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2010, Volume 24 Issue 08 Publication date: 26 August 2010 Previous Issue Next Issue

Progress in the Study of Structure and Properties of Heterophasic

2010, 24 (08): 1-8 ; DOI: 10.19491/j.issn.1001-9278.2010.08.001

Abstract ( 1680 )

The significant research progress in relationships between structure and properties of reactor-blended hetero-phase impact-resistant during the last decade were summarized. The morphology of reactor-blended hetero-phase impact-resistant pristine particles as well as pellets and casting films were discussed first. Particular attention was focused on the multilayered core-shell structure of the dispersed phase. Origin of product's heterogeneity, coupling effects of phase separation and crystallization, and the pre-shearing effect on the phase morphology and material properties were presented. The fracture characteristics as a function of the dispersed phase composition and viscosity were also discussed.

Analysis of Situations of China Agro-film Industry（2010） and Countermeasures for Its Development

2010, 24 (08): 9-12 ; DOI: 10.19491/j.issn.1001-9278.2010.08.002

Abstract ( 2717 )

The status of domestic agricultural film industry was analyzed from a market point of view. In the year of 2010, The planting area covered by canopy film and ground film would reach 2.8×1010 m2 and 1.8×1011 m2, respectively. There were around 1000 agricultural film manufacturers in China, the amount of products was above 2 million tons per year. The actual consumption of agricultural film (canopy and ground films) was more than 2.2 million tons per year. In order to promote healthy development of agricultural film industry, suggestions were made on speeding up corporate restructuring, focusing on the development of science and technology enterprise, integrating the industry chains, and promoting consumption and services of agricultural film.

Advances in Study of Chlorinated PVC Resins Prepared by Gas-solid Phase Method

2010, 24 (08): 13-16 ; DOI: 10.19491/j.issn.1001-9278.2010.08.003

Abstract ( 1956 )

The preparation of solid-phase chlorinated polyvinyl chloride (CPVC) resins was reviewed. The production technology, reaction mechanism, and reaction kinetics were described as well as various chlorination methods including thermal, light, and plasma initiated ones.

Study on the Conductivity of Multiwalled Carbon Nanotubes Filled Polycarbonate/Styrene-series Polymer Composites

2010, 24 (08): 17-22 ; DOI: 10.19491/j.issn.1001-9278.2010.08.005

Abstract ( 2063 )

Polystyrene (PS), styrene-acrylonitrile copolymer(SAN), and methyl methacrylate-styrene copolymer(MS) were separately melt mixed with polycarbonate (PC) and multiwalled carbon nanotubes (MWCNTs) leading to three to composites, PC/PS/MWCNTs, PC/SAN/MWCNTs, and PC/MS/MWCNTs. The distribution of MWCNTs in the composites were examined uisng transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM). It was found that MWCNTs were prefrably localized in PC phase, which was in agreement with Sumita's model. With increasing contents of PS, SAN or MS, the curves for resistivity of the composites versus contents of styrene-based polymer agreed well with curves for resistivity of PC/MWCNTs composites versus effective volume concentration of MWCNTs, which was in accordance with the concept of effective volume concentration.

Preparation and Properties of Phenolic Resin/Montmorillonite Nano-composites

2010, 24 (08): 23-27 ; DOI: 10.19491/j.issn.1001-9278.2010.08.006

Abstract ( 2107 )

Phenolic resin/montmorillonite(PF/MMT) nano-composites were prepared via in-situ polymerization in this paper. Through the research on mechanical and electrical properties of PF/MMT composites, it was found that the overall performance was the best when the content of montmorillonite was 5 wt %, the tensile strength of the PF/MMT nano-composite was 2.33 times that of neat phenolic resin, and the volume resistivity also increased four orders of magnitude. Meanwhile, the temperature at the maximum thermal weight loss rate increased 15.24 ℃, the line ablation rate was 80 % of neat phenolic resin. An ablation model of the anti-ablative composites was established through the observation of surface ablation of the composites by SEM.

