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2010, Volume 24 Issue 06 Publication date: 26 June 2010 Previous Issue Next Issue

New Pipes and Piping Systems in China Plastics Pipes Industry

2010, 24 (06): 1-5 ; DOI: 10.19491/j.issn.1001-9278.2010.06.001

Abstract ( 2000 )

Tthe new products included modified polyvinyl chloride(PVC-M) pipe, biaxial orientation polyvinyl chloride(PVC-O) pipe, polypropylene of raised temperature resistance(PE-RT) pipe, β-PP-R pipe, and Ultrahigh molecular weight polyethylene(PE-UHMW) pipe of plastic pipe industry in China were summarized. The features and application fields of composite metal/plastic pipe and composite plastics/plastic pipe were introduced,. In addition, some new piping system were described in detail, especially for the advantages when they were applicated in the new building technology. In the final, the analysis and prospect of plastic pipes industry in China were made in combination with national industrial policies as well.

Research progress in PVC/Wood flour Composites

WU Bo

2010, 24 (06): 6-12 ; DOI: 10.19491/j.issn.1001-9278.2010.06.002

Abstract ( 1954 )

Recent research progress at home and abroad on Poly(Vinyl chloride)/Wood flour(PVC/WF) composites was reviewed. The new equipments and techniques, including planetary roller twin-screw extruders, conical twin-screw extruders with a dry device and WoodTruder? extrusion system in which WF was conveyed to extruder without predrying and preblending were introduced. The research advance on additives used in PVC/WF composites such as lubricants, impact modifiers, plasticizers and compatibilizers was summarized. Technologies related to microcellular foaming and environment protecting were introduced and evaluated. Finally, development trend of PVC/WF composites was expected.

Micro-Injection Molding Technology and Differential Injection Molding Technology

2010, 24 (06): 13-18 ; DOI: 10.19491/j.issn.1001-9278.2010.06.003

Abstract ( 1789 )

The foreign historical and latest domestic development as well as some achievements achieved by domestic researchers on basic theory of micro-injection molding machines were reviewed. The existing micro-injection molding techniques were compared systematically. Meanwhile, a newly developed technology of differential injection molding based on the melt pump technology was introduced. Furthermore, a method of effectively manufacturing micro products via regular injection molding machines was proposed.

Effect of Crosslinking of EPDM on "Sandbag" Microstructure Evolution and Properties of PA6/EPDM/Nano-CaCO3 Ternary Composites

2010, 24 (06): 19-23 ; DOI: 10.19491/j.issn.1001-9278.2010.06.004

Abstract ( 1587 )

Crosslinked Ethylene-propylene-diene terpolymer(EPDM)/nano calcium carbonate(EPDM/nano-CaCO3) masterbatch was prepared via melt blending,which was mixed with ployamide6(PA6)forming a ternary composite in a "sandbag"structure with particles of crosslinked EPDM/nano-CaCO3 masterbatch dispersed in PA6 matrix. The effect of crosslinking of EPDM on morphology of the ternary composites was investigated using a field emission scanning electron microscope (FE-SEM). It showed that when the content of dicumyl peroxide(DCP) in EPDM dereased from 0.30 % to 0, the size of the dispersed particles decreased, the impact strength of the ternary composites increased from 22 kJ/m2 to 47 kJ/m2; the tensile and flexural strength were little affected. When the ternary composite was impacted, the impact energy was dissipated by the mechanisms of fiber-forming mode and dilataional bands which were induced by "sandbag" microstructure.

Isothermal crystallization behavior for polypropylene/sepiolite composites

LI Xiao-yan HU Xiao-Ping Dai Ya-tang Li Shao-xian

2010, 24 (06): 24-27 ; DOI: 10.19491/j.issn.1001-9278.2010.06.005

Abstract ( 2033 )

Polypropylene/sepiolite (PP/SEP) composites were investigated using differential scanning calorimeter (DSC) and polarized light microscope. Avrami equation was used to analyze isothermal crystallization. It showed that with increasing crystallization temperatuer（Tc）,The crystallization rate reduced, The parameter values of n and K become lower, and the half-time(t1/2) for become higher. At a given Tc, the presence of sepiolite resulted in high crystallization rate and small crystallite size due to its significant heterogeneous nucleating effect.

