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2010, Volume 24 Issue 12 Publication date: 26 December 2010 Previous Issue Next Issue

Research Development of Ordered Mesoporous Polymers

Panbo LIU Jian JIAO Liang ZOU Xiangdong XU

2010, 24 (12): 1-7 ; DOI: 10.19491/j.issn.1001-9278.2010.12.001

Abstract ( 2201 )

The recent development of ordered mesoporous polymers and mesostrucutured carbon synthesized by self-assembly, hard template, and soft template methods is summarized. The above three synthetic methods and principle of mesoporous polymer are compared. It is pointed out that the way of using self-assembly of amphiphilic block copolymers and soft template exhibited much more advantage compared with hard template method to synthesize ordered mesoporous polymers and mesoporous carbon. Obviously, the morphology, meosoporous structure, skeleton chemical structure and physical and chemical properties of mesoporous materials synthesized by using amphiphilic block copolymer method and soft template method are distinctly affected by amphiphilic block copolymer types, template types and structure of polymer precursors. It is also pointed out that the main problems in the study of ordered mesoporous polymers and carbon are improving the regularity of ordered mesoporous polymers and the stability of mesoporous structure. Finally, the developing direction and application fields of ordered mesoporous polymers and carbon are looked forward to.

The application and development trend of plastics used in “light weight and environmental protection” auto

Xiwen LIU

2010, 24 (12): 8-13 ; DOI: 10.19491/j.issn.1001-9278.2010.12.00

Abstract ( 2417 )

the current application situation of plastics used in “light weight and environmental protection” auto were reviewed.The current situation and problems of plastics used for auto in our country were introduced.The development trend of plastics used for auto in future were discussed.

Study Progess of Microcellular Plastics Foamed by Supercritical CO₂

Bo CHENG Shuhua QI Bo WU Peng CAO

2010, 24 (12): 14-20 ; DOI: 10.19491/j.issn.1001-9278.2010.12.003

Abstract ( 2192 )

The characteristics and function of supercritical CO2 are introduced in this article. The four stages of supercritical CO2 foaming, gas dissolving, bubble nucleation, bubble growth, and cell shaping were introduced. In addition, three frequently-used processing methods, batching, extrusion, and injecting moldings of microcellular plastics are summarized. The effects of temperature, pressure, time, and external force field on cell structure are particularly discussed. The development trend of microcellular plastics in the future is also forecasted.

Preparation and Properties of Polystyrene/Polypropylene/ Nano-interrelated Kaolinite Composites

Guixiang HOU Senlin LI Xiaoming SANG Xiaolin MA

2010, 24 (12): 21-24 ; DOI: 10.19491/j.issn.1001-9278.2010.12.004

Abstract ( 2038 )

Nanocomposites of PP/PS/DMSO-intercalated kaolinite were prepared via melt blending. Studies of properties and structure of the composites showed that the addition of modified DMSO-kaolinite improved the processing behavior, mechanical properties, and thermal stability. Compared with neat PP/PS, the melt flow index increased 2.925g·10min-1, the impact and tensile strengths of the composites increased by 48.8% and 24.1%, respectively, when the content of the DMSO-kaolinite was 6 wt%. The scanning electron microscope(SEM) showed that the size of polystyrene domains decreased with K-DMSO added, and the compatibility of PP and PS was increased.

Research on the Toughening Modification of CPVC

Weixi KE Lan WANG Weiwei HAN Meng ZHANG Chuanxi SHEN

2010, 24 (12): 25-29 ; DOI: 10.19491/j.issn.1001-9278.2010.12.004

Abstract ( 2113 )

The toughening effect of acrylonitrile-butadiene-styrene copolymer (ABS), acrylonitrile-butadiene-methyl methacrylate copolymer (MBS), chlorinated polyethylene (CPE), poly(vinyl chloride), and dioctyl phthalate for chlorinated poly(vinyl chloride)（CPVC）was studied. While MBS, CPE, and ABS could improve the impact strength, MBS provided the best toughening modification. When the contents of MBS was 10 phr, the impact strength was increased by 48.8%. However, the addition of these modifiers caused reductions in tensile strength and Vicat softening point. The smallest reduction was observed in MBS based system, only 1.9 ℃ lower than that of neat CPVC(118.7 ℃). These tougheners also improved the processability of CPVC and which MBS behaved best. When MBS dosage was 10 phr, an optimal comprehensive properties of the modified system was observed.

