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2010, Volume 24 Issue 09 Publication date: 26 September 2010 Previous Issue Next Issue

Research Progress in Preparation of Starch-based Foamed Plastics

CHEN Xiaojian, TAI Limin

2010, 24 (09): 1-5 ; DOI: 10.19491/j.issn.1001-9278.2010.09.001

Abstract ( 2035 )

Current situation of research and application of degradable starch-based foamed plastics was reviewed. The processing methods for the starch- based foam were summarized, including extrusion foaming, baking foaming, mold pressing foaming, and extrusion foaming with supercritical fluid as the foaming agent. The development trend in the starch-based foam was forecast.

Research Progress in Chitosan-based Intelligent Hydrogels

SHU Jing Xiaojing LI ZHAO DAbiao

2010, 24 (09): 6-10 ; DOI: 10.19491/j.issn.1001-9278.2010.09.002

Abstract ( 1745 )

Chitosan-based intelligent hydrogels including temperature sensitive, pH sensitive, and temperature/pH sensitive types were summarized with their merits and shortcomings analyzed. The applications of the chitosan-based hydrogels in drug releasing and organization engineering were reviewed. Finally, the current problems and future development of chitosan-based hydrogels were presented.

Research Progress in Synergistic Flame Retardant with Magnesium Hydroxide

Wang Juan

2010, 24 (09): 11-16 ; DOI: 10.19491/j.issn.1001-9278.2010.09.003

Abstract ( 2073 )

Performance and flame-retardant mechanism of magnesium hydroxide were introduced, its synergistic effect with other flame retardants was discussed. It was found that the composites containing magnesium hydroxide generally possessed better flame retarding property through its synergistic effect with other flame retardants. Finally, the trend of the development of magnesium hydroxide based synergistic flame retardants was explored.

Preparation and Properties of Poly (lactic acid)/ Montmorillonite Nano-composites

SHEN Bin, LIU Liang, LIN Shuixing, YANG Yi, ZHANG Liye

2010, 24 (09): 17-21 ; DOI: 10.19491/j.issn.1001-9278.2010.09.004

Abstract ( 2134 )

Poly（lactic acid）/ montmorillonite (PLA/MMT) nano-composites were prepared through melt intercalation in a twin-screw extruder. The microstructure, morphology, thermal properties, and crystallization behavior of the nano-composites were characterized using XRD, TEM, and DSC. It revealed that the layer spacing of MMT increased from 1.801 to 3.530 nm by the intercalating of PLA. When 3 % of MMT was used, the tensile strength, elongation at break, and impact strength reached the max. With MMT loaded, the degree of crystallinity of PLA increased and the average grain size reduced compared with neat PLA.

Research on Non-isothermal Crystallization Behavior of PA6/ABS blends

2010, 24 (09): 22-26 ; DOI: 10.19491/j.issn.1001-9278.2010.09.006

Abstract ( 1823 )

The non-isothermal crystallization behavior of PA6/ABS blends were investigated using differential scanning calorimetry（DSC）. The DSC data was analyzed with Jeziorny and Mo methods. With increasing ABS content, the Avrami index n increased from 4.55 to 7.04 and the crystallization peak temperature increased from 174.2 ℃ to 183.3℃. With increasing cooling rate, the crystallinity, crystallization temperature, and half-crystallization time decreased.

Study on Synthesis of Poly( utylenes succinate-co-diethylene succinate)

2010, 24 (09): 27-30 ; DOI: 10.19491/j.issn.1001-9278.2010.09.007

Abstract ( 1952 )

Biodegradable poly(butylene succinate-co-diethylene succinate)(PBDGS) was synthesized via polycondensation of succinate acid，1,4-butanediol，and diethylene glycol. The effect of molar ratio of acid and alcohol, catalyst, and temperature on the properties of polyesters was studied using nuclear magnetic resonance (1H-NMR), gel permeation chromatography (GPC), and differential scanning calorimetry (DSC). It is showed that when the molar ratio of acid and alcohol was 1.15:1, the condensation temperature was 230℃, and MBTO was used as a catalyst; the highest molecular weight of PBDGS was obtained，with weight and number-average molecular weight being 3.7×104 g/mol and 6.9×104 g/mol，respectively.

Research on Phosphorus-containing Flame-retardant Epoxy Resin for Solvent-free Winding

2010, 24 (09): 31-35 ; DOI: 10.19491/j.issn.1001-9278.2010.09.008

Abstract ( 1388 )

A novel liquid phosphorus-containing epoxy resin was synthesized via a reaction of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO) with diglycidyl ether of bisphenol A. The relations between phosphorus content and flame retardancy of epoxy systems were studied. Heat-resistance and machanical properties of cured epoxy resin were also characterized. It was found that the reaction between DOPO and diglycidyl ether of bisphenol A was completed after 6 hours at 170℃. Flame-retartant epoxy resin with 2.0 % phosphorus content achieved UL94 V-0 and resulted in a char yield of 23 % at 600℃. Compared with phosphorus-free diglycidyl ether of bisphenol A epoxy resin, the incorporation of DOPO caused no significant decrease in Tg and mechanical properties.

