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CATIONIC POLYMERIZATION OF ISOBUTYLENE COINITIATED BY AICI_3 IN THE PRESENCE OF ETHYL BENZOATE 被引量:4
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作者 吴一弦 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2010年第1期55-62,共8页
The cationic polymerizations of isobutylene (IB) coinitiated by AlCl3 were carried out in solvent mixture of nhexane/methylene dichloride (n-hex/CH2Cl2) of 60/40 V/V in the presence of ethyl benzoate (EB) at var... The cationic polymerizations of isobutylene (IB) coinitiated by AlCl3 were carried out in solvent mixture of nhexane/methylene dichloride (n-hex/CH2Cl2) of 60/40 V/V in the presence of ethyl benzoate (EB) at various temperatures range from -80℃ to -30℃. The effects of EB concentration ([EB]) and polymerization temperature on monomer conversion, weight-average molecular weight (Mw) and molecular weight distribution (MWD, Mw/Mn) of polyisobutylene (PIB) products were investigated. The rate of polymerization decreased while Mw of PIB products increased with increasing [EB]. The polymers with high molecular weight could be prepared in the presence of a suitable amount of EB. Significantly, the polymers with high Mw of 80.2 × 10^4 and 65.4 × 10^4 could be produced at -80℃ and -70℃ at [EB] = 0.24 × 10^3 mol/L respectively, which were much higher than that (Mw = 57.9 × 10^4) of PIB prepared at -100℃ in the absence ofEB. A simple but effective method for preparing the high molecular weight polyisobutylenes was developed in this work. It has been also found that the activation energy for propagation (Ep) depended on the polymerization temperature range in the presence of EB. An obvious inflection of the linear plots of lnXn versus 1/Tp occurred at the temperature range from -60℃ to -50℃ at four different concentrations of EB from 0.19 × 10^3 mol/L to 0.33× 10^3 tool/L, and thus the inflection temperature (Tinf) was in the range of -60℃ to -50℃. When [EB] was in the range of 0.24 × 10^3 mol/L to 0.33× 10^3 mol/L, Ep was determined to be around -12 kJ/mol when the polymerization was carried out at temperatures from -80℃ to Tinf and to be around -28 kJ/mol at temperatures from Tinf to -15℃ respectively. 展开更多
关键词 Electron donor cationic polymerization ISOBUTYLENE Polyisobutylene.
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SYNTHESIS OF POLYISOBUTYLENE WITH SEC-ARYLAMINO TERMINAL GROUP BY COMBINATION OF CATIONIC POLYMERIZATION WITH ALKYLATION 被引量:1
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作者 吴一弦 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2009年第4期551-559,共9页
The highly reactive polyisobutylenes(PIBs) withα-double bonds(87.5 mol%) or tert-chloro(tert-Cl) groups(95 mol%) could be prepared via the cationic polymerization of isobutylene(IB) coinitiated by BF_3 or TiCl_4 resp... The highly reactive polyisobutylenes(PIBs) withα-double bonds(87.5 mol%) or tert-chloro(tert-Cl) groups(95 mol%) could be prepared via the cationic polymerization of isobutylene(IB) coinitiated by BF_3 or TiCl_4 respectively.The Friedel-Crafts alkylation of diphenylamine(DPA) with the highly reactive PIB withα-double bonds was further conducted under different conditions,such as at different alkylation temperature,in the mixed solvents of CH_2Cl_2/n-hexane with different solvent polarity and at DPA concentr... 展开更多
关键词 POLYISOBUTYLENE cationic polymerization DIPHENYLAMINE ALKYLATION
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Synthesis and Characterization of Star-branched Polyisobutylene by Combination of Anionic Polymerization and Cationic Polymerization
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作者 Hai Feng LIU Yang LI +3 位作者 Yu Rong WANG Yah REN Zhan Xia LU Jin Bo ZHAO 《Chinese Chemical Letters》 SCIE CAS CSCD 2006年第8期1117-1120,共4页
A star-shaped multifunctional styrene-isoprene copolymer was synthesized with n-BuLi as initiator, divinyl benzene as coupling agent, cyclobexane as solvent by living anionic polymerization. Using this polymer as graf... A star-shaped multifunctional styrene-isoprene copolymer was synthesized with n-BuLi as initiator, divinyl benzene as coupling agent, cyclobexane as solvent by living anionic polymerization. Using this polymer as grafting agent, a novel star-shaped branched polymer, containing several polyisobutylene, was prepared via cationic ~aolymerization. The star PS-b-PI and star-branched polyisobutylene were characterized by GPC, 'HNMR and FT-IR, and the effects of different adding order and the amount of grafting agent were investigated. 展开更多
关键词 Anionic polymerization cationic polymerization star-branched polymer graft.
