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CRYSTALLIZATION KINETICS OF HOMOGENEOUS AND HETEROGENEOUS LLDPE

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chinese Journal of polymer science 2002年第4期20卷 339-345页

作者： Hong-xiang Teng Wen-hong Tang Yi Shi xi-gao {3. state key laboratory of polymer physics and chemistry center for molecular science, institute of chemistry chinese academy of sciences Bei{3.g 100080 china Department of chemistry Jilin University Changchun 13.023. china chinese Acad Sci Ctr Mol Sci Inst Chem State Key Lab Polymer Phys & Chem Beijing 100080 Peoples R China Jilin Univ Dept Chem Changchun 130023 Peoples R China

Based on thermal analysis, the isothermal and nonisothemal crystallization kinetics of Ziegler-Natta catalyzed linear low density polyethylene (Z-N LLDPE) and metallocene catalyzed LLDPE (m-LLDPE) were studied. Treating the results with the Avrami equation and the Ozawa equation, the crystallization constant Igk and the Avrami exponent n were obtained. Some other crystallization parameters were also discussed. According to the different characteristics of the chain structures of Z-N LLDPE and metallocene LLDPE, their crystallization behaviors were analyzed. It is indicated that the homogeneity and heterogeneity of the two polymers act in different way during the crystallization process of polymers, including the nucleation and the growth of crystals under various conditions.

关键词： crystallization kinetics homogeneity heterogeneity LLDPE

Interfacial behaviors of PMMA-PEO block copolymers at the air/water interface

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science china chemistry 2005年第6期48卷 567-573页

作者： CHENG Caixia1, JIAO Tifeng2, TANG Rupei1, LIU Minghua2 & xi Fu1 1. state {3. laboratory of polymer physics and chemistry, Joint laboratory of polymer science and Materials, institute of chemistry, chinese academy of sciences, Bei{13.g 100080, china 2. CAS {3. laboratory of Colloid and Interface science, institute of chemistry, chinese academy of sciences, Bei{13.g 100080, china 1. state key laboratory of {3. physics and chemistry Joint Laboratory of Polymer Science and Materials Institute of Chemistry Chinese Academy of Sciences 100080 Beijing China 2. CAS key laboratory of Colloid and Interface science Institute of Chemistry Chinese Academy of Sciences 100080 Beijing China

Diblock copolymer of PMMA291-b-PEO114 and triblock copolymer of PMMA120-b- PEO227-b-PMMA120 were synthesized and their interfacial properties at the air-water interface were investigated, where both blocks of polyethylene oxide (PEO) and poly(methyl methacrylate) (PMMA) are surface active but the former is soluble in water while the latter is not. Both the block copolymers could form monolayers with two obvious transition regions. The first transition point is around 10 mN/m, which could be assigned to the pancake-brush change of the PEO chains. The other is around 18 mN/m, which could be ascribed to the condensed packing of PMMA. The surface morphological changes during the compression of the Langmuir monolayers are inves-tigated by using the AFM and SEM methods for the films deposited at different surface pressure or molecular areas. At a lower surface pressure, a typical morphology of PEO-con- taining lipopolymers is observed. Upon compression, sphere-dominant morphologies were observed. While the diblock copolymer is easy to folding, the triblock copolymer is in favor of formation of circular domains through vesiculation.

关键词： PMMA-PEO, block copolymers, monolayer, Langmuir-Blodgett films, AFM.

MORPHOLOGICAL STUDY ON THE ORIENTED CHITOSAN FILM OBTAINED FROM PRE-SHEARED LIQUID CRYSTALLINE SOLUTION IN DICHLOROACETIC ACID

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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 {3. of polymer physics and chemistry, center for molecular science, institute of chemistry chinese academy of sciences, Beijing 100080, 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

Highly stereospecific polymerization of isoprene with homogeneous binary Ziegler-Natta catalysts based on NCN-pincer neodymium precursor

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science china chemistry 2010年第8期53卷 1641-1645页

作者： LIU DongTao1,2,CUI DongMei1 & gao Wei3.1state key {3. of polymer physics and chemistry Changchun institute of Applied chemistry,chinese academy of sciences,Changchun 13.022,china 2Graduate University of{13.,Beijing 10003.,china 3.chool of chemistry,Jilin University,Changchun 13.012,china 1. state key laboratory of {3. physics and chemistry Changchun institute of Applied chemistry Chinese Academy of Sciences Changchun 130022 China2. Graduate University of Chinese Academy of Sciences Beijing 100039 China3. School of Chemistry Jilin University Changchun 130012 China

