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2012, Volume 26 Issue 05 Publication date: 26 May 2012 Previous Issue Next Issue

Research Progress in Synthesis of Poly（ethylene glycol succinate）

Ma Kai Shaoying Liu Gongying Wang

2012, 26 (05): 1-6 ; DOI: 10.19491/j.issn.1001-9278.2012.05.001

Abstract ( 2096 )

Four kinds of methods for the synthesis of poly(ethylene glycol succinate)(PES) were reviewed, including direct esterification, ring-opening polymerization, transesterification polymerization, and coupling reaction. The technology of direct esterification and the involved catalysts were emphatically introduced. Moreover, the development of PES synthesis was forecasted.

Research Progress in Flame Retardancy of Rigid Polyurethane Foam /Expandable Graphite Composites

Liang ZHOU

2012, 26 (05): 7-16 ; DOI: 10.19491/j.issn.1001-9278.2012.05.002

Abstract ( 1811 )

Recent research progress in flame retardancy of rigid polyurethane foam/ expandable graphite composites was reviewed. A detailed introduction was given on its preparation method, thermal degradation behavior as well as flammability properties such as limited oxygen index, horizontal and vertical burning rate, heat release rate, CO/CO2 production weight ratio and carbonization performance. The influences of foam density, addition amount, particle sizes, encapsulation treatment of expandable graphite as well as the combination with other flame retardants on thermal stability and flammability of the corresponding foam composites were analyzed. Besides, the relative mechanism was discussed in depth.

Research Progress in Polypropylene/Graphite Conductive Composite

2012, 26 (05): 17-21 ; DOI: 10.19491/j.issn.1001-9278.2012.05.003

Abstract ( 2111 )

Research work on preparing methods of polypropylene/graphite conductive composite and effects of graphite types, compatibilizer, and processing conditions on the properties of the composite were summarized. The application of the composites in bipolar plates was also introduced. The possible direction about polypropylene/graphite conductive composite was pointed.

Study on Synthesis of Conjugated Azobenzene Polymer and Its Properties

DONG Ming-Ling

2012, 26 (05): 22-27 ; DOI: 10.19491/j.issn.1001-9278.2012.05.004

Abstract ( 1388 )

An azobenzenebridged main chain conjugated polymer was synthesized via oxidation of an aromatic diamine with sodium perborate. The conjugated azobenzene polymer was characterized using FTIR, UVVis, DSC, Raman spectroscopy. The numberaverage molecular weight of the conjugated polymer was 4428 and the glass transition temperature was 186 ℃. Thermal analysis conformed that the cis configuration azobenzene units were on the main chain. When doped with hydrochloride acid, I2 ,and sodium naphthalide, the electrical conductivities of the conjugated polymer were 8.7×10-5 S/cm,2.65×10-4 S/cm，and 1.92×10-4 S/cm，respectively. Upon irradiation with UVlight, the conductivity increased, subsequently irradiated with vislight or heated, the conductivity returned to its original levels, which showed that the azobenzene conjugate polymer possessed light modulation conductive properties.

Effect of Calcium Stearate on Structure and Properties of Soy Protein Isolate Plastics

BAI Xiaojiao ZHANG Liye

2012, 26 (05): 28-34 ; DOI: 10.19491/j.issn.1001-9278.2012.05.005

Abstract ( 1428 )

Films was cast from a mixture of soy protein isolate (SPI) and calcium stearate (CaSt2) containing glycerol as a plasticizer. The structure and properties of the plastics were investigated using attenuated total reflectance-Fourier transform infrared, X-ray diffraction, thermal properties, tensile properties and water vapor permeability. The results showed that CaSt2 existed in two structural forms, in which the ions form as the main structure. The crystallinity of modified SPI film increased by 70.4%, and then the internal structure was more compact. The thermal analysis indicated that thermal stability of modified SPI film enhanced. As the concentration of CaSt2 was increased, the values of water vapor permeability decreased, when the content of 12 %, the capacity of water vapor barrier increased by 40 %; the elongation at break increased by 67.63 %.

Preparation and Characterization of Polypyrrole/ Silver-coated Graphite Nanosheet Composites

Xinxin Zhang Yunchuan Qin Hua Qiu

2012, 26 (05): 35-39 ; DOI: 10.19491/j.issn.1001-9278.2012.05.006

Abstract ( 1376 )

Nano graphite sheet (nano G) was prepared was obtained via sonication and exfoliation of oxidized graphite in an aqueous alcohol solution. A silver coating was applied on the surface of (nano G) through electroless plating leading to silver-coated graphite nanosheet (Ag-nano G). Pyrrole was in situ polymerized in the presence of Ag-nano G forming polypyrrole(PPy)/Ag-nanoG composites. The thickness of nano G was 30~90 nm and the diameter was 1~20 μm. The high aspect ratio (about 200) of nano G was extremely beneficial to the formation of conductive networks in polymer matrix. The thickness of Ag-nano G nanoparticles was 200~250 nm. Ag-nano G dispersed uniformly in PPy matrix. It was found that the thermal and electrical properties of PPy/Ag-nano G composite were dramatically increased compared with pure PPy.