Study on Compatibilization Effect of Different Compatibilizers on Polyamide1010/Polypropylene Blends

2010, 24 (09): 36-40 ; DOI: 10.19491/j.issn.1001-9278.2010.09.009

Abstract ( 1973 )

Three compatibilizers, maleic anhydride(MA)-grafted ethylene-octene copolymer (POE-g-MAH), MA-grafted polypropylene(PP-g-MAH), and ethylene-butylacrylate-glycidyl methacrylate terpolymer (PTW), were compared for their compatibilizing effects in the blends of polyamide 1010 and polypropylene (PA1010/PP). The compatibilized blends were characterized using Fourier transform infrared (FTIR), mechanical property testing, and differential scaning calorimetry (DSC). Compared with the plain PA1010/PP blends, the tensile strength of the compatibilized systems based on PP-g-MAH，POE-g-MAH，and PTW were 125 %, 89 %, and 94 %, and the impact strength of PP-g-MAH，POE-g-MAH，and PTW were 140 %, 200 %, and 200 % , respectively. One may conclude that the overall performance of PTW was the best.

Research on Mechanical and Crystallization Properties of Ethylene-co-polypropylene Resin for Casting Films

Yangchuan Ke Lixiao Jin

2010, 24 (09): 41-45 ; DOI: 10.19491/j.issn.1001-9278.2010.09.010

Abstract ( 1817 )

By adjusting the ethylene contents in polypropylene for casting，a series of polypropylene copolymer was obtained. The effect of ethylene contents on the molecular weight and molecular weight distribution，mechanical properties，and crystalline structure of the resin was investigated. The ethylene sequence in the copolymer was characterized using 13C-NMR. It was found that the optimal ethylene contents was between 3.4 wt% and 4.0 wt%. When the contents of ethylene was 3.8 wt%，the impact strength and crystallinity of the copolymer reached 4. 7 kJ/m2 and 29.05 %，respectively.

Performance of a New Kind Bio-degradable Aliphatic Polyester in PBS group

Xiaocong SHAO Jianwen Chen Jialin Wu

2010, 24 (09): 46-48 ; DOI: 10.19491/j.issn.1001-9278.2010.09.011

Abstract ( 1714 )

A new kind of bio-degradable aliphatic polyester was synthesized via melt polycondensation from butanediol, succinic acid, terephthalic acid, ethanediol, and L-lactic acid. This polyester displayed two yield points located at 10 % and 300 % of elongations, respectively. The yield at 300 % elongation imparted the polymer better strength, flexibility, shape-memory, and elasticity. This new polyester could be used as a toughener for brittle biodegradable materials, such as PLA.

Resistivity Temperature Behavior of Acetylene Carbon Black Filled PE-HD/EVA/PE-LD Conductive Foamed Composites

2010, 24 (09): 49-52 ; DOI: 10.19491/j.issn.1001-9278.2010.09.012

Abstract ( 2003 )

PE-HD/EVA/PE-LD/ACET conductive foamed composites were prepared using acetylene carbon black (ACET) as a conductive filler, azobisformamide (AC) as a foamer, and dicumyl peroxide(DCP) as a cross-linker. Closed cell structure was obtained when PE-HD/EVA/PE-LD is 50：30：20（w/w/w）,and acetylene carbon black, azobisformamide, and dicumyl peroxide content were 35, 4, and 0.5 wt %, respectively. The prepared conductive foam composites had good switching characteristics, and displayed positive temperature coefficient (PTC) effect, which was the strongest when the contents of AC was 4 wt %.

Extrusion Process for Composite Reinforced Cannulas

2010, 24 (09): 53-55 ; DOI: 10.19491/j.issn.1001-9278.2010.09.013

Abstract ( 1619 )

In the extrusion processing of medical catheter, supporting tubes were inserted into the die, so as to produce composite catheters more easily. This novel technique was suitable for the extrusion of different kinds of materials, especially materials with large difference of melting point. The supporting tube could be of varying diameter and shape, multi-cavity. The minimum inner-diameter could be less than 0.2 mm. A variety of medical catheters could be produced with this technique.

Studies on Radiation Crosslinking of Halogen-free Flame- retardant Cable Jacketing Compound Used for Naval Vessels

2010, 24 (09): 56-60 ; DOI: 10.19491/j.issn.1001-9278.2010.09.014

Abstract ( 1914 )

Cable sheaths was prepared from ethylene-vinyl acetate copolymer (EVA), ethylene-octene copolymer (POE), and nano-aluminum hydroxide (ATH) and was radiation crosslinked. The effect of formula, the type and content of ATH, and radiation dose on the mechanical and flame-retardant properties were investigated. With increasing POE content, the tensile strength, elongation at break, and thermal aging resistance of the compound increased, and its hardness decreased. ATH improved the flame retardancy of the compound. Radiation crosslinking enhanced the mechanical properties. The optimal recipe was found to be EVA /POE/ATH ＝90/10/60 and the optimal radiation dose was 80 kGy.

