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2012, Volume 26 Issue 01 Publication date: 26 January 2012 Previous Issue Next Issue

Research Progress in Gas-phase Process for Polypropylene

FU Yi ZHAO Chengcai ZHAO Zenghui REN He ZHANG Liyang LANG Xiaomei

2012, 26 (01): 1-6 ; DOI: 10.19491/j.issn.1001-9278.2012.01.001

Abstract ( 1933 )

The gas-phase processes used in various corporations for production of polypropylene were summarized with their technical characteristics, catalyst used, reaction condition, and product introduced. The processes included Innovene process of Ineos Corporation, Unipol process of Dow Corporation, Novolen process of NTH Corporation, Spherizone process of Lyondell Basell Corporation, Horizone process of Japan Polypropylene Corporation, and Sumitomo process of Sumitomo Chemical Company. The developing situation of gas-phase process for polypropylene in China was analyzed，and some suggestions were made.

Degradation of ABS and HIPS during Processing：A Review

2012, 26 (01): 7-11 ; DOI: 10.19491/j.issn.1001-9278.2012.01.002

Abstract ( 1849 )

Some studies 00 the effectS of processing cycle and processing temperature as well as accelerated aging on the degradation of acrylonitrile-butadiene-styrene (ABS) copolymer and high impact polystyrene (PS-HI) were ?ntroduced to supply information for the people who processed and recycled ABS and PS-HI.

Research Progress in Magnetic Responsive Shape Memory Polymers

2012, 26 (01): 12-17 ; DOI: 10.19491/j.issn.1001-9278.2012.01.003

Abstract ( 1512 )

Research progresses in magnetic responsive shape memory polymers were reviewed, including poly(lactic acid), polycaprolactone, and polyurethane. The application of magnetic responsive shape memory polymers in biomedical engineering was introduced, including drug delivery, orthopaedic, fracture fixation, and stroke. The developing trend of magnetic responsive shape memory polymers was also outlooked.

Study on MBS copolymer Toughened PMMA Resin

Lichun GUO Liang REN Mingyuan LI Yimei LIU Mingyao ZHANG Huixuan ZHANG

2012, 26 (01): 18-22 ; DOI: 10.19491/j.issn.1001-9278.2012.01.004

Abstract ( 1562 )

A series of methyl methacrylate-butadiene-styrene copolymer (MBS), in which polybutadienc（PB） particles were grafted with St and methyl methacrylate (MMA), was synthesized via emulsion polymerization. The obtained MBS was blended with PMMA forming blends. The mechanical properties and morphology of PMMA/MBS blends were studied. It was found that the impact strength of blends increased and then decreased with increasing PB content in MBS. When the PB content in MBS was 50 %, the impact strength was 200 J/m. The morphology of the blends showed that the dispersion of MBS in the PMMA matrix became poorer with decreasing degree of grafting of PB.

Study on Thermal Conductivity and Mechanical Property of PE-HD Composites

CHENG Min WEI Yabing ZHANG Yuncan

2012, 26 (01): 23-28 ; DOI: 10.19491/j.issn.1001-9278.2012.01.005

Abstract ( 1768 )

The composites of PE-HD/graphite/toughening master batch were prepared using a twin-screw extruder. The effects of size and content of graphite, and surface treatment on thermal conductivity and mechanical properties of the composites were investigated. It indicated that the graphite was best treated with titanium acid grease NDZ201. The smaller the particle size of graphite, the larger the thermal conductivity and mechanical properties. CaCO3 toughening master batch could increase the thermal conductivity and mechanical properties of the composites. When the mass ratio of PE-HD/graphite/250B was 45/30/25, the thermal conductivity of the composite was 1.72 W/(m·K), the impact strength was similar to neat PE-HD, the tensile strength and flexural strength of the composites increased by 52 % and 88 %, respectively.

Non-isothermal Crystallization Kinetics of PA6/PPO Blends

2012, 26 (01): 29-34 ; DOI: 10.19491/j.issn.1001-9278.2012.01.006

Abstract ( 1502 )

The non-isothermal crystallization behavior of PA6/PPO blends was studied with differential scanning calorimetry. The methods of Jeziorny and Mo were used to analyze the non-isothermal crystallization kinetics of the blends. Results demonstrated that the crystallization of PA6 could be accelerated by PPO，however，depressed by PPO-g-MAH, SEBS-g-MAH and SEBS. Both Jeziorny and Mo methods were suitable for the analysis of non-isothermal crystallization of PA6/PPO blends.