Isothermal Crystallization Kinetics of PLLA/Reactable Nano-SiO2 Composites

Yougang GUO Yu-Dong Zhang Xiang-Min Xu Puyu ZHANG

2010, 24 (12): 30-35 ; DOI: 10.19491/j.issn.1001-9278.2010.12.006

Abstract ( 2063 )

PLLA/reactable nano-SiO2 (RNS) composites were prepared via melting blending. The isothermal crystallization behavior of PLLA and its composites was studied with differential scanning calorimetry(DSC) and the effect of RNS was explored. The crystallization Kinetics under isothermal conditions was described by using Avrami equation. It showed that RNS had the function of heterogeneous nucleation to PLLA matrix. With increasing RNS content, the crystallization rate K of PLLA matrix was increased and the half-time crystallization t1/2 decreased, while the Avrami exponent n had no significant change, which indicated that RNS hadn't changed the nucleation mechanism of PLLA. In addition, Arrhenius and Lauritzen-Hoffmann equations were employed to estimate the activation energy ΔE, the nucleation parameter Kg, and the end surface energies σe. It was found that the activation energy of the composites was smaller than that of the pure PLLA. The values of Kg and σe for the composites have increased slightly compared with pure PLLA.

Study on Properties and Morphology of PA6/POE Blends Compatibized by POE Grafted Itaconic Acid

Xijun LIU Baoqing HOU

2010, 24 (12): 36-41 ; DOI: 10.19491/j.issn.1001-9278.2010.12.007

Abstract ( 2083 )

In this paper, a series of ethylene-octene copolymer graft (POE-g-ITA) was prepared via melt grafting technique using a twin screw extruder. The grafted product was characterized uisng FT-IR，and the effect of the loading of itaconic acid initiator on the graft ratio and melt flow rate of POE-g-ITA were studied. The graft ratio of POE-g-ITA reached 1.36% when POE/ITA/DCP is 94/6/0.36. The obtained POE-g-ITA was introduced into PA6/POE blends through twin screw extruder. The mechanical properties and morphological structure of the blends were investigated. The impact strength of the PA6/POE blend containing 5 phr POE-g-ITA was 12.78 times higher than neat PA 6. The interface between PA 6 and POE phases became indistinct and the dispersion phase size significantly reduced, the interface interaction was markedly enhanced and the compatibility was significantly increased.

Thermal and Mechanical Properties of PMMA Reinforced by POSS

YANG Benhong Meng LI Zhijun HUANG Yun WU

2010, 24 (12): 42-45 ; DOI: 10.19491/j.issn.1001-9278.2010.12.008

Abstract ( 2051 )

A series of inorganic/organic nanocomposites was prepared by blending cage-like MMA-modified polyhedral oligomeric silsesquioxane (MMA-POSS) with PMMA in THF solvent. FT-IR and 29Si NMR were employed to characterize the structures of the nanocomposites. SEM micrographs showed that the as-prepared films were smooth with no aggregation of MMA-POSS observed. TG and DSC were used to investigate the thermal property, and tensile tests were carried out to determine the mechanical properties. It was found that a small amount of nano-sized MMA-POSS enhanced the thermal stability and mechanical properties of PMMA. When 1.0 wt % of MMA-POSS was incorporated, the Tg and Td increased by 16.9 oC and 21.0 oC, respectively.

