Copolymerization of styrene and 1-hexene with a TiCl<Subscript>4</Subscript>-Al(C<Subscript>6</Subscript>H<Subscript>13</Subscript>)<Subscript>3</Subscript> · Mg(C<Subscript>6</Subscript>H<Subscript>13</Subscript>)<Subscript>2</Subscript> catalytic system

The copolymerization of styrene and 1-hexene with the TiCl₄-Al(C₆H₁₃)₃ · Mg(C₆H₁₃)₂ catalytic system has been investigated. The microstructure of polymer chains, molecular-mass characteristics, and thermophysical properties of the resulting copolymers have been studied. These copolymers contain 15 to 65 mol % styrene and mostly consist of isotactic polystyrene and poly(1-hexene) blocks.     

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.     

Novel Copolymers of Styrene. 10. Halo Ring-Substituted 2-Cyano-3-phenyl-2-propenamides

Novel electrophilic trisubstituted ethylene monomers, halo ring-substituted 2-cyano-3-phenyl-2-propenamides, RPhCH ? C(CN)CONH₂, where R is 2-bromo, 3-bromo, 2-fluoro, 3-fluoro, 2-iodo, 3-iodo, and 4-iodo were prepared and copolymerized with styrene. The monomers were synthesized by potassium hydroxide catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and cyanoacetamide, and characterized by CHN elemental analysis, IR, ¹H- and ¹³C-NMR. Novel copolymers of the ethylenes and styrene were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator, ABCN at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, ¹H- and ¹³C-NMR, GPC, DSC, and TGA. High T_g of the copolymers in comparison with that of polystyrene indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200–500°C range with residue (7-19 wt%), which then decomposed in the 500–800°C range.     

Novel Copolymers of Styrene. 11. Ring-Substituted 2-Cyano-3-phenyl-2-propenamides

Novel electrophilic trisubstituted ethylene monomers, halo ring-disubstituted 2-cyano-3-phenyl-2-propenamides, RPhCH = C(CN)CONH₂, where R is 2,3-difluoro, 2,4-difluoro, 2,5-difluoro, 2,6-difluoro, 3,4-difluoro, 3,5-difluoro, 2-chloro-4-fluoro, 3-chloro-2-fluoro, 3-chloro-4-fluoro were prepared and copolymerized with styrene. The monomers were synthesized by potassium hydroxide catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and cyanoacetamide, and characterized by CHN elemental analysis, IR, ¹H- and ¹³C-NMR. Novel copolymers of the ethylenes and styrene were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator, ABCN at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, ¹H- and ¹³C-NMR, GPC, DSC, and TGA. High T_g of the copolymers in comparison with that of polystyrene indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200–500°C range with residue (10–14 wt%), which then decomposed in the 500–800°C range.     

α‐olefin homopolymerization and ethylene/1‐hexene copolymerization catalysed by novel ansa‐group IV complexes/MAO system

The catalytic properties of a set of ansa‐complexes (R‐Ph)₂C(Cp)(Ind)MCl₂ [R = ^tBu, M = Ti ( 3 ), Zr ( 4 ) or Hf ( 5 ); R = MeO, M = Zr ( 6 ), Hf ( 7 )] in α‐olefin homopolymerization and ethylene/1‐hexene copolymerization were explored in the presence of MAO (methylaluminoxane). Complex 4 with steric bulk ^tBu group on phenyl exhibited remarkable catalytic activity for ethylene polymerization. It was 1.6‐fold more active than complex 11 [Ph₂C(Cp)(Ind)ZrCl₂] at 11 atm ethylene pressure and was 4.8‐fold more active at 1 atm pressure. The introduction of bulk substituent ^tBu into phenyl groups not only increased the catalytic activity greatly but also enhanced the content of 1‐hexene in ethylene/1‐hexene copolymerization. The highest 1‐hexene incorporation was 25.4%. In addition, 4 was also active for propylene and 1‐hexene homopolymerization, respectively, and low isotactic polypropylene (mmmm = 11.3%) and isotactic polyhexene (mmmm = 31.6%) were obtained. Copyright © 2007 John Wiley & Sons, Ltd.     

