A Novel Catalytic System—NdCl_3·HMPA/Al(i-Bu)_3 for Copolymerization of Isoprene and Styrene

Introduction Rare-earth coordination catalysts are known for their high activity and high stereospecificity in the polymerization of conjugated dienes.1-5 The copolymerization of styrene (St) with butadiene using rare earth catalyst was followed with interest soon as the rare earth coordination catalyst appeared in the early 1960s.6-14 Copolymerization of isoprene (IP) and St using coordination catalysts was reported in a few papers,10,15-18 among them only Jin et al.10 and our group18 repor…     

Synthesis of ethylene/propylene elastomers containing a terminal reactive group: The combination of metallocene catalysis and control chain transfer reaction

This article discusses a chemical route to prepare new ethylene/propylene copolymers (EP) containing a terminal reactive group, such as ?‐CH₃ and OH. The chemistry involves metallocene‐mediated ethylene/propylene copolymerization in the presence of a consecutive chain transfer agent—a mixture of hydrogen and styrene derivatives carrying a CH₃ (p‐MS) or a silane‐protected OH (St‐OSi). The major challenge is to find suitable reaction conditions that can simultaneously carry out effective ethylene/propylene copolymerization and incorporation of the styrenic molecule (St‐f) at the polymer chain end, in other words, altering the St‐f incorporation mode from copolymerization to chain transfer. A systematic study was conducted to examine several metallocene catalyst systems and reaction conditions. Both [(C₅Me₄)SiMe₂N(^t‐Bu)]TiCl₂ and rac‐Et(Ind)₂ZrCl₂, under certain H₂ pressures, were found to be suitable catalyst systems to perform the combined task. A broad range of St‐f terminated EP copolymers (EP‐t‐p‐MS and EP‐t‐St‐OH), with various compositions and molecular weights, have been prepared with polymer molecular weight inversely proportional to the molar ratio of [St‐f]/[monomer]. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1858–1872, 2005     

Radical ring‐opening copolymerization behavior of vinyloxirane: Synthesis of copolymer from 2‐isopropenyl‐3‐phenyloxirane and styrene and its functionalization

The radical ring‐opening copolymerization of 2‐isopropenyl‐3‐phenyloxirane (1) with styrene (St) was examined to obtain the copolymer [copoly(1‐St)] with a vinyl ether moiety in the main chain. The copolymers were obtained in moderate yields by copolymerization in various feed ratios of 1 and St over 120 °C; the number‐average molecular weights (M_n) were estimated to be 1800–4200 by gel permeation chromatography analysis. The ratio of the vinyl ether and St units of copoly(1‐St) was estimated with the ¹H NMR spectra and varied from 1/7 to 1/14 according to the initial feed ratio of 1 and St. The haloalkoxylation of copoly(1‐St) with ethylene glycol in the presence of N‐chlorosuccinimide produced a new copolymer with alcohol groups and chlorine atoms in the side group in a high yield. The M_n value of the haloalkoxylated polymer was almost the same as that of the starting copoly(1‐St). The incorporated halogen was determined by elemental analysis. The analytical result indicated that over 88% of the vinyl ether groups participated in the haloalkoxylation. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3729–3735, 2000     

THE POLYMERIZATION OF EPICHLOROHYDRIN WITH Nd(i-oPr)_3-Al(i-Bu)_3 SYSTEM

Epichlorohydrin (ECH) was polymerized with a rare earth catalytic system: Nd (i-OPr)_3-Al (i-Bu)_3. The effects of Al/Nd molar ratio, solvents, the polymerization time and temperature,the aging time and temperature of the catalyst preparation were studied. The results showed thatat a low Al/Nd molar ratio (4) of the Nd(i-OPr)_3-Al(i-Bu)_3 system ECH polymerized at a lowtemperature (248K) with a high conversion. The average molecular weight ofpolyepichlorohydrin (PECH) ranged from 1×10~5 to 3×10~5.     