Influence of PP-MAH on the Morphology and Properties of PP/Hemp Fiber Composites

Pengfei NIU Jianye CHEN Xiaoming WEI Xiaojun WANG Jie YANG

2010, 24 (12): 46-51 ; DOI: 10.19491/j.issn.1001-9278.2010.12.009

Abstract ( 2107 )

This paper investigated the influence of PP-MAH on skin/core morphology and mechanical properties of injection molded polypropylene/hemp fiber composites. Without PP-MAH, highly oriented HFs along flowing direction was observed in both skin and core zone of the specimen. Moreover, the incorporation of HFs induced the formation of β-form crystal in skin zone. The skin zone showed ductile fracture while core zone brittle fracture. When 5 phr PP-MAH was introduced, only in the skin zone was highly oriented HFs observed, in the core zone but random ones. The relative content of β-form crystals in the skin zone was reduced. Impact strength of the composite decreased slightly. Brittle fracture behavior in both skin and core zone of the composite was observed. Additionally, the tensile and flexural strengths were significantly improved with the presence of PP-MAH.

Study on Non-isothermal Crytallization Kinetics of POM and POM/ Calcium Carbonate Composites

Jiangtao HUI Zhengguang CHEN Yunyong LI Weiyan ZHOU Tao ZHOU Aimin ZHANG

2010, 24 (12): 52-56 ; DOI: 10.19491/j.issn.1001-9278.2010.12.010

Abstract ( 2051 )

The non-isothermal crystallization kinetics of polyoxymethylene (POM) and polyoxymethylene/calcium carbonate at different cooling rates was investigated using differential scanning calorimetry (DSC). The parameters of non-isothermal crystallization kinetics were obtained through Jeziorny and MO methods. It showed that the increase of cooling rates made the crystallization peaks of POM and POM/calcium carbonate move towards lower temperature and become wider. When the cooling rates was 5℃，10℃，15℃, and 20℃/min, the crystallization temperature peaks and crystallization heat of POM/calcium carbonate system were 144.6, 142.4, 141.2, 140.2℃ and 177.4, 152.2, 148.0, 137.2 J/g, respectively. Acting as a nucleating agent, calcium carbonate increased the crystallization temperature and accelerated the crystallization rate.

Study on Mechanical and Dynamic Mechanical Properties of PEG/PCL Mixed Soft Segments Degradable Polyurethane Foams

Liang Shu-En

2010, 24 (12): 57-62 ; DOI: 10.19491/j.issn.1001-9278.2010.12.011

Abstract ( 2134 )

PUF based on PEG/PCL mixed soft segments was prepared in one-step. The effect of the ratio and the molecular weight of PEG and PCL on both static and dynamic mechanical behavior was investigated. For both PEGs with molecular weight of 400 and 1000, the tensile strength, elongation at break, and constant strain stress increased with increasing content of PCL. Higher molecular weight of PEG favored the elongation at break, but did not favor the tensile strength and constant strain stress.

Crystallization Behavior of Linear Polypropylene/Low-density Polyethylene Foaming Systems

LIU Wei Bengang LIU Xiangdong WANG Yuxia ZHANG Guozhi XU

2010, 24 (12): 63-71 ; DOI: 10.19491/j.issn.1001-9278.2010.12.012

Abstract ( 2114 )

Linear polypropylene was blended with low-density polyethylene, and the crystallization behavior was studied by DSC/POM. It showed that low-density polyethylene could decrease the peak crystallization temperature and the absolute crystallinity of linear polypropylene, however, the melt behavior was slightly affected. Moreover, the non-isothermal crystallization kinetics study showed that low-density polyethylene could also increase the amount and reduce the size of spherulites by changing the crystallization nucleation behavior of linear polypropylene. As a consequence，the foaming potentiality of the blends was enhanced.