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STUDY ON THE CATIONIC POLYMERIZATION OF 1, 3-PENTADIENE INITIATED BY AlCl_3/ALKYL HALIDE SYSTEMS
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作者 彭宇行 刘佳林 +1 位作者 戴汉松 寸琳峰 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1996年第1期91-96,共6页
The cationic polymerizations of 1, 3-pentadiene were initiated by AlCl_3 in n-hexaneat 30℃ in the presence of alkyl halides, i.e., tert-butyl chloride, tert-butyl bromide andisobutyl chloride. The effects of these ha... The cationic polymerizations of 1, 3-pentadiene were initiated by AlCl_3 in n-hexaneat 30℃ in the presence of alkyl halides, i.e., tert-butyl chloride, tert-butyl bromide andisobutyl chloride. The effects of these halides on the polymer yield, molecular weight,crosslinking reaction, cyclization and polymer microstructure, have been investigated. Twomain side reactions, crosslinking and cyclization, were suppressed and reduced by theaddition of the halides. The proportion of 1, 4 units of polymer chains was increasedby the presence of the halides, which reduced the polymer yield and the molecular weightof polymers. 展开更多
关键词 1 3-Pentadiene cationic polymerization Alkyl halide Chain transfer
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(CH_3)_3SiCl/TiCl_4 INITIATING SYSTEM FOR CATIONIC POLYMERIZATION OF 1,3-PENTADIENE
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作者 彭宇行 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1999年第5期459-464,共6页
Cationic polymerizations of 1,3-pentadiene (PD) initiated by trimethylsilyl chloride (TMSCl) incombination with TiCl_4 were carried out in n-hexane at 30℃. The yield of polymer was greatly increased bythe addition of... Cationic polymerizations of 1,3-pentadiene (PD) initiated by trimethylsilyl chloride (TMSCl) incombination with TiCl_4 were carried out in n-hexane at 30℃. The yield of polymer was greatly increased bythe addition of TMSCl, indicating that the TMSCl/TiCl_4 combination is an efficient initiating system for PDcationic polymerization. However, the introduction of TMSCl gave rise to a drop in the molecular weight ofthe polymer. Kinetic results demonstrated that the polymerization initiated by TMSCl/TiCl_4 is 4.5 times fasterthan that induced by TiCl_4 alone. Various ethers were used to mediate the TMSCl/TiCl_4 initiating system.Adding diphenyl ether could increase both the yield and molecular weight of the polymer. Structural evidenceillustrates that the polymerization is indeed initiated by TiCl_4 in combination with HCl resulting fromhydrolysis by adventitious water. 展开更多
关键词 1 3-Pentadiene cationic polymerization TMSCI TiCl_4
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CATIONIC POLYMERIZATION OF 1,3—PENTADIENE INITIATED BY ORGANIC AZIDE/Et_2AlCl
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作者 赵宇行 戴汉松 +1 位作者 刘佳林 寸琳峰 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1995年第4期381-384,共4页
The cationic polymerization of 1, 3-pentadiene was initiated by the organic azide/Et_2 AlClinitiating system in CH_2Cl_2 and n-hexane. The polymerizations were also carried out in parallelwith organic chloride/Et_2AlC... The cationic polymerization of 1, 3-pentadiene was initiated by the organic azide/Et_2 AlClinitiating system in CH_2Cl_2 and n-hexane. The polymerizations were also carried out in parallelwith organic chloride/Et_2AlCl and Et_2 AlCl alone for comparison. The Et_2 AlCl- induced polymer-ization gives a low yield while the polymerization initiated by organic chloride/Et_2 AlCl producesmainly insoluble product. In contrast, the polymerization with azide/Et,AlCl has a high conver-sion and the resulting polymer having a high molecular weight is totally soluble. The SEC spectraof the polymers have clearly shown the differences between these initiating systems. 展开更多
