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2011, Volume 25 Issue 01 Publication date: 26 January 2011 Previous Issue Next Issue

Review of Chinese Plastics Machinery Industry during the Eleventh Five-year Plan Period and Its Prospect in the Twelfth Five-year Plan Period

LI Jian

2011, 25 (01): 1-7 ; DOI: 10.19491/j.issn.1001-9278.2011.01.001

Abstract ( 2351 )

This article discusses the development status and problems of the domestic plastics machinery industry during the eleventh five-year plan period. Development trends of domestic plastics machinery industry in the coming twelfth five-year plan period were prospected according to the demands of application industries, including the fields of energy-saving building sector, medical sector, logistics sector, and the requirements of the development of low-carbon economy.

Research Progress in Poly(propylene carbonate)

WANG Qiuyan WENG Yunxuan XU Guozhi

2011, 25 (01): 8-14 ; DOI: 10.19491/j.issn.1001-9278.2011.01.003

Abstract ( 2510 )

Research progresses in synthesis, modification, and production of poly(propylene carbonate) (PPC) were reviewed. Market prospect of PPC was also forecasted. Main catalyst systems used for polymerization of PPC are zinc catalysts, dual metal reforming catalysts, rare earth catalysts, Salen(MX) catalysts, and metal loporphyrin-based catalysts, in which zinc catalysts possess the highest catalytic activity, binary or bifunctional Salen（MX）composites provide the highest efficiency. Among the modification methods, crosslinking, copolymerizing, solution blending, and melt blending are frequently used. In China, PPC has very capacious market prospect.

Development of Energy-saving Technologies for Plastics Machinery

ZHAO Feng ZHANG Yuxia XUE Ping QI Xiaoyun LIU Jing

2011, 25 (01): 15-24 ; DOI: 10.19491/j.issn.1001-9278.2011.01.004

Abstract ( 1872 )

New energy-saving technologies for plastics machinery and their application effects were introduced, especially in the respect of energy-saving effect, including power transmission, extrusion and injection molding systems, auxiliary equipments and control systems, etc.。

Ersearch Progress in Polyphorous-containing Polymer Flame Retardants

LIU Jiyan LIU Xueqing

2011, 25 (01): 25-30 ; DOI: 10.19491/j.issn.1001-9278.2011.01.005

Abstract ( 2225 )

Recent progress in phosphorus-containing polymer flame retardants was reviewed. Based on the location of P element in the polymer, they can be divided into main-chain and side-chain phosphorus-containing polymers. Recent research works on the phosphorus-containing polymer focused on following aspects: (1) synthesis of synergistic phosphorus-base polymers and exploring the mechanism of synergistic effect; (2) synthesis of phosphorus-containing polymers with hyperbranched or mesogen architectures; (3) the way to improve mechanical and thermal properties without reducing fire retardancy; (4) synthesis of phosphorus-containing polymers with multiple functions.

Study on Thermal Degradation Kinetics of PP/MWNTs and PP/OMMT Composites

Wei WU Lixing LUAN Weiguang PU Sanxiong HE Yujie CHEN

2011, 25 (01): 31-35 ; DOI: 10.19491/j.issn.1001-9278.2011.01.007

Abstract ( 2253 )

Polypropylene/multiwalled carbon nanotube (PP/MWNTs) and polypropylene/organo-montmorillonite (PP/OMMT) composites were prepared via melting blending. Thermal gravimetric analysis was applied to record the thermal degradation behavior of the composites under nitrogen atmosphere with different heating rates. The thermal decomposition data were analyzed with Kissinger and Ozawa Methods. It showed that both MWNTs and OMMT could enhance the thermal resistance of PP matrix, and the apparent activation energy of PP/OMMT was higher than PP/MWNTs. SEM observation showed that MWNTs took disordered rod-like distribution while OMMT presented lamellar-structure dispersion in PP matrix.

