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“Cutting effect” of organoclay platelets in compatibilizing immiscible polypropylene/polystyrene blends

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第11期9卷 1614-1620页

作者： Yan ZHU Hai-yun MA Li-fang TONG zheng-ping fang MOE Key Laboratory of Macromolecular Synthesis and Functionalization Institute of Polymer Composites Zhejiang University Hangzhou 310027 China Department of Blochemical and Chemical Engineermg Ningbo Institute of Technology Zhejiang University Ningbo 315100 China

In this work, polypropylene (PP)/polystyrene (PS) blends with different organoclay concentrations were prepared via melt compounding. Differing from the results of previous reports, the organoclay platelets are mostly located in the dispersed PS phase instead of the interface. The dimensions of the dispersed PS droplets are greatly reduced and apparent compatibilization effect still exists, which cannot be explained by the traditional compatibilization mechanism. A novel compatibilization mecha- nism, "cutting" to apparently compatibilize the immiscible PP/PS blends was proposed. The organoclay platelets tend to form a special "knife-like structure" in the PS domain under the shear stress of the continuous PP phase during compounding. The "clay knife" can split the dispersed PS domain apart and lead to the dramatic reduction of the dispersed domain size.

关键词： Compatibilization Organoclay Polymer blends Polypropylene (PP) Polystyrene (PS)

SYNTHESIS OF AROMATIC DIAMINE-BASED BENZOXAZINES AND EFFECT OF THEIR BACKBONE STRUCTURE ON THERMAL AND FLAMMABILITY PROPERTIES OF POLYMERS

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Chinese Journal of Polymer Science 2013年第10期31卷 1359-1371页

作者： Tao Zhang Hong-qiang Yan zheng-ping fang Mao Peng MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and Engineering Zhejiang University Department of Packaging Engineering College of Materials and Textiles Zhejiang Sci-tech University Lab of Polymer Materials and Engineering Ningbo Institute of Technology Zhejiang University

Three kinds of novel aromatic diamine-based benzoxazines containing naphthalene, propane-2,2-diyldibenzene and neopentyl groups in the backbone, respectively （designated as BAPNCP, BAPBACP and BAPNPGCP, respectively）, were synthesized and characterized. In addition, the effects of backbone structures on curing behaviors of the monomers and thermal and flammability properties of the resulting polymers were systematically studied. The results indicated that BAPNPGCP displayed the highest enthalpy of the curing reaction associated with the ring-opening of benzoxazine, which was due to the effect of benzoxazine ring content per unit mass. Interestingly, the 5 wt% weight loss temperature and char residue after thermogravimetric test for poly（BAPNPGCP） were 8 ℃ and 7% higher than those of poly（BAPBACP）. Meanwhile, the total heat release of poly（BAPNPGCP） was less than half of that for poly（BAPBACP）, indicating the substantial effect of benzoxazine ring content on flammability and char formation. Furthermore, it was found that poly（BAPNCP） gave the best thermal stability and flame retardancy, which was due to the synergistic effect between naphthalene group and benzoxazine ring content. This study provides new insight into the curing behavior of benzoxazine and further understanding on the high performance of polybenzoxazine.

关键词： Aromatic diamine-based benzoxazine Thermal properties Flammability properties.

Functionalization of polyhedral oligomeric silsesquioxanes with bis(hydroxyethyl) ester and preparation of the corresponding degradable nanohybrids

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Chinese Chemical Letters 2012年第9期23卷 1083-1086页

作者： Bing Tao Wang Yan Zhang ping Zhang zheng ping fang Institute of Packaging Engineering Ningbo Institute of TechnologyZhejiang UniversityChina Ningbo 315100 Lab of Polymer Materials and Engineering Ningbo Institute of TechnologyZhejiang UniversityChina Ningbo 315100

One novel difunctionalized polyhedral oligomeric silsesquioxanes （POSS） derivative was designed and synthesized by a convenient method with high yield. 1H NMR and P＇r-IR characterizations suggested that Michael addition reaction successfully took place between 2-hydroxyethyl acrylate （HEA） and aminopropylisobutyl POSS （POSS-NH2） under mild conditions, which finally formed bi（hydroxyethyl） ester-functionalized POSS derivatives （BH-POSS）. Due to the similar functional groups and high reactivity, BH-POSS could be easily incorporated into the main-chain of biodegradable aliphatic-aromatic copolyesters PBTL via in situ melt polycondensation to prepare corresponding degradable nanohybrids with high mechanical properties.

