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2012, Volume 26 Issue 03 Publication date: 26 March 2012 Previous Issue Next Issue

Research Progress in Inorganic Nano Flame Retardants

FENG Fafei QIAN Lijun

2012, 26 (03): 1-9 ; DOI: 10.19491/j.issn.1001-9278.2012.03.001

Abstract ( 1580 )

In this paper, the recent research development of four kinds of flame-retardant additives was summarized i.e., inorganic nanoparticulate, nanolayered, fibrous, and nanocatalysed additives. Their effects on thermal, physical-mechanical properties, and flame retardancy of materials were discussed. At last, the existing problems and the developing direction of inorganic flame-retardants were pointed out.

Technical Development of Antimicrobial Materials for Food Active Packaging

Bizhong LI Zeguo LI Wen YANG Huixian CUI Bo MA Mingjie LU

2012, 26 (03): 10-16 ; DOI: 10.19491/j.issn.1001-9278.2012.03.002

Abstract ( 1554 )

Active packaging constituted a new technology for food preservation. Reviews in this paper were the antimicrobial agents, antimicrobial films, and bulk antimicrobial plastics used in packaging of a variety of foods. The development of antibacterial materials must be considered processing conditions, food type, storage environment and regulatory requirements.

Development of Toughening Modification of Cyanate Ester Resin

Kun WANG Guangming ZHU Ximin LI Lei NIU

2012, 26 (03): 17-22 ; DOI: 10.19491/j.issn.1001-9278.2012.03.003

Abstract ( 1579 )

The research progress in toughening modification of cyanate ester resin in recent years was reviewed. The toughening methods with different thermosetting resin such as epoxy resin and bismaleimide were introduced. The copolymers had excellent mechanical properties,l electricity, water resistance and thermal stability, and would be applied in electronic and aerospace materials.

Research on Poly(lactic acid)/Poly(butylenes succinate) Blends

2012, 26 (03): 23-27 ; DOI: 10.19491/j.issn.1001-9278.2012.03.004

Abstract ( 1318 )

In this study, poly (lactic acid) (PLA )/poly(butylenes succinate) (PBS) blends were obtained via melt blending and their compatibility, thermal property, viscosity, and mechanical property were investigated using scanning electron microscope, differential scanning calorimetry, and rotational rheometer. It showed that there was some compatibility between PLA and PBS, and the tensile strength was almost unchanged at low PBS loadings. The impact strength of the blend increased first and then decreased with increasing PBS content, providing a maximum at a PBS content of 10 phr. The viscosity of the blends increased with increasing PBS content. PBS also functioned as a heterogeneous nucleation agent, which promoted the crystallinity of PLA.

Study on Effect of TGDDM on Properties of PPO/PA66 Alloy

2012, 26 (03): 28-33 ; DOI: 10.19491/j.issn.1001-9278.2012.03.005

Abstract ( 1250 )

Polystyrene oxide (PPO)/polyamide 66 (PA66) alloys containing a reactive compatibilizer, N,N,N′,N′tetraglycidyl4,4′diaminodiphenyl methane (TGDDM), were prepared via melting reactive extrusion. The structure of the alloys was studied using Fourier transform infrared spectroscopy. The mechanical properties, rheological behavior, and microstructure of the obtained blends were investigated. It showed that, PA66coTGDDMcoPPO copolymers were formed in the reactive extrusion. With increasing amounts of TGDDM, melt flow rates of the alloys decreased, and energy consumption increased. A drastic improvement of mechanical property was observed upon addition of a very small amount of TGDDM. Scanning electron microscope showed that TGDDM changed the shape of the dispersed phase particles.

Study on Multi-layer Core-shell Rubber Particles Toughening PVC

2012, 26 (03): 34-38 ; DOI: 10.19491/j.issn.1001-9278.2012.03.006

Abstract ( 1385 )

Three-layer core-shell rubber particles (PSBMs) were prepared via emulsion polymerization. The PSBMs were designed with a hard inner polystyrene (PS) core, an interim soft poly(butadiene) (PB) layer, and a hard external poly(methyl methacrylate)(PMMA) layer, with mass ratios of 23/57/20, 13/67/20 and 0/80/20. PSBMs were introduced into PVC and the effects of morphology and distribution of PSBM on mechanical, optical properties, and deformation mechanism of the blends were studied. It was found that PSBMs dispersed finely in PVC. When the PS/PB/PMMA was 13/67/20, PSBMs toughened the PVC matrix effectively and retained high yield strength and transmittance. It also discovered that the interface between the inner core and interim layer could promote the cavitation of the rubber particles. The cavitation of rubber particles and shearing yielding of the matrix were the toughening mechanisms.

