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2012, Volume 26 Issue 07 Publication date: 26 July 2012 Previous Issue Next Issue

Development of Flame Retardant Polyolefin/Carbon Nanotube Nanocomposites

2012, 26 (07): 1-8 ; DOI: 10.19491/j.issn.1001-9278.2012.07.001

Abstract ( 1633 )

This paper reviews the latest research development of three polyolefin nanocomposites containing carbon nanotubes. The discussed materials are mainly those composed of multiwall carbon nanotube (MWCNT), including EVA/MWCNT/LS/ATH composites which exhibit the flame retardant synergism, and show promising of using as nonhalogen flame retardant insulation for wires and cables.

Research Progress in Structure and Performance of Shape Memory Polyurethane

2012, 26 (07): 9-15 ; DOI: 10.19491/j.issn.1001-9278.2012.07.002

Abstract ( 1439 )

The key factors which influence the performance of the shape memory polyurethane (SMPU) were discussed. The research progress in structure of hard or soft segments, cross-linking，blending, waterproof, and breathable performance of SMPU was summarized.

Statistics and Analysis of Patents for Chinese Flame Retardant Technology

2012, 26 (07): 16-19 ; DOI: 10.19491/j.issn.1001-9278.2012.07.003

Abstract ( 1175 )

The application data of Chinese patents on flame retardant materials from 1981 to 2011 have been analyzed. The general development of the flame retardant materials was compared with other fields. The application situations of invention patent and utility model during the recent 30 years have also been discussed and compared. Furthermore, the development trends of different kinds of flame retardant patents have been compared together. Finally, the future development of flame retardant technology of China was prospected.

Reinforcing and Toughening of Polymer Matrix Composites

DONG Jinhu

2012, 26 (07): 20-27 ; DOI: 10.19491/j.issn.1001-9278.2012.07.004

Abstract ( 2014 )

The methods and mechanisms in the reinforcement and toughening of polymers with small organic molecules, elastomers, rigid particles, fiber, and carbon nano-tubes were reviewed. Some representative polymer/reinforcer systems were introduced. The development of reinforcement toughening of polymers was forecast.

Synthesis of a Novel Polyamide Charring Agent and Its Flame Retardancy Effect in ABS

2012, 26 (07): 28-33 ; DOI: 10.19491/j.issn.1001-9278.2012.07.005

Abstract ( 1220 )

A novel polyamides charring agent (PPTA) was synthesized from terephthaloyl chloride and 1, 3-propanediamine through interfacial polymerization. The products were characterized using Fourier transform infrared spectroscopy (FTIR), 1H-NMR and thermogravimetric (TG) analysis. The effect of organic solvents, material ratio, and reaction time on the intrinsic viscosity of PPTA was investigated to confirm the optimized synthesis technique for PPTA. An intumescent flame retardant (IFR) comprised of PPTA as a carbon sources and ammonium polyphosphate (APP) as an acid sources was introduced into acrylonitrile-butadiene-styrene copolymer(ABS) and improved flame retardancy and increased char residue were observed. When the content of APP was 22.5 wt % and PPTA was 7.5 wt %, the limiting oxygen index of the composite was found to be 32.4 %, and grade V-0 of UL 94 test was passed. The microstructures of the composite indicated that PPTA promotes the formation of uniform and compact char layers in the composite after burning.

Flame Retardancy and Mechanical Property of Silicate Nanofiber Reinforced EVA Composites

2012, 26 (07): 34-38 ; DOI: 10.19491/j.issn.1001-9278.2012.07.006

Abstract ( 1227 )

The non-halogen flame retardant EVA composite containing magnesium hydroxide [Mg(OH)2] and microencapsulated red phosphorus (MRP) was prepared. EVA-g-MAH and silicate nanofiber (SNF) have also been used to improve the flame retardancy and mechanical property of EVA. Limiting oxygen index and thermal gravimetric (TG) analysis have been used to characterize the flammability and thermal behavior of EVA composites. The morphology of the composite has been observed and analyzed by SEM. It was found that the presence of EVA-g-MAH could improve the limiting oxygen index and mechanical properties. The composite containing 12 phr EVA-g-MAH has a limiting oxygen index value of 39% , the tensile strength of 10.2 MPa and the elongation at break of 521 % . When the loading of SNF was 20 phr, the limiting oxygen index reached 38%, the horizontal flame test reached V-0 level, the tensile strength reached 12.3 MPa, and the elongation at break reached 210 %.