Preparation and Properties of Polycaprolactone/Esterified Starch/Nano-Calcium Carbonate Composites

Zhengliang Wang Xin Deng Suwen Yang Jin Yang

2012, 26 (05): 40-44 ; DOI: 10.19491/j.issn.1001-9278.2012.05.007

Abstract ( 1570 )

The corn starch was esterified with maleic anhydride via a dry process, which was blended with polycaprolactone (PCL), nano-calcium carbonate (nano-CaCO3) forming composites. Mechanical properties, morphology, crystallization behavior and thermal properties of the composites were investigated using Fourier transform infrared spectroscopy, mechanical test, melt flow rate, scanning electron microscopy, wide-angle X-ray diffraction, and simultaneous thermogravimetry differential scanning calorimetry. It showed that the tensile strength and elongation at break of the composites first increased and then decreased with the increasing content of nano-CaCO3, and reach maxima when the content of nano-CaCO3 was 6 phr, 49.8 % and 34.8 % higher than CaCO3-free samples, respectively. When esterified starch was used in the composites, melt point, crystallinity, tensile strength, and melt flow rate became higher, however decomposition temperature was a little lower.

Research on Thermal Reactions of Low-density Polyethylene/Coal Composites

ZHANG Shu-Jie

2012, 26 (05): 45-53 ; DOI: 10.19491/j.issn.1001-9278.2012.05.008

Abstract ( 1383 )

Pulverized SHENFU coal (SFC) was treated with ferric chloride (FeCl3·6H2O) to prepared active coal via solid phase ion exchange. The active coal was blended with low-density polyethylene (PE-LD). Differential scanning calorimetry (DSC) and other analytical methods were used to study the pyrolysis reaction and thermal decomposition kinetics of SFC, PE-LD, and PE-LD/SFC composite and the data was analyzed with Kissinger and Flynn-Wall-Ozawa methods. The activation energy of SFC was calculated as at 340~380 ℃113 kJ/mol and at 520~550 ℃ 149 kJ/mol. When adding 10 wt % and 20 wt % Fe3+ modified SFC, the thermal activation energies at the low temperature (120~135 ℃) of the PE-LD/SFC composites were 182.87 kJ/mol and 250.62 kJ/mol. When adding 10 wt % Fe3+ modified SFC, the reactivity of coal and PE-LD was better, so there must be coordinated action between two points.

Study on Preparation and Fatigue Property of Short Carbon Fiber Reinforced Thermoplastic Composites

Yonghua SHENG Li Li

2012, 26 (05): 54-57 ; DOI: 10.19491/j.issn.1001-9278.2012.05.009

Abstract ( 1449 )

Thermoplastic composites of polyethylene and chopped carbon fiber were prepared via injection molding. The influence of carbon fiber content on the fatigue property of the composites was studied, and the fracture mechanism of the composites was analyzed. The lifespan of the composites was prolonged with increasing content of carbon fiber.

Study on Structure and Properties of PAA-Na/BT Composite Superabsorbent Resin Synthesized Under Microwave Irradiation

CHENG Zhiqiang MA Qi KANG Lijuan ZHU Guangqian

2012, 26 (05): 58-63 ; DOI: 10.19491/j.issn.1001-9278.2012.05.010

Abstract ( 1345 )

Bentonite/polyacrylic acid composite superabsorbent was prepared via microwave irradiation. The structure and morphology were analyzed by FTIR, XRD, and SEM. The effect of the preparation conditions on absorption of water was investigated. The optimal conditions were that the weight ratio of bentonite to AA was 8/1, microwave power was 720 W, neutralization degree was 80 %, the mass fraction of initiator and crosslinker were respectively 0.02 % and 0.8 %. XRD showed that the distance between the silicate layers of bentonite was increased, the monomer was intercalated into the bentonite layer and formed a crosslinked structure. SEM showed that porous products were easily obtained through microwave irradiation. The characterization of synthesized highabsorbent resin showed that the maximum water absorbency was 1312 g/g in distilled water and 320 g/g in 0.9 % NaCl, respectively. The water absorption rate was high, and the swelling processes of the composites agreed with firstorder kinetics, and the retain water of the composites was temperature dependent.