Homopolymerization and Copolymerization of Isoprene and Styrene with a Neodymium Catalyst Using an Alkylmagnesium Cocatalyst

The catalyst system Nd(acac)₃·2 H₂O/Bu₂Mg/CHCl₃ shows a fairly high activity in both the homo‐ and copolymerization of isoprene (IP) and styrene (St) in toluene at 60°C. Copolymers obtained from various comonomer feed ratios were characterized by means of NMR spectroscopy and gel‐permeation chromatography. The polyisoprene and poly(IP‐co‐St) obtained predominantly consist of cis‐1,4 IP units. Monomer reactivity ratios were evaluated to be r_IP = 5.4 and r_St = 0.38 in the copolymerization.     

Copolymerization of ethylene and norbornene using cyclopentadienylzirconium trichloride activated by isobutyl‐modified methylaluminoxane

The copolymerization of ethylene (E) and norbornene (NB) was investigated using the commercially available and inexpensive catalyst system, cyclopentadienylzirconium trichloride (CpZrCl₃)/isobutyl‐modified methylaluminoxane (MMAO), at a moderate polymerization temperature in toluene. For the CpZrCl₃ catalyst system activated by aluminoxane with a 40 mol % methyl group and a 60 mol % isobutyl group (MMAO), the quantities of the charged NB and the polymerization temperature significantly affected the molecular weights, polydispersities, and NB contents of the obtained copolymers and the copolymerization activities in all the experiments. As the charged NB increased and thereby the NB/E molar ratio increased, the NB content in the copolymer increased and reached a maximum value of 71 mol %. The CpZrCl₃/MMAO ([Al]/[Zr] = 1000) catalyst system with the [NB] of 2.77 mol L^?1 and ethylene of 0.70 MPa at 50 °C showed the highest activity of 1690 kg mol_Zr^?1 h^?1 and molecular weight of 21,100 g mol^?1. The ¹³C NMR analysis showed that the CpZrCl₃/MMAO catalyst system produced the E‐NB random copolymer with a number of NB homosequences such as the NN dyad and NNN triad. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7411–7418, 2008     

Copolymerization of norbornene and 5‐norbornene‐2‐yl acetate using novel bis(β‐ketonaphthylamino)Ni(II)/B(C6F5)3/AlEt3 catalytic system

Vinyl‐type copolymerization of norbornene (NBE) and 5‐NBE‐2‐yl‐acetate (NBE‐OCOMe) in toluene were investigated using a novel homogeneous catalyst system based on bis(β‐ketonaphthylamino)Ni(II)/B(C₆F₅)₃/AlEt₃. The copolymerization behavior as well as the copolymerization conditions, such as the levels of B(C₆F₅)₃ and AlEt₃, temperature, and monomer feed ratios, which influence on the copolymerization were examined. Without combination of AlEt₃, the catalytic bis(β‐ketonaphthylamino)Ni(II)/B(C₆F₅)₃ exhibited very high catalyst activity for polymerization of NBE. Combination of AlEt₃ in catalyst system resulted in low conversion for polymerization of NBE. For copolymerization of NBE and NBE‐OCOMe, involvement of AlEt₃ in catalyst is necessary. Slight addition of NBE‐OCOMe in copolymerization of NBE and NBE‐OCOMe gives rise to significant increase of catalyst activity for catalytic system bis(β‐ketonaphthylamino)Ni(II)/B(C₆F₅)₃/AlEt₃. Nevertheless, excess increase of the NBE‐OCOMe content in the comonomer feed ratios results in decrease of conversion as well as activity of catalyst. The achieved copolymers were confirmed to be vinyl‐addition copolymers through the analysis of FTIR, ¹H NMR, and ¹³C NMR spectra. ¹³C NMR studies further revealed the composition of the copolymer and the incorporation rate was 7.6–54.1 mol % ester units at a content of 30–90 mol % of the NBE‐OCOMe in the monomer feeds ratios. TGA analysis results showed that the copolymer exhibited good thermal stability (T_d > 410 °C) and failed to observe the glass transitions temperature over 300 °C. The copolymers are confirmed to be noncrystalline by WAXD analysis results and show good solubility in common organic solvents. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3990–4000, 2009     

Copolymerization of styrene and conjugated dienes with half‐sandwich titanium(IV) catalysts: The effect of the ligand structure on the monomer reactivity,monomer sequence distribution,and insertion mode of dienes