Preparation and Flame Retardancy of PC/ABS Alloy Flame Retarded by Polyborosiloxane

2010, 24 (08): 28-31 ; DOI: 10.19491/j.issn.1001-9278.2010.08.007

Abstract ( 2235 )

The effect of polyborosiloxane on the flame retardancy properties of PC/ABS alloy was evaluated using limited oxygen index and cone calorimeter analysis. When 5 wt % of polyborosiloxane was added, the limited oxygen index of PC/ABS alloy increased from 24 % to 28.6 %, the fire performance index increased 63 %. The addition of polyborosilonaxe also decreased the total heat release and the emission of CO, CO2, and smoke during the combustion of PC/ABS alloy. The presence of polyborosiloxane promoted the formation of the char that protected the material matrix and moderated the combustion process.

Study on Emulsion Copolymerization Kinetics of Styrene/3-(trimethoxysilyl)propyl Methacrylate

ZHAO Hong-Chi Xiuting WU Shanshan GAO Lingling GAO Zhiwei SONG Haiying BAI

2010, 24 (08): 32-36 ; DOI: 10.19491/j.issn.1001-9278.2010.08.008

Abstract ( 2078 )

The copolymer of styrene (St) and 3-(trimethoxysilyl)propyl methacrylate (TMSPMA) was synthesized via emulsion copolymerization using sodium dodecyl sulfate and octylphenol polyoxyethylene ether as emulsifiers. The effects of content of emulsifier, initiator, and TMSPMA as well as polymerization temperature on the polymerization rate were investigated in detail. The copolymerization between TMSPMA and St was confirmed by the appearance of absorption peaks at 1090 cm-1 (due to Si-O-Si bonds) and 1723 cm-1 (due to C=O bonds) in FT-IR spectrum. The polymerization rate increased with increasing polymerization temperature, molar concentration of emulsifier and initiator, but decreased with increasing molar concentration of TMSPMA.

Rheology Research of Polymer Crystallization Behavior

2010, 24 (08): 37-40 ; DOI: 10.19491/j.issn.1001-9278.2010.08.009

Abstract ( 2337 )

The rheological behavior during the polymer crystallization was discussed. The early behavior in crystallization was determined by the gel transition point, and the overall crystallization process as well as the crystallization kinetics in static and dynamic conditions were described by the real-time determined rheological parameters. It was showed that rheological study played an important role in the analysis of polymer crystallization process.

Synthesis and Characterization of Polyaniline-La

wu tao

2010, 24 (08): 41-44 ; DOI: 10.19491/j.issn.1001-9278.2010.08.011

Abstract ( 2004 )

Polyaniline-La (PANI-La) was synthesized in a solution containing 0.3 mol/L aniline，2.0 mol/L HCl, and a certain amount of LaCl3, using peroxydisulphate as an oxidant. The effect of the La3+ concentration on the conductivity and structure of PANI-La was studied. It was indicated that when the concentration of La3+ was 0.3 mol/L, the PANI-La had higher conductivity at room temperature. UV and FT-IR spectra showed that there was the interaction between La3+ and N on the PANI chains.

Flame Retardancy and Influencing Factors of Epoxy Resin Flame Retarded by Intumescent Flame Retardant

LU Guang-Yu

2010, 24 (08): 45-48 ; DOI: 10.19491/j.issn.1001-9278.2010.08.012

Abstract ( 1686 )

Three intumescent flame retardant, KDIFR, MAPP, and APP were introduced separately into epoxy resin (EP) and their effects were compared. Limiting oxygen index and horizontal burning test showed that APP had the best flame retardancy behavior among the three. When the mass ratio of APP/EP was 0.3, the limiting oxygen index reached 32.2 %. The flame retardancy property of EP/APP could be further improved by introducing either aluminum or boron, or better the both. When the content of aluminum borate was 0.8 wt % of APP, the self-extinguishing time of EP/APP decreased to 24 s from 48 s. Thermal analysis indicated that heat absorbed during the thermal decomposition of APP nearly equal to that released during the thermal degradation of EP, which was the main reason for APP's good behavior. The char yield of EP/APP was promoted obviously when introducing aluminum and boron in the EP/APP composite.

