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2011, Volume 25 Issue 10 Publication date: 26 October 2011 Previous Issue Next Issue

Situation and Developing Trend of HCFCs Phase-out of XPS Foam Sector in China

WANG Yong WANG Xiangdong LI Ying

2011, 25 (10): 1-6 ; DOI: 10.19491/j.issn.1001-9278.2011.10.001

Abstract ( 2011 )

The situation and developing trends of HCFCs phase-out of extruded polystyrene foam (XPS) sector in China was reviewed. Technologies of HCFCs phase-out in materials, equipment, blowing agents were discussed. The properties and market situation of alternative products were analyzed. Finally, the alternative technologies of HCFCs were introduced.

Research Progress in Modification of Heat Resistance and Toughness of Poly (vinyl chloride)

ZENG Weili

2011, 25 (10): 7-13 ; DOI: 10.19491/j.issn.1001-9278.2011.10.002

Abstract ( 1874 )

Research progresses in modification of heat resistance and toughness of poly(vinyl chloride) (PVC) were reviewed. The heat resistance of PVC could be enhanced by adding heat stabilizer, crosslinking, blending, copolymerization, chlorination, and adding inorganic nanoparticles, etc. The toughness of PVC could be improved by blending with elastomer, nanoparticles, and nanoscale micro fiber, and in-situ polymerization. The development trend of PVC modification was pointed out.

Research Progress in Application of Low Temperature Plasma Technology for Polymers

SHANG Chengxin MA Chi CHEN Erfan

2011, 25 (10): 14-18 ; DOI: 10.19491/j.issn.1001-9278.2011.10.003

Abstract ( 1827 )

The definition and classification of plasma was introduced briefly, with low temperature plasma especially emphasized. The low temperature plasma technology was extensively used in fiber, plastic, porous materials, and biomaterials to improve various properties, such as the hydrophilicity, hydrophobicity, adhesive properties, spinnability, dyeability, flame retardancy, and antistatic. Finally, problems currently met in the modification of polymers with low temperature plasma were pointed out.

Study on Processing and Property of Three-layer Co-extrusion Barrier Films

LI Side LUO Jianxun GAO Li MAO Lixin

2011, 25 (10): 19-23 ; DOI: 10.19491/j.issn.1001-9278.2011.10.004

Abstract ( 1810 )

Using ethylene/vinyl acetate copolymer (EVOH), polyamide 6 (PA6), metallocene polyethylene (mPE) and linear low density polyethylene (PE-LLD) as raw materials, PA6/EVOH/PA6, PA6/PE-LLD/mPE and EVOH/PE-LLD/mPE three-layer barrier films were prepared via co-extrusion in this paper. The optimal processing technology of three-layer barrier films was obtained by analyzing thermal and rheological properties of raw materials. The results showed that the mechanical and helium barrier properties of PA6/EVOH/PA6 films were the best.

Synthesis of Epoxy-modified Polysiloxane by Hydrosilylation Reaction

ZHANG Yuanping YANG Xiang

2011, 25 (10): 24-27 ; DOI: 10.19491/j.issn.1001-9278.2011.10.005

Abstract ( 1678 )

Epoxy-modified polysiloxane was prepared by hydrosilylation reaction of hydromethylcyclosiloxane (HMCS) and allyl glycidyl ether (AGE) using isopropanol solution of H2PtCl6 as a catalyst. The products were characterized using Fourier transform infrared spectrometer and nuclear magnetic resonance spectra. The effects of reaction temperature, reaction time, catalyst dosage, and molar ratio of HMCS/AGE on conversion ratio of reactive hydrogen were discussed. It showed that the optimal reaction conditions were reaction temperature of 85 ℃, reaction time of 6 h, catalyst dosage of 5 mg/L, and molar ratio of AGE/HMCS of 1.2/1. The conversion rate of reactive hydrogen was 87.5 %.