Study on the Properties of PA6/ABS Blends

2012, 26 (01): 35-40 ; DOI: 10.19491/j.issn.1001-9278.2012.01.007

Abstract ( 1398 )

PA6 / ABS blends were prepared by blending PA6 (polyamide 6) and ABS (acrylonitrile-butadiene-styrene) resins. The effect of the amount of ABS resins on the properties of PA6/ABS blends was investigated. And different of rubber content in ABS/SAN blends were prepared in situ by blending SAN resins (acrylonitrile-styrene copolymer) and ABS graft copolymer. The effect of rubber content in ABS/SAN blends on the properties of PA6/ABS blends was investigated. SAM resins (styrene -acrylonitrile-maleic anhydride copolymer) were introduced into the blends to replace part of the SAN resins. The effect of SAM resins content on the properties of blends was investigated. The results indicated that the blends with 50 wt%-60 wt% ABS resins showed optimum properties. The tensile strength, elastic modulus, bending strength and bending modulus of blends decreased with the increment of rubber content in ABS/SAN blends. Tensile and bending performance of blends first decreased, then increased with the increment of SAM resins content in SAN resins. But the melt flow rates of blends decreased with the increment of SAM resins content. Difference of blending sequence with SAM resins showed little effect on mechanical properties of blends.

Study on Properties of Poly(lactic acid)/Acetic Starch/OMMT Nano-composites

Xiuling LU

2012, 26 (01): 41-45 ; DOI: 10.19491/j.issn.1001-9278.2012.01.008

Abstract ( 1434 )

The nano-composites of poly(lactic acid)/acetic starch/ organic montmorillonite (PLA/AS/OMMT) were prepared via extrusion melt intercalation. Thermal properties, rheological behavior and phase morphology of the nano-composites were analyzed using scanning calorimetry, dynamic rheometer, and scanning electron microscopy. It showed that OMMT increased the interaction between PLA and AS, inhibited the aggregation of AS, caused the decrease of particle size of AS. However, OMMT decreased Tg and Tc of the nano-composites.

Research in Compound Modification for Mix Rare Earth Oxides by Surface Coating Hyperbranched Poly(amine-ester)

2012, 26 (01): 46-53 ; DOI: 10.19491/j.issn.1001-9278.2012.01.009

Abstract ( 1369 )

The surface organic modification of ultrafine RE2O3 (RE2O33, RE = La, Ce, Pr, Nd, etc.) was studied. Hyperbranched poly(amide-ester)（HBPAE）were obtained from solution polycondensation of an AB2-type monomers（prepared in a reaction between diethanolamine and succinic anhydride at room temperature）, which was compounded with RE2O3 and was uniformly coated on the surface of RE2O3 particles through mechanical stirring. The HBPAE/RE2O3 composites were characterized using FTIR, elemental analysis, XPS, SEM, XRD, and TGA and compared with raw RE2O3. It was found that 4.71 % of HBPAE were attached with RE2O3 particles via coordination bonding, thus the modification was limited on the surface of RE2O3 and no effect on the crystal structure of bulk RE2O3 particles. The thermal stability of HBPAE/RE2O3 could be tailored by the ratio of HBPAE to RE2O3. The dispersion stability of RE2O3 in organic solvents was also improved by the surface coating.

Preparation and Properties of Polypropylene/PP-g-MAH/Epoxy Resin/Glass Fiber Composites

LIANG Shan LUO Zhu YU Jie LI Yang LI Qingfeng TU Xingwen

2012, 26 (01): 54-58 ; DOI: 10.19491/j.issn.1001-9278.2012.01.010

Abstract ( 1578 )

The composites of polypropylene/maleic anhydride grafted polypropylene/epoxy resin/glass fiber (PP/PP-g-MAH/EP/GF) were prepared via a twin-screw extruder. Effects of contents of PP-g-MAH, epoxy resin and curing agent on mechanical properties of the composites were studied. It showed that the tensile strength, the flexural strength, and the impact strength of the composites were increased by 41 %, 47 % and 86 %, respectively, compared with the composites without epoxy resin. The optimal mechanical properties of the composites were obtained when the contents of PP-g-MAH and EP containing curing agent were 10 phr and 3 phr, respectively. SEM showed that the bonding strength between GF and PP had been improved with the addition of epoxy resin.

