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“LIVING”/CONTROLLED RADICAL polymerIZATION OF ETHYL METHYLACRYLATE WITH 2,2’-AZOBISISOBUTYRONITRILE/FERRIC CHLORIDE/TRIPHENYLPHOSPHINE INITIATION SYSTEM

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Chinese Journal of polymer science 2000年第2期18卷 149-153页

作者： Xiao-ping Chen kun-yuan qiu department of polymer science and engineering, college of chemistry, peking university, beijing 100871, china 北京大学北京

'Living'/controlled radical polymerization of ethyl methacrylate (EMA) was carried out with a 2,2'-azobisisobutyronitrile (AIBN)/ferric chloride (FeCl_3)/triphenylphosphine (PPh_3) initiation system at 85℃. Thc numberaverage molecular weight (M_n) increases linearly with monomer conversion and the rate of polymerization is first order withrespect to monomer concentration. The M_w of PEMA ranges from 3900 to 17600 and the polydispersity indices are quitenarrow (1.09～1.22). The conversion can reach up to～100% and M_w of the polymers obtained is close to that designed. Thepolymerization mechanism belongs to the reverse atom transfer radical polymerization (ATRP). The polymer was end-functionalized by chlorine atom, which acts as a macroinitiator to proceed extension polymerization in the presence ofCuBr/bipy catalyst system via an ATRP process. The presence of ω-chlorine in the PEMA obtained was identified by ~1H-NMR spectrum.

关键词： 'Living'/controlled radical polymerization Reverse ATRP Ethyl methacrylate AIBN/FeCl_3/PPh_3 Bulk polymerization

SYNTHESIS AND BIOTECHNOLOGICAL APPLICATIONS OF VINYL polymerINORGANIC HYBRID AND MESOPOROUS MATERIALS

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Chinese Journal of polymer science 2000年第1期18卷 1-7页

作者： Yen Wei kun-yuan qiu department of chemistry, Drexel university, Philadelphia, Pennsylvania 19104, USA department of polymer science and engineering, peking university, beijing 100871, china Drexel university 美国北京大学高分子科学与工程系北京

We describe the sol-gel synthesis of a new family of organic-inorganic hybrid materials, in which various vinyl polymers are covalently bonded to and uniformly distributed in inorganic oxide matrices. The materials can be tailored to have both good toughness and hardness while maintaining excellent optical transparency. Doping the sol-gel metal oxides with optically active compounds such as D-glucose results in new optical rotatory composite materials. Removal of the dopant compounds from the composites affords mesoporous oxide materials; which represents a new, nonsurfactant-templated route to mesoporous molecular sieves. We have successfully immobilized a series of enzymes and other bioactive agents in mesoporous materials. Catalytical activities of the enzyme encapsulated in mesoporous materials were found to be much higher than those encapsulated in microporous materials.

关键词： vinyl polymer-inorganic hybrid materials mesoporous materials sol-gel process biotech-nological applications

SYNTHESIS OF HYBRID MESOPOROUS POLYSTYRENE-SILICA MATERIALS WITH NON-SURFACTANT CITRIC ACID AS TEMPLATE VIA SOL-GEL PROCESS

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Chinese Journal of polymer science 2002年第6期20卷 565-572页

作者： Jie Bai Jin-yu Zheng kun-yuan qiu Yen Wei department of polymer science & engineering college of chemistry & molecular engineering, peking university beijing 100871, china department of chemistry, Drexel university, Philadelphia, PA 19104, USA department of polymer science & engineering College of Chemistry & Molecular Engineering Peking University 北京 100871 department of chemistry Drexel University Philadelphia PA 19104 美国

Hybrid mesoporous polystyrene-silica materials were successfully prepared through HCl-catalyzed sol-gel reactions of tetraethyl orthosilicate (TEOS) and triethoxysilyl-functionalized polystyrene obtained via atom transfer radical polymerization (ATRP) of styrene, in the presence of citric acid (CA) as non-surfactant template or pore-forming agent and followed by ethanol extraction to remove template molecules. The materials were characterized by infrared spectroscopy OR), N-2 adsorption-desorption measurements, powder X-ray diffraction (XRD), thermogravimetric analysis (TGA) and transmission electron microscopy (TEM). The results indicate that the materials prepared with 50 wt%-60 wt% template contents have average pore sizes of 2-3 nm and large surface areas (ca. 886 m(2)/g) as well as high pore volumes (ca. 0.53 cm(3)/g). The mesoporosity arises from interconnected channels and pores with disordered arrangements. The pore diameters and pore volumes increase as the template content is increased. The pore diameters show a little change upon heating at 200degreesC overnight. However, the materials do not have good hydrothermal stability.

