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2014, Volume 28 Issue 01 Publication date: 26 January 2014 Previous Issue Next Issue

“Plastics Instead of Steel” Trend in Directlyburied Preinsulated Hot Water Pipes in China

LI Xian-Shi Yuecong ZHOU Guanghua YANG

2014, 28 (01): 1-5 ; DOI: 10.19491/j.issn.1001-9278.2014.01.001

Abstract ( 1262 )

The article provided an overview of the situation and development trend of the insulation pipe and plastic pipe industry. The policy, technology and market of insulation industry were analyzed. Problems in technology and cost for the realization of “replacing steel with plastics” were discussed. Finally the development tendency of plastic pipes in the future was predicted.

Modification of Polypropylene/Wollastonite Composites

2014, 28 (01): 6-11 ; DOI: 10.19491/j.issn.1001-9278.2014.01.002

Abstract ( 1210 )

Research progress in polypropylene/wollastonite composites was reviewed. Effect of surface treatment，processing technique, and the addition of filllers on properties of the composites was introduced. Developing trend of polypropylene/wollastonite composite was predicted.

Research Progress in Melamine Flame Retardants

2014, 28 (01): 12-16 ; DOI: 10.19491/j.issn.1001-9278.2014.01.003

Abstract ( 1355 )

Flame retarding mechanisms, its applications in various kinds of polymers, and flame retardant efficiency of melamine were summarized in this article. Especially, the decrease mechanical property of polymers caused by poor compatibility was emphasized. The modification of melamine to improve its behavior was summarized.

Research of Glass Fibers/Aramid Fibers Hybridreinforced Phenolic Foam

YANG Yan-Feng

2014, 28 (01): 17-21 ; DOI: 10.19491/j.issn.1001-9278.2014.01.004

Abstract ( 860 )

Glass fibers and aramid fibers were used to reinforce and toughen phenolic foams. The effect of content ratio of short glass fibers and aramid fibers on compressive, bending, and impact strengths of the phenolic foam was investigated. It showed that glass fibers significantly improved the compressive strength, while aramid fiber markedly increased the toughness of the phenolic foam, both fibers could improve the bending strengths. When the mass ratio of glass fibers and aramid fibers was 1∶1, the bending strength of the phenolic foams gave rise to the maximum.

Properties of CE/PPO/Hyperbranched Polysiloxane Grafting SiO₂ Composites

Li Ting Ting

2014, 28 (01): 22-27 ; DOI: 10.19491/j.issn.1001-9278.2014.01.005

Abstract ( 962 )

Composites of CE/PPO/HBP-SiO2 and CE/PPO/nano-SiO2 were prepared using CE modified by PPO as a matrix, and HBP-SiO2 and nano-SiO2 as fillers. Infrared spectroscopy confirmed that hyperbranched polysiloxane was grafted onto SiO2 surface. Differential scanning calorimetry showed that HBPSiO2 and nano-SiO2 had catalytic effect on CE/PPO system, and could reduce the curing temperature. The addition of SiO2 improved the mechanical properties of system, and the addition of HBP-SiO2 showed a better effect than nano-SiO2. The dielectric constant of CE/PPO/HBP-SiO2 composite was less than that of CE, CE/PPO, CE/PPO/nano-SiO2, and the dielectric loss factor was smaller than that of CE and CE/PPO, while higher than that of CE/PPO/nano-SiO2.

Influence and Mechanism of Nucleation Agents on PET/PEN Blends

Ren WU Wei WU Yu CHEN Xingqing LIN Chenchen JIANG

2014, 28 (01): 28-33 ; DOI: 10.19491/j.issn.1001-9278.2014.01.006

Abstract ( 1100 )

In this paper, nucleation agents were added to PET/PEN blends to improve their crystallization and mechanical properties. The effects of sodium bicarbonate, sodium benzoate, and ethylene methacrylic acid ionomer (Surlyn) on the crystallization and mechanical properties of PET/PEN blends were investigated by Differential Scanning Calorimetry, XRay Diffraction, and torque rheological tests. It showed that all the nucleation agents promoted the nucleation in PET/PEN blends. The crystallization peak temperature was increased nearly 20 ℃ and the crystallization rate was doubled due to the addition of sodium benzoate and Surlyn. With the addition of Surlyn, the mechanical properties of the blend were improved. The ideal nucleation agent for PET/PEN blends was Surlyn.