The copolymerization of styrene and 1,3‐butadiene (Bd) or isoprene (Ip) was carried out with half‐sandwich titanium(IV) Cp′TiCl₃ catalysts (where Cp′ is cyclopentadienyl 1 , indenyl 2 , or pentamethylcyclopentadienyl 3 ) with methylaluminoxane as a cocatalyst. For the copolymerization with Bd, catalyst 3 gave the copolymers containing the highest amount of Bd among the catalysts used. The resulting copolymers were composed of a styrene–Bd multiblock sequence. High melting points were observed in the copolymers prepared with catalyst 1 . The structures of hydrogenated poly(styrene‐co‐Bd) were studied by ¹³C NMR spectroscopy, and the long styrene sequence length was detected in the copolymers prepared with catalyst 1 . For styrene/Ip copolymerization, random copolymers were obtained. Among the used catalysts, catalyst 1 gave the copolymers containing the highest amount of Ip. The copolymers prepared with catalyst 1 showed a steep melting point depression with increasing Ip content because of the high ratio of 1,4‐inserted Ip units and/or the low molecular weights of the copolymers. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 939–946, 2003     

Copolymerization of ethylene and cyclopentene with bis(β‐enaminoketonato) titanium complexes

The copolymerizations of ethylene and cyclopentene with bis(β‐enaminoketonato) titanium complexes {[(Ph)NC(R₂)CHC(R₁)O]₂TiCl₂; R₁ = CF₃ and R₂ = CH₃ for 1a , R₁ = Ph and R₂ = CF₃ for 1b ; and R₁ = t‐Bu and R₂ = CF₃ for 1c } activated with modified methylaluminoxane (MMAO) as a cocatalyst were investigated. High‐molecular‐weight copolymers with cis‐1,2‐cyclopentene units were obtained. The catalyst activity, cyclopentene incorporation, polymer molecular weight, and polydispersity could be controlled over a wide range through the variation of the catalyst structure and reaction parameters, such as the Al/Ti molar ratio, cyclopentene feed concentration, and polymerization reaction temperature. The complex 1b /MMAO catalyst system exhibited the characteristics of a quasi‐living ethylene polymerization and an ethylene–cyclopentene copolymerization and allowed the synthesis of polyethylene‐block‐poly(ethylene‐co‐cyclopentene) diblock copolymer. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1681–1689, 2005     

Synthesis of three‐armed poly(trans‐4‐hydroxy‐N‐benzyloxycarbonyl‐L‐proline)‐block‐poly(ε‐caprolactone) copolymers

A series of novel types of three‐armed poly(trans‐4‐hydroxy‐N‐benzyloxycarbonyl‐L ‐proline)‐block‐poly(ε‐caprolactone) (PHpr‐b‐PCL) copolymers were successfully synthesized via melt block copolymerization of trans‐4‐hydroxy‐N‐benzyloxycarbonyl‐L ‐proline (N‐CBz‐Hpr) and ε‐caprolactone (ε‐CL) with a trifunctional initiator trimethylolpropane (TMP) and stannous octoate (SnOct₂) as a catalyst. For the homopolycondensation of N‐CBz‐Hpr with TMP initiator and SnOct₂ catalyst, the number‐average molecular weight (M_n) of prepolymer increases from 530 to 3540 g mol^?1 with the molar ratio of monomer to initiator (3–30), and the molecular weight distribution (M_w/M_n) is between 1.25 to 1.32. These three‐armed prepolymer PHpr were subsequently block copolymerized with ε‐caprolactone (ε‐CL) in the presence of SnOct₂ as a catalyst. The M_n of the copolymer increased from 2240 to 18,840 g mol^?1 with the molar ratio (0–60) of ε‐CL to PHpr. These products were characterized by differential scanning calorimetry (DSC), ¹H NMR, and gel permeation chromatography. According to DSC, the glass‐transition temperature (T_g) of the three‐armed polymers depended on the molar ratio of monomer/initiator that were added. In vitro degradation of these copolymers was evaluated from weight‐loss measurements and the change of M_n and M_w/M_n. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1708–1717, 2005     