关键词： atom transfer radical polymerization hybrid material mesoporous polystyrene silica

SYNTHESIS AND CHARACTERIZATION OF STRUCTURALLY WELL-DEFINED polymer-INORGANIC HYBRID NANOPARTICLES VIA ATRP

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Chinese Journal of polymer science 2002年第3期20卷 261-267页

作者： Jie Bai Jie-bin Pang kun-yuan qiu Yen Wei department of polymer science & engineering college of chemistry & molecular engineering peking university beijing 100871, china department of chemistry Drexel university Philadelphia, PA 19104 USA department of polymer science & engineering College of Chemistry & Molecular Engineering Peking University 北京 100871 department of chemistry Drexel University 美国 Philadelphia PA 19104

Atom transfer radical polymerization (ATRP) using cuprous chloride/2,2'-bipyridine (bipy) was applied to graft polymerization of styrene on the surface of silica nanoparticles to synthesize polymer-inorganic hybrid nanoparticles, 2-(4Chloromethylphenyl) ethyltriethoxysilane (CTES) was immobilized on the surface of silica nanoparticles through condensation reaction of the silanol groups on silica with triethoxysilane group of CTES. Then ATRP of St was initiated by this surface-modified silica nanoparticles bearing benzyl chloride groups, and formed PSt graft chains on the surface of silica nanoparticles. The thickness of the graft chains increased with reaction time. End group analysis confirmed the occurrence of ATRP. Thermal analysis indicated that thermal stabilization of these resulting hybrid nanoparticles also increases with polymerization conversion. The results above show that this 'grafting from' reaction could be used for the preparation of polymer-inorganic hybrid nanoparticles with controlled structure of the polymer's end groups.

关键词： atom transfer radical polymerization polymer-inorganic hybrid nanoparticles 2-(4-chloromethylphenyl)ethyltriethoxysilane surface-modification

SYNTHESIS OF MESOPOROUS POLY(STYRENE-co-MALEIC ANHYDRIDE)/SILICA HYBRID MATERIALS VIA A NONSURFACTANT-TEMPLATED SOL-GEL PROCESS

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Chinese Journal of polymer science 2000年第5期18卷 469-472页

作者： Jie-bin Pang kun-yuan qiu Yen Wei department of polymer science and engineering, college of chemistry and molecular engineering, peking university, beijing 100871, china. department of chemistry, Drexel university, Philadelphia, Pennsylvania 19104, USA. 北京大学北京 Drexel university 美国

Mesoporous poly(styrene-co-maleic anhydride)/silica hybrid materials have been prepared. The synthesis was achieved by the HCl-catalyzed sol-gel reactions of tetraethyl orthosilicate (TEOS) and styrene-maleic anhydride copolymer in the presence of 3-aminopropyl triethoxysilane (APTES) as a coupling agent and citric acid as a nonsurfactant template or pore-forming agent, followed by ethanol extraction. Characterization results from nitrogen sorption isotherms and powder X-ray diffraction indicate that polymer-modified mesoporous materials with large specific surface areas (e.g. 900 m(2)/g) and pore volumes (e.g. 0.6 cm(3)/g) could be prepared. As the citric acid concentration is increased, the specific surface areas, pore volumes and pore diameters of the hybrid materials increase.

关键词： mesoporous hybrid material poly(styrene-co-maleic anhydride)/silica citric acid nonsurfactant template sol-gel process

TARTARIC ACID TEMPLATED SYNTHESIS OF MESOPOROUS Ti-INCORPORATED SILICA AND ITS CATALYTIC ACTIVITY FOR THE RING-OPENING polymerIZATION OF ε-CAPROLACTONE

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Chinese Journal of polymer science 2002年第4期20卷 361-368页

作者： Jie-bin Pang Chang-ming Dong kun-yuan qiu Yen Wei department of polymer science and engineering college of chemistry and molecular engineering peking university beijing 100871, china department of chemistry Drexel university Philadelphia, Pennsylvania 19104, USA department of polymer science and engineering College of Chemistry and Molecular Engineering Peking University 北京 100871 department of chemistry Drexel University 美国 Pennsylvania

Ti-incorporated mesoporous silica materials with pore diameters of 3-4 nm have been prepared via the co-hydrolysis and co-condensation reactions, that is the sol-gel reactions, of titanium (IV) tetrabutoxide and tetraethylorthosilicate in the presence of tartaric acid as template, followed by extraction with ethanol to remove the templatemolecules. The materials were characterized in detail by Fourier transform infrared spectroscopy, nitrogen adsorption-desorption test, powder X-ray diffraction, transmission electron microscopy and X-ray energy dispersive spectroscopy. Theresults indicate that the Ti-containing silica materials have large specific surface areas (ca. 1200 m^2 g^(-1)) and pore volumes(ca. 0.900 cm^3 g^(-1)). The mesoporosity arises from disordered interconnecting channels or pores. The Ti-incorporated silicasexhibit catalytic activity for the ring-opening polymerization of ε-caprolactone, otherwise, the pure mesoporous silicamaterial shows no catalytic activity under the identical conditions.