Copolymerization of ethylene with styrene catalyzed by a linked bis(phenolato) titanium catalyst

Copolymerization of ethylene with styrene, catalyzed by 1,4‐dithiabutanediyl‐linked bis(phenolato) titanium complex and methylaluminoxane, produced exclusively ethylene–styrene copolymers with high activity. Copolymerization parameters were calculated to be r_E = 1.2 for ethylene and r_S = 0.031 for styrene, with r_E r_S = 0.037 indicating preference for alternating copolymerization. The copolymer microstructure can be varied by changing the ratio between the monomers in the copolymerization feed, affording copolymers with styrene content up to 68%. The copolymer microstructure was fully elucidated by ¹³C NMR spectroscopy revealing, in the copolymers with styrene content higher than 50%, the presence of long styrene–styrene homosequences, occasionally interrupted by isolated ethylene units. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1908–1913, 2006     

Novel Copolymers of Styrene. 9. Methyl and Methoxy Ring-Substituted 2-Cyano-3-phenyl 2-propenamides

Novel electrophilic trisubstituted ethylene monomers, methyl and methoxy ring- substituted 2-cyano-3-phenyl-2-propenamides, RPhCH=C(CN)CONH₂, where R is 2,3-dimethyl, 2,4-dimethyl, 2,5-dimethyl, 2-(3-methoxyphenoxy), 2-(4-methoxyphenoxy), 3-(4-methoxyphenoxy), 4-(4-methylphenoxy), 2,3-methylenedioxy were prepared and copolymerized with styrene. The monomers were synthesized by potassium hydroxide catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and cyanoacetamide, and characterized by CHN elemental analysis, IR, ¹H- and ¹³C-NMR. Novel copolymers of the ethylenes and styrene were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator, ABCN at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, ¹H- and ¹³C-NMR, GPC, DSC, and TGA. High T_g of the copolymers in comparison with that of polystyrene indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 200–500°C range with residue (5.8–33.8 wt%), which then decomposed in the 500–800°C range.     

Selective Insertion in Copolymerization of Ethylene and Styrene Catalyzed by Half‐Titanocene System Bearing Ketimide Ligand: A Theoretical Study

The copolymerization of ethylene and styrene can be efficiently carried out by using Cp*TiCl₂ (N = C^t Bu₂)/MAO (Cp*=η ⁵‐C₅Me₅ ) system, yielding the poly(ethylene‐co ‐styrene)s with isolated styrene units. In order to investigate the reasons for formation of the structure, the mechanism of copolymerization, especially the selective insertion of ethylene and styrene, is studied in detail by density functional theory (DFT ) method. At the initiation stage, insertion of ethylene is kinetically more favorable than insertion of styrene, and insertion of styrene kinetically and thermodynamically prefers 2,1‐insertion. That is different from the conventional half‐titanocene system, in which the 1,2‐insertion is favorable. At chain propagation stage, the computational results suggest that the continuous insertion of styrene is hard to occur at room temperature due to the high free energy barriers (28.90 and 35.04 kcal/mol for 1,2‐insertion, and 29.15 and 34.00 kcal/mol for 2,1‐insertion) and thermodynamically unfavorable factors in two different conditions. That is mainly attributed to the steric hindrance between the coming styrene and chain‐end styrene or ketimide ligand. The computational results are in good agreement with the experimental data.     

苯乙烯－乙烯共聚物的合成及其结构性能的研究

用负载型钛系催化剂ＭｇＣｌ２／ＴｉＣｌ４，ＮｄＣｌ３／ＡｌＥｔ３（ＳＮ－１催化剂）制备出组份比例变化的苯乙烯－乙烯共聚产物，共聚产物通过溶剂萃取分离，＾１３Ｃ－ＮＭＲ，ＩＲ，动态粘弹谱进行表征，并初步进行了与聚苯乙烯共混作用的研究。结果表明，ＳＮ－１催化剂能有效地催化苯乙烯与乙烯共聚合，共聚产物为含有均聚聚苯乙烯的共聚复合物，其中约２５ｍｏｌ％的苯乙烯参加了共聚。共聚产物与ａＰＳ共混可明显提高ａＰ     

Block copolymer from α,ω-dihydroxyl polystyrene and polyethylene glycol

α,ω-Dihydroxyl polystyrene was synthesized by the addition of styrene oxide to polystyryl dianion initiated with sodium naphthalene. Diglyme was found to be an unsuitable solvent for the preparation of low molecular weight compounds. Block copolymerization of the α,ω-dihydroxyl polystyrenes (M?_n = 2250, 3140, and 6200) with poly(ethylene glycols) (M?_n = 404, 1960, and 5650) was pursued by introducing urethane linkages with 4,4′-diphenylmethane diisocyanate. The mechanical, thermal, and viscoelastic properties, solution viscosity, molecular weight distribution, and moisture absorption of the block copolymers obtained were examined. Incorporation of styrene blocks was found to disturb the crystallization and fusion of poly(ethylene glycol) blocks. Films cast from benzene solution were soft and elastic and absorbed up to 5.8% moisture.     