关键词： Michael addition Degradable nanohybrids POSS In situ melt polycondensation

Synthesis of Methyl-(γ-chloropropyl)dichlorosilane Catalyzed by Silica-supported Karstedt-type Catalyst

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Chinese Chemical Letters 2006年第9期17卷 1155-1158页

作者： zheng ping fang Hai Tang YANG Qian Jiang MIAO Guo ping CAI Institute of Polymer Composites Zhejiang University Hangzhou 310027 Key Laboratory of Macromolecule Synthesis and Functionahzation（Zhejiang University） Ministry of Education Hangzhou 310027

Methyl-（γ-chloropropyl）dichlorosilane was synthesized under the catalysis of a silicasupported Karstedt-type catalyst. By orthogonal experimental design method, the optimum reaction parameters such as reactants ratio, reaction temperature and time, and the dosage of catalyst, were determined. At the optimum reaction condition the product yield reached 78.42%, which is higher than that reported in the literatures.

关键词： Methyl-(γ-chloropropyl)dichlorosilane silica-supported Karstedt-type catalyst hydrosilylation synthesis.

Synthesis and hydrosilation of multi-vinyl branched siloxane for self-healing system

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Chinese Chemical Letters 2008年第6期19卷 655-657页

作者： Xiao Yun Fu zheng ping fang Hai Tang Yang Li fang Tong lnstitute of Polymer Composites Zhejiang University Hangzhou 310027 China Key Laboratory of Macromolecular Synthesis and Functionalization （Zhejiang University） Ministry of Education Hangzhou 310027 China

In this work, the preparation of α,ω-dichloride-terminated multi-vinyl branched siloxane 1 （yield： 57.1%） used for self-healing polymer composites were synthesized via ring-opening of 1,3,5,7-tetravinyl-1,3,5,7-tetramethyl-cyclotetrasiloxane （D4^vi） in the presence of vinylmethydichlorosilane （VM-32）. 1 was hydrogenated by aluminum lithium hydride （LiAlH4） to get self-healing monomer 2 （yield： 79.8%） which contained both Si-H bonds and Si-vinyl bonds. Then hydrosilation occurred between these two bands and finally silicone 3 was obtained, showing the potential of self-healing.

关键词： Ring-opening Hydrogenation Hydrosilylation Vinylmethydichlorosilane 1,3,5,7-Tetravinyl-1,3,5,7-tetramethyl-cyclotetrasiloxane

Preparation and characterization of biodegradable aliphatic-aromatic copolyesters/nano-SiO_2 hybrids via in situ melt polycondensation

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Chinese Chemical Letters 2009年第11期20卷 1348-1352页

作者： Yan Zhang Bing Tao Wang zheng Hong Guo Jie Chen zheng ping fang Lab of Polymer Materials and Engineering Ningbo Institute of Technology Zhejiang University Ningbo 315100 China Institute of Polymer Composites Zhejiang University Hangzhou 310027 China

In situ melt polycondensation was proposed to prepare biodegradable aliphatic-aromatic copolyesters/nano-SiO2 hybrids based on terephthalic acid （TPA）, poly（L-lactic acid） oligomer （OLLA）, 1,4-butanediol （BDO） and nano-SiO2. TEM and FT-IR characterizations confirmed that TPA, OLLA and BDO copolymerized to obtain biodegradable copolyesters, poly（butylene terepbthalate-co-lactate）（PBTL）, and the abundant hydroxyl groups on the surface of nano-SiO2 provided potential sites for in situ grafting with the simultaneous resulted PBTL. The nano-SiO2 particles were chemically wrapped with PBTL to form PBTL/nano- SiO2 hybrids. Due to the good dispersion and interfacial adhesion of nano-SiO2 particles with the copolyester matrix, the tensile strength and the Young＇s modulus increased from 5.4 and 5.6 MPa for neat PBTL to 16 and 390 MPa for PBTL/nano-SiO2 hybrids with 5 wt.% nano-SiO2, respectively. The mechanical properties of PBTL/nano-SiO2 hybrids were substantially improved.