Research in Properties of Rigid Polyurethane Foam Based on Soybean Oil-based Polyol

2012, 26 (01): 59-64 ; DOI: 10.19491/j.issn.1001-9278.2012.01.011

Abstract ( 1529 )

Petrochemical polyol was partially replaced with soybean oil-based polyol in the preparation of rigid polyurethane foam (RPUF). The effects of fraction of soybean oil-based polyol and density of RPUF on the properties of RPUF were studied. It showed that with increasing contents of soybean oil-based polyol, impact strength and compression modulus of RPUF reduced, however, the yield point gradually disappeared, and glass-transition temperature increased. With increasing density, the impact strength, compression modulus, and storage modulus of RPUF increased, the compression modulus reached 56.44 MPa.

Study on Melt Filling Mode and Trapping Air Mechanism in High Speed Micro-injection Molding

Shixun ZHANG Wei CAO Shubing YE Qian LI Changyu SHEN

2012, 26 (01): 65-70 ; DOI: 10.19491/j.issn.1001-9278.2012.01.012

Abstract ( 1866 )

In order to simulate the melt flow and melt front more precisely, mathematic models of coupled melt and air flows were formulated in terms of two phase flow theory. A viscoelastic model rather than conventional viscous model was employed to represent the relationship between stress and shear rate. To simplify the melt front simulation, a uniform mathematic model for melt and air flows at melt front was established using dimensionless parameters, and an iterative method was proposed to solve the viscoelastic flow problem. The melt front was tracked using level set method. Based on the proposed mathematic models and numerical methods, three type of flows and filling modes for low-, medium-, and high-speed micro-injection molding were investigated. In addition, the mechanism of air-trapping was analyzed and the possible location of trapped air was predicted. To verify the validity of the proposed method, a skew gear was designed and manufactured using high speed micro-injection molding. The actual trapped air location is in good agreement with the simulated results. This study showed that the filling mode depends on injection speed, material characters, and cavity size. The air-trapping was likely to occur at the jetting mode.

Study on Infiltrating Performance and Chemo-Rheological Behavior of Epoxy Resin Used for Resin Transfer Molding

2012, 26 (01): 71-76 ; DOI: 10.19491/j.issn.1001-9278.2012.01.013

Abstract ( 1424 )

The infiltration performance of epoxy resin used for resin transfer molding (RTM) to fibers was studied. It indicated that after fibers was treated with acetone, the infiltration performance of RTM epoxy resin became improved. A chemo-rheological model based on the dual-Arrhenius equation was formulated, and it was predicted that the viscosity of RTM epoxy resin was below 800 mPa·s at temperatures between 35 and 75 ℃, and the hold time of low viscosity was more than 20 min, which was satisfied with RTM processing.

Influence of Various Factors on Vertical Combustibility of Polyurethane Rigid Foam

ZHOU Xiao-qian Ying-nan LIU Yan Wang

2012, 26 (01): 77-81 ; DOI: 10.19491/j.issn.1001-9278.2012.01.014

Abstract ( 1381 )

Polyurethane rigid foam was prepared from polyether polyols and isocyanate，containing DMMP and melamine as flame retardants. The influences of isocyanate index, contents of water, melamine, and DMMP on vertical combustion performance of the foam were studied. When the isocyanate index was 1.20, the content of water, melamine and DMMP were 2, 30, 35 phr, respectively, its vertical flame level reached FV-0 and compression strength was 8.86 MPa.