Stereospecific styrene polymerization and ethylene–styrene copolymerization with titanocenes containing a pendant amine donor

A series of monocyclopentadienyl titanium complexes containing a pendant amine donor on a Cp group ( A = CpTiCl₃, B = Cp^NTiCl₃, C = Cp^NTiCl₂TEMPO, for Cp = C₅H₅, Cp^N = C₅H₄CH₂CH₂N(CH₃)₂, and TEMPO = 2,2,6,6‐tetramethylpiperidine‐N‐oxyl) are investigated for styrene homopolymerization and ethylene–styrene (ES) copolymerization. When activated by methylaluminoxane at 70 °C, complexes with the amine group ( B and C ) are active for styrene homopolymerization and afford syndiotactic polystyrene (sPS). The copolymerizations of ethylene and styrene with B and C yield high‐molecular weight ES copolymer, whereas complex A yields mixtures of sPS and polyethylene, revealing the critical role that the pendant amine has on the polymerization behavior of the complexes. Fractionation, NMR, and DSC analyses of the ES copolymers generated from B and C suggest that they contain sPS. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1579–1585, 2010     

Novel Copolymers of Styrene and Some Halogen Ring-substituted 2-Phenyl-1,1-dicyanoethylenes

Novel copolymers of trisubstituted ethylene monomers, ring-substituted 2-phenyl-1,1-dicyanoethylenes, RC₆H₃CH═C(CN)₂ (where R is 2-bromo,3-bromo, 3-chloro, 2,3-dichloro, 2-chloro-6-fluoro, 2,6-difluoro, 3,4-difluoro, and 3,5-difluoro) and styrene were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator (AIBN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, ¹H and ¹³C-NMR, GPC, DSC, and TGA. High T _g of the copolymers in comparison with that of polystyrene indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. The gravimetric analysis indicated that the copolymers decompose in the 200–800°C range.     

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     

Isomeric effect of the Et(H4Ind)2Zr(CH3)2 catalyst on the copolymerization of ethylene and styrene: A computational study

A density functional theory (B3LYP) computational study of the ethylene–styrene copolymerization process using meso‐Et(H₄Ind)₂Zr(CH₃)₂ as the catalyst is presented. The monomer insertion barriers in meso species are evaluated and compared with previously obtained barriers in rac diastereoisomers. Differences related to ethylene homopolymerization and ethylene–styrene copolymerization activities as well as styrene incorporation into the copolymer are found between the meso and rac diastereoisomers. Nevertheless, a migratory insertion mechanism seems to hold for both diastereoisomeric species. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4752–4761, 2006     

Palladium‐Promoted Carbon Monoxide/Ethylene/Styrene Terpolymerization Reaction: Throwing Light on the Different Reactivity of the Two Alkenes

The catalytic behavior of dicationic bis‐chelated Pd^II complexes, [Pd(N? N)₂][PF₆]₂, in the CO/ethylene/styrene terpolymerization reaction is studied in detail. The bidentate N‐donor ligands were chosen among 2,2′‐bipyridine ( 1 ), 1,10‐phenanthroline ( 3 ), their symmetrically substituted derivatives 2, 4 , and 5 , and 3‐alkyl‐substituted 1,10‐phenanthrolines 6 – 10 . The effect of several parameters (like temperature, CO/ethylene pressure, styrene content, reaction time) was investigated and related to the productivity of the catalytic system, to the relative content of the two olefins in the polymeric chains, and to the molecular mass of the synthesized polyketones. The presence of 1,4‐benzoquinone was necessary to reach productivities as high as 16 kg of terpolymer (TP) per gram of Pd. ¹³C‐NMR spectroscopy was useful to characterize the distribution of the two repetitive units along the polymer chain. Terpolymers with prevailingly isolated CO/styrene units in CO/ethylene blocks as well as terpolymers with CO/styrene and CO/ethylene blocks were obtained by varying the reaction conditions. Detailed MALDI‐TOF‐MS analysis was performed on the CO/ethylene/styrene terpolymers for the first time, and it allowed us to characterize the end groups of the terpolymer chains. The presence of different chain end groups was found to be related to the initial amount of the two alkenes, thus suggesting that different reactions are involved in the initiation and termination steps of the terpolymerization catalytic cycle.     