Fabrication and Performance Investigation of Polyimide Film by Blending BPDA/ODA and PMDA/ODA

Guofeng Tian Dezhen WU

2014, 28 (01): 34-37 ; DOI: 10.19491/j.issn.1001-9278.2014.01.007

Abstract ( 1712 )

A new type of polyimide material was prepared via a blending method utilizing BPDA/ODA and PMDA/ODA polyamide acid as precursors. The relationship of the mechanical, thermal and electric properties of the derived material and the blending ratio was also investigated. Universal material testing machine, dynamic mechanical analysis and precision impedance analyzer were employed during the optimization of the blending ratio which associated closely with the physicochemical properties mentioned above. The characterization indicated that the elongation at break of the blended polyimide could be significantly improved by simply using a suitable blending ratio, meanwhile without compromising its good heatresistant property. The temperature at the turning point for dielectric loss rapid rise was above 250 ℃. This kind of material was very promising in wide application of manufacturing the enameled wire leveled above 240.

Research on Rubber for Continuous Bulk Preparation of Highperformance ABS

2014, 28 (01): 38-42 ; DOI: 10.19491/j.issn.1001-9278.2014.01.008

Abstract ( 965 )

This paper made an analysis on the microstructure and sol process of rubbers using in ABS. The grafting copolymerization of styrene and acrylonitrile monomers in the pilot production process of continuous bulk polymerization of ABS were preformed and researched using different types of rubber and rubber ratio. The comprehensive performance of ABS produced under different conditions was emphatically investigated. The results indicate that the resultant ABS has better performance using Dushanzi lowcis polybutadiene rubber 50AF than Gaoqiao 55AE lowbutadiene rubber or blend rubber. In the blend rubber, the resultant ABS has better performance when the ratio of rubber is 7∶3(Dushanzi 50AF lowbutadiene rubber: Yanshan petrochemical corporation highbutadiene rubber BR9004).The impact strength of ABS increases, and melting index of ABS decreases with the increase of the rubber content.

Preperation and Properties of Distillers Grains Reinforced Polypropylene Composites

2014, 28 (01): 43-48 ; DOI: 10.19491/j.issn.1001-9278.2014.01.009

Abstract ( 871 )

In the present study, distiller grain (DG) was introduced into polypropylene (PP) forming composites through melt blending. The effect of content and particle size of DG on the mechanical properties and crystallization behavior of PP/DG composites was investigated. It was found that the thermal stability and flame retardancy were improved with the addition of DG(100 μm). The crystallization temperature increased with increasing content of DG, indicating a heterogeneous nucleation effect. The mechanical properties of composites increased with increasing size of DG. Compared with neat PP, the Izod impact strength of the composites containing 10 wt % of DG increased by 55.2 %, the tensile strength increased by 9.3 %. When 2wt % of PP-g-MAH was introduced as a compatibilizer, an increase of 4.1 % of tensile strength was observed. The fracture surfaces of the composites reveal that interfacial bonding between the filler and the matrix was significantly improved with the addition of PP-g-MAH.

Synthesis and Enzymatic Degradation of Polyethylene Glycol Block Copolymers with Longchain Diacid

2014, 28 (01): 49-54 ; DOI: 10.19491/j.issn.1001-9278.2014.01.010

Abstract ( 808 )

A copolymer (PBSe-PEG) was obtained from the polycondensation product of sebacic acid, PEG-200, and polyethylene glycol. The structure of PBSePEG was characterized by 1H-NMR; molecular weight and its distribution were tested by GPC; crystallinity and thermal properties of the copolymers were analyzed by WXRD, DSC and TGA, and the degradation property was tested by lipase N435. GPC gave a molecular weight about 5×104; 1H-NMR proved that PBSe-PEG had a similar crystal structure to neat PBSe. With increasing content of PEG-200, both Tm and Tc of the copolymer decreased. Compared with PBS，lipase N435 catalyzed degradation of PBSe-PEG better.