Research on the Formula System of Injection Molded Foamed PP/Wood-flour Composites

2010, 24 (08): 49-54 ; DOI: 10.19491/j.issn.1001-9278.2010.08.013

Abstract ( 2041 )

Polypropylene (PP)/wood-flour foam composites were prepared in a regular injection molding machine via chemical foaming method. The effects of contents of AC, PP-g-MAH, and wood-flour on the apparent density, mechanical property, and microstructure of the composites were studied. When the content of AC was 1.2 phr, the foaming effect of the composite was the best, and the impact strength reached a maximum value of 20.23 kJ/m2. When the content of PP-g-MAH was 15 phr, the interfacial compatibility between wood-flour and PP, mechanical properties, and foaming effect of the composite were significantly improved. Excess loading of wood-flour led to decreasing of mechanical properties and foaming effect, and increasing of apparent density. The optimum content of wood-flour was 30 phr.

Crystallization Properties of Injection Molded PE-HD Thin-wall Parts

Bing-Yan Jiang HOU Wen-Tan

2010, 24 (08): 55-59 ; DOI: 10.19491/j.issn.1001-9278.2010.08.014

Abstract ( 1739 )

By simulation analysis utilizing Flow/3D module in Moldflow MPI5.0 and simultaneous thermal analysis, the effects of melt temperature and injection rate on the distribution of shear rate and melting enthalpy in thin-wall injection molding were studied. Three melt temperatures, 175, 195, and 215 ℃ were selected. Results of the injection moulding experiments of the thin-wall PE-HD part with a thickness of 0.8 mm showed that in the flow direction, the shear rate and the melting enthalpy of the melt close to the gate were much higher than those at other positions and decreased with increasing distance from the gate. For the melt at a distance between1.5 mm from the gate and the end of part, the shear rate stayed somewhere between 2000~4000 s-1 and no significant change in the melting enthalpy was observed when the distance was longer than about 5 mm. The melting enthalpy reached its peak value at the melt temperature of 215 ℃; The shear rate at the gate increased with increasing injection speed.

Effect of Nucleating Masterbatch and Screw Combination on the Properties of Glass Fiber Reinforced PET Composites

2010, 24 (08): 60-63 ; DOI: 10.19491/j.issn.1001-9278.2010.08.015

Abstract ( 1884 )

High effective nucleating masterbatch was prepared by melt intercalation approach, and its effect on the properties of glass fiber reinforced PET composites was investigated. When the content of nucleating masterbatch was 6 wt %, the initiative crystallization temperature and crystallization range of the composite increased 24.8 ℃ and 66.3 ℃ compared to the neat PET, respectively. The addition of masterbatch essentially diminished the cooling crystallization and made it possible for the molding was carried out at a mold temperature of 70 ℃. The effect of screw combination on the properties of fiber reinforced PET composites was also studied. It was found that if the shearing stress was too high the impact strength of composites would decline. Base on the optimized screw combination, the fiber reinforced PET composites with excellent comprehensive properties was prepared, the heat distortion temperature reached 228 ℃, the tensile, flexural, and impact strengths obtained were 159 MPa, 235 MPa, and 101 J/m, respectively.

Multi-objective Optimization of Injection Molding Processing Parameters Based on Neural Networks Ensemble

2010, 24 (08): 64-71 ; DOI: 10.19491/j.issn.1001-9278.2010.08.017

Abstract ( 1437 )

The data from CAE simulation orthogonal test was used as training samples to establish the neural networks ensemble approximate calculation agent model. With clear mathematical formula, the model may carry out global optimization by genetic algorithm quickly and accurately, and the optimal process parameters were obtained. By comparing and verification, this multi-objective optimization method can improve multiple quality indicators in the case of lacking sufficient orthogonal data.

Effect of Take-up Speed While Extruding on the Properties of PE/Stannum Conductive Composites

2010, 24 (08): 72-74 ; DOI: 10.19491/j.issn.1001-9278.2010.08.018

Abstract ( 1891 )

Polyethylene/Stannum (PE/Sn) conductive composites were prepared via high temperature extrusion and stretching-low temperature injection process. The effect of pelletizer speed (that is stretching speed) and content of Sn on the microstructure, electrical conductivity and mechanical properties were studied. Results showed that when the pelletizer speed increased from 35 r/min to 50 r/min, the stannum dispersed phase was stretched into smaller and longer fibers in the PE matrix, the content of Sn that induced electrical conductivity decreased from 9.2 % to 6.2 %, which means the percolation threshold of the PE/Sn composites decreased, and the mechanical properties of the composites increased.