关键词 cationic polymerization 1 3-Pentadiene initiator Azide/Et_2AlCl
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Phenols/Al(C_(6)F_(5))_(3) Initiation Systems for Cationic Polymerizations of Isobutylene
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作者 Ling Cai Qi-Yuan Wang +1 位作者 Xin-Li Liu Dong-Mei Cui 《Chinese Journal of Polymer Science》 SCIE EI CAS CSCD 2023年第5期713-719,I0008,共8页
We report herein the cationic polymerization of isobutylene(IB)under mild conditions is realized with a new binary initiation system generated by simply mixing a Lewis super acid Al(C_(6)F_(5))_(3) and a substituted p... We report herein the cationic polymerization of isobutylene(IB)under mild conditions is realized with a new binary initiation system generated by simply mixing a Lewis super acid Al(C_(6)F_(5))_(3) and a substituted phenol(RPhOH).Polymers with medium and/or high molecular weights(M_(W)=4.9×10^(4)-27.7×10^(4) g·mol^(-1))can be obtained in toluene and temperatures from-20℃to 0℃.NMR spectrum analysis and DFT sim ulation reveals the in situ generated acidic coordinating complex Ak(C_(6)F_(5))_(3)·RPhOH is the initiating active species,which fu rther tran sformed into the ion-pair[Al(C_(6)F_(5))_(3)ORPh]^(-)[PIB]^(+)of the active intermediates upon growing IB monomers where the counter anion[Al(C_(6)F_(5))_(3)R^(O)Ph]-coordinates to the macrocation via the phenoxy oxygen.The catalyst performances are the concert effects of the steric bulkiness and electronics of the counter anion on the coordinating strength to the macrocation,which is significant to the stability of the active species. 展开更多
关键词 cationic polymerization PHENOLS Lewis super acid POLYISOBUTYLENE
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SYNTHESIS OF HIGH MOLECULAR WEIGHT POLYISOBUTYLENE VIA CATIONIC POLYMERIZATION AT ELEVATED TEMPERATURES 被引量:4
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作者 Qiang Huang Ping He +1 位作者 Jue Wang 吴一弦 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2013年第8期1139-1147,共9页
A novel simple but effective initiating system of H2O/AlCl3/veratrole (VE) has been developed to synthesize high molecular weight polyisobutylene (PIB) at elevated temperatures via cationic polymerization of isobu... A novel simple but effective initiating system of H2O/AlCl3/veratrole (VE) has been developed to synthesize high molecular weight polyisobutylene (PIB) at elevated temperatures via cationic polymerization of isobutylene (IB) in solvent mixture of hexane/methylene dichloride (n-Hex/CH2Cl2 = 2/1, V/V). VE played very important roles in decreasing cationicity of the growing chain ends, suppressing side reactions of chain transfer and termination during polymerization, leading to production of high molecular weight PIBs. PIBs with high yields, having very high weight-average molecular weight (Mw) of 1117000 and 370000 g/tool could be synthesized with H2O/AICl3/VE initiating system at VE concentration of 5.4 mmol/L at -80 and -60 ℃ respectively. Molecular weight of PIB increased remarkably with increasing VE concentration. The reaction order with respect to VE concentration was determined to be -3.52 via FTIR spectroscopy in combination with a diamond tipped attenuated total reflectance (ATR) immersion probe. The negative reaction order of VE was consistent with its retarding effect on IB polymerization by interacting with the propagating species. Molecular weight of PIB decreased with increasing polymerization temperature. The activation energy for polymerization degree (Eop) could be determined to be around -23 kJ/mol when VE concentration was 5.4 mmol/L or 6.4 mmol/L. 展开更多
关键词 ISOBUTYLENE Molecular weight cationic polymerization POLYISOBUTYLENE Kinetics.