Molecular Dynamics Simulation of Mechanical Properties and Surface Interaction for NR/BR Blends

江浩 JIANG Hao

2012, 26 (05): 64-68 ; DOI: 10.19491/j.issn.1001-9278.2012.05.011

Abstract ( 1319 )

Molecular dynamics simulation was applied to investigate the mechanical properties of NR/BR blends, and the reasons of their superior performance were interpreted in microstructure. Finally, by calculating binding energy and pair correlation function, the interface interaction and its essence of the blends were elucidated. The results showed that the average binding energy of NR/BR blends was 21.35 kJ/mol, the number of average binding energy was approximately the nonbond energy (17.91 kJ/mol) except energy calibration (-3.64 kJ/mol) produced by program, which meant that interaction between NR and BR was formed by Vander Waals force.

Study on Dependency of Rheological Behavior of PMMA/SMA Blends on Temperature

Nan WANG Wei YU Chixing ZHOU

2012, 26 (05): 69-73 ; DOI: 10.19491/j.issn.1001-9278.2012.05.012

Abstract ( 1320 )

The rheological behavior of poly(methyl methacrylate)/styrene maleic anhydride copolymer(PMMA/SMA) was investigated, where the effects of content of maleic anhydride(MA) on the timetemperature superposition (TTS) and the temperature dependency in PMMA/SMA were discussed. It indicated that for PMMA/SMA12 with 12 % MA in SMA, TTS was valid and there were positive deviations in the loglinear relation between relaxation time and composition at lower temperature, while the positive deviation became weaker with the rising of temperature and negative deviation occurred in some compositions. For PMMA/SMA28, TTS failed due to the dynamic asymmetry, where the relaxation time and the composition followed a loglinear relation at lower temperature while positive deviation occurred at higher temperature.

Study on Corona Discharge Treatment of In Printing and Cold Resistant CPP Packaging Film

2012, 26 (05): 74-77 ; DOI: 10.19491/j.issn.1001-9278.2012.05.013

Abstract ( 1287 )

The influence of different antistatic agent, corona discharge power, and treating technology on wetting tension of three-layer casting polypropylene film (CPP) film was studied. When antistatic agent ASPA 2446 OB DC was introduced, the CPP film treated with two station corona could preserve a wetting tension over 38 mN/m after 30 days. This film could used in both in printing and heat sealing，and could directly be used in low temperature packaging field without laminating.

Development and Application of Polypropylene Used in Injection Molded Appliances

MA Guoyu WANG Hui CAO Huan

2012, 26 (05): 78-82 ; DOI: 10.19491/j.issn.1001-9278.2012.05.014

Abstract ( 1277 )

In this paper, the density, melt flow rate, impact strength, and shrinkage of four kinds of polypropylene resins used in injection molded appliances were tested, and their crystallization behavior and crystal structure were characterized using polarizing microscope. The affecting factors on impact strength and processing performance of EP548R were analyzed. When nucleating agents were added, the mechanical properties of EP548R increased, and met the demands for large injection molded thinwalled products.

Effect of Vacuum-predecomposition on the Thermal Stability of PMMA

Cao Chunlei

2012, 26 (05): 83-87 ; DOI: 10.19491/j.issn.1001-9278.2012.05.015

Abstract ( 1477 )

The thermal degradation behavior of PMMA, which were predecomposed with different time under vacuum condition, were investigated by thermogravimetry (TG)，and the initiation activation energy and activation energy at different weight loss stages were calculated by the methods of Flynn and Flynn-Wall-Ozawa. It showed that, only the PMMA chains with unsaturated ends decomposed during vacuum-predecomposition, and the predecomposing time had not any effect on the molecular weight of them. Those PMMAs after predecomposing were much more thermal stable than original ones, and the less the unsaturated ends on the chain, the better its thermal stability. The reduction of unsaturated ends in the chain could increase the activation energy of the mass loss near 50 %, but had no effect on that at subsequent stages.

Br/N Intrinsically Flame Retardant Epoxy Resins

2012, 26 (05): 88-93 ; DOI: 10.19491/j.issn.1001-9278.2012.05.016

Abstract ( 1862 )

Flame retardancy，thermal properties, and smoke suppression of epoxy resins treated with poly(N2,3,5,6tetrabromopdimethyl phenyl)ethylamine (BNFR) were investigated by means of thermogravimetric analysis, Fourier transform infrared (FTIR), limited oxygen index, and comprehensive vertical flame detector. It showed that owing to participation in the curing reaction of epoxy compounds and hardeners, BNFR was covalently bonded in the hardened threedimensional network, the leaching during processing cycle and usage periods was inhibited. BNFR had excellent flame retardant effectiveness. After adding 12 % BNFR, the limited oxygen index of conventional epoxy resins was 30 %, and the char residual ration reached to 10 % at 600 ℃.