Thermal Stabilization Effect of Composite Carboxylic Lanthanum on PVC

2014, 28 (01): 55-59 ; DOI: 10.19491/j.issn.1001-9278.2014.01.011

Abstract ( 821 )

Using lanthanum nitrate, monocarboxylic acid, dicarboxylic acid and tricarboxylic acid as the precursors, six carboxylic lanthanums were synthesized, which were used in PVC as thermal stabilizers. By Congo red and torque rheometer, the static and dynamic thermal stability of the modified PVC was tested. It showed that the thermal stabilizers based on mono or dicarboxylic acid behaved better than those based on tricarboxylic acid. FTIR showed that when heated, lanthanum ion could coordinate with the chlorine atoms and thus the thermal stability was provided. In addition, HCl released during the degradation of PVC could be absorbed by lanthanum.

Numerical Simulation of Mechanical Response of Buried Polyethylene Pipes Under Surface Load

Shun-Li LU Jin-Jin MA SHI Jian-Feng

2014, 28 (01): 60-64 ; DOI: 10.19491/j.issn.1001-9278.2014.01.012

Abstract ( 876 )

Based on uniaxial tensile test at a given strain rate, the constitutive model parameters of polyethylene (PE) were obtained by fitting method, and its yield stress was determined. The mechanical response was studied using finite element method with a rectangular pipesoil model, which was symmetrical about the pipe cross section, and influences of the surface load parameters (length of surface load area=L, width of surface load area=W) were analyzed. The results showed that the maximum vertical direction offset of buried PE pipe under surface load occurred in the axial crosssectional plane of symmetry, the maximum Mises stress increased and its location changed as the surface load increased, and the surface load decreased exponentially as L and W increased when PE pipe yielded.

Research of Molding Formability by Ultraviolet Radiation

2014, 28 (01): 65-69 ; DOI: 10.19491/j.issn.1001-9278.2014.01.013

Abstract ( 776 )

A new concept named “chemical manufacturing” was proposed from the combination of traditional injection molding with UV curing. A cylinder with a diameter of 6 mm and a height of 10 mm was set as the molding goal and the weight of the products was set as standard to evaluate; a single factor analysis of variance method was used to determine the effect of the intensity of ultraviolet, the duration of ultraviolet, and the distance between UVLED device and product surface on curing and molding of the final products. The experimental results showed that the intensity of UV radiation, UV irradiation duration, and the distance between UVLED device and product surface, have significant effects on the molding of the product. The weight of the product would increase with increasing intensity of UV radiation; and would decrease with increasing UV irradiation duration and increasing distance between UVLED device and product surface.

Research on Processing Conditions of PVF Films by Solution Casting

2014, 28 (01): 70-73 ; DOI: 10.19491/j.issn.1001-9278.2014.01.014

Abstract ( 1048 )

PVF films containing different plasticizers and cosolvent were prepared by solution casting. The effects of processing parameters on the structure and properties of the films were investigated. The results showed PVF could be dissolved in DMF. The crystal structures of PVF films were destroyed, resulting in improved elongation at break and decreased tensile stress. DOP was a good plasticizer for PVF. The PVF films with good mechanical properties could be obtained with the concentration of PVF solution 3 % at 85 ℃ and 100 r/min stirring speed in the presence of deforming agent.