Study on Synthesis and Application of Fatty Acid Ester Antistatic Agent

XIA Peng NI Zhongbin DONG Weifu CHEN Mingqing

2012, 26 (01): 82-86 ; DOI: 10.19491/j.issn.1001-9278.2012.01.015

Abstract ( 1495 )

An antistatic agent was synthesized by esterification reaction of recycled poly(ethylene glycol) (PEG) with palmitic acid. The effects of catalyst content，ratios of PEG to palmitic acid，reaction temperature and time on esterification reaction were studied. It showed that the optimum conditions were as follows: the molar ratio of PEG to palmitic acid was 1.5/1，the amount of catalyst was 0.8 %，the reaction temperature was 140 ℃, and the reaction time was 5 h. The obtained fatty acid ester was used to polyethylene (PE) as antistatic agent. The influences of amount of antistatic agent, storage time of PE sample, and environment temperature on antistatic property were investigated. It was found that the antistatic effect become more obvious with prolonged storage time and increased environment temperature. The optimum antistatic effect was obtained when the content of antistatic agent was 3 phr.

Effect of Silane Coupling Agent Treatment on the Mechanical Properties of PLA/BF Composite

SHENG Yufeng WEN Bianying HU Xiaoqian

2012, 26 (01): 87-92 ; DOI: 10.19491/j.issn.1001-9278.2012.01.016

Abstract ( 1337 )

Effects of four kinds of silane coupling agents on the mechanical properties of PLA/ bagasse composites were investigated. The morphology of impact fractured surface of the composites was observed using scanning electron microscopy. It showed that treatment of silane coupling agent improved the mechanical properties of the composites to some extent. Z-6032 had better effect among the four silane coupling agents. The mechanical properties of the composites were also influenced by the particle size and content of bagasse. The impact strength of the composites increased as the particle size of bagasse decreased. With increasing bagasse content, the mechanical properties of the composite decreased.

Study on Blends Prepared by Waste PE-LD/PVDC/PE-LD Composite Film

yongxin shen wen zhang xiao chen lili yang

2012, 26 (01): 93-97 ; DOI: 10.19491/j.issn.1001-9278.2012.01.017

Abstract ( 1579 )

Waste PE-LD/PVDC/PE-LD composite film was recycled with addition of Ca-Zn stabilizer and chlorinated polyethylene (CPE) as a compatibilizer. The thermal stability, mechanical properties, barrier properties, and fracture surface micro-morphology of the blends were studied. It showed that with the addition of 1.2 phr Ca-Zn, the initial and complete Congo red color deterioration temperature of the blends increased by 8 ℃and 11 ℃, and the initial and complete Congo red color deterioration time extended by 67 s and 354 s, respectively. With the addition of 4.5 % CPE, the compatibility between PE-LD and PVDC improved because PVDC was embedded into PE-LD. The elongation at break of the blend increased by 76.70 %, the notched impact strength increased by 30.01 %, the oil absorption rate decreased by 33.61 % , compared with the blends without CPE. The flexibility and barrier properties of the blends increased markedly.

Study on Factors InfI uencing Clamping Force Repeatability of Injection Molding Machines

WANG Xiao-Hua Panpan Zhang Pengcheng Xie Weimin Yang

2012, 26 (01): 98-102 ; DOI: 10.19491/j.issn.1001-9278.2012.01.018

Abstract ( 1792 )

Charalcteristics of conventional measurerment methods of clamping force repeatability was discussed. Influencing factors on clamping force repeatability were invest igat ed by Baumer strain clamps (Switzerland) . It was found that the influences of variatlons of mold closing/ opening position and speed could be neglected. The test methods of clamping force repeatability based on Baume strain clamps had characteristics of easy operation and high accuracy.

Numerical Study on Mixing Characteristics of Screw Elements in Three-screw Extruders

PANG Junjian HE Yadon XIN Chunling YU Dongqua LI Qingchun

2012, 26 (01): 103-108 ; DOI: 10.19491/j.issn.1001-9278.2012.01.019

Abstract ( 1590 )

Three-dimensional isothermal flows of different screw elements in three-screw extruder were simulated using a polymer analysis package Polyflow. By statistical treatment of numerical results using Fieldview software, the mixing performances of screw elements were characterized and compared in terms of different evaluation methods It was found that the kneading blocks had stronger shearing and stretching actions than other elements, neutral kneading block and left-handed elements had better effect of backflow. Compared with screw thread elements, SME element has weaker shearing capacity, but higher stretching and backflow capacity. The screw elements could reasonably be selected based on the shear sensitivity of the materials in order to improve the quality of the products.