Research in Polycarbonate Weathering

ZHANG Xiao-dong

2012, 26 (07): 39-42 ; DOI: 10.19491/j.issn.1001-9278.2012.07.007

Abstract ( 1328 )

Structure and properties of polycarbonate before and after weathering in WanNing，HaiNan province were investigated. Mechanical testing showed that, after weathering, the tensile strength of PC slowly reduced, and stiffness increased remarkably. During weathering, craze or crack appearing on the exposed surface resulted in decreasing light transmittance and generating carbon-carbon coupling double bond resulted in increasing yellowness; ATR-FTIR of exposed and back surface showed that, the possible degradation mechanism of exposed surface were Fries-rearrangement and photo-oxidation, but only Fries-rearrangement for back surface.

Research on Preparation and Mechanical Properties of Glass Fiber Reinforced Polyamide 6 / Montmorillonite Composites

Jiang Yong Zhao-hui Hu

2012, 26 (07): 43-45 ; DOI: 10.19491/j.issn.1001-9278.2012.07.008

Abstract ( 1281 )

Glass fibers reinforced polyamide 6 / montmorillonite composites were prepared via screw extruding method. Their mechanical properties were measured by an electronic all-powerful tester. It was observed that the tensile and impact strengths of the composites increased with increasing content of glass fiber. At a same loading, the strengths based on 12 mm glass fiber were higher than those on 6 mm glass fiber. When the content of glass fibers was 10% (12 mm)，the tensile strength and impact strength of the composites respectively improved 17.4 % and 84.1 % compared with those of the plain polyamide 6 / montmorillonite composites.

Study on Poly(lactic acid) Toughening Modified by Polyamide Elastomer

2012, 26 (07): 46-50 ; DOI: 10.19491/j.issn.1001-9278.2012.07.009

Abstract ( 1267 )

Polyamide elastomer(polyamide-polyoxyethylene copolymer, PAE) was used to toughen PLA via melt blending. It was found that a brittle-ductile transition occurred when PAE content was between 20 %～30 %. The maximum impact strength was 67.6 J/m, but the tensile strength and modulus decreased sharply. When the PAE contents were between 5 %～10 %, the blend exhibited the maximal comprehensive strength and toughness with the elongation at break increased by 40 times. SEM micropgraphs showed the blend was phase separated, but the DSC data showed that Tg and Tm changed as PAE content was changed. TG data showed that the degradation temperature of PLA increased with increasing PAE content. All the behavior indicated that the blend was partial miscibility for somewhat specific interaction between the two phases.

Preparation，Properties and Structure Characterization of Polypropylene/Modified Feldspar Composites

2012, 26 (07): 51-56 ; DOI: 10.19491/j.issn.1001-9278.2012.07.010

Abstract ( 1234 )

Hami feldspar was modified through surface wet method, which was used in polypropylene(PP)/modified feldspar composites. The properties and structure of PP/modified feldspar composites were characterized and analyzed. Interface contact angle measurement showed that the surface of modified feldspar particle was hydrophobic. When the loading of modified feldspar was 5 %, the tensile and impact strengths of PP/modified feldspar composites increased by 3.78 %, and 3.40 %, respectively, compared with those of neat PP. TGA showed that the heat decomposition temperature of the composites was 6.47 ℃ higher than that of neat PP. DSC determination indicated that modified feldspar acted as nucleation agent which promoted the crystallization rate and increased the crystallinity of PP.