Preparation and Properties of Thermally Conductive and Electro-insulating PP/T-ZnOw/MgO Composites

LI Guang-Ji

2010, 24 (06): 28-35 ; DOI: 10.19491/j.issn.1001-9278.2010.06.006

Abstract ( 1917 )

Thermally conductive and electric insulating polypropylene(PP)/T-ZnOw /MgO composites were prepared using a twin-screw extruder with the tetrapod-like zinc oxide whisker (T-ZnOw) and magnesium oxide (MgO) as thermally conductive fillers. The effects of content of the MgO on the thermally conductivity(λ), volume resistivity (ρv), mechanical properties, and processability of the prepared PP/T-ZnOw/MgO composites containing 10 % T-ZnOw were investigated. Results indicate that as the MgO contents increased, the λ of the composites increased and their ρv decreased. Besides, the tensile and flexural strength and the melt flow rate reduced but the impact strength remained stable first and then fall with increasing contents of MgO amounts to or above 30 %. The PP/T-ZnOw/MgO composites filled with 60 % (33 vol %) of MgO possesses the maximum λ and the minimum ρv. The former was 0.7563 W/(m·K), which was 108.0 % and 210.0 % higher than that of the PP/T-ZnOw composite without MgO and that of the unfilled PP, respectively; and the latter was 9.20×1015 Ω·cm, which can meet the requirements for electro insulating materials.

Synthesis, Structure and Properties of Biphenyl Epoxy Resin for Integrated Circuit Encapsulation

YANG Ming-Shan Jie He Qiang Xiao

2010, 24 (06): 36-39 ; DOI: 10.19491/j.issn.1001-9278.2010.06.007

Abstract ( 1867 )

Tetramethyl biphenyl epoxy resin (TMBP) was synthesized from 3,3',5,5'-tetramethyl-biphenyl-4,4'-diol and epichlorohydrin via a two-step method using 18-crown-6-ether as a Phase-transfer catalyst. The effect of temperature, reaction time, and phase-transfer catalyst on product yield was investigated. It was found that a maximum product yield of 83 % was obtained at 80 ℃ for 8 h. The chemical structure of TMBP was characterized with 1H-NMR、FTIR、XRD、POM and DSC. DSC showed that the melting temperature of TMBP was 107.8 ℃. POM results indicated that TMBP was a crystalline oligomer and its liquid crystalline behavior appears when cooled down from 120 to 76.2 ℃. TMBP has very low ηa (0.02 Paos at 150 ℃) and can be blended with ortho-cresol novolac epoxy resin(ECN) in order to decrease ηa of epoxy molding composite(EMC). It was concluded that TMBP can be used as a matrix resin for manufacturing epoxy molding compounds for integrated circuit encapsulation.

Effect of Fe Powder Contents on Friction and Wear Properties of Polyformaldehyde /Fe Composite

2010, 24 (06): 40-44 ; DOI: 10.19491/j.issn.1001-9278.2010.06.008

Abstract ( 1808 )

Effect of content of Fe powder,load,time,and speed of test on the friction and wear properties of polyformaldehyde/Fe powder composites was studied using a ring-on-block tester. With increasing contents of Fe powder, the frictional coefficient and mass loss of the composites were firstly decreased and then increased. W The results show that the friction and wear properties of POM /Fe powder composites were firstly decreased and then increased with content of Fe powder increased. Efficient of friction of composites with 4 phr Fe powder was reduced from 0.13 of POM to 0.098；The coefficient of friction of composites with 4 phr Fe powder was always the lowest under different loads.

Mechanical and electromagnetic properties of Poly(p-phenylene sulfide)/ NdxFe94-xB6 composites

2010, 24 (06): 45-49 ; DOI: 10.19491/j.issn.1001-9278.2010.06.009

Abstract ( 1795 )

Poly (phenylene sulfide ) ( PPS) / NdxFe94?xB6 composites were prepared via melt mixing. The morphology ,mechanical and electromagnetic properties of PPS / NdxFe94?xB6 composites were studied. The results indicated that NdxFe94?xB6 particles were well dispersed in the PPS matrix. In contrast to pure PPS resin , tensile strength，bending strength and impact strength of the composites increased by 100 %,44 %,800 %,respectively; whereas overloading NdxFe94?xB6 decreased the mechanical properties；the permittivity and magnetic conductivity increase with the content of NdxFe94?xB6. At the frequency range 0.5~18 GHz, the imaginary parts of permittivity increase obviously in high contents. It was found that the composites have excellent microwave absorbing characteristics at the high frequency range, while matching thickness was 2 mm, the maximum reflection loss was about -18.3 dB corresponding to the frequency 16.6 GHz when the NdxFe94?xB6 content was 50 %.