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Cationic Ring Opening Polymerization of Octamethylcyclotetrasiloxane Initiated by Acid Treated Bentonite 被引量:5
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作者 陈碧 詹晓力 +1 位作者 易玲敏 陈丰秋 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2007年第5期661-665,共5页
Cationic ring opening polymerization of octamethylcyclotetrasiloxane (Da) initiated by acid treated bentonite was investigated. The experimental conditions were chosen on the basis of preliminary experiments.Higher ... Cationic ring opening polymerization of octamethylcyclotetrasiloxane (Da) initiated by acid treated bentonite was investigated. The experimental conditions were chosen on the basis of preliminary experiments.Higher temperature was found beneficial for the reaction process while stirring intensity beyond a certain level showed no obvious effect on the reaction rate. Polymers were characterized by Fourier transform infrared, proton nuclear magnetic resonance (IH-NMR) and gel perneation chromotography. The width of molecular mass distribution was found ranging between 1.2 and 1.4, which is extraordinarlly narrow compared with that of cationic polymerizations reported elsewhere (〉 1.9). The results were believed due to the absence of free proton and counter ion which simplifies the polymerization process and the huge steric hindrance provided by bentonite particles which keeps the propagation of polysiloxane onto the surface of bentonite particles in a much more regular way. A feasible mechanism is proposed and seems to be supported well by experiments. Additionally, from the results of α, ω-dihydrogen terminated polysiloxanes prepared, the possibility of applying this potential environmentally friendly heterogeneous catalyst in industrial polymerization of cyclosiloxanes is anticipated. 展开更多
关键词 OCTAMETHYLCYCLOTETRASILOXANE cationic polymerization POLYSILOXANE
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Novel acid initiators for the rapid cationic polymerization of styrene in room temperature ionic liquids 被引量:1
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作者 VIJAYARAGHAVAN R. MACFARLANE D. R. 《Science China Chemistry》 SCIE EI CAS 2012年第8期1671-1676,共6页
Cationic polymerization of styrene has been achieved using several novel acidic initiators in room temperature ionic liquids (ILs) under mild reaction conditions to obtain polymers of low molecular weight with narrow ... Cationic polymerization of styrene has been achieved using several novel acidic initiators in room temperature ionic liquids (ILs) under mild reaction conditions to obtain polymers of low molecular weight with narrow polydispersity. Both strong protic acids such as bis(trifluoromethanesulfonyl) amide acid (HTFSA) and a moderately weak acid such as bisoxalato phosphorous acid (HBOP) have been studied as initiators. It has been observed that HTFSA initiates the polymerization rapidly even at room temperature and below, as compared to HBOP which produces a slower polymerization requiring elevated temperatures to complete. The relative difference in reactivity of the initiators as compared to the previously described HBOB initiator is discussed in terms of the difference in their proton acidity and the consequential basicity of the anions. The efficiency of different ILs as the reaction solvent is also presented. 展开更多
关键词 cationic polymerization HTFSA HBOP ILS POLYDISPERSITY
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ABA TRIBLOCK COPOLYMERS WITH PENDANT HYDROXYL GROUPS PREPARED BY CONTROLLED CATIONIC POLYMERIZATION AND THEIR USE AS DELIVERY CARRIER FOR PACLITAXEL 被引量:1
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作者 Ping Ren Yi-bo Wu +2 位作者 郭文莉 Shu-xin Li Ying Chen 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2013年第2期285-293,共9页
To improve the hydrophilicity ofpoly(styrene-b-isobutylene-b-styrene) (SIBS), this study focuses on the synthesis of novel functional ABA triblock copolymer thermoplastic elastomers (TPEs) with polyisobutylene ... To improve the hydrophilicity ofpoly(styrene-b-isobutylene-b-styrene) (SIBS), this study focuses on the synthesis of novel functional ABA triblock copolymer thermoplastic elastomers (TPEs) with polyisobutylene (PIB) as rubbery segments. The precursor poly{(styrene-co-4-[2-(tert-butyldimethylsiloxy) ethyl]styrene)-b-isobutylene-b-(styrene-co-4-[2- (tert-butyldimethylsiloxy)ethyl]styrene)}(P(St-co-TBDMES)-PIB-P(St-co-TBDMES)) triblock copolymer was first synthesized by living sequential cationic copolymerization of isobutylene (IB) with styrene (St) and 4-[2-(tert- butyldimethylsiloxy)ethyl]styrene (TBDMES) using 1,4-di(2-chloro-2-propyl)benzene (DiCumC1)/titanium tetrachloride (TiCla)/2,6-di-tert-butylpyridine (DtBP) as the initiating system. Then, P(St-co-TBDMES)-PIB-P(St-co-TBDMES) was hydrolyzed in the presence of tetra-butylammonium fluoride to yield poly{[styrene-co-4-(2-hydroxyethyl)styrene]-b- isobutylene-b-[styrene-co-4-(2-hydroxyethyl)styrene]} (P(St-co-HOES)-PIB-P(St-co-HOES)) with pendant hydroxyl groups. P(St-co-HOES)-PIB-P(St-co-HOES) used as the paclitaxel carrier was also investigated in this study. Comparing with SIBS, P(St-co-HOES)-PIB-P(St-co-HOES) has exhibited better compatibility with paclitaxel and higher release rate. 展开更多
关键词 Living cationic polymerization HYDROPHILICITY MISCIBILITY Paclitaxel.