Synthesis of poly(dimethylsiloxane)‐containing diblock and triblock copolymers by the combination of anionic ring‐opening polymerization of hexamethylcyclotrisiloxane and nitroxide‐mediated radical polymerization of methyl acrylate,isoprene, and styrene

Poly(dimethylsiloxane)‐containing diblock and triblock copolymers were prepared by the combination of anionic ring‐opening polymerization (AROP) of hexamethylcyclotrisiloxane (D₃) and nitroxide‐mediated radical polymerization (NMRP) of methyl acrylate (MA), isoprene (IP), and styrene (St). The first step was the preparation of a TIPNO‐based alkoxyamine carrying a 4‐bromophenyl group. The alkoxyamine was then treated with Li powder in ether, and AROP of D₃ was carried out using the resulting lithiophenyl alkoxyamine at room temperature, giving functional poly(D₃) with M_w/M_n of 1.09–1.16. NMRPs of MA, St, and IP from the poly(D₃) at 120 °C gave poly(D₃‐b‐MA), poly(D₃‐b‐St), and poly(D₃‐b‐IP) diblock copolymers, and subsequent NMRPs of St from poly(D₃‐b‐MA) and poly(D₃‐b‐IP) at 120 °C gave poly(D₃‐b‐MA‐b‐St) and poly(D₃‐b‐IP‐b‐St) triblock copolymers. The poly(dimethylsiloxane)‐containing diblock and triblock copolymers were analyzed by ¹H NMR and size exclusion chromatography. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 6153–6165, 2005     

Nd3Si5AlON10 – Synthese,Kristallstruktur und Eigenschaften eines Sialons im La3Si6N11‐Strukturtyp

Nd₃Si₅AlON₁₀ – Synthesis, Crystal Structure, and Properties of a Sialon Isotypic with La₃Si₆N₁₁ Nd₃Si₅AlON₁₀ was synthesized by the reaction of silicon diimide, aluminium nitride, aluminium oxide, and neodymium in a pure nitrogen atmosphere at 1650 °C using a radiofrequency furnace. The compound was obtained as a coarsely crystalline solid. According to the single‐crystal structure determination the title compound is isotypic with Ln₃Si₆N₁₁ (Ln = La, Ce, Pr, Nd, Sm). Nd₃Si₅AlON₁₀ (P4bm, a = 1007.8(1), c = 486.3(1) pm, Z = 2, R₁ = 0.016, wR₂ = 0.031) is built up by a three‐dimensional network structure of corner sharing SiON₃ and (Si/Al)N₄ tetrahedra (molar ratio Si : Al = 3 : 1). According to lattice energetic calculations using the MAPLE concept a differentiation of O and N seems to be reasonable. One of the two different sites for the tetrahedral centres is probably occupied by Si (distances: Si–O: 168.4(1), Si–N: 173.6(3)–176.0(4) pm) the second site by Si and Al with the molar ratio 3 : 1 (distances: (Si/Al)–N: 172.0(3)–176.6(2) pm). The Nd³⁺ ions are located in the voids of the (Si₅AlON₁₀)^9– framework (distances: Nd–O: 261.07(8), Nd–N: 246.1(2)–286.6(2) pm).     

Copolymerization of ethylene with acrylonitrile promoted by novel nonmetallocene catalysts with phenoxy‐imine ligands