Stereoregular polymerization of 1-vinylnaphthalene, 2-vinylnaphthalene,and 4-vinylbiphenyl

1-Vinylnaphthalene, 2-vinylnaphthalene, 4-vinylbiphenyl, and styrene were polymerized with Et₃Al–TiCl₄, Et₂AlCl–TiCl₃, and Et₃Al–TiCl₃ catalyst systems. The latter catalyst system gave polymers in 75–95% conversion which were at least 90% isotactic. Extraction with 2-butanone (MEK) separated the atactic from the isotactic fractions. The polymers were characterized by infrared and nuclear magnetic resonance spectroscopy.     

Group 4 Metallocene Catalysts with Hapto‐Flexible Cyclopentadienyl‐Aryl Ligand

Catalytic precursors Ti(IV) and Zr(IV) complexes bearing cyclopentadienyl and substituted cyclopentadienyl anionic ligands, bonded to phenyl or substituted phenyl through an isopropylidene bridge have been utilized in the polymerization of propene and styrene and in ethylene‐styrene copolymerization. In the presence of trichloro[(1,2,3,4,5‐η)‐1‐(1‐methyl‐1‐phenylethyl)‐2,4‐cyclopentadien‐1‐yl]titanium (LTiCl₃) we have obtained either partially isotactic (chain‐end type) or atactic poly‐(propylene), and either atactic or syndiotactic polystyrene depending on the reaction temperature. [1‐Methyl‐1‐naphthylethyl‐2‐inden‐1‐yl]titanium(IV) behaves like (LTiCl₃) in styrene polymerization, while it affords metal‐controlled partially isotactic poly(propylene), as well as the corresponding zirconium compounds. The experimental data are tentatively explained by the temperature dependence of coordination of the bridged aryl group of the ligand.     

Terpolymerization of carbon monoxide, ethylene and styrene in the presence of supported palladium catalyst

Terpolymers of carbon monoxide with ethylene and styrene are synthesized in the presence of supported palladium catalyst in toluene and heptane medium for the first time. The terpolymerization rate exceeds the rate of carbon monoxide and ethylene copolymerization. The maximum terpolymer yield amounts 7.9 g per g of supported catalyst per hour or 321 g per g of palladium per hour. The influence of reaction temperature, pressure, 1.4-benzoquinone amount and co-monomers mole ratio on the yield and the composition of terpolymer have been studied. The NMR ¹³C data obtained testify to a distribution of ethylene and styrene units in terpolymer with the predominance of short blocks at equal contents of comonomer units.     

Novel Copolymers of Styrene and Alkyl Ring‐Substituted Methyl 2‐Cyano‐3‐phenyl‐2‐propenoates

Electrophilic trisubstituted ethylene monomers, alkyl ring substituted methyl 2‐cyano‐3‐phenyl‐2‐propenoates, RC₆H₄CH[dbnd]C(CN)CO₂CH₃, where R is 2‐methyl, 3‐methyl, 4‐methyl, 4‐isopropyl, and 2,5‐dimethyl were synthesized by piperidine catalyzed Knoevenagel condensation of ring‐substituted benzaldehydes and methyl cyanoacetate, and characterized by CHN elemental analysis, IR, ¹H and ¹³C NMR. Novel copolymers of the ethylenes and styrene were prepared at equimolar monomer feed composition by solution copolymerization in the presence of a radical initiator (AIBN) at 70°C. The composition of the copolymers was calculated from nitrogen analysis, and the structures were analyzed by IR, ¹H and ¹³C NMR, GPC, DSC, and TGA. High T_g of the copolymers in comparison with that of polystyrene indicates a substantial decrease in chain mobility of the copolymer due to the high dipolar character of the trisubstituted ethylene monomer unit. The gravimetric analysis indicated that the copolymers decompose in the 260–400°C range.     

Synthesis of the block copolymer of styrene and 1-butene with a novel supported Ti-catalyst

The present investigation deals with sequential block copolymerization of styrene and 1-butene with a novel MgCl₂-supported TiCl₄ catalyst modified with a rare earth compound NdCl_x(OR)_y (SN-1 catalyst), which was developed in our laboratory. The catalytic activities are 1300–2500 g/g·Ti·h. Analyses of copolymers with solvent extraction, ¹³C-NMR, WAXD, GPC, and DSC was performed. The results indicate that the SN-1 catalyst selectively gave crystalline diblock copolymers of isotactic polystyrene and isotactic poly(1-butene), with the styrene unit content of 30–60 mol %. © 1996 John Wiley & Sons, Inc.