Numerical Study of Polymer Melt Before and After Section

2014, 28 (01): 74-78 ; DOI: 10.19491/j.issn.1001-9278.2014.01.016

Abstract ( 881 )

Using Polyflow software, a 3D transient simulation of the melt pressure field and melt mass flow at front and rear sections of screw during continuous extrusion of microcellular plastics was carried out. Different locations of gas injection, melt viscosity, screw speed were considered. It was found that along the axial direction, the distance from 640 to 670 mm constituted the best location for supercritical gas injection. At this location, the melt pressure varied weakly along the radial direction, therefore as long as the pressure of injected supercritical gas was slightly larger than the melt pressure, the injection of gas could be readily completed. The polymer melt mass flow increased with increasing screw speed, and thus controllable.

Preparation and Properties of Glycerin Branched Polyesters as Plasticizer for PVC

JIANG Ping-Ping

2014, 28 (01): 79-83 ; DOI: 10.19491/j.issn.1001-9278.2014.01.017

Abstract ( 858 )

Polyesters with a branched structure were synthesized from adipic acid, a glycol and glycerin, and used in PVC as plasticizers. Using FTIR, TG, and GPC, the tensile properties, thermal stability, and extraction resistance， the PVC/polyester systems were studied. When triethylene glycol was used as the dibasic alcohol，the molecular weight, dispersion coefficient, and viscosity of the products were 4900 g/mol, 2.26, and 11.198 Pa·s, respectively. The plasticized PVC samples showed low water absorbing capacity, high thermal stability, and good extraction resistance.

Investigation on Fire Retardant and Heat Insulation Performance of PMMA/Fly Ash/Mg(OH)₂ Composite

Xin-Qiang YUAN

2014, 28 (01): 84-87 ; DOI: 10.19491/j.issn.1001-9278.2014.01.018

Abstract ( 832 )

PMMA/fly ash/Mg(OH)2 composites were prepared through gradient temperature bulk polymerization. The microstructure of the composite was viewed by using JCM5000 desktop scanning electron microscope (SEM). Its combustion and heat insulation performance had been studied. When the loading of Mg(OH)2 was 35 phr, its fire retardant level was HB. When the content of the fly ash was 60~80 phr, and the sample thickness was less than or equal to 20 mm, and its heat insulation effect was very good.

Simulation of Film Pasting of Mouses Based on Outside Mold Decoration and Optimization of Process Parameters

2014, 28 (01): 88-92 ; DOI: 10.19491/j.issn.1001-9278.2014.01.019

Abstract ( 740 )

The outside mold decoration technology was used for mouse shell pad pasting with a polypropylene film. The film thickness distribution and its deforming distribution in X and Y direction was obtained from a simulation with finite element method. The influencing factors of film forming were analyzed. Aimed at the minimum standard deviation of average film thickness and its deforming distribution in X, Y direction, the process parameters were optimized and analyzed through experiment design. The best process parameters were obtained, uniform film thickness distribution and high deformation accuracy were achieved.

Controlling of Molding Cycle and Warpage of Large Size and Slender Thinwalled Plastics Parts in Hot Runner Mold

2014, 28 (01): 93-98 ; DOI: 10.19491/j.issn.1001-9278.2014.01.020

Abstract ( 827 )

With the antirub of an automobile as an example, the improvement of the runner system and process parameters was carried out. CAE was used to analyze the injection molding cycle and the development of warpage in these parts. The actual injection process was guided by the improved program, and the result was consistent with that of simulation.

Application of Reverse Engineering in Plastics Products and Mold Design

2014, 28 (01): 99-102 ; DOI: 10.19491/j.issn.1001-9278.2014.01.021

Abstract ( 834 )

The digital design of mold for plastics parts based on reverse engineering technology was introduced. Using the mold for car lamp reflector as an example, the analysis of plastics products in the reverse modeling process was illustrated, with the basic principles and main points emphasized. During the analysis, point cloud data of the reflector shell surface was first collected using a LaserRE 3d laser scanner, then using the Geomagic Studio software for data processing and rapid surface reconstruction, finally imported the surface model into Pro/E software for threedimensional model reconstruction and die parting of the reflector, and formed a mold cavity. The practice showed that, without missing the original geometrical data for parts with complex curved shapes, this method could realize the rapid design of an injection mold, shorten the product development cycle.