Research on the Effect of Synergistic Flame Retardants on the Flame Retardancy of PE-HD/Ca(OH)₂ Composites

2010, 24 (08): 75-80 ; DOI: 10.19491/j.issn.1001-9278.2010.08.019

Abstract ( 2570 )

Ammonium polyphosphate (APP), MoO3, expandable graphite (EG), and micro-capsulated red phosphorus (MRP) were used as the synergistic flame retardants of the PE/Ca(OH)2 composite [Ca(OH)2 content 35wt%]. The mechanical property and flame retardancy of the composite were studied and the thermal behavior of the composite was analyzed by TG in nitrogen circumstance. It showed that the oxygen index of PE/Ca(OH)2 composites containing a few synergistic agent（APP，MoO3，EG，MRP）were improved by 2.38%, 4.76%, 7.14%, and 26.19%, respectively, compared with the default system. More solid and steady charcoal layer would be built during the process of thermal oxidation degradation.

Oxidation Resistance of a Star

Jun WANG Hui-ping ZHANG

2010, 24 (08): 81-85 ; DOI: 10.19491/j.issn.1001-9278.2010.08.020

Abstract ( 1515 )

A kind of star type hindered phenolic antioxidant was synthesized by introducing β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionyl chloride into poly(amidoamine)（PAMAM）as end groups. The oxidation resistance of the star antioxidants in PE-LLD and PP were studied. It showed that it had excellent processing property and oxidation resistance behavior in polyolefin resin. Applying to PE, the oxidation induction time (OIT) was 1.3 times that of antioxidant 1010 and was 1.4 times that of antioxidant 3114. Applying to PP, the oxidation resistance property was equal to antioxidant 1010 or 3114. The tensile strength of PE-LLD increased from 12.6 MPa to 17.9 MPa and the elongation at break increased from 652 % to 696 % with the addition of the star type antioxidant. The tensile strength of PP increased from 36.9 MPa to 40.0 MPa and the elongation at break increased from 182 % to 248 % with the addition of the star type antioxidant. After 25 min mastication, the melt flow rate of PE-LLD and PP with the star type antioxidants changed insignificantly.

Research on Heating Temperature and Holding Time of Waste Plastics/Phosphogypsum Compound Formwork

2010, 24 (08): 86-90 ; DOI: 10.19491/j.issn.1001-9278.2010.08.021

Abstract ( 1857 )

Waste plastics/phosphogypsum compound formwork was prepared via melt blending and hot-pressing molding. The effect of pressing temperature and holding time on the mechanical property and macroscopic morphology of the compound formwork were discussed. It showed that the best pressing temperature and holding time were 240 ℃ and 40 min, respectively. The static bending strength, elasticity modulus, and impact strength of thus obtained compound formwork were 50.6 MPa, 4.5 GPa, and 50.6 kJ/m2, respectively. The macroscopic morphology was dense, even-textured.

Analysis of Standards of Plastics Piping Systems for Hot and Cold Water Installations and the Basic Calculation

XIE Jian-Ling

2010, 24 (08): 91-98 ; DOI: 10.19491/j.issn.1001-9278.2010.08.022

Abstract ( 2238 )

The international standards and national standards and recent amending for plastic pressure piping systems for hot and cold water installation were introduced. Focusing on the properly designing and selecting technical parameters, calculation examples were provided to show how to determine the piping grade, level of pressure, and the pipe thickness.

Influence of Staggering Angle and Thickness of Kneading Blocks in an Intermeshing Co-rotating Twin-screw Extruder on Degradation of Polypropylene

2010, 24 (08): 99-102 ; DOI: 10.19491/j.issn.1001-9278.2010.08.023

Abstract ( 2219 )

The effect of staggering angle and width of kneading block of the intermeshing co-rotating twin-screw extruder on the degradation of polypropylene (PP) in granulation process were studied. It showed that with increasing staggered kneading disc angle and kneading plate thickness, the degradation of PP increased.