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2016, Volume 30 Issue 04 Publication date: 26 April 2016 Previous Issue Next Issue

China Plastics Industry (2015)

2016, 30 (04): 1-5 ; DOI: 10.19491/j.issn.1001-9278.2016.04.001

Abstract ( 812 )

General situation of China plastics industry in 2015 was reviewed, including the output and export of plastics products, as well as major economic data, such as the total industrial values, sales and profits of plastics products, etc. Analysis of the market of plastics products in 2015 was made, and the developing trend of China plastics industry in 2016 was proposed.

Research Progress in the Flame Retardancy of EVA

2016, 30 (04): 6-11 ; DOI: 10.19491/j.issn.1001-9278.2016.04.002

Abstract ( 936 )

Recent research progress in flame retardant EVA systems containing inorganic compounds,phosphorus, nitrogen as well as intumescent flame retardant were reviewed. In addition, flame retarding mechanism, the influence of flame retardanton the properties of EVA, and the research trend of retardant EVA were discussed.

Valorization of Agricultural and Forestry Biomass Byproducts:Progress in Isolation，Modification and Application of Hemicellulose

2016, 30 (04): 12-22 ; DOI: 10.19491/j.issn.1001-9278.2016.04.003

Abstract ( 933 )

Research progress in hemicelluloses-based hydrogel and membrane was described. Emphasis was put on their plasticization, chemical and physical modification via blending with other biopolymers or inorganic particles. Their potential application and challenge were forecasted.

Research Progress of Preparation and Applications of Layered Double Hydroxides

2016, 30 (04): 23-29 ; DOI: 10.19491/j.issn.1001-9278.2016.04.004

Abstract ( 875 )

The characteristics and application of LDHs as a heat stabilizer in poly(vinyl chloride)(PVC) were reviewed. The production，reaction mechanism, and research progress of LDHs were briefly introduced. Finally, the development of LDHs was prospected.

Preparation and Properties of Thermal Conductive Insulating Composites of Epoxy Resin/Polydopamine Modified Aluminum Powders

2016, 30 (04): 30-34 ; DOI: 10.19491/j.issn.1001-9278.2016.04.005

Abstract ( 680 )

Aluminum powder was first coated with a layer of polydopamine (PDA) and then was introduced into an epoxy resin forming a high thermal conductive insulation composite (EP/PDA@Al).When the content of coated Al particles was 20 wt%, the thermal conductivity of the composite reached 0.521 W/(m·K), which was 184 % higher than that of neat EP.The coating of PDA made Al particles more effective in enhancing of thermal conductivity.

Preparation of Conductive Polystyrene Foams via Concentrated Emulsion Polymerization

2016, 30 (04): 35-39 ; DOI: 10.19491/j.issn.1001-9278.2016.04.006

Abstract ( 637 )

The polystyrene(PS)-based nanocomposite electrical conductive foams filled with multi-walled carbon nanotubes(MWCNTs) were prepared by concentrated emulsions polymerization, where the conductive poly(3,4-ethylene dioxythiophene): poly(styrene sulfonate) (PEDOT/PSS) was introduced into and acted as surfactant. The effect of fillers content on the porous morphology and electrical conductivity of the materials were characterized by SEM and electrometer. The results show that the polymer foams with different porous structure and conductivity can be achieved with the different loading of fillers and conductive surfactant. Furthermore, the incorporation of the conductive polymer can greatly improve the electrical conductivity of the PS-MWCNTs composite foams.

Preparation and Structure of Superhydrophobic PDMS/PVDF Microporous Membranes

2016, 30 (04): 40-44 ; DOI: 10.19491/j.issn.1001-9278.2016.04.007

Abstract ( 862 )

Superhydrophobic PDMS/PVDF microporous membrane was prepared by solution casting and phase inversion. The influence of composition of coagulation bath on the precipitation rate of the casting solution, membrane morphology, pore structure, hydrophobicity, and mechanical properties were studied. It was found that as the ethanol content in coagulation bath increased from 0 to 100 wt%, the finger-like hole at cross-section of the membrane was gradually replaced by a sponge-like structure.When ethanol was used as the coagulation bath, phase separation occurred between PDMS and PVDF, the hydrophobicity increased and the contact angle reached 139.68 °. Young’ modulus, tensile strength, and elongation at break decreased from (48.06±4.20),(2.82±0.15) MPa, and (92.90±2.53) % to (15.70±2.83), (0.72±0.13) MPa, and (15.47±1.63) %, respectively.

Preparation and Impact Property of PP/Flax Composite

2016, 30 (04): 45-49 ; DOI: 10.19491/j.issn.1001-9278.2016.04.008

Abstract ( 560 )

Flax fiber was used as reinforcing material to commingle with polypropylene (PP) fiber to realize mixture at the stage of yarn, meanwhile, PP filaments were introduced to produce a core-spun yarn with flax/pp as core and PP filament as outer sheath. Commingled yarns were woven into 2-D fabrics which were used as the prefabricated materials. Composite laminates were prepared by hot press technology. Effects of manufacture technology, yarn structure and fiber weight fraction on puncture properties of composites were investigated through analyzing the puncture testing results. Testing results show that the punctuation properties of composite laminate with 68% fiber weight fracture are the best; laminate made by “sandwich” method shows better punctuation properties than “mixing” method one; punctuation properties of 0°/0° laminates are higher than that of 0°/90° laminates.