A series of novel nonmetallocene catalysts with phenoxy‐imine ligands was synthesized by the treatment of phthaldialdehyde, substituted phenol with TiCl₄, ZrCl₄, and YCl₃ in THF. The structures and properties of the catalysts were characterized by ¹H NMR and elemental analysis. These catalysts were used for copolymerization of ethylene with acrylonitrile after activated by methylaluminoxane (MAO). The effects of copolymerization temperature, Al/M (M = Ti, Zr, and Y) ratio in mole, concentrations of catalyst and comonomer on the polymerization behaviors were investigated in detail. These results revealed that these catalysts were favorable for copolymerization of ethylene with acrylonitrile. Cat. 3 was the most favorable one for the copolymerization of ethylene with acrylonitrile, and the catalytic activity was up to 2.19 × 10⁴ g PE/mol.Ti.h under the conditions: polymerization temperature of 50 °C, Al/Ti molar ratio of 300, catalyst concentration of 1.0 × 10^–4 mol/L, and toluene as solvent. The resultant polymer was characterized by FTIR, cross‐polarization magic angle spinning, ¹³C NMR, WAXD, GPC, and DSC. The results confirmed that the obtained copolymer featured high‐weight–average molecular weight, narrow molecular weight distribution about 1.61–1.95, and high‐acrylonitrile incorporation up to 2.29 mol %. Melting temperature of the copolymer depended on the content of acrylonitrile incorporation within the copolymer chain. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Copolymerization of ethylene and propylene catalyzed by magnesium chloride supported vanadium/titanium bimetallic Ziegler-Natta catalysts

Magnesium chloride supported vanadium/titanium bimetallic Ziegler-Natta catalysts with di-i-butyl phthalate as internal donor for copolymerization of ethylene and propylene were prepared.The effects of reaction temperature, ethylene/propylene molar ratio,aluminium/vanadium（Al/V）molar ratio and titanium/vanadium molar ratio on the catalytic activity were investigated.The molecular weight,molecular weight distribution,sequence composition and crystallinity of the products were measured by gel permeation chromatography,¹³C-NMR and differential scanning calorimetry analysis, respectively.In comparison to the vanadium and titanium catalysts,the bimetallic catalyst showed higher catalytic activity and better copolymerization performance.The obtained ethylene/propylene copolymers have high molecular weight （10⁵）,broad molecular weight distribution,high propylene content with random or short blocked sequence structures （r_Er_P=1.919）,low melting temperatures and low crystallinities（X_c<20%）.     

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 1-OCTENE WITH STYRENE BY RARE EARTH COORDINATION CATALYSTS

The copolymerization of l-octene with styrene catalyzed by rare earth coordination catalysts has been studied for the first time. Some features and kinetic behavior are described. The overall activation energy of the copolymerization was 22.2 KJ/mol and the copolymerization rate could be expressed as R_p=K_p [Nd] [M]~2. (=1.68×10~(-3) L~2/mol~2. S, 50℃, [Oct]/[St]=1). The catalytic activity of various rare earth elements in Ln (naph)_3 for the copolymerization was compared and shows the following sequence: Dy, Y, Yb>Ho>Sm, Gd, Nd>Pr>Ce>La>Tm. Both monomers of l-octene and styrene in the copolymerization by Nd (naph)_3-AlEt_3 have the tendency of constant proportion copolymerization. The structure of the copolymers was studied by ~1H-NMR.     

Homo- and copolymerization of butadiene and styrene with neodymium tricarboxylate catalysts

Homo- and copolymerizations of butadiene (BD) and styrene (St) with rare-earth metal catalysts, including the most active neodymium (Nd)-based catalysts, have been examined, and the cis-1,4 polymerization mechanism was investigated by the diad analysis of copolymers. Polymerization activity of BD was markedly affected not only by the ligands of the catalysts but also by the central rare-earth metals, whereas that of St was mainly affected by the ligands. In the series of Nd-based catalysts [Nd(OCOR)₃:R = CF₃, CCl₃, CHCl₂, CH₂Cl, CH₃], Nd(OCOCCl₃)₃ gave a maximum polymerization activity of BD, which decreased with increasing or decreasing the pKa value of the ligands. This tendency was different from that for Gd(OCOR)₃ catalysts, where the CF₃ derivative led to the highest polymerization activity of BD. For the polymerization of St and its copolymerization with BD, the maximum activities were attained at R = CCl₃ for both Nd- and Gd-based catalysts. The copolymerization of BD and St with Nd(OCOCCl₃)₃ catalyst was also carried out at various monomer feed ratios, to evaluate the monomer reactivity ratios as r_BD = 5.66 and r_St = 0.86. The cis-1,4 content in BD unit decreased with increasing St content in copolymers. From the diad analysis of copolymers, it was indicated that Nd(OCOCCl₃)₃ catalyst controls the cis-1,4 structure of the BD unit by a back-biting coordination of the penultimate BD unit. Furthermore, the long range coordination of polymer chain by the neodymium catalyst was suggested to assist the cis-1,4 polymerization. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 241–247, 1998     