Synthesis and Application of Polyamidoamine Dendrimer

LIANG Jianguo HAO Hong WEI Xiongxiong CAO Yahong TIAN Zhongshe

2011, 25 (10): 28-33 ; DOI: 10.19491/j.issn.1001-9278.2011.10.006

Abstract ( 1794 )

This paper briefly introduced the synthesis methods of polyamidoamine（PAMAM）dendrimer, including divergent, convergent, and divergent-convergent methods. The advantages and disadvantages of these methods were discussed. The application of PAMAM in drug carrier, surfactant, catalyst, biosensor, and photochemical device was reviewed.

Study on Synthesis and Properties of L-Lactide and ε-Caprolactone Copolymers

MA Conghe CHAI Yun ZHANG Puyu

2011, 25 (10): 34-37 ; DOI: 10.19491/j.issn.1001-9278.2011.10.007

Abstract ( 1846 )

L-Lactide/ε-caprolactone copolymers with varying compositions and molecular weight were synthesized via ring-opening polymerization using Sn(Ⅱ)octoate as a catalyst and ethylene glycol as an initiator. The structure of the copolymers was characterized using Fourier transform infrared spectrometer, nuclear magnetic resonance spectra, and gel permeation chromatography, the thermal properties using differential scanning calorimeter, and the hydrophilicity using contact angle. Changing the monomer molar ratios and using ethylene glycol as an initiator in feed could adjust the chemical compositions，molecular weight and thermal properties of the copolymers, however, had little effect on the hydrophilicity.

Study on Electrochemical Synthesis and Properties of Poly (vinyl alcohol) /Polyaniline/Ag Composite Films Co-doped with Mixed Acids

DENG Shuhao WANG Yu

2011, 25 (10): 38-43 ; DOI: 10.19491/j.issn.1001-9278.2011.10.008

Abstract ( 1580 )

Conductive polyaniline (PANI) films co-doped with sulfosalicylic acid (SSA) and sulfuric acid (H2SO4) were prepared via electrochemical method on a poly (vinyl alcohol) (PVA) supporting film, and the optimum condition of preparation was found through an orthogonal design. The influences of deposit current density and time of silver (Ag) and stretching on the conductivity of composite film were also studied. The composite films were characterized by IR, XRD and SEM. The result showed that the conductivity of PVA/PANI composite film obtained under optimum conditions was 22.72 S/cm. Deposited Ag by current density of 50 mA/cm2 for 2 min into prior film sequentially, the conductivity increased to 1250 S/cm significantly. Applying appropriate stretching to PVA/PANI and PVA/PANI/Ag composite films, the conductivity could be enhanced by 20.74 % and 18.04 %, respectively, and the crystallinity was improved.

Study on Non-isothermal Crystallization Kinetics and Melting Behaviors of Polyamide 11/Graphene Oxide Nanocomposites

CHEN Chunyin MA Jianli WANG Biaobing

2011, 25 (10): 44-49 ; DOI: 10.19491/j.issn.1001-9278.2011.10.009

Abstract ( 1510 )

Polyamide 11/graphene oxide (PA11/GO) nanocomposites were prepared via in-situ polymerization. Non-isothermal crystallization and melting behaviors of PA11 and PA11/GO nanocomposites were investigated using differential scanning calorimetry, and Non-isothermal crystallization kinetics of them was analyzed by Jeziorny and Mo method. It was found that both PA11 and PA11/GO nanocomposites displayed double melting peaks. The addition of GO decreased the crystallization rate of PA11. The mechanisms of nucleation and growth of crystallization were changed by adding GO.

Research Progress in Surface Modification of Fibers in Biodegradable Plastics/Plant Fiber Composites

FENG Yanhong ZHANG Yeqing QU Jinping HE Hezhi

2011, 25 (10): 50-54 ; DOI: 10.19491/j.issn.1001-9278.2011.10.010

Abstract ( 1601 )

Research progresses in physical and chemical surface modification methods for fibers in biodegradable plastics/plant fiber composites were reviewed in this paper. The main physical methods included heat treatment, electrostatic discharge treatment and steam explosion. The main chemical methods included surface grafting, surfactant treatment, alkali treatment, esterification treatment, and coupling agent treatment. It was pointed out that the steam explosion and low temperature plasma treatments constituted the development trend in the future.