The aryldiimine NCN-pincer stabilized neodymium dichloride combined with aluminum alkyls established a new type of homogeneous binary neutral Ziegler-Natta catalyst *** system exhibited high activity and high cis-1,4 selectivity for the polymerization of isoprene (Tp=20 °C,98.2%;Tp=-20 °C,> 99%).Such catalytic performances remained under a broad range of polymerization temperatures and monomer-to-neodymium ratios (from 500 to 8000),reaching high number-average molecular weight (Mn=1582 kg/mol) and relatively narrow molecular weight distribution (PDI=1.68),which was,however,influenced by the amount and bulkiness of aluminum *** investigation of the polymerization was performed,which showed the number-average molecular weight of the resultant polyisoprene had an almost linear correlation with the conversion,suggesting,in some degree,the polymerization with this catalytic system was controllable.

关键词： neodymium cis-1 4 selectivity NCN-pincer complex polyisoprene

Unleashing the Power of Bio-based Thermotropic Liquid Crystal Modifiers:Toughening and Reinforcing Petroleum-based Epoxy Resin without Compromising Other Properties

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chinese Journal of polymer science 2024年第8期42卷 1093-1102页

作者： Qing-Yun Lu Hong-Wei Gu Jia-Hui Li Qian-Qian Fan Bei-Tao Liu Yan Kou xi-gao Jian Zhi-Huan Weng state key laboratory of Fine Chemicals Frontiers Science Center for Smart MaterialsLiaoning Technology Innovation Center of High Performance Resin MaterialsDepartment of Polymer Science&EngineeringDalian University of TechnologyDalian 116024China Thermochemistry laboratory Liaoning Province Key Laboratory of Thermochemistry for Energy and MaterialsDalian National Laboratory for Clean EnergyDalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023China

Toughening the petroleum-based epoxy resin blends with bio-based modifiers without compromising their modulus,mechanical strength,and other properties is still a big challenge in view of the *** this study,a bio-based liquid crystal epoxy resin(THMT-E P)with an s-triazine ring structure was utilized to modify a petroleum-based bisphenol A epoxy resin(E51)with 4,4'-diaminodiphenylsulfone(DDS)as a curing agent,and the blended systems were evaluated for their thermal stability,mechanical properties,and flame *** results showed that the impact strength of the blended system initially increased and then decreased with the increase in THMT-EP content,and it reached the a maximum value of 26.5 kJ/m^(2)when the THMT-EP content was 5%,which was 3..2%higher than that of E51/***,the flexural strength,modulus,and glass transition tem perature of the blended system were all simultaneously improved with the addition of *** the same time,the addition of THMT-EP enhanced the flame retardancy of the system by increasing the char yield at 700℃and decreasing the peak heat release rate and total heat release *** work paves the way for a more sustainable improvement in the comprehensive performance of epoxy resin.

关键词： Epoxy resin Toughening Bio-based Thermotropic liquid crystal

Enhancing efficiency and stability of organic solar cells through a simplified four-step synthesis of fully non-fused ring electron acceptor

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Journal of Energy chemistry 2024年第6期93卷 601-608,I0015页

作者： Chenyang Han Huanhuan gao Yanna Sun Yuanyuan Kan Zhaozhao Bi Wei Ma Yani Zhang Juan Antonio Zapien Yingguo Yang Ke gao College of New Energy Xi’an Shiyou UniversityXi’an 710065ShaanxiChina Shandong Provincial key laboratory for science of Material Creation and Energy Conversion Institute of Frontier ChemistrySchool of Chemistry and Chemical EngineeringShandong UniversityQingdao 266237ShandongChina state key laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049ShaanxiChina Department of Materials science and Engineering City University of Hong KongKowloonHong Kong 99907China School of Microelectronics Fudan UniversityShanghai 200433China

