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chinese Journal of polymer science 2001年第4期19卷 385-390页

作者： Zhong-ming Hu Li-heng Wu Da-cheng Wu shou-xi chen state key laboratory of polymer physics and chemistry, center for molecular science, institute of chemistry chinese academy of sciences,{4., china china textile academy beijing 100025, china textile College, sichuan university chengdu 610065. china china Text Acad Beijing 100025 Peoples R China chinese Acad Sci Inst Chem Ctr Mol Sci State Key Lab Polymer Phys & Chem Beijing 100080 Peoples R China sichuan Univ Coll Text Chengdu 610065 Peoples R China

The oriented chitosan films obtained from pre-sheared liquid crystalline chitosan/dichloroacetic acid (DCA) solutions were studied by means of polarized optical microscopy (POM), scanning electron microscopy (SEM), infra-red dichroism technique and wide angle X-ray diffraction (WAXD). The sheer induced band texture in the film was found to correspond to the sinusoidal fibrillar microstructure along the shearing direction on the basis of POM and SEM observations. The sinusoidal fibril was found to be lying within the film plane. The model of chitosan molecular orientation in the pre-sheared film with band texture can be established assuming that the main chain orients in the shearing direction and the side group is perpendicular to the shearing direction. The WAXD azimuthal scanning at 2 theta = 20 degrees indicates that the (002) plane orients perpendicular to the shearing direction.

关键词： chitosan morphology orientation shear induced band texture liquid crystalline solution

EFFECT OF PARTICLE SIZE ON THE FILMING PROCESS OF POLYSTYRENE LATEX STUDIED BY AFM

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chinese Journal of polymer science 2002年第6期20卷 509-515页

作者： xiao-zhong Qu Yi Shi Liu-sheng chen xi-gao Jin state {4. laboratory of polymer physics & chemistry, center for molecular science,institute of chemistry, chinese academy of {14., beijing 100080 china chinese Acad Sci Inst Chem Ctr Mol Sci State Key Lab Polymer Phys & Chem Beijing 100080 Peoples R China

The film formation process of micro-PS particles (diameter 74. nm) and nano-PS particles (diameter 29 nm) was studied by atomic force microscopy and differential scanning calorimetry. During a step heating process, the particles were annealed for 0.5 h at each selected temperature. It was found that the deformation and interdiffusion temperatures of the micro-PS particles are ca. 120-130degreesC and 14.-150degreesC, that of the nano-PS particles are 90degreesC and 100-110degreesC respectively. The DSC traces of nano-PS particles showed that there was an exothermic peak near T-g after annealing for 0.5 h at the selected temperatures below 90degreesC; otherwise, the exothermic peak disappeared after annealing at 100degreesC or above. Compared with the micro-PS particles, the sintering process of nano-PS particles occurs at much lower temperature determined by the confined state of polymer chains with higher conformational energy in nano-particles, and completes in a much narrower temperature range driven mainly by the larger total surface energy.

关键词： polystyrene latex filming process particle size effect

THE SPHERULITE-LIKE STRUCTURE OF MAIN CHAIN THERMOTROPIC AROMATIC COPOLYESTERS

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chinese Journal of polymer science 1999年第3期17卷 245-251页

作者： shou-xi chen Hua-chun Zhai Yong-ze Jin institute of {4., chinese academy of sciences, beijing 100080, china chinese Acad Sci Inst Chem Beijing 100080 Peoples R China

A new spherulite-like structure of main chain thermotropic aromatic copolyesters formed in solution cast specimens was observed and was studied by means of polarizing microscopy, X-ray diffraction, SEM and IR spectrometry. Results indicate that the spherulite-like structure of main chain thermotropic aromatic copolyesters formed from the casting solution (phenol/Cl2CH2CH2Cl2) is not a real crystal but only a high oriented arrangement of the macromolecular chains as a spherulite. This resulted from the interaction between the needle-like crystal of phenol and the rigid mesomorphic groups of molecular chain. The parallel packing of extended copolyester molecules along the needle-like crystal of phenol leads to the formation of the spherulite-like structure.