Study on Crystallization and Tribological Behaviors of PTFE/POB Composites

HOU Mei KOU Kaichang ZHANG Dongna JIANG Yang LI Ning

2011, 25 (10): 55-58 ; DOI: 10.19491/j.issn.1001-9278.2011.10.011

Abstract ( 1528 )

The crystallization behaviors of polytetrafluoroethylene/polybenzoate (PTFE/POB) composites were investigated using differential scanning calorimetry. Tribological behaviors of PTFE/POB composites sliding against 45# steel under dry condition were discussed, and the worn surfaces of the composites were observed using scanning electron microscope. Effects of POB content on crystallization and tribological behaviors of the composites were studied. It showed that the crystallinity of the composites increased with increasing content of POB up to 20 %. The crystallization rate of the composites was enhanced by the addition of POB. With increasing POB content, the friction coefficient of the composites increased, while its wear scar width greatly decreased.

Thermal Stability of Poly (vinyl chloride)/Lignin Blends

LIU Feiyue XU Kai CHEN Mingcai CAO Derong

2011, 25 (10): 59-63 ; DOI: 10.19491/j.issn.1001-9278.2011.10.012

Abstract ( 1500 )

Thermal stability of poly (vinyl chloride) (PVC)/lignin blends was studied with thermogravimetric analysis, and depended on the integration of two behaviors: sterically hindered phenol structure of lignin could improve thermal stability of the blends; dehydration of lignin could decrease thermal stability of the blends. In the early stage of the decomposition, the latter was dominant, and the early thermal stability of the blends was worse than that of PVC. In the medium-term of the decomposition, thermal stability of the blends was better than that of PVC due to the end of dehydration, and the former turned to predomination in this stage.

Stabilization Effect of Antioxidants and Light Stabilizers on UV-light Aging of PE-LLD

YANG Haomiao HU Bin WU Peng

2011, 25 (10): 64-68 ; DOI: 10.19491/j.issn.1001-9278.2011.10.013

Abstract ( 1485 )

The UV stabilizing effects of antioxidant 1010, 168 and light stabilizer 622 on linear low density polyethylene (PE-LLD) were studied. Mechanical testing and gel permeation chromatography were carried out to study tensile properties and molecular weight of PE-LLD before and after UV-light aging. When antioxidant and light stabilizer were absent, the reserved elongation at break of PE-LLD was less than 50 % after UV-light aging for 3 d. With adding 0.15 phr of antioxidant 1010, 168 and light stabilizer 622 separately, the time of UV-light aging needed to decrease the elongation at break below 50 % were extended to 7, 6 and 15 d, respectively. When antioxidant 1010, 168 and light stabilizer 622 were used together, an obvious synergistic effect on the UV-light resistance of PE-LLD was observed.

Development of CPP Heat-sealing Film for Modified Atmosphere Packaging

LIN Yuanzhi CHEN Wentao CHEN Sheng SHI Fengyan

2011, 25 (10): 69-71 ; DOI: 10.19491/j.issn.1001-9278.2011.10.014

Abstract ( 1601 )

Polyolefin elastomer (POE), polyolefin plastomer (POP), metallocene polyethylene (mPE) blended with polypropylene terpolymer as low-temperature heat-sealing layer, heat sealing polypropylene cating films (CPP) for modified atmosphere packaging were prepared via three-layer co-extrusion casting technology. It showed that the properties of obtained CPP films met the demands, and their heat-sealing temperature was under 102 ℃, while the heat-sealing layer was composed of polypropylene terpolymer blended with 12 phr of POE-868 and 2 phr of anti-blocking slip additive, melting temperature was controlled between 245 ℃ and 255 ℃, and cooling roll temperature was 22 ℃.

