‐methylstyrene into the copolymer. If the minimum structural cone angle of the ligand of the transition‐metal catalyst decreases, the incorporation of the comonomer para‐methylstyrene increases significantly. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2061–2067, 2005     

Chemistry of sulfonyl isocyanates and sulfonyl isothiocyanates. XI. Cyclizations with epoxides

4-Toluenesulfonyl isocyanate cyclized with 1,2-epoxy-3-phenoxypropane and 2,3-epoxypropyl 4-methoxyphenyl ether, respectively, to give 3-(4-toluenesulfonyl)-5-phenoxymethylene-2-oxazolidone ( I ) and 3-(4-toluenesulfonyl)-5-(4-methoxyphenoxymethylene)-2-oxazolidone ( II ). Compounds I and II were hydrolyzed in 2 M sodium hydroxide solution to the corresponding uncyclized hydroxy amides, VII and VIII. Compound I was remarkably stable toward 6 M hydrochloric acid and amines. Styrene oxide, 1,2-epoxybutane, 3-chloro-1,2-epoxypropane, and 1-methoxy-2-methylpropylene oxide reacted with the isocyanate to afford 3-(4-toluene-sulfonyl)-4-phenyl-2-oxazolidone (III), 3-(4-toluenesulfonyl)-4-ethyl-2-oxazolidone ( IV ), 3-(4-toluenesulfonyl)-5-chloromethyl-2-oxazolidone ( V ), and 3-(4-toluenesulfonyl)-4,4-dimethyl-5-methoxy-2-oxazolidone ( VI ), respectively. The yield of VI was constant over a temperature range of 25–90°.     

Polymerization of 3,4-dihydro-2H-carboxyaldehyde (acrolein dimer). Part II. Copolymerization with isocyanates

Copolymers of 3,4-dihydro-2H-pyran-2-carboxyaldehyde (acrolein dimer) with phenyl isocyanate were obtained under several conditions. Infrared and NMR analyses showed that the isocyanate always reacted with acrolein dimer forming urethane linkages, not block units of isocyanate. An alternating copolymer was obtained from the copolymerization in the presence of anionic catalysts such as butyllithium at room temperature, irrespective of the monomer ratios employed. The isocyanate content in the copolymer prepared with an Al(C₂H₅)₂Cl catalyst was increased by elevating polymerization temperature. The copolymerizability of aldehydes with the isocyanate depends upon the polarity of aldehyde group.     

Copolymerization of vinyl monomers with Gd(OCOCCl3)3-(i-Bu)3Al-Et2AlCl

The polymerization of polar monomers such as methyl methacrylate (MMA), methyl acrylate (MA), methacrylonitrile (MAN), and acrylonitrile (AN) was carried out with gadolinium-based Ziegler–Natta catalysts [Gd(OCOCCl₃)₃-(i-Bu)₃Al-Et₂AlCl] in hexane at 50°C under N₂ to elucidate the effect of the monomer's HOMO(highest occupied moleculor orbital) and LUMO (lowest unoccupied molecular orbital) levels on the polymerizability. In the case of homopolymerization, all monomers were found to polymerize and the order of relative polymerizability was as follows: MM > MA > MAN > AN. On the other hand, the result of copolymerization of St with MMA shows that the values of the monomer reactivity ratios are r₁ = 0.06 and r₂ = 1.98 for St(M₁)/MMA(M₂). The monomer reactivity ratios of styrene (St), p-methoxystyrene (PMOS), p-methylstyrene (PMS), and p-chlorostyrene (PCS) evaluated as r₁ = 0.55 and r₂ = 1.07 for St(M₁)/PMOS(M₂), r₁ = 0.38 and r₂ = 0.51 for St(M₁)/PMS(M₂), and r₁ = 0.72 and r₂ = 1.25 for St(M₁)/PCS(M₂) were compared with those for St(M₁)/MMA(M₂). The copolymerization behavior is apparently different from the titanium-based Ziegler—Natta catalyst, regarding a larger monomer reactivity ratio of PCS. The lower LUMO level of PCS and MMA may enhance a back-donation process from the metal catalyst, therefore resulting in high polymerizability. These results are discussed on the basis of the energy level of the gadolinium catalyst and the HOMO and LUMO levels of the monomers. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2591–2597, 1997     