Study on Structure and Property of Propylene Copolymers with High Impact Strength and High Flowability

WANG Yunhong LUO Xian ZHANG Baolin LEI Junqing

2011, 25 (01): 36-41 ; DOI: 10.19491/j.issn.1001-9278.2011.01.008

Abstract ( 2374 )

Several propylene copolymers with high impact strength and high flowability were characterized using nuclear magnetic resonance, dynamic mechanical analysis, differential scanning calorimeter, and rheological properties. Sample 1# had a high ethylene content and high isotacticity, low xylene solubility, the homopolymer and copolymer phases showed good compatibility, provided the best comprehensive mechanical properties. Sample 3# had higher content of PE node and ethylene, so it possessed the highest impact strength. Gel permeation chromatography data showed that sample 4# and 5# had a wide molecular weight distribution and displayed good processing property at high shear rates. The comparison showed that the high melt flow impact propylene copolymer should contain a high fraction of ethylene-propylene rubber segments, a high isotactic index in the homopolymer phase, and a good compatibility between the two phases. Molecular weight distribution should be moderately wide, so that good processing behavior could be obtained, and dimensional stability of the products could be increased.

Preparation and Characterization of PLA/Esterified Cellulose/Nano-CaCO₃ Composites

DENG Changyong ZHANG Xiucheng

2011, 25 (01): 42-46 ; DOI: 10.19491/j.issn.1001-9278.2011.01.009

Abstract ( 2146 )

Polylactic acid (PLA)/esterified cellulose/nano-CaCO3 composites were prepared via melt blending. Properties of the composites were investigated by means of mechanical properties testing, differential scanning calorimeter, thermogravimetry, and scanning electron microscope. When the filler content was less than 5 %, esterified cellulose could be well dispersed in PLA matrix, and the mechanical properties of the composites were improved obviously compared with pure PLA. The filler acted as a nucleating agent in PLA matrix. However, the thermal stability of the composites was lower than that of PLA. When the filler content was more than 10 %, the aggregation of nano-CaCO3 was observed, which led to unsatisfactory properties of the composites.

Study on PTFE/SiO₂ Hybrid Materials Prepared by Sol-gel Method

ZHANG Dongna KOU Kaichang GAO Pan WANG Zhichao CHAO Min

2011, 25 (01): 47-50 ; DOI: 10.19491/j.issn.1001-9278.2011.01.010

Abstract ( 2263 )

The sol-gel preparation of polytetrafluoroethylene/silicon dioxide (PTFE/SiO2) hydrid materials was investigated. The effect of ethanol on the dispersion of PTFE and SiO2 was also discussed. The formula was designed for a 50 % theoretical SiO2 content in PTFE/SiO2 hybrid materials. The impacts of aging time and aging temperature on the actual content of SiO2 were studied. The results showed that with the elongation of aging time, the content of SiO2 increased. In the first 5 h, the increase was very fast and reached 38.9 % by 48 h. The effect of aging temperature was studied at aging time of 1 h. It showed that with the increasing temperature, the content of SiO2 increased at first and then decreased. The content of SiO2 was 19.8 % when aging temperature was 40 ℃.

Study on Properties of PE-LD/CaCO₃/EVA Composites

DONG Jinhu

2011, 25 (01): 51-54 ; DOI: 10.19491/j.issn.1001-9278.2011.01.012

Abstract ( 2234 )

The effects of CaCO3 and EVA on the mechanical properties of low density polyethylene/calcium carbonate/ethylene-vinylacetate copolymer (PE-LD/CaCO3/EVA) composites were studied, and the reason was explained combined with scanning electron microscope observation of the fractured surface. It showed that when the content of EVA was 0.67 % and the content of CaCO3 between 10 % and 20 %, the mechanical properties of the composites were the best. And when the content of CaCO3 was 20 % and the content of EVA between 1.33 % and 2.33 %, the toughness increased to a maximum, and the tensile strength changed slightly with the increasing content of EVA.