关键词： Biodegradable aliphatic-aromatic copolyesters PBTL/nano-SiO2 hybrids In situ melt polycondensation

Flammability Characterization and Effects of Magnesium Oxide in Halogen-free Flame-retardant EVA Blends

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Chinese Journal of Polymer Science 2015年第12期33卷 1683-1690页

作者： Yan Zhang Rui-qun Peng 周光大 zheng-ping fang Xiao-nan Li Lab of Polymer Materials and Engineering Ningbo Institute of Technology Zhejiang University Hangzhou First PV Material Co. Ltd. MOE Key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and Engineering Zhejiang University

The effects of magnesium oxide （MgO） on the flame retardant performance of intumescent systems based on ammonium polyphosphate （APP） and pentaerythritol （PER） in ethylene vinyl acetate copolymer （EVA） were studied. The results showed that MgO affects both the quality and quantity of residual char. There is an optimal value for the loading amount of MgO. More or less MgO loading may cause the formation of defective char layers and worsen the flame retardancy of EVA. According to the results of limiting oxygen index （LOI）, vertical flammability test （UL94 rating） and cone calorimetry （CONE）, the best flame retardancy with a strong and well intumescent char is obtained from the sample with 1 wt% of MgO, which has the highest LOI value of 27.9, UL94 rating of V-0 and the lowest peak heat release rate of 242 kW·m-2.

关键词： Flammability Magnesium oxide Flame retardancy Ethylene vinyl acetate copolymer Intumescence.

Flame-retardant Coating by Alternate Assembly of Poly(vinylphosphonic acid) and Polyethylenimine for Ramie Fabrics

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Chinese Journal of Polymer Science 2014年第3期32卷 305-314页

作者： Li-li Wang Tao Zhang Hong-qiang Yan 彭懋 zheng-ping fang Yan Li Wang Hao MOE Key Laboratory of Macromolecular Synthesis and Functionalization Institute of Polymer CompositesZhejiang University Laboratory of Polymer Materials and Engineering Ningbo Institute of TechnologyZhejiang University School of Aerospace Engineering and Applied Mechanics Tongji University Centre of Excellence in Engineered Fibre Composites University of Southern Queensland

A novel intumescent flame retardant coating, consisting of poly（vinylphosphonic acid）（PVPA） as the acid source and branched polyethylenimine （BPEI） as the blowing agent, was constructed on the surface of ramie fabrics by alternate assembly to remarkably improve the flame retardancy of ramie. The PVPA/BPEI coating on the surface of individual fibers of ramie fabric pyrolyzes to form protective char layer upon heating/burning and improves the flame retardancy of ramie. Thermogravimetric analysis reveals that the PVPA/BPEI-coated ramie fabrics left as much as 25.8 wt% residue at 600 ~C, while the control （uncoated） fabric left less than 1.4 wt% residue. Vertical flame test shows that all PVPA/BPEI-coated fabrics have shorter after-flame time, and the residues well preserved the original weave structure and fiber morphology, whereas, the uncoated fabric left only ashes. Microscale combustion calorimetry shows that the PVPA/BPEI coatings greatly reduce the total heat release by as much as 66% and the heat release capacity by 76%, relative to those of the uncoated fabric.

关键词： Alternative assembly Poly(vinylphosphonic acid) Flame retardant Ramie fabric.

A NEW METHOD TO PREPARE CHITOSAN MEMBRANE AS A BIOMEDICAL MATERIAL

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Chinese Journal of Polymer Science 2001年第5期19卷 467-470页

作者： Qiao-ling Hu zheng-ping fang Ying Zhao Cheng-wei Xu Institute of Polymer Composites Zhejiang University Hangzhou 310027, China 浙江大学浙江杭州

This paper reports a new method to prepare chitosan membrane which could be used as a biomedical material. Addition of a fixation agent composed of alcohol, glycerol and potassium hydroxide can accelerate the sol-gel transformation process and hence shorten the preparation period. The present method takes about 6 h to get a flexible membrane with fine appearance, The physical and biological properties of the membrane were also investigated and compared with the membrane prepared by conventional method.

关键词： chitosan membrane sol-gel transformation fixation agent