Balancing Deding and Analysis of Runners of Plastics Injection Molds Based on Moldflow

2010, 24 (06): 50-54 ; DOI: 10.19491/j.issn.1001-9278.2010.06.010

Abstract ( 1769 )

Injection molding of front cover and front panel of mobile phone with different volume two-cavity is regarded as the research object , based on numerical simulation software MPI ,the study is distributed into the contrastive analysis of different runners. The influence of three typical injection on three important process factors , such as injection time，conversion pressure and clamping force are analyzed, then the appropriate runner design is selected according to the demand for products, at last the runner size is ascertained based on the ratio of two cavity filling time . Optimization of the runner makes the melt flow into the volume cavity keep flow balance and minimize the shortcomings of parts.

Effect of Thermal Aging on Fire Performance of YJV Cables

2010, 24 (06): 55-57 ; DOI: 10.19491/j.issn.1001-9278.2010.06.011

Abstract ( 2295 )

The effect of thermal aging on ignition time, heat release rate of the specimens of YJV cables was studied by means of thermal aging chamber, cone calorimeter and thermogravimetric (TG). The test data indicated that the ignition time of the specimens increased and the first peak value of heat release rate decreased with ageing time in early thermal aging period. This suggest that the fire hazard of the plastics in YJV cables would be reduced considerably while subjected to the thermal aging in early period in which most of the additives in plastic of cable was heated to volatilized from cable.

Research on Atmospheric test and Chemical Resisitance Test of headlamp's Lens

Wang Tie-Cheng

2010, 24 (06): 58-61 ; DOI: 10.19491/j.issn.1001-9278.2010.06.012

Abstract ( 1747 )

16 sets of test samples of headlamps and front fog lamps with different materials were tested for atmospheric agent and chemical resistance. The test results showed that, in accordance with the provisions of GB 4599-2007 on atmospheric agent test, 62.5% of 16 sets of test samples can meet the limit value of 0.020 in GB 4599-2007. Therefore, it illustrated that atmospheric agent test highly investigates the performance of plastic lens, which is very difficult for present products to meet its requirements. For the chemical resistance test, the majority of samples can meet the provisions. At the same time, we analyzed the affects of different raw materials to the performances of products, which is very instructive in the material chosen of plastic lens and their coating.

Test Research on Tribological Properties and Bonding Strength of Metal Matrix Composites

2010, 24 (06): 62-66 ; DOI: 10.19491/j.issn.1001-9278.2010.06.013

Abstract ( 1793 )

A series of metal matrix composites of different proportion composed of PA66,PPS,Mn65 were prepared. The tribological properties test were carried out in different condition. Bonding strength test was carried out. The tribological properties test indicate that the friction coefficient and wear rate will be reduced with the increase of nylon66. The friction coefficient and wear rate of same materials increases first and then decreased with time and speed increased. The bonding strength test indicate that the bonding strength of metal matrix composites will be gradually increase with the increase of PPS.

Preparation and Mechanical Properties of PP based WPC

Jing-Yu GONG Chao HAN Yang YE

2010, 24 (06): 67-71 ; DOI: 10.19491/j.issn.1001-9278.2010.06.014

Abstract ( 1508 )

PP based wood plastic composite samples were prepared by compression molding. The effects of the content of wood flour and compatibilizer modification on the properties of crystal, rheology and mechanics of WPC were studied using some analysis instruments, such as X-ray diffraction, scanning electron microscopy etc. The result showed that β-PP crystal was restrained by wood flour according, The growth of (040) surface of α-PP may be enhanced at 10 phr of WF. The tensile strength of WPC samples were increased, while its toughness showed a shade decrease by adding the content of WF. The growth of (010), (040), and (130) surface of composites that adding 0.5 phr of aluminic ester coupling agent to the WPC with 30 phr WF is better than that without aluminic ester coupling agent. The notched impact strength of composites with 0.5 phr aluminic ester coupling agent is 6.25 kJ/㎡, 23.52 % higher than that without aluminic ester coupling agent. The results of SEM showed a similar tending. Moreover, the molding properties of WPC were also improved by the AE coupling agent.

Preparation and Characterization of Microencapsulated Red Phosphorus with Phenol-formaldehyde Resin as Shell Material

2010, 24 (06): 72-75 ; DOI: 10.19491/j.issn.1001-9278.2010.06.016

Abstract ( 1590 )

A flame retardant in the form ultramicro microencapsulated red phosphorus（MRP）was prepared by encapsulating red phosphorus with phenol-formaldehyde(PF) resin via in-situ polymerzation. The MRP was characterized using infrared spectroscopy, scanning electron microscope, X-ray photoelectron spectroscopy, laser particle size analyzer and thermogravimetric analysis, The average size of MRP was 7.5 μm and a compactness surface was formed. The ignition point of MRP rose to 485 ℃. The moisture absorption was less than 1.8 %, oxidation resistance 7.8 mg/g·h, and phosphine emission 3.6 μg/g·h. In contrast with red phosphorus, the performance of MRP was obviously improved.