关键词： spherulite-like structure thermotropic aromatic copolymer PET PHB

SMALL ANGLE LIGHT SCATTERING MEASUREMENT OF THE ISOTROPIC TO NEMATIC TRANSITION OF A SIDE CHAIN NEMATIC POLYMETHACRYLATE

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chinese Journal of polymer science 2002年第5期20卷 431-437页

作者： Zhong-ming Hu Ren-yuan Qian shou-xi chen xiao-fang chen Qi-feng Zhou Centre for molecular science, institute of chemistry chinese academy of sciences, beijing 100080, china Department of polymer science & Engineering College of chemistry & molecular Engineering Peking {14. beijing 100871, china chinese Acad Sci Inst Chem Ctr Mol Sci Beijing 100080 Peoples R China Peking Univ Coll Chem & Mol Engn Dept Polymer Sci & Engn Beijing 100871 Peoples R China

The kinetics of I-->N transition of a side chain nematic polymethacrylate has been studied by small angle depolarized light scattering intensity measurements using a charge coupled device linear image sensor. The polymer shows the transition temperatures K52N79I in degreesC, The H-v scattering intensity T(q,t) during the transition I (at 80.2degreesC)-->N (at 75.8degreesC) shows that T(q) is independent of q for all t, and during the initial stage (in 6 s) T(t) increases exponentially with t. In the later stage of the transition T(t) approaches a saturation value in 2 min. This experimental result indicates that the I-->N transition of a liquid crystalline polymer is a spinodal type of phase transition mediated by orientation fluctuation.

关键词： side chain nematic polymer isotropic-nematic transition small angle depolarized light scattering

CRYSTALLINE MORPHOLOGY IN A SERIES OF CH_(3)-SUBSTITUTED THERMOTROPIC AROMATIC POLYESTERS WITH EVEN AND ODD FLExiBLE SPACERS

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chinese Journal of polymer science 2001年第1期19卷 71-78页

作者： shou-xi chen Zhong-ming Hu Wen-hui Song Yong-ze Jin Ren-yuan Qian state key laboratory of polymer {4. and chemistry Center for Molecular ScienceInstitute of ChemistryChinese Academy of SciencesBeijing 100080China

Crystalline morphology in a series of CH_(3)-substituted main chain thermotropic aromatic polyesters with even and odd numbered methylene spacers has been studied by polarizing optical microscopy(POM),scanning electron microscopy(SEM)and transmission electron microscopy(TEM).On crystallization from solution evaporation spherulites of radial structure were observed in the polymers with even numbered spacers,but spherulites with concentric rings form in the polymer with odd numbered *** spherulites have a lamellar structure,which is about 10 nm in *** crystallization from nematic glassy state spherulites can not be grown;lamellar structure was only observed around disclinations in a specimen during *** the case of crystallization from nematic melt two types of spherulites can be observed far the sample with even numbered *** the sample with add numbered spacers spherulites can not be formed,but only irregular crystallites.

关键词： crystalline morphology spherulite even-odd flexible spacers CH_(3)-substituted thermotropic aromatic polyester

STUDIES ON THE NATURE OF THE MACROmolecular CONDENSED state OF "NASCENT" ULTRA HIGH MOLAR MASS POLYETHYLENE

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chinese Journal of polymer science 2001年第1期19卷 25-31页

作者： Zhong-yong Fan Qiang Lan Hai-shan Bu Li-heng Wu Lin Sun Ren-yuan Qian shou-xi chen Yong-feng Men Bing-zheng Jiang Department of Materials science Fudan UniversityShanghai 200433 china textile 4.ademy PO Box 651Beijing 100025 institute of chemistry Chinese Academy of SciencesBeijing 100080 Changchun institute of Applied chemistry Chinese Academy of SciencesChangchun 130022 Faculty of physics University of Freiburg

Ultra high molar mass polyethylene(UHPE)powder as polymerized in a slurry process has been studied,in its nascent state,after recrystallization on rapid cooling from the melt and after hot compression molding to a film,by DSC,effect of annealing the recrystallized specimen at 120 similar to 130 degreesC,morphology by polarizing optical microscopy and small angle X-ray *** on the experimental results obtained the macromolecular condensed state of the nascent UHPE powder is a rare case of a multi-chain condensed state of non-interpenetrating chains,involving interlaced extended chain crystalline layers and relaxed parallel chain amorphous *** melting,a nematic rubbery state of nanometer size domain *** nematic-isotropic transition temperature was judged from literature data to be at least 220 degreesC,possibly higher than 300 ℃,the exact temperature is however not sue because of chain degradation at such high *** recrystallization process from the melt is a crystallization from a nematic rubbery *** drop of remelting peak temperature by 10 K of the specimen recrystallized from its melt as compared to the nascent state has its origin in the decrease both of the crystalline chain stem length and of the degree of *** remelting peak temperature could be returned close to that of the nascent state by annealing at 120~130 ℃.