Study on m-Isopropenyl-α, α-dimethylbenzyl Isocyanate Grafted Polypropylene

MA Lichun SUN Caiying LI Liping GUO Chuigen

2011, 25 (01): 55-59 ; DOI: 10.19491/j.issn.1001-9278.2011.01.013

Abstract ( 2373 )

Polypropylene (PP) was melt grafted with styrene (St) and m-isopropenyl-α, α-dimethylbenzyl isocyanate (m-TMI) which has unsaturated bonds and isocyanate group. The grafted products were characterized using non-aqueous titrations, infrared spectrum, thermogravimetry and differential scanning calorimeter. It was found that both m-TMI and St were grafted onto PP. St inhibited effectively the degradation of PP during the grafting and improved the thermal stability of grafted products. At given concentration of St, the grafting degree and grafting efficiency of m-TMI increased at first and then slightly decreased with increasing m-TMI concentration; At given concentration of m-TMI, the grafting degree of m-TMI reached a maximum at St/ m-TMI of 1.6.

Study on Novel Catalyst for Direct Polycondensation of Poly(lactic acid)

SUN Meihua ZHOU Hongjun CHEN Qian LU Hong SONG Guangquan

2011, 25 (01): 60-64 ; DOI: 10.19491/j.issn.1001-9278.2011.01.014

Abstract ( 2124 )

The direct polycondensation method with different catalyst was used to synthesize polylactic acid (PLA) from D, L-lactic acid, the catalytic effect of NaBr, NaCl, NaI, KI, KCl and KBr was compared. The influences of dosage of catalysts, reaction time and reaction temperature on the polymerization were discussed. The PLA was characterized using infrared spectroscopy, nuclear magnetic resonance, gel permeation chromatography, differential scanning calorimetry and thermogravimetry. It showed that KI was the optimum catalyst. When the molar ratio of KI to D, L-lactic acid was 0.2，polymerization time was 12 h, reaction temperature was 130 ℃, the weight-average molecular weight of obtained PLA was 1.151×105 with a yield of 70.73 %. With increasing average molecular weight of PLA, the glass transition temperature increased. The thermal decomposition temperature of PLA decreased with increasing dosage of catalysts.

Effect of Aluminum Particles with Binary Particle Size Distribution on Thermal Conductivity and Dielectric Properties of Epoxy Resins

ZHOU Wenying YU Demei

2011, 25 (01): 65-70 ; DOI: 10.19491/j.issn.1001-9278.2011.01.015

Abstract ( 1989 )

Three bimodal aluminum particle mixtures, i.e., 2 μm/18 μm, 2 μm/50 μm, and 18 μm/50 μm, were used to reinforce epoxy resin. The thermal conductivity and dielectric properties of filled epoxy resins were investigated as a function of relative content of small particles (Ws) when the total filler content was fixed at 60 %. It showed that the thermal conductivity, thermal diffusivity and dielectric properties of epoxy resins varied with changing the Ws. The smaller the difference between two particles, the smaller the Ws was when the thermal conductivity reached a maximum. The maximum dielectric constant appeared at the W50 μm/W18 μm about 2. However, the Ws had negligible influence on the dielectric loss factors, which was near 0.02.

Calculation of Long-term Hydrostatic Pressure Strength of Overlap-welding and Butt-welding Aluminum-plastic Pipes

LI Mingxuan

2011, 25 (01): 71-75 ; DOI: 10.19491/j.issn.1001-9278.2011.01.016

Abstract ( 2251 )

The long-term hydrostatic pressure test curves of overlap-welding aluminum-plastic pipes with diameters of 16mm to 32mm were extrapolated to 50 years by considering the same overall design factor as 1.25 with butt-welding aluminum-plastic pipes. It showed that at 95 ℃ long-term operating temperature, 16-32 type overlap-welding aluminum-plastic pipes had a comparative allowable working pressure P0 compared with butt-welding aluminum-plastic pipes, and could meet the requirements of the 50-year service life under 95 ℃ and 1.25 MPa. According to the requirements of minimum thickness and minimum tensile strength of aluminum layer in national standards, P0 of the overlap-welding aluminum-plastic pipes and butt-welding aluminum-plastic pipes with diameters of 16mm to 50mm was calculated. The results showed that both had the same P0 for the small size, but butt-welding aluminum-plastic pipes had the obvious advantage for the large size.