Study on Natural Rubber Grafted by Silane and Crosslinking in Hot Water

2012, 26 (03): 39-46 ; DOI: 10.19491/j.issn.1001-9278.2012.03.007

Abstract ( 1269 )

Using benzoyl peroxide (BPO) as an initiator, vinyl silane was grafted onto nature rubber via melt-blend forming NR-g-silane, which could be further treated via hot water crosslinking. The grafted rubbers were characterized using Fourier transform infrared spectroscopy (FTIR) and scanning electric microscopy (SEM). The effects of contents of silane and BPO, grafting and crosslinking conditions (time and temperature) on the gel content of crosslinked NR-g-silane were studied in this article. At the same time, the relationship between the gel content and mechanical property of the crosslinked NR-g-silane was also explored. With increasing contents of silane and BPO, blending time and temperature, crosslinking time and temperature, the gel content of the crosslinked NR-g-silane increased monotonously. With increasing gel content, an obvious improvement in mechanical property was observed. Compared with raw nature rubber, tensile strength and elongation at break of the crosslinked silane grafted nature rubber (80wt% gel) were improved by 30 % and 8.5 times, respectively.

Effect of Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) on the Crystalline Properties of Poly(3-hydroxybutyrate-co-3-hydroxyvalerate)

2012, 26 (03): 47-50 ; DOI: 10.19491/j.issn.1001-9278.2012.03.008

Abstract ( 1186 )

Biodegradable PHBV/PHBHHx blends were prepared by means of solventcasting method. The effect of PHBHHx on the thermal and crystalline properties of PHBV was investigated using differential scanning calorimetry and polarized optical microscopy. It showed that the cold crystallization temperature of PHBV shifted towards higher temperature with the increase of PHBHHx content in the blends. PHBV/PHBHHx blends exhibited banded spherulites. Furthermore, the banded spherulites of PHBV/PHBHHx blends became regular and clarity gradually with increasing PHBHHx content, and the band spacing became smaller.

Study on Damping Properties of Silicone Rubber/CPE Blend Foams

DING Guofang CAO Jun LUO Shikai SHI Yaogan

2012, 26 (03): 51-56 ; DOI: 10.19491/j.issn.1001-9278.2012.03.009

Abstract ( 1269 )

The foams of silicone rubber/CPE blends were prepared via mechanical blending methods. The compatibility of the components, influence of heat treatment time on density, foam structure and damping properties were investigated. The blends of silicone rubber/CPE showed a good compatibility. Compared with neat silicone rubber, the effective damping temperature range (tanδ＞0.3) was broadened from 16℃ to 45℃, the maximum loss factor was increased from 0.43 to 0.68, and the glass transition temperature increased by 13℃. However, the damping properties of the foams were damaged by heat treatment.

Research on Properties of In-situ Compatibilized PA6/PE-HD Blends

WANG Zhongqiang

2012, 26 (03): 57-61 ; DOI: 10.19491/j.issn.1001-9278.2012.03.010

Abstract ( 1226 )

polyamide 6（PA6）/high density polyethylene（PEHD） blends were prepared via insitu compatibilized reactive extrusion using a twin screw extruder. The reactive compatibilization of PA6/PEHD blends as well as the effect of content changes of PEHD on mechanical properties of PA6/PEHD blends were studied through mechanical property test, SEM, and Molau. The experimental results showed that PEHDgMAH was formed during the blending extrusion, which provided a good compatibilization on PA6/PEHD blends. Mechanical property and interfacial morphology of PA6/PEHD blends were improved obviously, meanwhile the water absorption decreased.

