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Sphere-to-rod transition of short-chain PEO-b-PDMS-b-PEO in aqueous solution induced by copolymer concentration

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Chinese Chemical Letters 2008年第11期19卷 1363-1366页

作者： xiao li zhan Bi Chen Qing Hua zhang ling Min Yi College of Materials Science and Chemical Engineering Zhejiang University Hangzhou 310027 China Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education Zhejiang Sci-Tech University Hangzhou 310018 China

A short-chain triblock copolymer EO9-DMS7-EO9 was synthesized by coupling reaction of allyl-terminated poly（ethylene oxide） and Si-H-terminated poly（dimethylsiloxane）. The structure and purity of synthesized copolymer was carefully characterized. Self-assembly behavior of EO9-DMST-EO9 triblock copolymer in water was investigated. And it was found that along with the increase of copolymer concentration, morphology of self-assembled aggregates transits from sphere to rod. A plausible understanding of the morphology transition for the investigated triblock copolymer was proposed.

关键词： Block copolymer Self-assembly Polysiloxane Morphology transition

The reversible addition-fragmentation chain transfer(RAFT) miniemulsion polymerization of vinyl acetate mediated by xanthate

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Chinese Chemical Letters 2009年第6期20卷 733-737页

作者： Bo Jiang Qing Hua zhang xiao li zhan Feng Qiu Chen Department of Chemical and Biochemical Engineering Zhejiang University Hangzhou 310027 People's Republic of China

The reversible addition-fragmentation chain transfer （RAFT） miniemulsion polymerization of vinyl acetate （VAc） mediated by methyl （methoxycarbonothioyl） sulfanyl acetate （MMSA） was carried out. The results showed that polymerizations initiated by AIBN and KPS proceeded in a controlled way. The RAFT miniemulsion polymerization of VAc initiated by KPS showed the shorter inhibition period, higher propagation rate coefficient and final conversion than those in experiment initiated by AIBN. When the monomer conversion reached 25%, the polydispersity index （PDI） of polymer became broad, which was related to chain transfer reaction in RAFT miniemulsion of VAc.

关键词： Xinyl acetate Xanthate Reversible addition-fragmentation chain transfer Miniemulsion

Monomer reactivity ratios for fluoroacrylate and butyl methacrylate in miniemulsion copolymerizations initiated by potassium persulphate

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Chinese Chemical Letters 2009年第4期20卷 478-482页

作者： Qing Hua zhang Zhen Huan Luo xiao li zhan Feng Qiu Chen College of Materials Science and Chemical Engineering Zhejiang University Hangzhou 310027 China

Miniemulsion copolymerization of butyl mathacrylate （BMA） with fluoroacrylate （HFMA, TFMA） was carried out at 70 ℃ by employing potassium persulphate （KPS） as initiator. Copolymer compositions at low conversion levels were determined by ^1H NMR spectra techniques. The reactivity ratios were evaluated by employing Kellen-Tudos （K-T） methods, which yields the apparent reactivity ratios, rBMA = 0.74, rHFMA = 0.87 and rBMA = 0.73, rTFMA = 0.75, respectively, and Q- and e-values of HFMA and TFMA were calculated by the Alfrey-Price method. The results show that HFMA and TFMA are more active than BMA, and the cross-propagation rate constant is greater than the self-propagation one in these two copolymerizations.

关键词： Fluoroacrylate Reactivity ratios Miniemulsion Copolymerization

Synthesis of poly[methyl(3,3,3-trifluoropropyl)siloxane]-b-poly(ethylene oxide) block copolymers

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第9期9卷 1304-1308页

作者： xiao-li zhan Bi CHEN Qing-hua zhanG ling-min YI Bo JIANG Feng-qiu CHEN College of Materials Sclence and Chemical Engmeering Zhejiang University Hangzhou 310027 China MOE Key Laboratory of Advanced Textile Materials and Manufacturing Technology Zhejiang Sci-Tech University

A series of new amphiphilic poly[methyl（3,3,3-trifluoropropyl）siloxane]-b-poly（ethylene oxide）（PMTFPS-b-PEO） diblock copolymers with different ratios of hydrophobic segment to hydrophilic segment were prepared by coupling reactions of end-functlonal PMTFPS and PEO homopolymers. Copolymers were shown to be well defined and narrow molecular weight distribution （MWD）（1.07-1.3） by characterizations such as gel permeation chromatography （GPC） and ^1H-nudear magnetic resonance （^1H-NMR）.