关键词： ultra high molar mass polyethylene recrystallization remelting annealing nematic state

MESOPOROUS ACID SOLID AS A CARRIER FOR METALLOCENE CATALYST IN ETHYLENE polymerIZATION AND A CATALYST IN CATALYTIC DEGRADATION OF POLYETHYLENE

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chinese Journal of polymer science 2007年第2期25卷 187-195页

作者： Wen-xi cheng Li-ya Shi Shi-yun Li Hui chen Tao Tang state key laboratory of polymer {4. and chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 China Graduate School of the chinese academy of sciences Beijing 100039 China

The possibility of mesoporous acid solid as a carder for metallocene catalyst in ethylene polymerization and catalyst for polyethylene （PE） catalytic degradation was investigated. Here, HMCM-4. and AIMCM-4., and mesoporous silicoaluminophosphate molecular sieves （SAPO1 and SAPO2） were synthesized and used as acid solid. Much more gases were produced during catalytic degradation in PE/acid solid mixtures via in situ polymerization than those via physical mixing. The particle size distribution results exhibited that the particle size of SAPO1 in the PE/SAPOI mixture via in situ polymerization was about 1/14.times of that of the original SAPO1 or SAPO1-supported metallocene catalyst. This work shows a novel technology for chemical recycling of polyolefin.

关键词： Catalytic degradation Acid solids Supported metallocene catalysts Polyethylene.

Solid state NMR and Fluorescence Studies of Conjugated polymer Nanocomposties

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chinese Chemical Letters 2005年第11期16卷 1519-1522页

作者： Chao Jun JING Liu Sheng chen Yi SHI xi Gao JIN state key laboratory of polymer {4. and chemistry Institute of Chemistry Chinese Academy of Sciences Beijing 100080 Graduate School of the chinese academy of sciences Beijing 100080

^13C spin-lattice relaxation times （T1） of a conjugated polymer MEH-PPV in polymer/ layered silicate nanocomposites together with the steady state fluorescence emission and transient fluorescence decay measurements have been investigated. The T1 values of the conjugated carbons decrease dramatically according to the reduction of polymer concentration in the nano composites, while the fluorescence life times （τ） show a linear prolonging tendency. The results are explained from the point of view of {4. dynamics.

关键词： Conjugated polymer nanocomposites fluorescence solid state ^13C NMR

A Special Issue of chinese Journal of polymer science:Ordered Structure of polymers

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chinese Journal of polymer science 2022年第6期40卷 544-544页

作者： Quan chen shou-Ke Yan state key laboratory of polymer {4. and chemistry Changchun Institute of Applied ChemistryChinese Academy of Sciences state key laboratory of Chemical Resource Engineering Beijing University of Chemical Technology

The property and functionality of polymers are basically related to their chain ***,the aggregation of molecular chains in condensed state is vital to bring them into fullest *** example,ordered structures,widely seen in natural and synthetic polymers and macromolecules,can endow them unique thermodynamics,kinetics and mechanical performance.

关键词： kinetics thermodynamics chains

Synthesis of Dendritic-Linear Block Copolymers by Atom Transfer Radical polymerization

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chinese Chemical Letters 2001年第7期12卷 595-596页

作者： You Liang ZHAO Ai Jun GONG Jing JIANG Hong Wei LIU Chuan Fu chen Fu xi state key laboratory of polymer {4. and chemistry Center of Molecular ScienceInstitute of ChemistryChinese Academy of SciencesBeijing 100080

The dendritic polyarylether 2-bromoisobutyrate as the macromolecular initiator for the controlled free radical polymerization of styrene was investigated. The polymerization was carried out with CuBr/2,2 ' -bipyridine catalyst at 110 degreesC. It is found that the hybrid dendritic-linear block copolymers possess well-defined molecular weights and low polydispersities.

关键词： Atom transfer radical polymerization dendrimer polystyrene block copolymer