Studies on the Cationic Copolymerization of α-Pinene and Styrene with Complex SbCl3/AlCl3 Catalyst Systems. I. Effects of the Polymerization Conditions on the Copolymerization Products

Abstract

The copolymerization products of α-pinene and styrene were prepared with the compound catalyst system SbCl₃/AlCl₃ by changing the Sb/Al ratio, feeding monomer ratio, solvent, and polymerization temperature. The compositions of the copolymerization products were quantitatively characterized by the method of the combination of micro-ozonization and thin-layer chromatography in terms of the contents of the homopolymers and the copolymers containing high or low mole fractions of α-pinene, the yields of pure copolymer, and the monomer unit ratios (F ₁) of copolymers. The results show that it was easier to obtain the higher yield (up to 80%) of the pure copolymer with the complex catalyst system than with AlCl₃ alone. The F ₁ values could be controlled between 30 and 56% under the following polymerization conditions: Sb/Al  1/2, α-pinene/styrene  70%, and the conversion of styrene  90%.     

Preparation of linear low‐density polyethylene by the in situ copolymerization of ethylene with an iron oligomerization catalyst and rac‐ethylene bis(indenyl) zirconium (IV) dichloride

An iron oligomerization catalyst, [(2‐ArN?C(Me))₂C₅H₃N]FeCl₂ [Ar = 2,6‐C₆H₃(F)₂], was combined with rac‐ethylene bis(indenyl)zirconium (IV) dichloride [rac‐Et(Ind)₂ZrCl₂] to prepare linear low‐density polyethylene (LLDPE) by the in situ copolymerization of ethylene. A series of LLDPEs with different properties were prepared by the alteration of the reaction temperature, Fe/Zr molar ratio, Al/(Fe + Zr) molar ratio, and reaction time. The structures of the polymers were characterized with differential scanning calorimetry, ¹³C NMR, gel permeation chromatography (GPC), and so forth. The melting points, crystallizations, and densities of the resulting products increased, and the average branching degree decreased, as the reaction temperature, Al/(Fe + Zr) ratio, and reaction time increased. The melting points, crystallizations, and densities of the polymers decreased, and the average branching degree increased, when the Fe/Zr ratio increased. The ¹³C NMR and GPC results showed that there were no unreacted α‐olefins remaining in the resulting polymers because the percentage of low‐molar‐mass sections (C₄–C₁₀) of the oligomers obtained with this catalyst was very high (>70%). In addition, the formation of polymers with two melting points under different reaction conditions was examined in detail, and the results indicated that the two melting points of the polymers could be attributed to polyethylene with different branches. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 984–993, 2005     

Asymmetric cyclopolymerization of N‐tert‐butyl‐N‐allylacrylamide in the presence of β‐cyclodextrin

The radical polymerization of N‐tert‐butyl‐N‐allylacrylamide (t‐BAA) was carried out in a dimethyl sulfoxide/H₂O mixture in the presence of β‐cyclodextrin (β‐CD). The polymerization proceeded with the complete cyclization of the t‐BAA unit and yielded optically active poly(t‐BAA). The IR spectrum of the obtained polymer showed that the cyclic structure in the polymer was a five‐membered ring. The optical activity of poly(t‐BAA) increased with an increasing molar ratio of β‐CD to the t‐BAA monomer. The interaction of β‐CD with t‐BAA was confirmed by ¹H NMR and ¹³C NMR analyses of the polymerization system. It is suggested that interaction of the t‐BAA monomer with the hydrophobic cavity of β‐CD plays an important role in the asymmetric cyclopolymerization of t‐BAA. The radical copolymerization of t‐BAA with styrene (St), methyl methacrylate, ethyl methacrylate, or benzyl methacrylate (BMA) also produced optically active copolymers with a cyclic structure from the t‐BAA unit. St and BMA carrying a phenyl group were predicted to compete with t‐BAA for interaction with β‐CD in the copolymerization system. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2098–2105, 2000