Study on End Sealing Technologies of Steel-plastics Composite Pipe

Mingyin JIA Ping XUE Aijun LI Yun DING

2010, 24 (12): 72-76 ; DOI: 10.19491/j.issn.1001-9278.2010.12.014

Abstract ( 2094 )

Production situation of steel-plastics composite pipes was summarized and the emphasis was focused on the end sealing technology. Discussed in this paper included the first-generation injection sealing, the second-generation butt welding sealing, and the third-generation self-melting sealing technology. Steel-plastics composite pipes can be sealed using the plastics itself by third-generation self-melting sealing technology. The third generation self-melting sealing technology can effectively overcome the disadvantages of conventional sealing technology which included big equipment investment, high energy consumption, and poor sealing quality. The third-generation self-melting sealing technology constituted also the important development trend of end sealing technology of steel-plastics composite pipes.

Solution of Cracking Problem on Injectiong molded Chair Parts

Xin WANG Linfang DU Haimei LI

2010, 24 (12): 77-79 ; DOI: 10.19491/j.issn.1001-9278.2010.12.016

Abstract ( 2436 )

For the cracking problem of chair parts, it was found that the injection molded parts had the downward deflection warpage under the original conditions by the simulation analysis of Moldflow. The largest warpage reached 1.6 mm. A quantitative calculation showed that the frictional force between the injection molded parts was greater than 14 kN. It was deduced that the process conditions and mould structure factor were the reason of cracks on the injection molded parts. Finally, by optimizing process parameters and changing the original mould structure, the problem was solved.

Study on Rheological Behavior of Non-halogen Flame-retarded PC/ABS Alloy

Ruo WU Huili DUAN Chunlin LIU

2010, 24 (12): 80-83 ; DOI: 10.19491/j.issn.1001-9278.2010.12.017

Abstract ( 2237 )

Rheological behavior of non-halogen flame-retarded PC/ABS alloy was studied, the relationship of melt apparent viscosity and shear stress/shear rate was found. It showed that this system was non-Newtonian pseudo plastic fluid and the apparent viscosity of the melt decreased with the increase of shear rate. At the temperature of 230 ℃, non-Newtonian index of the alloy increased with increasing content of the flame-retardant. When the shear rate was 200-3000s-1, the viscosity value of the alloy was not sensitive to temperature.

Preparation of PTFE/YSZ Composite Microporous Membrane by PTFE Resin Emulsion and Investigation on Porosity

Jinli DU Xinhua DENG Yuan SUN Yanhui LUO Xiangchuan PANG

2010, 24 (12): 84-88 ; DOI: 10.19491/j.issn.1001-9278.2010.12.018

Abstract ( 1732 )

In this paper, PTFE/YSZ composite microporous membrane was prepared by mechanical tension of a PTFE emulsion containing YSZ micro/nanoparticles. The structure and performance of PTFE/YSZ composite microporous membrane were characterized uisng scanning electron microscope (SEM). The effects of the dispersant PVA, draw ratio, YSZ content, and calcination temperature on the porosity of composite microporous membrane were systematically investigated. It was found that the porosity increased significantly with increasing PVA and YSZ contents. The porosity reached 73.09 % when the draw ratio was 3.5 times, YSZ contents 8 %, and the calcinations temperature 320 ℃.

Research on Preparation and Properties of Water Blown Antistatic Semi-rigid Polyurethane Foams

Liang Shu-En TIAN Chun-rong TIAN WANG Jian-hua WANG WEI Chun-rong WEI

2010, 24 (12): 89-93 ; DOI: 10.19491/j.issn.1001-9278.2010.12.019

Abstract ( 2084 )

Water blown antistatic semi-rigid polyurethane foams (SRPUF) with different content of conductive carbon black (CB) or hard segment (HS) were prepared through one-step moulding process. IR spectra, electro conductivity, mechanical and viscoelastic properties of SRPUF were characterized. With increasing content of CB or HS, volumetric resitivity of SRPUF decreased. With increasing content of CB, tensile modulus of SRPUF increased, but tensile strength and elongation at break decreased. With increasing content of HS, modulus and compressive strength increased, tensile strength remained unchanged, but elongation at break decreased obviously. With increasing content of CB or HS, glass transition temperature (Tg) of SRPUF moved to lower temperature or higher temperature respectively, but dynamic modulus changed similarly: decreased gradually at lower temperature than Tg, and increased gradually at higher temperature than Tg.