Influence of Ethylene Composition on Crystal Types and Properties of β-Nucleated Propylene/Ethylene Random Copolymer

2016, 30 (04): 50-54 ; DOI: 10.19491/j.issn.1001-9278.2016.04.009

Abstract ( 734 )

The crystallization behaviors and thermal and mechanical properties of neat and β-nucleated polypropylene (PP) and propylene/ethylene random copolymer (PPR) were comparatively investigated. The experimental results indicated that the melting points and crystallization points of PP and PPR increased with decreasing ethylene content. Low ethylene content led to high β crystalline form. The heat distortion temperature and impact properties of PPRs were greatly improved with increasing β-form crystallites. The lab-made β-nucleator of polypropylene attributed to a high proportion of β-form in PPRs, higher than 80 %.

Preparation and Characterization of Bisphenol A Cyanate Ester Foam

2016, 30 (04): 55-60 ; DOI: 10.19491/j.issn.1001-9278.2016.04.010

Abstract ( 494 )

Cyanate ester foam(CEF) was prepared via molding foaming with bisphenol A cyanate ester resin (BADCy) as the main material.The chemical structure, cell structure, thermal behavior, and mechanical property of the foam were studied. It showed that CEF could be fully-cured under 155 ℃/2 h+200 ℃/2 h. Closed cells were uniformly distributed.Glass transition temperature (Tg) of the CEF was 263 ℃, and 5 % weight loss temperature was 344 ℃,which revealed an excellent thermal stability.CEF had excellent mechanical properties, and the compressive modulus and compressive strength had a linear relationship with ρ1.043 and ρ2.204.

Studies on Compatibility and Dispersibility of sPS/PBA-aPS Blend

2016, 30 (04): 61-68 ; DOI: 10.19491/j.issn.1001-9278.2016.04.011

Abstract ( 665 )

In this paper, the syndiotacticpolystyrene (sPS) was toughened with home-made poly(butyl acrylate)-atactic polystyrene (PBA-aPS) core-shell latex particles, and the compatibility and dispersity of the sPS/PBA-aPS blend were studied by differential scanning calorimetry (DSC), rotational rheometer, transmission electron microscope (TEM), scanning electron microscope (SEM), and infrared/near-infrared imaging system. It showed that the PBA-aPS core-shell latex particles had a dual role of lubrication and thickening.The glass transition temperature and melting point of the blends decreased slightly with the addition of PBA-aPS. No phase separation appeared in sPS/PBA-aPS blend under the test temperature and frequency range. Uniform dispersibility of PBA-aPS was observed in sPS with optimum contents, but excessive PBA-aPS (＞30 %) will cause particle aggregation.

Preparation and Performance of Nafion/Pillar［5］ Arene Composite Membrane for Direct Methanol Fuel Cells

2016, 30 (04): 69-75 ; DOI: 10.19491/j.issn.1001-9278.2016.04.012

Abstract ( 530 )

A Nafion/pillar ［5］ composite membrane was prepared and was characterized by Fourier transform infrared analyzer, nuclear magnetic resonance spectrometer, scanning electron microscopy, thermo gravimetric analyzer.It showed that the Nafion/pillar ［5］ composite membrane had a good thermal stability, high water absorption, and low swelling ratio, and the pillar ［5］ could effectively hinder the penetration of methanol，the methanol permeability at room temperature was as low as 2.1×10-7 cm2/s. The power of direct methanol fuel cell (DMFC) with Nafion/pillar ［5］ membrane was 15.6 mW/cm2 at a current density of 65 mA/cm2.

Preparation and Performance of POM/GF-MWCNTs Composites

2016, 30 (04): 76-82 ; DOI: 10.19491/j.issn.1001-9278.2016.04.013

Abstract ( 606 )

Acid-treated MWCNTs were grafted onto the surface of glass fiber (GF) by the coupling effect of 3-aminopropyltriethyloxy silane (KH550), resulting in GF-MWCNTs. The GF-MWCNTs was used to reinforce POM, and the mechanical properties, thermal and electrical performance of the POM composites were investigated. It showed that when the filler content was low, the tensile strength and notched impact strength were increased and achieved the maximum at the filler content of 3 wt% and 1 wt%, respectively, and then decreased continuously with increasing filler content. When the content of GF-MWCNTs was 10 wt%，the tensile strength and notched impact strength of the POM/GF-MWCNTs composites were lower than those of neat POM. The thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) indicated that the addition of GF-MWCNTs could not only increase thermal stability of composite systems, but also affect the crystallization behavior of POM, increase the crystallization temperature and crystallinity. In addition, the testing results of electrical performance showed that the incorporation of GF-MWCNTs helped to decrease the volume resistivity of the composites.