Synthesis of Zinc Hydroxystannate and Effect on Flame Retardancy and Smoke Suppression of PVC Cable Materials

YANG Ling

2010, 24 (06): 76-81 ; DOI: 10.19491/j.issn.1001-9278.2010.06.017

Abstract ( 1922 )

Zinc hydroxystannate (ZHS) were obtained by hydrolyzation of Tin (Ⅳ) reacting with zinc (Ⅱ) in aqueous alkali at the presence of solid sodium hydroxide. X-ray diffraction and environmental Scanning Electron Microscope (ESEM) images show that the product grows into cubic poly-crystals having a mean edge length of about 380 nm. Flame retardant and smoke suppressant effects of ZHS in PVC cable materials and relevant mechanism were investigated by means of Limited oxygen index, smoke density measurement, environmental scanning electron microscope analysis and Gas chromatography-mass spectrometry. The results showed that ZHS had better flame retardance and smoke suppression effect than that of antimony trioxide in PVC When the content exceeds 15 phr.

Preparetion and Properties of polystyrene film for Fertilizers' Encapsulation

SONG Xue-jun, ZHANG Xu-dong, SHI Yuan-liang

2010, 24 (06): 82-85 ; DOI: 10.19491/j.issn.1001-9278.2010.06.018

Abstract ( 2126 )

Waste foamed polystyrene was used as the main materials to produce coated fertilizer of urea. Ethyl acetate or toluene was the solvent. Dibutyl phthalate was selected as plasticizer to reduce the brittleness of polystyrene. SBS resin was used as enhancer to improve the adhesion of polystyrene film. The concentration of coating solution was 12 %, containing 3 % plasticizer and 1 % enhancer. The amount of coated materials was 10 %. Dissolution rate of nitrogen in the water and soil was determined. The initial dissolution rate of slow-release fertilizers in water was lower than 40 % and the cumulative dissolution rate in soil was significantly lower than that of no-coated urea.

Development of Ultrasonic Detection Database of Ployethylene Pipe Joints

Fei Wang Guang-Zhong LI Han-Zeng SHAO SHI Jian-Feng

2010, 24 (06): 86-90 ; DOI: 10.19491/j.issn.1001-9278.2010.06.019

Abstract ( 1902 )

A database system was successfully developed, using Visual Basic and SQL Server. Using the database, the defect types, characteristics and the corresponding ultrasonic images of electrofusion and butt-fusion can be sorted, queried and browsed. The database system can help the non-destructive testing workers detect and identify the defect feature in electrofusion or butt-fusion joints rapidly and accurately, so as to estimate the defect type and the harmfulness.

Performance Evaluation of Injection Molding Screws Based on Melt Temperature Homogeneity

Zhou Ya-Wen LI Qing-Chun

2010, 24 (06): 91-96 ; DOI: 10.19491/j.issn.1001-9278.2010.06.020

Abstract ( 1484 )

A temperature difference measurement system was designed for measuring the axial and radial temperature distribution of melt online in the injection molding process. Experiment on four different types of injection molding screws. Study on performance evaluation of injection molding screw by measuring the melt temperature homogeneity. When PS pares was molded,the axial average temperature difference was down to 0.45 ℃，and the radial average temperature difference is down to 2 ℃ , the repeating weight precision of products can reach 0.035 %,the impact strength is up to 10 kJ/m2 and the melt pressure fluctuations is down to 0.7 MPa by using a screw processing PS at the same operating condition. It was consider that such a screw in the melt temperature homogeneity could meet the requirements for precise injection molding of PS products

Design of the Injection Mold for a Wall Speaker Covers Based on Moldflow Technologies

2010, 24 (06): 97-101 ; DOI: 10.19491/j.issn.1001-9278.2010.06.021

Abstract ( 2210 )

Development of injection mold for a wall speaker covers was carried out based on moldflow technology in this paper. The gates location were determined by gate location analysis and the balanced runner was got by runner balance analysis, then filling analysis was carried out to inspect the filling result of the two cavities, maximum injection pressure and clamp force. Finally, the mold was design based the result of moldflow analysis and its structure and movement principle were illuminated in details. Practice has proved that moldflow technology can be used to ensure the reasonable and efficiency of mold design and high quality products can be obtained quickly.