Synthesis and characterization of copolyperoxides of indene with styrene, α‐methylstyrene,and α‐phenylstyrene

The oxidative copolymerization of indene with styrene, α‐methylstyrene, and α‐phenylstyrene is investigated. Copolyperoxides of different compositions have been synthesized by the free‐radical‐initiated oxidative copolymerization of indene with vinyl monomers. The compositions of the copolyperoxides obtained from the ¹H and ¹³C NMR spectra have been used to determine the reactivity ratios of the monomers. The reactivity ratios indicate that indene forms an ideal copolyperoxide with styrene and α‐methylstyrene and alternating copolyperoxides with α‐phenylstyrene. Thermal degradation studies via differential scanning calorimetry and electron‐impact mass spectroscopy support the alternating peroxide units in the copolyperoxide chain. The activation energy for thermal degradation suggests that the degradation is dependent on the dissociation of the peroxide (? O? O? ) bonds in the backbone of the copolyperoxide chain. Their flexibility has been examined in terms of the glass‐transition temperature. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2004–2017, 2002     

Functional monomers and polymers. XIX. Copolymerization of vinyl monomers containing nucleic acid bases

Taking into account the specific base–base interaction existing between nucleic acid molecules, we studied the free-radical copolymerization of N-β-methacryloyloxyethyl derivative of uracil with that of adenine at 60°C in various solvents. N-β-Methacryloyloxyethyltheophylline as well as methyl methacrylate were used also as comonomers. From the data on the rates in different comonomer feed ratios and the r₁ and r₂ values obtained, copolymerizability was discussed in some detail. The results suggest that the interaction between uracil and adenine bases plays a role in the copolymerization behavior.     

Ternary Molecular Complex in the Alternating Copolymerization of Methyl Methacrylate with Styrene Using Stannic Chloride

The equimolar alternating copolymerization of methyl methacrylate (MMA) with styrene (St) in the presence of stannic chloride in toluene (Tl) is investigated kinetically. The concentrations of the ternary molecular complexes, [SnCl₄-MMA … St] and [SnCl₄-MMA … T1], are calculated by use of the formation constants of the ternary molecular complexes. The rates of copolymerization under photo-irradiation and with tri-n-butyl boron-benzoyl peroxide as an initiator are proportional to the 1.5th order and 1. Oth order, respectively, of the concentration of the ternary molecular complex [SnCl₄ · MMA … St]. The alternating copolymerization precedes the homopolymerization of the methyl methacrylate charged in excess. The alternating regulation of the copolymerization is ascribed to the homopolymerization of the ternary molecular complex from the kinetic results. The magnitudes of the shifts for     

Monomer-isomerization polymerization. XXXVIII. Monomer-isomerization copolymerizations of styrene and 2-Butene with Ziegler–Natta catalyst

Monomer-isomerization copolymerizations of styrene (St) and cis-2-butene (c2B) with TiCl₃-(C₂H₅)₃Al catalyst were studied. St and c2B were found to undergo a new type of monomer-isomerization copolymerization, i.e., only isomerization of 2B to 1-butene ( 1B ) took place to give a copolymer consisting of St and 1B units. The apparent copolymerization parameters were determined to be r_st = 16.0 and r_c2b = 0.003. The parameters were changed by the addition of NiCl₂ (r_St = 8.4, r_c2b = 0.05). The copolymers containing the major amount of St units were produced easily through monomer-isomerization copolymerization of St and 2B. © 1995 John Wiley & Sons, Inc.     