Research of Polymer Melt Transfer Process by Vibrating Based on Synergetics

2016, 30 (04): 83-87 ; DOI: 10.19491/j.issn.1001-9278.2016.04.014

Abstract ( 697 )

In applying the synergetic analysis method,viscosity of flat vibrating shear flows,such as an orthogonal superposition of vibration and steady flow, was studied.Using constitutive equations for polymer melts under effects of vibration force field, the order parameter equations were deduced. In addition, the melt kinetic model of single-screw vibrating transfer was formulated.

Research on the Mechanical Properties and Constitutive Model of High Density Polyethylene Plastics

2016, 30 (04): 88-92 ; DOI: 10.19491/j.issn.1001-9278.2016.04.015

Abstract ( 705 )

In order to study the constitutive behaviour of high density polyethylene, uniaxial tension experiments were performed to obtain stress-strain curves. The experimental results indicated that the mechanical properties of PE-HD was strain-rate-dependent, the yield strength increased obviously with increasing strain rate, and the relationship between yield strength and logarithm of strain rate was linear. Considering the strain-rate-dependent mechanical properties of PE-HD, the Sherwood-Frost constitutive model was used to study the mechanical behaviour of high density polyethylene. Comparison of the model-predicted curves with the experimental ones showed that the Sherwood-Frost model could well predict the mechanical properties of PE-HD.

Viscoelasticity Mechanics Model of Medium Density Polyethylene Pipes

2016, 30 (04): 93-98 ; DOI: 10.19491/j.issn.1001-9278.2016.04.016

Abstract ( 615 )

Laboratory tests were performed to investigate the time-dependent stress behavior of polyethylene(PE) pipes under mechanical loading conditions. Analytical methods using convolution integrals and numerical modeling using finite elements were employed to model stress relaxation behavior. It showed that under small strain, the new PE viscoelasticity constitutive model which using Boltzmann superposition principle could be used to predict the relaxation behavior of PE pipe. With the support of material parameters, using the finite element method could effectively analyze the viscoelastic behavior of PE material.

Structural Optimization of Glass Fiber Reinforced Polypropylene Water Tank Supporters

2016, 30 (04): 99-101 ; DOI: 10.19491/j.issn.1001-9278.2016.04.017

Abstract ( 559 )

A finite element model for water tank supporter of vehicles was formulated, structural statics and fatigue analysis were performed. Introducing the results into iSight software, with the longest fatigue life and lightest quality as the targets, three structural variables were analyzed. Finally, selecting the optimal value based on genetic algorithms, re-analyzed optimized model.For the optimized water tank supporter, the weight decreased 2.8 kg, the maximum stress decreased 0.7 MPa, and the fatigue life increased 7.3 %.

Analysis of Molding Defects and Optimization Design for Automotive Exterior Parts Based on Moldflow

2016, 30 (04): 102-108 ; DOI: 10.19491/j.issn.1001-9278.2016.04.018

Abstract ( 725 )

In order to find the reasons of the molding defects of automotive exterior parts in process, the injection process was simulated using Moldflow software based on production parameters. The optimization measures were proposed to solve the problems in production process. It could reduce the number of trial, thus increase the productivity and reduce production costs.

Properties of Extruded Polystyrene Foam Boards with Three Component Foaming Agent#br#

ZHANG Yongjia, WANG Yaqiao, LIU Bengang, WANG Xiangdong, CHEN Peng, WANG Wenbo

2016, 30 (04): 109-113; DOI: 10.19491/j.issn.1001-9278.2016.04.019

Abstract ( 59 )

Influence of Chain Extenders on Foam Injection Molding of Poly(lactic acid)

2016, 30 (04): 114-118 ; DOI: 10.19491/j.issn.1001-9278.2016.04.020

Abstract ( 648 )

PLA was modified with chain extenders, and was foamed molded through injection molding. Melt flowability, cell morphology,and mechanical properties of the foam were investigated. It was found that, there was a significant reduction in the melt flow rate and an improvement in the melt strength by the chain extender. With increasing contents of the chain extender, the foaming performance and mechanical properties of both injection and extrusion grade PLA were improved gradually. When the content of the chain extender reached 0.8 wt%, the optimal cell morphology and mechanical properties were obtained. Foamed samples of the modified injection molding grade had better mechanical properties.

In-mold Decoration Injection Mold Design for Electronic Sound Enclosures

2016, 30 (04): 119-123 ; DOI: 10.19491/j.issn.1001-9278.2016.04.021

Abstract ( 731 )

Molds for PET decoration film on the out-shell of ABS loud speakers was discussed in this paper. In order to deliver the film automatically, the mold with a flip structure was designed. For avoiding prevent the defects such as ink, gas lines, a submarine plunger gate system was used. The inside and outside gas paths were designed and the film could be well located.