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Mechanistic Transformations Involving Radical and Cationic Polymerizations 被引量:1
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作者 Gorkem Yilmaz Yusuf Yagci 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2020年第3期205-212,I0004,共9页
Mechanistic transformation approach has been widely applied in polymer synthesis due to its unique feature combining structurally different polymers prepared by different polymerization mechanisms.Reported methods for... Mechanistic transformation approach has been widely applied in polymer synthesis due to its unique feature combining structurally different polymers prepared by different polymerization mechanisms.Reported methods for the formation of block and graft copolymers through mechanistic transformation involve almost all polymerizations modes.However,certain polymerization processes require extensive purification processes,which can be time-consuming and problematic.Recent developments on controlled/living polymerizations involving radical and cationic mechanisms with the ability to control molecular weight and functionality led to new pathways for mechanistic transformations.In this mini-review,we systematically discussed relevant advances in the field through three main titles namely(i)from radical to cationic mechanism,(ii)from cationic to radical mechanism,and(iii)application of specific catalyst systems for both radical and cationic polymerizations. 展开更多
关键词 TRANSFORMATION Radical polymerization cationic polymerization Controlled/living polymerization PHOTOpolymerization
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Cationic polymerization of 1,3-pent adiene in the presence of arenes
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作者 Peng, YX Liu, JL +1 位作者 Cun, LF Dai, HS 《Chinese Journal of Chemistry》 SCIE CAS CSCD 1996年第2期180-185,共6页
The cationic polymerizations of 1,3-pentadiene initiated by AlCl3 inn-hexane at 30 degrees C have been carried out in the presence of various arenes, i.e., benzene, toluene, p-xylene, o-xylene, m-xylene and mesitylene... The cationic polymerizations of 1,3-pentadiene initiated by AlCl3 inn-hexane at 30 degrees C have been carried out in the presence of various arenes, i.e., benzene, toluene, p-xylene, o-xylene, m-xylene and mesitylene. The presence of all these arenes have reduced in different degrees the formation of crosslinked products. Namely, the crosslinking reaction, a major side-reaction during the cationic polymerization of 1,3-pentadiene, has been suppressed by adding the aromatic compounds. The results showed that a chain transfer to arene took place and this transfer process hindered the generation of the crosslinked polymer. IR and H-1 NMR spectra have confirmed the existence of the corresponding aryl groups in the resulting polymers. 展开更多
关键词 cationic polymerization 1 3-pentadiene chain transfer crosslinking reaction
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Initiating system Me_3SiCl/AlCl_3 for cationic polymerization of 1,3-pentadiene in toluene
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作者 邓建国 彭宇行 《Chinese Journal of Chemistry》 SCIE CAS CSCD 1998年第5期452-457,共6页
Cationic polymerization of 1,3-pentadiene (PD) initiated by trimethylsilyl chloride/aluminium chloride (TMSCl/AlCl3) was carried out in toluene at 30℃.The polymer yield was increased by the addition of TMSC1.However,... Cationic polymerization of 1,3-pentadiene (PD) initiated by trimethylsilyl chloride/aluminium chloride (TMSCl/AlCl3) was carried out in toluene at 30℃.The polymer yield was increased by the addition of TMSC1.However,introduction of TMSC1 gave rise to a drop of the polymer molecular weight.Kinetic results demonstrated that the polymerization initiated by TMSCl/AlCl3 was 2.8 times faster than that induced by AlCl3 alone.Various ethers and ketones were used to mediate the initiating system TMSCl/AlCl3.The polymer yield and molecular weight of the polymer were decreased in the presence of ether.Ketones and ethers had different effects on the polymerization,and the polymer yield and molecular weight were lower than those initiated by AlCl3 alone or TMSCl/AlCl3 Structural evidence revealed that the polymerization was indeed initiated by AlCl3 and HCl rcsulting from hydrolysis of TMSC1 by adventitious water. 展开更多