Copolymerization of styrene and butadiene with Ni(acac)2-methylaluminoxane catalyst

Copolymerization of styrene (St) and butadiene (Bd) with nickel(II) acetylacetonate [Ni(acac)₂]-methylaluminoxane (MAO) catalyst was investigated. Among the metal acetylacetonates [Mt(acac)_x] examined, Ni(acac)₂ showed a high activity for the copolymerization of St and Bd giving copolymers having high cis-1,4-microstructure in Bd units in the copolymer. The effect of alkylaluminum as a cocatalyst on the copolymerization of St and Bd with the Ni(acac)₂-MAO catalyst was observed, and MAO was found to be the most effective cocatalyst for the copolymerization. The monomer reactivity ratios for the copolymerization of St and Bd with the Ni(acac)₂-MAO catalyst were determined to be r_St = 0.07 and r_Bd = 3.6. Based on the obtained results, it was presumed that the random copolymers with high cis-1,4-microstructure in Bd units could be synthesized with the Ni(acac)₂-MAO catalyst without formation of each homopolymer. The polymerization mechanism with the Ni(acac)₂-MAO catalyst was also discussed. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3838–3844, 1999     

Alternating copolymerization of N-(alkyl-substituted phenyl)maleimides with isobutene and thermal properties of the resulting copolymers

Radical copolymerization of N-(alkyl-substituted phenyl)maleimides (RPhMI) with isobutene (IB) was carried out with an initiator in various solvents at 60°C. The copolymerization of N-(2,6-diethylphenyl)maleimide (2,6-DEPhMI) with IB in benzene proceeded readily in a homogeneous system to give an alternating copolymer over a wide range of the comonomer compositions in the feed. Whereas the alternating tendency of the copolymerization of other RPhMI with IB decreased depending on the alkyl substituents of RPhMI in the following order: 2,6-DEPhMI > N-(2,6-dimethylphenyl)maleimide ≥ N-(2-methylphenyl)maleimide >. N-(4-ethylphenyl)maleimide. The copolymerization reactivities were discussed based on the rate constants for the homo-propagations and cross-propagations. Subsequently, the effect of the solvent on the rate and the reactivity ratios was examined. It was revealed that the copolymerization in chloroform proceeded with higher alternating tendency at a higher copolymerization rate than in the copolymerizations in benzene or dioxane. The copolymers of RPhMI with IB showed excellent thermal stability, i.e., high glass transition temperature and initial decomposition temperature over 200 and 350°C, respectively. © 1996 John Wiley & Sons, Inc.     

Reactivities of carbocations and monomers in carbocationic polymerization and copolymerization

In carbocationic polymerization and copolymerization, a recent publication concluded that the substituent effect on carbocation reactivity is much larger than its effect on monomer reactivity, and this by a factor 10⁶ in the case of the rate constant k_12capp for p‐methylstyrene addition (monomer M₂) on, respectively, poly(p‐methoxystyrene)^± or poly(p‐methylstyrene)^± (M). This conclusion is disputed, as well as the assumption that the rate constants of capping (k_12capp) obtained in deactivation reactions of poly(p‐methoxystyrene)^± are identical with cross propagation rate constants in copolymerization (k_12copol). It is shown that the large calculated k_12capp are based on propagation constant values for p‐methylstyrene (k ≈ 10⁹) obtained by the diffusion‐clock method. They are 10⁴ times smaller as found for all styrenes, that is, between 10⁴ and 10⁵ when they are based on the ionic species concentrations. In such a case, the available data are still in agreement with an approximate compensation between the reactivities of a monomer and of the corresponding carbocation. It is also shown that copolymerization data for styrenes are not compatible with k values near to diffusion control, and that variations of log k_12capp and log k_12copol with the nucleophilicity parameter N of the monomers indicate a much lower selectivity of the monomers in the case of copolymerization. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2666–2680, 2010     

Polymerization of allyl esters of unsaturated acids. VII. Copolymerization of methyl allyl maleate and fumarate with styrene

Radical copolymerizations of methyl allyl maleate (MAM) and methyl allyl fumarate (MAF) with styrene (St) are carried out in bulk using AIBN as an initiator at 60°C, and their copolymerization behaviors are compared in detail. The different rate features are observed with each other; thus in the MAF-St copolymerization the rate was quite enhanced and, also, the maximum rate was found at the molar ratio of 1:1 in the monomer feed, whereas no maximum phenomenon of the rate was apparent for the MAM—St copolymerization. The copolymerizability of MAF with St was quite high, whereas that of MAM was very poor. The cyclization of MAM or MAF was hindered by the highly reactive St monomer. These results are discussed in terms of the formation of the charge—transfer complex between MAF and St and, furthermore, the cyclocopolymerization kinetics involving the 17 elementary reactions as the propagation reactions.