Synthesis of Polyborosiloxane and Its Effect on Flame Retardancy and Mechanical Properties of PE-HD/EVA/IFR　Composites

WANG Feng GU Xiaoyu ZHANG Sheng CHEN Xiaoping CHEN Xiaosui DONG Mingzhe

2012, 26 (05): 94-97 ; DOI: 10.19491/j.issn.1001-9278.2012.05.017

Abstract ( 1578 )

Polyborosiloxane resin was synthesized from diphenyldimethoxysilane and phenyltrimethoxysilane through hydrolysis and condensation, and then was blended with low density polyethylene/ethylene vinyl acetate coplymer/intumescent flame retardants (PELD/EVA/IFR) composites to improve the compatibility between IFR and polymer. The flammability and the thermal behavior of the composites were investigated using limiting oxygen index and thermogravimetric analysis. It showed that a better flame retardancy was achieved by the addition of the polyborosiloxane resin with minimal negative effects in the mechanical properties.

Devulcanization of Ground Tire Rubber Through Stress-induced Reaction and Preparation of Dynamic Vulcanized HDPE Thermoplastic Elastomer

2012, 26 (05): 98-103 ; DOI: 10.19491/j.issn.1001-9278.2012.05.018

Abstract ( 1193 )

The effects of screw rotation speed, extrusion temperature and the addition of devulcanizing agents (2butyl alcohol, nbutyl amine, and alkyl phenol disulfide 420 or 450) on the various behavior of mixtures of ground tire rubber (GTR) and PEHD were investigated. The high shear stress during melt extruding induced chain scission and oxidative degradation of the crosslinking network of the ground tire rubber, leading to the decrease of the gel content of the devulcanized blends, the increase of their melt flow rate, and the decrease of the size of gel grain in dynamic vulcanized PEHD thermoplastic elastomer. The four devulcanizing agents all accelerated the devulcanization reaction during the extruding process, especially the alkyl phenol disulfide 450 and nbutyl amine achieved a better accelerating effect. In the best devulcanization condition (240 ℃ and 1000 r/min and in presence of nbutyl amine), the tensile strength and elongation at break of a dynamically vulcanized devulcanized blends/EPDM thermoplastic elastomer reached 12.5 MPa and 440.6 %, respectively.

Application of Digital Filtering on Online Measuring System for Polymer Rheometer

ZHONG Long XU Hong WU Daming LIU Ying

2012, 26 (05): 104-108 ; DOI: 10.19491/j.issn.1001-9278.2012.05.019

Abstract ( 1256 )

During the measurement of melt viscosity, the pressure would change throughout the process, and the accuracy of shear viscosity was affected. The filtering algorithm was chosen to adapt the changes of system to filter the pressure and the temperature through experiments and theoretical analysis. The digital filter was done to improve the final accuracy of polymer melt viscosity. Through the use of recursive average algorithm, the measurement accuracy of polymer melt shear viscosity was significantly improved.

Numerical Simulation of Extruded Microcapillary Film

Jianhua XIAO Yanfeng GAO

2012, 26 (05): 109-111 ; DOI: 10.19491/j.issn.1001-9278.2012.05.020

Abstract ( 1270 )

UG software was used to design the geometric structure of eighthole microcapillary film die. And the finite element method was used to simulate the forming section of extrusion die and extrudate parts. Parameter gradual change algorithm was used to investigate the relationship between different tensile stress and the shape or the cross section of extrudate. It showed that with increasing tensile stress, the dimensions of microcapillary film cross section became smaller. The eight air holes were deformed, from the circular to and then diamond, the oval. Because each part had different melt volume content, extrusion surfaces had obvious characteristics of stripe.

Design of Post Co-extrusion Die for Sealing Strip in Plastic Door and Window

YANG Ning

2012, 26 (05): 112-115 ; DOI: 10.19491/j.issn.1001-9278.2012.05.021

Abstract ( 1241 )

The design of post coextrusion die for sealing strip in the plastic door and window was introduced. Using gradient pressurized runner, installing preheating block to extend the heating distance, and dot location by screws were discussed. Using gradient pressurized runner effectively ensured the extrusion pressure. Installing preheating block prolonged the heating time for the bonding position, which could improve the bonding strength. Dot location by screws decreased the extrusion resistance, and effectively improved the extrusion speed. Production practices proved that the coextrusion die was simple for operation, exact for location, solved the problems of the plastic profile location, and improved the bond strength of sealing strip.