关键词： Block copolymers Polysiloxanes Fluoropolymers Synthesis Polyethyleneoxide

Synthesis and characterization ofα-{3-[(2,3-dihydroxy) propoxy]propyl}-ω-butylpolydimethylsiloxanes

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Chinese Chemical Letters 2009年第6期20卷 729-732页

作者： xiao li zhan Zhen Huan Luo Qing Hua zhang Bi Chen Feng Qiu Chen Department of Chemical and Biochemical Engineering. Zhejiang University Hangzhou 310027 China

Hydrosilylation has been carried out between Si-H terminated polydimethylsiloxanes with narrow molecular weight distribution and protected 3-allyloxy-l,2-propanediol, and after subsequently alcoholyzed, α-{3-[（2,3-dihydroxy）propoxy]propyl}-ω- butyl-polydimethylsiloxanes with varying number of （（Si（CH3）2-O） unit were obtained. At each step, the produced compounds were carefully characterized. The results showed that each step was successfully carried out and target products were achieved.

关键词： Polydimethylsiloxane Anionic ring-opening polymerization Hydrosilylation Alcoholysis

混合丁烯氧化脱氢双层床催化剂体系的协同作用机理(英文)

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2017年第3期18卷 225-233页

作者： xiao-yi li Dang-guo CHENG Feng-qiu CHEN xiao-li zhan Key Laboratory of Biomass Chemical Engineering of Ministry of Education Zhejiang University Hangzhou 310027 China College of Chemical and Biological Engineering Zhejiang University Hangzhou 310027 China

目的:通过对混合丁烯氧化脱氢过程进行反应表征,对由Zn Fe_2O_4和Co_9Bi_1Fe_3Mo_(12)O_(51)组成的双床层催化剂体系中存在的协同机理进行解释;将异构化反应过程纳入反应体系,得出混合丁烯转化率和丁二烯收率上升的原因。创新点:1.提出... 详细信息

目的:通过对混合丁烯氧化脱氢过程进行反应表征,对由Zn Fe_2O_4和Co_9Bi_1Fe_3Mo_(12)O_(51)组成的双床层催化剂体系中存在的协同机理进行解释;将异构化反应过程纳入反应体系,得出混合丁烯转化率和丁二烯收率上升的原因。创新点:1.提出基于丁烯异构体在床层之间浓度重分布和异构化效应抑制作用的协同作用机理;2.设计验证实验,从直观角度证实机理,并优化了催化剂的装填量和装填顺序。方法:1.通过单一丁烯和混合丁烯的氧化脱氢反应,对单一催化剂和双床层催化剂进行反应评估,得到相关反应数据;2.通过设计对比实验,从改变参加反应物质的直观角度对协同机理进行验证和解释;3.对参加反应的双层床催化剂中两种催化剂的装填量和装填顺序进行优化,为进一步研究组合型催化剂提供实验基础。结论:*** Fe_2O_4对两种2-丁烯有更优的催化效果,而Co_9Bi_1Fe_3Mo_(12)O_(51)对1-丁烯有更优的催化效果,由两者组成的双层床催化体系对单一丁烯和混合丁烯的反应效果都有所提升,证明两种催化剂之间存在协同效应。2.双层床催化剂体系中,两种催化剂之间的协同作用机理是:催化剂不同活性导致丁烯异构体在床层之间的浓度发生重分布,同时由于多种异构体同时存在抑制了异构化反应。3.对双层床催化剂体系的装填顺序和装填量的优化结果表明,Zn Fe_2O_4装填在上层,Co_9Bi_1Fe_3Mo_(12)O_(51)装填在下层,且两者比例处于4:6到6:4之间时催化效果最佳。