Effects of Injection Molding Parameters on Glossiness of Polypropylene Parts

LIU Xiwen YANG Zhongwen

2011, 25 (01): 76-79 ; DOI: 10.19491/j.issn.1001-9278.2011.01.017

Abstract ( 2221 )

In order to explore the effect of injection molding parameters on the glossiness of polypropylene parts, Taguchi method was employed to determine the experiment factors and their weighs. It was found that the increase of melt temperature, mold temperature, dwell pressure, and injection rate could increase the glossiness of the parts; meanwhile the tensile and bending strengths would also increase at the cost of notch impact strength. The descending order in weigh of the influence factors was melt temperature, mold temperature, packing pressure, and injection rate.

Study on Aging Properties of Plastics-coated Woven Bags for Cement

YU Zhongdong

2011, 25 (01): 80-82 ; DOI: 10.19491/j.issn.1001-9278.2011.01.018

Abstract ( 2096 )

The aging properties of plastics-coated woven bags for cement were studied by analyzing the breaking strength and elongation at break before and after ultraviolet irradiation. For the bags without anti-aging agent, the breaking strength retention rate of the bags of summer grade was 14 % after sunlight for 21 d, and that of winter grade was 48 % after sunlight for 30 d. For those containing anti-aging agent, the breaking strength retention rate of winter grade was 65 % after ultraviolet irradiation for 12 h (equivalent to sunlight for 32 d).

Study on 3D Simulation for Filling Behavior and Fibers Orientations of Injection Molded Parts with Convex Cross Section

XIONG Aihua LIU Hesheng HUANG Xingyuan LUO Zhang LAI Jiamei HUANG Yibin

2011, 25 (01): 83-89 ; DOI: 10.19491/j.issn.1001-9278.2011.01.019

Abstract ( 2290 )

According to the Folgar-Tucker model, full 3D simulation of injection filling behavior and fiber orientations were studied for a sample of 15% short glass fiber reinforced polyamide 6 with a convex cross section. It showed that full 3D technology could simulate effectively filling behavior and the fountain effect of injection molding. The fiber orientation in the skin was parallel to shearing flow, and the degree of fiber orientation in the sample's big end was lower than in the small end. The fiber orientation of 3D solid was complex along the three axes. In the x direction, the degree of fiber orientation increased at first then decreased with increasing the filling length. Along the y axis, the degree of fiber orientation in the sample's small end increased gradually with increasing distance to the core, but the degree of fiber orientation in the big end increased at first then decreased. Along the direction of z axis, the degree of fiber orientation in the sample's small end tended to increase from core to skin, while that was reducing gradually in the big end.

Study on Rheological Behavior of PTT/MMT Composites

WANG Liyan LI Guang GUO Jing LI Jixin XIANG Hengxue

2011, 25 (01): 90-93 ; DOI: 10.19491/j.issn.1001-9278.2011.01.020

Abstract ( 2239 )

The rheological properties of poly(trimethylene terephthalate) /montemorillonite(PTT/MMT) composites prepared by melt blending were studied using capillary rheometer. It showed that PTT and PTT/MMT melts were all pseudo-plastic fluids, and the addition of 1%~3% MMT could obviously improve the flow property of the composites. The non-Newtonian index of the composites was higher than that of PTT. The apparent viscosity of the composite was lower than that of PTT, and their flow behavior was better than that of PTT, so the composites could be processed at lower temperature. The viscous flow activation energy of the composite was higher than that of PTT, and it was more proper for the composite to improve their flow properties by increasing temperature.