关键词： Mesoporous material Ti-incorporated silica ε-Caprolactone Ring-opening polymerization Sol-gel reactions

Measurement of Monomer Reactivity Ratios of D,L-3-Methylglycolide with Glycolide or D,L-Lactide

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Chinese Chemical Letters 2000年第9期11卷 815-818页

作者： Chang Ming DONG kun yuan qiu Zhong Wei GU Xin De FENG department of polymer science and engineering, college of chemistry and molecular engineering, peking university, beijing 100871 National Research Institute for Family Planning, beijing 100081 Dept. of Poly. Sci. and engineering Coll. of Chem. and Molec. Eng. Peking University Beijing 100871 China Natl. Res. Inst. for Family Planning Beijing 100081 China

For monomer reactivity ratios study, the copolymerization of D,L-3-methylglycolide (MG) with glycolide (GA) or D,L-lactide (LA) was carried out in bulk to a certain low conversion in the presence of stannous octoate at 140 degrees C. The copolymer compositions were determined by H-1 NMR spectroscopy. The monomer reactivity ratios were evaluated by Fineman-Ross method, Kelen-Tudos method and linear least-squares method. The monomer reactivity ratios of D,L-3-methylglycolide and glycolide or D,L-lactide are r(mg)= 0.73, r(ga)= 1.47; r(mg)= 1.71, r(la)= 0.92, respectively.

关键词： D,L-3-methylglycolide glycolide D,L-lactide ring-opening copolymerization monomer reactivity ratios

REVERSE ATOM TRANSFER RADICAL polymerIZATION OF STYRENE WITH COPPER-BASED CATALYST

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Chinese Journal of polymer science 2001年第1期19卷 59-64页

作者： Dong-qi Qin Shu-hui Qin kun-yuan qiu department of polymer science and engineering College of Chemistry and Molecular EngineeringPeking University Beijing 100871 China Department of Polymer Science and Engineering College of Chemistry and Molecular EngineeringPeking University Beijing 100871 China Department of Polymer Science and Engineering College of Chemistry and Molecular EngineeringPeking University Beijing 100871 China

'Living'/controlled radical polymerization of styrene was carried out with diethyl 2,3-dicyano-2,3-diphenylsuccinate (DCDPS)/CuCl2/bipyridine (bipy) initiation system at 120 degreesC. The molecular weights of resultant PSt increased with the monomer conversion and the polydispersities were in the range of 1.37 similar to1.52. A linear ln([M](o)/[M]) versus time plot was also obtained indicating the constant concentration of growing radicals during the polymerization with this initiation system. End group analysis by H-1-NMR spectroscopic studies showed that the end groups of the polymer obtained is omega -functionalized by a chlorine group from the catalyst and alpha -functionalized by a (carbethoxy-cyano-phenyl)methyl group from the fragments of the initiator. Having CI atom at the chain end, the PSt obtained can be used as a macroinitiator to promote a chain-extension reaction with fresh St and block copolymerization reaction with a second monomer, such as methyl methacrylate, in the presence of CuCl/bipy catalyst via a conventional ATRP process.

关键词： 'living'/controlled radical polymerization reverse ATRP styrene DCDPS/CuCl2/bipy initiation system

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分子半导体改性聚合物复合电介质研究进展

高分子通报 2024年第7期37卷 868-877页

作者：刘芾源佟辉曹诗沫臧丽坤北京科技大学化学与生物工程学院北京100083 中国科学院电工研究所微纳加工技术与智能电气设备研究部北京100190 中国科学院大学工程科学学院北京100049

薄膜电容器因具有功率密度高、损耗低、循环寿命长、安全环保等特点而被广泛应用于智能电网、风力发电、电动汽车、脉冲功率系统等领域。电介质是决定薄膜电容器性能的关键,但材料中的缺陷、杂质等在高温、高电场下产生泄漏电流,使薄膜... 详细信息

薄膜电容器因具有功率密度高、损耗低、循环寿命长、安全环保等特点而被广泛应用于智能电网、风力发电、电动汽车、脉冲功率系统等领域。电介质是决定薄膜电容器性能的关键,但材料中的缺陷、杂质等在高温、高电场下产生泄漏电流,使薄膜电容器的储能性质急剧降低,难以在热、电耦合场下获得高能量密度。向聚合物电介质中引入微量有机分子半导体的改性方式可使电介质中产生能量陷阱捕获载流子、抑制泄漏电流,从而降低电导损耗,提高充放电效率。本文综述了通过向聚合物基体中引入有机分子半导体提升电介质高温储能性质的方法,讨论了有机小分子半导体、聚合物分子半导体改性对储能性质的影响机制,并展望了相关领域未来的发展方向。

关键词：有机小分子半导体聚合物分子半导体复合电介质泄漏电流高温储能