关键词：混合丁烯氧化脱氢双层床催化剂体系协同作用

A Review on the Mullins Effect in Tough Elastomers and Gels

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Acta Mechanica Solida Sinica 2024年第2期37卷 181-214页

作者： lin zhan Shaoxing Qu Rui xiao MOE Key Lab of Disaster Forecast and Control in Engineering College of Mechanics and Construction EngineeringJinan UniversityGuangzhou510632China State Key Laboratory of Fluid Power and Mechatronic System Key Laboratory of Soft Machines and Smart Devices of Zhejiang ProvinceDepartment of Engineering MechanicsZhejiang UniversityHangzhou310027China

Tough elastomers and gels have garnered broad research interest due to their wide-ranging potential ***,during the loading and unloading cycles,a clear stress softening behavior can be observed in many material systems,which is also named as the Mullins *** this work,we aim to provide a complete review of the Mullins effect in soft yet tough materials,specifically focusing on nanocomposite gels,double-network hydrogels,and multi-network *** first revisit the experimental observations for these soft *** then discuss the recent developments of constitutive models,emphasizing novel developments in the damage mechanisms or network *** phenomenological models will also be briefly *** attention is then placed on the anisotropic and multiaxial modeling *** is demonstrated that most of the existing models fail to accurately predict the multiaxial data,posing a significant challenge for developing future anisotropic models tailored for tough gels and elastomers.

关键词： Mullins effect Double-network hydrogels Nanocomposite gels Multi-network elastomers Anisotropic damage model Multiaxial model

Synthesis of polystyrene-styrene/butadiene diblock copolymers via reversible addition-fragmentation chain transfer miniemulsion polymerization

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Chinese Chemical Letters 2010年第12期21卷 1497-1500页

作者： Zhen Xi Wang Qing Hua zhang Yi Tao Yu xiao li zhan Feng Qiu Chen Ji Hai Xiong Department of Chemical and Biological Engineering Zhejiang University Hangzhou 310027 China Institute of Energy Conversion Jiangxi Academy of Sciences Nanchang 330029 China

Polystyrene-styrene/butadiene diblock copolymers were synthesized via reversible addition-fragmentation chain transfer （RAFT） miniemulsion *** the polymerization process,the molecular weight distribution was narrow and the numerical molecular weight of the copolymers increased with increasing conversion of monomers,which was close to the ***-IR and ^1H NMR results indicated that the microstructure of the polymer was mainly 1,4-trans-butadiene with small amount of 1,2-units,and composition in the copolymers was obtained.

关键词： Reversible addition-fragmentation chain transfer Polystyrene-styrene/butadiene diblock copolymers Miniemulsion polymerization

A New Species of the Genus Boulenophrys(Anura,Megophryidae)from Eastern Guangdong,China

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Asian Herpetological Research 2024年第1期15卷 12-21页

作者： Zhaochi ZENG Jian WANG Honghui CHEN Weiwen xiao Binbin zhan Yuanhang li Shishi liN Guangdong Polytechnic of Environmental Protection Engineering Foshan 528216GuangdongChina

A new horned toad species,Boulenophrys elongata ***.,is described from ***,Huidong County,eastern Guangdong,*** new species is phylogenetically closest to ***,which is restricted to the east of the Pearl River Estuary(i.e.,Shenzhen City and Hong Kong SAR).The new species can be distinguished from all recognized congeners by a combination of morphological characters and genetic divergences in the combined mitochondrial 16S,12S and CO1 *** recommend the new species be listed as Data Deficient(DD)in the IUCN categorization,pending further investigation.

关键词： Boulenophrys elongata sp.nov. lianhua Mountains molecular phylogeny morphology taxonomy