Study on Aging Property of Polypropylene/Wood Flour Composites

2012, 26 (03): 62-66 ; DOI: 10.19491/j.issn.1001-9278.2012.03.011

Abstract ( 1197 )

Polypropylene/wood flour composites (WPC) were prepared via injection molding, containing carbon black, titanium dioxide, and iron oxide as pigments. Effect of the pigments on aging property of WPC was studied through thermal-oxidative aging in oven and xenon lamp aging. It showed that with increasing aging time of WPC, the tensile strength and oxidation induction time decreased, and melt flow rate and color change increased with or without pigments. Before and after aging in the oven, the tensile strength, oxidation induction time and color change was lower for the WPC with titanium dioxide or iron oxide as pigment, and the melt flow rate of WPC was larger. In xenon lamp aging condition, the change speeds of tensile strength, melt flow rate, color and oxidation induction time of WPC with the pigments was lower than that of WPC without the pigments.

Effect of Drawing Process on Structure and Properties of Polyphenylene Sulfide Films

ZHANG Shouyu NIU Pengfei HUANG Baokui WANG Xiaojun YANG Jie

2012, 26 (03): 67-70 ; DOI: 10.19491/j.issn.1001-9278.2012.03.012

Abstract ( 1425 )

Polyphenylene sulfide (PPS) sheets were prepared using a HAAKE extruder and then were uniaxially-stretched into PPS film. The processing technology of uniaxially-stretched PPS films was discussed and the optimum stretching temperature was determined between 85℃~100℃. According to the analysis results of universal material testing machine, differential scanning calorimetry and X-ray diffraction tests, the impact of extrusion processing and tensile rate on the structures and mechanical properties of the uniaxially-stretched film was studied. With increasing tensile rate the orientation degree of the film increased, but the crystallinity, tensile strength and elongation at break of the film increased firstly and then decreased.

Effect of Modification Conditions on Properties of Rigid Polyurethane Foams

ZHOU Xiaoqian REN Jingxin LI Qingyu DOU Rui

2012, 26 (03): 71-74 ; DOI: 10.19491/j.issn.1001-9278.2012.03.013

Abstract ( 1313 )

Melamine and dimethyl methyl phosphate (DMMP) was used as flame retardants for rigid polyurethane foams. The effects of isocyanate index, the amounts of water, melamine, and DMMP on the flame retardant performance and tensile strength of the foams were studied. It was found that when the contents of melamine and DMMP were 25 parts each, water content was 1.5 parts, isocyanate index was 1.15, the foams provided the optimal comprehensive performance.

Effect of Modification Treated Waste Newspaper Recycling Fibers on Properties of Fibre Reinforced Poly(lactic acid) Composites

LI Xingong ZHENG Xia WU Yiqiang

2012, 26 (03): 75-78 ; DOI: 10.19491/j.issn.1001-9278.2012.03.014

Abstract ( 1226 )

The composites of recycled waste newspaper fiber (NRF) and poly(lactic acid) (PLA) were prepared via injection molding technology, and were further modified with MAPP or alkali. It showed that，addition of 2% MAPP improved the compatibility of PLA and NRF, and mechanical properties of the composites were enhanced. After NRF was treated with 1 % NaOH, crystallinity of NRF increased, surface bonding between NRF and PLA was improved, also resulted in increase of mechanical properties.

Hydrophilicity and Surface Structure of PET Films Modified by Radio Freqency Ar Plasma

XIE Linkun DAI Qingling HE Rui ZHANG Xuliang

2012, 26 (03): 79-83 ; DOI: 10.19491/j.issn.1001-9278.2012.03.015

Abstract ( 1421 )

The surface of polyethylene terephthalate film was modified using radio frequency RF-Ar plasma under a working pressure of 20 Pa and a power of 60 W for different length of time. The changes of hydrophilicity and surface structure of the film before and after modification were analyzed with static contact angle measurement, Fourier transformed infrared spectroscopy, X-ray photoelectron spectroscopy, and atomic force microscopy. It showed that the contact angles were gradually decreased with increasing treatment time within 0~120s, however, further treated for longer time caused no further changes and remained in the region between 22° and 23.5°. Polar groups such as C-N, N-C=O, C=O, C-O were formed on the treated film surface. Meanwhile, the surface roughness was increased and appeared conical or globular protuberances.