Synthesis of Poly(amidoamine) Dendrimers and Property of Its Capped CdSe@CdS Core-shell Quantum Dots

2012, 26 (07): 57-62 ; DOI: 10.19491/j.issn.1001-9278.2012.07.011

Abstract ( 1166 )

Poly(amido amine)(PAMAM) dendrimers with different terminal groups and generations were synthesized from ethylene amine and methyl acrylate via diffusion method, and the product was characterized using infrared spectra. PAMAM capped CdSe@CdS core-shell structure quantum dots was prepared taking G5.0-NH2 PAMAM as templates at room temperature in dimethyl sulfoxide(DMSO) and characterized using UV-Vis absorption spectra and photoluminescence(PL) emission spectra. The coating of CdS on the surface of CdSe quantum dots was confirmed an effective method of enhancing photoluminescence property of CdSe quantum dots. Compared with neat CdSe quantum dots, the PL intensity of CdSe@CdS quantum dots was enhanced by 123 %.

Effect of Rotate Speed and Temperature on the Molecular Orientation of PE-HD/PP/SGF Pipes

Yi YUAN

2012, 26 (07): 63-65 ; DOI: 10.19491/j.issn.1001-9278.2012.07.012

Abstract ( 1322 )

By shearing-drawing two-dimensional compound stress field pipe-extrusion die developed by the authors, two-dimensional reinforcement short glass fiber/high density polyethylene/polypropylene (PE-HD/PP/SGF) pipes were extruded. The molecule orientation of the pipes affected by the rotate speed of shearing sleeve and temperature of shearing stress field were studied in this paper. The results indicate that the molecular orientation of PE-HD/PP/SGF pipes was improved by the circumrotation of shearing sleeve. But the improvement dies down gradually along with the rise of the rotate speed and the temperature. The molecular disorientation of the PE-HD/PP/SGF pipes becomes more serious simultaneously.

Research on Constitutive Relation of High-density Polyethylene Structural Foam Under Tensile

2012, 26 (07): 66-69 ; DOI: 10.19491/j.issn.1001-9278.2012.07.013

Abstract ( 1227 )

In order to improve the long-term stability of high-density polyethylene (PE-HD) structural foaming engineering, the constitutive relation of PE-HD structural foam including strain rate and density was established on the basis of Sherwood-Frost model. Based on the tensile stress and strain curve of plastic foamed, the related parameters were fitted via a numerical method. A comparison between the calculated and experimental values indicated that the proposed constitutive model may describe the stress-strain relationship of PE-HD.

Study on performance of polyurethane-bamboo charcoal foams composites

2012, 26 (07): 70-74 ; DOI: 10.19491/j.issn.1001-9278.2012.07.014

Abstract ( 1352 )

The polyurethane foams containing bamboo charcoal stuff were synthesized via on step method. Materials density, mechanical properties, color indices, anion release and far-infrared emissivity of flexible polyurethane-bamboo charcoal composites were determinate. The result showed that the materials density, anion release, rebound ratio and far-infrared emissivity of this composites increased with content of bamboo charcoal. The tensile strength, elongation at break, fracture strength decreased with content of bamboo charcoal, and just were 63.8%, 57.04% and 55.32% of these in CK when content of bamboo charcoal in composites was 8%. When content of bamboo charcoal in composites was 2%, the mechanical properties of polyurethane-bamboo charcoal composites achieve the Chinese National Standard for flexible polyurethane foams.

Fracture Behavior of PE－HD/Wollastonite/POE-g-MAH Composites

张冬初 Zhang Dong-Chu

2012, 26 (07): 75-79 ; DOI: 10.19491/j.issn.1001-9278.2012.07.015

Abstract ( 1300 )

The fracture behavior of PE-HD/wollastonite/POE-g-MAH composites in the mixed mode region was studied using the essential work of fracture (EWF) method. The applicability of EWF method and the stress state of the samples were verified. Linear regression was used on the experimental data to obtain the EWF parameters. With increasing wollastonite contents, the essential work of fracture increased, while the non-essential work of fracture decreased. The plastic deformation capability and the fracture toughness of the composites was mainly affected by the crack propagation resistance during the necking and tearing processes after yielding. It was also found that the impact strength of the material decreased with increasing wollastonite content. The materials with high impact strength, however, had low specific essential work of fracture.