关键词 1 3-Pentadiene cationic polymerization INITIATION trimethysllvl chloride
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Cationic ring-opening polymerization of 3,3-bis(chloromethyl)oxacyclobutane in ionic liquids 被引量:1
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作者 Yuan Yuan Wang Wei Li Li Yi Dai 《Chinese Chemical Letters》 SCIE CAS CSCD 2007年第10期1187-1190,共4页
Cationic ring-opening polymerization of 3,3-bis(chloromethyl)oxacyclobutane catalyzed by BF3.OEt2 was carded out in ionic liquids [bmim]BF4 and [bmim]PF6. The influences of BCMO concentration and molar ratio of BCMO... Cationic ring-opening polymerization of 3,3-bis(chloromethyl)oxacyclobutane catalyzed by BF3.OEt2 was carded out in ionic liquids [bmim]BF4 and [bmim]PF6. The influences of BCMO concentration and molar ratio of BCMO/BF3.OEt2 on the molecular weights and yield of PBCMO were investigated. The polymerization in ionic liquids proceed to high conversions, although molecular weights are limited, similar to polymerization in organic solvent such as CH2Cl2. Follow a viewpoint of green chemistry, we feel ionic liquid [bmim]BF4 is superior to [bmim]PF6. Extracting [bmim]PF6 from the product using organic solvent as extractant limits its advantage as a green reaction media. 展开更多
关键词 Ionic hquid 3 3-Bis(chloromethyl)oxacyclobutane cationic ring-opening polymerization CHARACTERIZATION
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SYNTHESIS AND CATIONIC RING-OPENING POLYMERIZATION OF 1, 4-ANHYDRO-2, 3-DI-O-(P-AZIDOBENZYL)-α-D-RIBOPYRANOSE
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作者 Toshiyuki Uryu 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1999年第2期123-128,共6页
New highly stereoregular 2, 3 -di- O-(p-azidobenzyl )-(1 →5 ) - α-D -ribofuranan was synthesized byselective ring-opening polymerization of 1, 4-anhydro-2, 3 - di-O -(p-azidobenzyl )-α-D -ribopyranose(ADABR) using ... New highly stereoregular 2, 3 -di- O-(p-azidobenzyl )-(1 →5 ) - α-D -ribofuranan was synthesized byselective ring-opening polymerization of 1, 4-anhydro-2, 3 - di-O -(p-azidobenzyl )-α-D -ribopyranose(ADABR) using phosphorus pentafluoride or tin tetrachloride as catalyst at low temperature indichloromethane. The monomer was obtained by the reaction of p - bromomethyl -phenyleneazide with 1, 4 -anhydro-α-D-ribose in DMF. The structure of poly(ADANR) was identified by specific rotation and ^(13)C-NMR spectroscopy. Acid chloride-AgCl_4 complex catalyst such as CH_2=C(CH_3)C^+OClO_4^- used in thepolymerization resulted in polymers with mixed structures, i.e. (1→5)-α-D-ribofuranosidic and (1→4)-β-D-ribopyranosidic units. However, with C_6H_5C^+OClO_4^- as catalyst, pure (1→5)-α-D-ribofuranan was obtained.The effects of catalyst, polymerization temperature and time on polymer stereoregularity were examined, andthe mechanism of the ring-opening polymerization was discussed. 展开更多
关键词 cationic ring-opening polymerization Azido-containing polysaccharide Lewis acid catalysts 1 4-anhydro-2 3-di-O-(p-azidobenzyl)-α-D-ribopyranose STEREOREGULARITY
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Organic Brønsted Acid-Catalyzed Stereoselective Cationic RAFT Polymerization:The Effect of RAFT Agents
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作者 Zheng-Yi Zhang Zan Yang +1 位作者 Yun Liao Sai-Hu Liao 《Chinese Journal of Polymer Science》 SCIE EI CAS CSCD 2024年第6期711-717,共7页
The tacticity of vinyl polymers is a key factor affecting the properties of materials.Recently,organic Brønsted acids have been demonstrated as effective catalysts for the development of highly stereoselective ca... The tacticity of vinyl polymers is a key factor affecting the properties of materials.Recently,organic Brønsted acids have been demonstrated as effective catalysts for the development of highly stereoselective cationic reversible addition-fragmentation chain transfer(RAFT)polymerizations of vinyl ethers,in which the use of RAFT agents could allow the control the molecular weight and tacticity of polymer products simultaneously.However,the effect of RAFT agents on the tacticity-regulation remains elusive and lacks of investigation.In this study,we synthesized four types of RAFT agents and evaluated their influence in the stereoselective cationic polymerization of isobutyl vinyl ether in the presence of PADI as a Brønsted acid catalyst,which unveils that the Z group of RAFT agents could not only affect the polydispersity of the products,but also exert a profound effect on the stereoselectivity.After extensive screening of the RAFT agents,high stereoregularity(isotacticity,90%m)was obtained when using dithiocarbonate ester-type RAFT agents with a benzyloxy Z group. 展开更多