Application of Polymeric Flame-retardant BPS in HIPS

Liang CHEN Haojie WANG Can ZHANG LIU Ji-Chun

2010, 24 (12): 94-97 ; DOI: 10.19491/j.issn.1001-9278.2010.12.020

Abstract ( 2140 )

Flame retardant blend of high impact polystyrene (PS-HI) and bromopolystyrene (BPS) was obtained by melt-compounding. Proper amounts of antimony oxide (AO) and organically modified montmorillonite (OMMT) were introduced to the blend as flame-retarding synergists. The flame retardancy of the blend was investigated by means of horizontal burning, vertical burning, oxygen index, and high temperature pyrolysis experiments. When the mass ratio of PS-HI/BPS/AO was 100/30/10, the oxygen index of the composite reached 28.1 % and the horizontal burning rating and vertical burning rating of the material were FH-1 and FV-0, respectively. When both AO and OMMT were added, the high temperature charring ability of the composite was enhanced obviously, suggesting that the flame retardant mechanism of the composite has changed from gas phase flame retardation to gas phase and condensed phase synergistic flame retardation. However, due to the much longer afterglow time, the composite containing both additives cannot reach FV-0 rating in the vertical burning test.

Effect of Crystallization Behavior and Transparency of Rosin Nucleated PP with Disperdsant Agent

Yaozhu Tian Song WANG Jun QIN Zhu LUO Jie YU

2010, 24 (12): 98-101 ; DOI: 10.19491/j.issn.1001-9278.2010.12.021

Abstract ( 1958 )

The effect of dispersant on the non-isothermal crystallization behavior of neat PP and rosin-nucleated PP was studied by means of DSC and PLM. It showed that dispersant A and C could increase crystallization temperature and crystallization rate, and decrease the spherulite sizes. However, the effect of dispersant B was moderate. Key words: polypropylene；rosin type nucleating agent；dispersant agent；non-isothermal crystallization

Research Status of Safety of Microwave Food-use Plastic Packaging Materials at Home and Aboard

Cui SONG Shuxiang CHEN Cuiling GAO Weishan WANG Chao XU

2010, 24 (12): 102-106 ; DOI: 10.19491/j.issn.1001-9278.2010.12.022

Abstract ( 2057 )

The research status of safety of microwave food-use plastics packaging materials in the developed countries and China was reviewed, including the research on the substance migration of microwave food-use plastic packaging materials, and the impact of microwave on the substance migration of packaging materials, etc. The related regulations and standards in America, Europe, Japan, and China were also introduced in the paper. Compared with the developed countries, the research in China on the safety of microwave food-use plastics packaging materials was still in the initial stage, related regulations and standards were lack. Some suggestions were proposed.

Effects of Configuration Parameters Metering of zone on Pressure-Developing Capability of Injection Screws

Ying LIU Chunling XIN Qingchun LI Baorui YAN Yawen ZHOU Yadong HE

2010, 24 (12): 107-112 ; DOI: 10.19491/j.issn.1001-9278.2010.12.023

Abstract ( 2120 )

In this paper, we use IMP software to simulate different screws. First, we have designed experiments to verify the reliability of the simulation software. And by the comparison between the experiment results and the simulation results, we have verified that the software is accurate and reliable, then we can use the software to simulate the plasticizing process of different screws, and we can avoid doing a great deal of complicated experiments to obtain regular results. For studying the effects of metering depth and metering pitch on building pressure of screws, we have simulated some screws which are different in metering depth or metering pitch. And we get the pressure along the screws. By analyzing the pressure curve along the screws or the pressure gradient, we get the relations between the metering depth and the pressure developing capability, or the relations between the metering pitch and the pressure developing capability. The results show that the smaller depth or pitch gives the stronger pressure developing capability..