Application of Halogen-free Intumescent Flame Retardant in Low-density Polyethylene

Xiang ZHANG Fan Zhang

2012, 26 (07): 80-84 ; DOI: 10.19491/j.issn.1001-9278.2012.07.016

Abstract ( 1125 )

In this paper, a flame retardant system consisting of P-N intumescent flame retardant (IFR), ammonium polyphosphate (APP) and zinc oxide (ZnO) was applied to low-density polyethylene (PE-LD). SEM was used to analyze the structure of the carbon layer after burning. The components of carbon layer of the sample, obtained from different thermal treatment had been analyzed using Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy and the flame mechanism of the PE-LD/IFR/APP/ZnO system was studied. The PE-LD/IFR/APP/ZnO system reached a limiting oxygen index value of 27.9 % and UL 94 V-0 level.

Synthesis of Epoxidized Sunflower Oil and Its Influence on Properties of PVC

2012, 26 (07): 85-89 ; DOI: 10.19491/j.issn.1001-9278.2012.07.017

Abstract ( 1246 )

Epoxidized sun?ower oil was synthesized through a nonsolvent method and the synthesis conditions were optimized by orthogonal experiments. The influence of epoxidized sun?ower oil on the thermal stability and mechanical properties of PVC was studied using torque rheometer and DSC. The epoxy value of the sun?ower oil reached 6.78 % when the synthesis temperature and time were 60 ℃ and 5 h, the mole ratio of hydrogen peroxide to sunflower oil was 2:1, the dosage of catalyst was 3 % of the total mass. Epoxidized sun?ower oil exhibited good synergistic effects with Ca-Zn soap in long-term thermal stability of PVC and showed greater efficiency than epoxidized soybean oil. In addition, epoxidized sun?ower oil could decrease tensile strength, glass transition temperature and hardness of PVC, but increased elongation at break of PVC, thus could be used as a plasticizer for it.

Current Situation for Evaluating the Chlorine Resistance of Plastic Pipes

LI Yu-e

2012, 26 (07): 90-94 ; DOI: 10.19491/j.issn.1001-9278.2012.07.018

Abstract ( 1957 )

The principle in chlorine resistance and present international standards for plastics pipe were introduced in this paper. Progress of evaluating work for the performance of chlorine resistant pipe was also presented. In the end, the domestic water quality was analyzed, some suggestions for the test method of chlorine resistant pipe in China was made.

Design Performance of Optimized CAD System for Double-toggle Clamping Unit

Zhao Jun Yuguang-Yang Yang

2012, 26 (07): 95-100 ; DOI: 10.19491/j.issn.1001-9278.2012.07.019

Abstract ( 1642 )

Computer aid design (CAD) system based on the optimization design process of double-toggle clamping unit was developed and its design performance was emphasized. Through the analysis of kinematics simulation and deformation simulation, the design result was verified rationality. By comparing with the existing same specifications mechanism though the experiment, the designed structure by the system was proven reasonable, and had good performance. All study showed that the CAD system could optimize and design different series clamping unit efficiently.

Design of Injection Mold with Feeding System Switching from Pin-point Gate to Side Gate

2012, 26 (07): 101-104 ; DOI: 10.19491/j.issn.1001-9278.2012.07.020

Abstract ( 1327 )

Based on the analysis of the structure characteristics and processing technology of the perfume bottle cap, an injection mould for this part was designed. The mould structure and its working process were introduced. The feeding system switching from pin-point gate to side gate，the demolding mechanism and the side core-pulling mechanism with lifter were illustrated in detail. The application instances of the feeding system switching from pin-point gate to side gate were introduced. It was proved that the feeding system switching from pin-point gate to side gate was adequate for setting of gate and filling of molded part.