关键词 Bronsted acid catalysis Stereoselective cationic polymerization RAFT polymerization Chain transfer agents TACTICITY
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Novel Ferricenium Tetrafluoroborate Salt as Latent Thermal Cationic Initiator for Curing of Epoxy Resins 被引量:1
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作者 王涛 王志华 刘金萍 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2004年第4期570-573,共4页
A novel latent thermal initiator, ferricenium tetrafluoroborate salt (FcBF4), for cationic polymerization of epoxides is reported. The activities of FcBF4 for different epoxides, including bisphenol-A-type epoxy oligo... A novel latent thermal initiator, ferricenium tetrafluoroborate salt (FcBF4), for cationic polymerization of epoxides is reported. The activities of FcBF4 for different epoxides, including bisphenol-A-type epoxy oligomer E44, cycloaliphatic epoxy ERL4221, and glycidylether epoxy GGE, were evaluated by differential scanning calorimetry (DSC). The results showed a moderate thermal initiation activity for E44 and GGE at 78℃ and 108℃ respectively. When adding GGE to E44, the reaction was enhanced. The temperature of thermal degradation of the cured specimens for the system of E44/FcBF4, E44+10%GGE/FcBF4 and E44+10%ERL4221/FcBF4 is higher than 350℃. 展开更多
关键词 latent thermal initiator cationic polymerization ferricenium salt
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STUDY ON POLYMERIZATION MECHANISM OF 3, 9,-DIALLYL-3, 9, -DIBENZYL-1, 5, 7, 11-TETRAOXASPIRO [5, 5] UNDECANE
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作者 白如科 胡悦 +3 位作者 邹应芳 潘才元 Toshiyuki Uryu 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 1992年第4期343-349,共7页
A new monomer, 3,9-diallyl-3, 9-dibenzyl-1, 5,7,11 - tetraoxa- spiro [5,5] undecane (6) was prepared by the reaction of 2- allyl- 2' - benzyl- propanediol - 1.3 with dibutyltin oxide, and then treated with CS_2. M... A new monomer, 3,9-diallyl-3, 9-dibenzyl-1, 5,7,11 - tetraoxa- spiro [5,5] undecane (6) was prepared by the reaction of 2- allyl- 2' - benzyl- propanediol - 1.3 with dibutyltin oxide, and then treated with CS_2. Monomer 4 could be initiated by cationic initiators to give a viscous polymer (white powder in the case of polymerization at 0℃). Upon the NMR and IR spectra of the obtained polymer, the components and their relative amount were estimated. The polymerization mechanism was discussed. 展开更多
关键词 polymerization Mechanism cationic polymerization Spirocarbonates 3 9-diallyl-3 9-dibenzyl-1 5 7 11-tetraoxaspiro (5 5) undecane
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Synthesis of ABA Type Block Copolymers of Poly(Ethylene Glycol)and Poly(Dodecyl Vinyl Ether)and Its Using as Surfactant in Emulsion Polymerization
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作者 Yesim Hepuzer Gursel Ayfer Sarac Bahire Filiz Senkal 《American Journal of Analytical Chemistry》 2014年第1期39-44,共6页
A poly(ethylene glycol) (PEG) based macroinitiator (MI) with terminal chloride atom at both ends was prepared by the reaction of PEG-400 with chloroacetyl chloride and used for the cationic polymerization of dodecyl v... A poly(ethylene glycol) (PEG) based macroinitiator (MI) with terminal chloride atom at both ends was prepared by the reaction of PEG-400 with chloroacetyl chloride and used for the cationic polymerization of dodecyl vinyl ether (DVE) yielding ABA type block copolymer. The block copolymer was then used as the surfactant for the emulsion polymerization of vinyl acetate and styrene in the presence of potassium persulfate as an initiator. The effects of new polymeric emulsifier on the physicochemical properties of obtained latexes were investigated depending on surfactant percentage in homopolymerizations. 展开更多
关键词 cationic polymerization Emulsion polymerization Poly(Ethylene Glycol) SURFACTANTS
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