Effect of 4A Zeolite and SiO₂ on Properties of EVA/IFR Composites

Bin ZHAO Zilong XU Xiaoyu GU Jian XU Sheng ZHANG

2012, 26 (03): 84-87 ; DOI: 10.19491/j.issn.1001-9278.2012.03.016

Abstract ( 1239 )

Ammonium polyphosphate (APP) and pentaerythritol (PER) were introduced into EVA resin as an intumescent flame retardant (IFR). SiO2 and 4A zeolite have been used to improve the fire performance of the IFR-containing EVA. Limited oxygen index and thermal gravimetric analysis were used to characterize the flammability and thermal behavior of EVA composites. The morphology of the composite was observed and analyzed using SEM. It was found that a little amount of 4A zeolite could significantly improve the limited oxygen index value. The limited oxygen index of the sample containing 1 phr 4A zeolite reached 31%, contrasted to 29 % of the plain sample. When 3 phr silica was further added, the limited oxygen index increased to 32 % and V-0 level was reached in UL 94 test.

Preparation of Polystyrene-expanded Graphite Intercalated Complex and Its Modification on Polystyrene

Guixiang HOU Shaowei YAO Xiaoming SANG

2012, 26 (03): 88-91 ; DOI: 10.19491/j.issn.1001-9278.2012.03.017

Abstract ( 1317 )

Expandable graphite was prepared from natural flake graphite via chemical oxidation and high temperature processing. Via situ polymerization of styrene in presence of expanded graphite polystyrene-expanded graphite (PS-EG) composites were obtained. Melt blending PS-EG with neat polystyrene leading to polystyrene/polystyrene-expanded (PS/PS-EG) composites. The mechanical properties, thermal stability, and the microstructure of the composites were studied. The impact strength，thermal stability were improved with the adding of PS-EG. Compared with the neat polystyrene, the impact strength of PS/PS-EG composites was improved 63.4 %, when the content of PS-EG was 9 %, however the tensile strength showed a large decreasing. Micro-analysis showed that expanded graphite dispersed homogeneously in the form of vermiculate in the composites, and the existence of PS-EG increased the interface effect of the PS/PS-EG composite, the cross section of composites displayed a pinhole structure.

Numerical Simulation and Experimental Study on Recycle of Waste Thermosetting Polyurethane

WU Zhongwei LIU Guangfu LIU Zhifeng YANG Xuefeng PAN Shaobo

2012, 26 (03): 92-98 ; DOI: 10.19491/j.issn.1001-9278.2012.03.018

Abstract ( 1268 )

Recycling process of waste thermosetting polyurethane was proposed based on mechanical and physical methods, assuming the plastic had a three-dimensional reticular cross-linkage body structure. Using RNG k-ε dual equation turbulence model, a high speed flow field numerical simulation in the smashing recovery process was completed and optimal parameters of materials degradation process were obtained. The experiment showed speed and time factors had the greatest impact on the process. Finally, At last, the physical properties and morphology structure during the recycling was studied. ATR-FTIR infrared analysis proved that carbamate group may break at C-O bonding when the device speed exceeds 1500r/min and the experimental time exceeded 120 min. It meant that crosslinked structure was destroyed and the material resumed a thermoplastic behavior.

Optimization Integration of Injection Molding Analyzed Based on HyperMesh, Moldflow and Nastran

ZHAO Mei

2012, 26 (03): 99-102 ; DOI: 10.19491/j.issn.1001-9278.2012.03.019

Abstract ( 1383 )

The modeling, plotting finite element grids, analyzing, and calculating for an injection mold were completed with the aid of softwares HyperMesh, Moldflow, and Nastran, optimization integration of mold structure and mold flow was realized. The integration of injection technology and mold structure could comprehensively simulate the flowing of materials and the deformation of injection mold, and thus provided a basis for the mold design.

Dynamic Stress Analysis of the Ball Screw for Electric Operated Injection Molding Machine

2012, 26 (03): 103-107 ; DOI: 10.19491/j.issn.1001-9278.2012.03.020

Abstract ( 1359 )

A dynamic force model of the ball screw used for electric operated injection molding machine was established using contact angle, velocity, acceleration, and others as structure parameters. Relationship between the velocity and acceleration of nut and screw was obtained. The contact stress at the nut and screw sides was described in terms of Hertz stress formula, and the effect of the structure and motion parameters on the contact stress of ball screw was further analyzed. It showed that, for a ball screw, increase in either velocity or acceleration could cause increase in contact stress significantly.