Design and synthesis of superior cost-effective non-fullerene acceptors(NFAs)are still big challenges for facilitating the commercialization of organic solar cells(OSCs),yet to be ***,two medium bandgap fully non-fused ring electron acceptors(NFREAs,medium bandgap,i,e.,1,3.1,8 eV),namely PTR-2Cl and PTR-4Cl are synthesized with only four steps by using intramolecular noncovalent interaction central core,structured alkyl side chain orientation linking units and flanking with different electron-withdrawing end *** them,PTR-4C1 exhibits increased average electrostatic potential(ESP)difference with polymer donor,enhanced crystallinity and compactπ-πstacking compared with the control molecule *** a result,the PTR-4Cl-based OSC achieved an impressive power conversion efficiency(PCE)of 14.72%,with a much higher open-circuit voltage(V_(OC))of 0.953.V and significantly improved fill factor(FF)of 0.758,demonstrating one of the best acceptor material in the top-performing fully NFREA-based OSCs with both high PCE and V_(OC).Notably,PTR-4Cl-based cells maintain a good T_80lifetime of its initial PCE after over 93. h under a continuous thermal annealing treatment and over13.0 h T_(80)lifetime without *** work provides a cost-effective design strategy for NFREAs on obtaining high V_(OC),efficient exciton dissociation,and ordered molecular packing and thus high-efficiency and stable OSCs.

关键词： Organic solar cells Fully non-fused ring acceptors End group engineering Morphology regulation High efficiency

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 {3. physics and chemistry Institute of Chemistry Chinese Academy of Sciences Beijing 100080 Graduate School of the chinese academy of sciences Beijing 100080

^13. 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 molecular dynamics.

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

Synthesis of Exfoliated MEH-PPV /Clay Nanocomposites

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chinese Chemical Letters 2005年第8期16卷 1117-1120页

The synthesis of poly（2-methoxy-5-（2＇-ethyl-hexyloxy）-l,4-phenylenevinylene）（MEH-PPV） in the presence of organophilic montmorillonite （OMMT） was reported and the exfoliated MEH-PPV/OMMT nanocomposites was ob... 详细信息

关键词： MEH-PPV nanocomposite in-situ polymerization.

Semicrystalline Unfused polymer Donors with Backbone Halogenation toward Cost-Effective Organic Solar Cells

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chinese Journal of chemistry 2024年第7期42卷 752-759页

作者： Yuxin Kong Shijie Ju Hongmei Qin Min Hun Jee Simeng xia Jiaqi Ren Chao gao Jianyu Yuan Wenyan Su Han Young Woo Yuxiang Li School of Materials science and Engineering Xi'an University of Science and TechnologyXianShaanxi 710054China Department of chemistry Korea UniversitySeoul 02841Republic of Korea xi'an key laboratory of Liquid Crystal and Organic Photovoltaic Materials State Key Laboratory of Fluorine&Nitrogen ChemicalsXi'an Modern Chemistry Research InstituteXi'anShaanxi 710065China Jiangsu key laboratory for Carbon-Based Functional Materials&Devices Institute of Functional Nano&Soft Materials(FUNSOM)Soochow University199 Ren'ai RoadSuzhouJiangsu 215123China

Developing novel unfused building blocks with simple synthesis and low cost is essential to advance and enrich cost-effective poly-mer donors;however,it remains a challenge due to the lack of efficient molecular ***,a class of low-cost and fully unfused polymer donors with precisely regulated backbone planarity via halogenation was designed and synthesized,namely PDTBTBz-2H,PDTBTBz-2F,and *** polymer donors possess a four-step synthesis route with over 80%yield from cheap raw chemicals comparable to e{3.sting low-cost polymer donors,such as *** from the planar backbone via in-corporating the F…S non-covalent interactions,PDTBTBz-2F exhibits more robust J-type aggregation in solution and a long-ranged molecular stacking in film relative to PDTBTBz-2H and ***,the systematical study of PDTBTBz-based organic so-lar cells(OSCs)reveals the close relationship between optimized molecular self-assembly and charge separation/transport regarding backbone halogenation when paired with the non-fullerene acceptor(Y6-BO-4F).As a result,the photovoltaic devices based on semicrystalline PDTBTBz-2F achieved a promising power conversion efficiency(PCE)of 12.3.%.Our work highlighted the influence of backbone halogenation on the molecular self-assembly properties and a potential unfused backbone motif for further developing cost-effective OSCs.

关键词： Low-cost polymer donors Backbone halogenation molecular self-assembly Organic solar cells