Study on Chain Extension of PET Flakes by Reactive Extrusion with Chain Extenders

CHEN Qiuyun WANG Yilong LIU Jia WANG Hui

2011, 25 (10): 72-76 ; DOI: 10.19491/j.issn.1001-9278.2011.10.015

Abstract ( 2192 )

The chain extension of recycled PET flake was studied via reactive extrusion using diisocyanatotoluene (TDI), antimony trioxide (Sb2O3), phthalic anhydride, pyromellitic dianhydrde (PMDA), and naphthalenetetra carboxylic dianhydride (NTDA) as chain extenders. It was found that effect of TDI, Sb2O3, phthalic anhydride, and NTDA was weak, while PMDA could increase the intrinsic viscosity of the material obviously. A mixture of PMDA and phthalic anhydride provided the best chain extension. The intrinsic viscosity of the material reached 0.96 dL/g when the content of PMDA and phthalic anhydride was 0.3 % and 0.2 %, respectively.

Coupling Function of Titanate Coupling Agent in PP/IFR Composites

MA Zhiling FAN Congran MA Xin

2011, 25 (10): 77-80 ; DOI: 10.19491/j.issn.1001-9278.2011.10.016

Abstract ( 1758 )

Effect of titanate coupling agent on mechanical properties and flame retardancy of polypropylene/intumescent flame retardant (PP/IFR) composites was studied. Micromorphology and crystallization behavior of the composites were analyzed by scanning electron microscope, polarization microscope and X-ray diffraction. It showed that dispersion of IFR and spherulite size of PP became uniform, and TTOPP could promote the formation of β-form crystal. The adhesions between PP and IFR was enhanced by TTOPP. PP/IFR/TTOPP(75/25/0.375) composite had the optimal properties, and its impact strength and tensile strength were improved by 14.0 ％ and 12.0 ％ than that of PP/IFR, respectively, and its extinguish time decreased to 24 s.

Study on Structure and Properties of Recycled High Density Polyethylene

YUAN Conghui WANG Shifeng ZHANG Yong ZHANG Yinxi

2011, 25 (10): 81-85 ; DOI: 10.19491/j.issn.1001-9278.2011.10.017

Abstract ( 1526 )

Commercial recycled high density polyethylene (PE-HD) was characterized using Fourier transform infrared spectrometry, differential scanning calorimetry and thermogravimetric analysis, and their rheological and mechanical properties were also studied. During the recycling processing, the structure of recycled PE-HD changed obviously. Carbonyl groups on the chains increased, the melt flow rate and mechanical properties decreased as a result of aging. According to tensile strength, recycled PE-HD could be divided into three grades.

Study on Extensional Flow of Polymer Fluids Tested by PIV System

LIN Xiang REN Dongyun WAN Kuisheng JIANG Shunliang

2011, 25 (10): 86-89 ; DOI: 10.19491/j.issn.1001-9278.2011.10.018

Abstract ( 1366 )

The velocity distribution and extensional flow behavior for low molecular and low viscosity Newtonian fluids (polyisobutylenes) and Non-Newtonian fluids (sodium benzoate solution) while flowed through a continual contraction channel were determined and compared with the help of a particle image velocimetry system (PIV). The shear rate at wall of channel and extensional rate along its axis were estimated. The differences between the two fluids were analyzed and explained.

Design of Highly Dispersive Mixing Elements for Twin-screw and Their Performances

HUANG Fengchun MA Xiuqing ZHOU Bingbin LIANG Wenhu

2011, 25 (10): 90-94 ; DOI: 10.19491/j.issn.1001-9278.2011.10.019

Abstract ( 1558 )

A highly-dispersive mixing twin-screw element was designed based on the meshing theory of intermeshing co-rotating twin-screw extruders. The flow fields for three screw configurations were simulated by Polyflow. Experimental study was carried out in an intermeshing co-rotating twin-screw extruder. It was found that the screw element with a staggering angle of 150 ° had a better dispersive mixing performance than those of 30 ° and 90 °.

Design of Screen Changing Devices for Extrusion of PP Melt-blown Resin

TIAN Weidong LI Shitong

2011, 25 (10): 95-97 ; DOI: 10.19491/j.issn.1001-9278.2011.10.020

Abstract ( 1480 )

The disadvantages of single-plate screen changing devices were analyzed based on the characteristic of polypropylene melt-blown resin. A double-plate screen changing device was proposed in which the original two-station design was replaced with a four-station one. The problems such as breakage and leakage of polypropylene melt during the screen changing were avoided, and continuous and low-cost production was achieved.