Synthesis and Application of Nucleating Agent—1,3,5- Benzenetricarboxylic Acid Tris (cyclohexylamide)

ZHANG Yuefei LUO Xianzu CHANG Yao

2011, 25 (01): 94-96 ; DOI: 10.19491/j.issn.1001-9278.2011.01.021

Abstract ( 2227 )

1,3,5-benzenetricarboxylic acid tris (cyclohexylamide) (BTCA-TCHA) was synthesized and used as a nucleating agent of isotatic polypropylene, and its effects on mechanical properties, crystallization and melting behaviors of isotatic polypropylene were studied. When the loading of BTCA-TCHA was 0.2 %, tensile strength and flexural modulus of isotatic polypropylene were increased by 9.72 % and 12.4 %, respectively, and haze value decreased by 53.5 %. When the cooling rate was 20 ℃/min, crystallization peak temperature was increased from 114.6 ℃ of virgin isotatic polypropylene to 126.8 ℃.

Synthesis and Properties of Novel Hindered Phenolic Antioxidant

LI Cuiqin WANG Jun FANG Hong GE Tengjie

2011, 25 (01): 97-101 ; DOI: 10.19491/j.issn.1001-9278.2011.01.022

Abstract ( 2159 )

A novel hinderd phenolic antioxidant 2,6-di-tert-butyl-4-aminophenol was synthesized with 2,6-di-tert-butylphenol as a raw material. When zinc powder was used as a reducing agent, ethanol as a solvent was 100 mL, the amount of calcium chloride solution was 90 mL, the reaction temperature was 80℃ and the reaction time was 8 h, the yield of the product reached 80 % and its melting point was between 112.2 ℃and 113.3 ℃. When loaded in polyolefin resins, the anti-oxidation property of the novel one was equal to antioxidant 1076 and was superior to antioxidant BHT. After 5 times extrusion, the melt flow rate of the two polyolefins containing the novel antioxidant changed a little, and the tensile strength and the elongation at break increased.

Optimization of Maximum Output of Solid Convey for Co-rotating Twin Screw Extruders by Response Surface Methodology

YUAN Jiechao LUO Bing BI Chao WANG Wenfei YI Dalong

2011, 25 (01): 102-105 ; DOI: 10.19491/j.issn.1001-9278.2011.01.023

Abstract ( 2482 )

The maximum output of solid convey for Φ34 mm co-rotating twin screw extruder were optimized by response surface methodology method. A quadratic multinomial equation model using the maximum output of solid convey as the objective function was built, and the main influence factors and their corresponding relationships were discussed. It showed that the deviation between predicted values by the model and experimental values was less than 10 %. The maximum output of solid convey were obtained as follows, screw speed was 124 r/min, the helix angle of the screw was 32 °, and the diameter of the solid particle was 2.7 mm. After optimizing the factors, the maximum output of solid convey was 534 g/min and was increased by 7.2 % compared with the value before optimizing.

Control Method for Wall Thickness of Extrusion-blow-molded Parts

WU Yunong WANG Shuhui XU Zhongming

2011, 25 (01): 106-109 ; DOI: 10.19491/j.issn.1001-9278.2011.01.024

Abstract ( 2095 )

In order to improve the uniformity of wall thickness of extrusion-blow-molded parts, several improvements were made, including an automatic control device of wall thickness was used, the structure of parison extrusion die was improved, and automatic close-loop control was used during the whole working process. The efficiency of the improved machine was greatly improved, and at the same time the weight deviation of the extrusion-blow-molded parts and the average energy consumption was decreased.

Report on the 18th International Trade Fair of Plastics & Rubber (K2010)--New Technology for Injection Molding

YANG Weimin WANG Xiaohua XIE Pengcheng

2011, 25 (01): 110-115 ; DOI: 10.19491/j.issn.1001-9278.2011.01.025

Abstract ( 2518 )

On the 18th international trade fair of plastics & rubber (K2010), global injection molding leading enterprises displayed the latest injection molding technology and machines, including full electric injection molding machine, electro-hydraulic injection molding machine, large-scale injection molding machine, micro-injection molding machine, control system with extended function, etc. the injection molding technologies are developed towards energy-saving, high precision, high efficiency and environmental-friendly. Total solution with highly integrated and automated characteristics becomes the mainstream of plastics injection molding industry. Development of this solution continuously broadens the applications of injection molding process in the packaging, medical and automobile fields.