Application of Homogeneous Design in the Investigation of POE/POE-g-MAH Toughening PA6

CHEN kun

2010, 24 (09): 61-63 ; DOI: 10.19491/j.issn.1001-9278.2010.09.016

Abstract ( 1871 )

Based on homogeneous design and regression analysis, the toughening of PA6 with POE/POE-g-MAH was investigated. When the contents of POE-g-MAH and POE were 7 and 18 wt%, respectively, the notched impact strength of toughened PA6 reached 86.8 KJ/m2.

Development and Application of a Novel Special Material for Plastic Inspection Chambers

2010, 24 (09): 64-67 ; DOI: 10.19491/j.issn.1001-9278.2010.09.017

Abstract ( 1540 )

The application background and current situation of the plastics inspecting chambers were introduced. A novel for inspection chambers was developed. Compared with conventional materials, the melt flow rate, notched impact strength and bonding modulus the special material increased from 4~6 g/10 min to 6~10 g/10 min, 6 to 8~24 kJ/m2, 2.0 to 4.5~6.0 GPa, respectively. Using this material，the strength and toughness of the inspecting chamber increased，while its cost decreased.

Gate Location Optimization Based on the Stress Value of Weld Lines

2010, 24 (09): 68-71 ; DOI: 10.19491/j.issn.1001-9278.2010.09.018

Abstract ( 1869 )

The stress value of weld lines of plastics product under a real working condition was studied by the combination of injection molding numerical simulation and structural analysis numerical simulation. The correctness at the gate location was judged by the stress value around the weld line. It showed that the numerical simulation and analysis provided a useful method and reliable guidance for the design of gate location.

Effects of Phosphorus flame retardants on the properties of PPO/HIPS Alloy

2010, 24 (09): 72-76 ; DOI: 10.19491/j.issn.1001-9278.2010.09.019

Abstract ( 1956 )

The effect of various phosphorus flame retardants on the flame-retarded performance, mechanical properties, and heat resistance of PPO/PS-HI alloy was investigated. It was found that red phosphorus was better than organic phosphate in flame retardancy. At the loading meet the flame-retarded grades（UL 94 V-0）, organic phosphate flame retardant would greatly reduce the heat resistance, and red phosphorus was harmful to the toughness.

Effect of Flame Retardant on HCN from the Thermal Degradation of Soft PU Foam

YANG Shousheng

2010, 24 (09): 77-83 ; DOI: 10.19491/j.issn.1001-9278.2010.09.020

Abstract ( 1955 )

The equipment of absorbing HCN was used to study the effect of the type of fire retardant and contents on the yield of HCN in the process of polyurethane foam pyrolysis. It was found that NH4Cl, (NH4)2SO4, and (NH4)3PO4•3H2O increased the HCN yield, while MgCl2, C2H4N4, NH4H2PO4 , KH2PO4, and Na2B4O7•10H2O reduced the HCN yield. Particularly, when the content of Na2B4O7•10H2O was 23.08 %，the release amount of HCN was 3.2915 mg/g，which was 38.33% that of plain polyurethane foam.

Model analysis on the mechanical properties of recycled poly(ethylene terephthalate)/glass fibre composites

WU De-Feng

2010, 24 (09): 84-89 ; DOI: 10.19491/j.issn.1001-9278.2010.09.021

Abstract ( 2147 )

Composites of recycled PET (rPET) filled with glass fiber (GF) were prepared via melt mixing. The mechanical properties of the rPET/GF composites were studied through various models including Halpin-Tsai, Krenchel-COX, and Kelly-Tyson equations, aiming at exploring the relations between the short-term and long-term structures of GF and the properties of composites. It showed that the filled GF had evident reinforcing and toughening effects on the rPET. When the GF loading was 30 wt %, the toughness, tensile and bending strengths increased by about 245%, 113%, and 84%, respectively. The aspect ratio and the orientation of GF constituted two important structural parameters vital to the final properties of composites. The Halpin-Tsai equation could be well used to describe aspect ratio of GF. The orientation factor of GF obtained from Kelly-Tyson equation was closer to the experimental value than that from Krenchel-COX equation.

Design of Injection Moulding For Tread Flange Based on Pro/E

Hui-Lan Zhou tangqing kuang

2010, 24 (09): 90-93 ; DOI: 10.19491/j.issn.1001-9278.2010.09.022

Abstract ( 1820 )

A mechanism of auto tread demolding was designed, in which hydraulic pressure motors and sprocket-gear were applied to demold the tread flange. The parting plane and molding parts were designed with the help of Pro/E（Pro/Engineer Wildfire3.0）and standard moldbase was established with EMX4.1.

Influence of Kneading Blocks on the Mixing Effect of PE-HD/PS Immiscible Blend in Intermeshing Counter-rotating Twin Screw Extruder

2010, 24 (09): 94-98 ; DOI: 10.19491/j.issn.1001-9278.2010.09.023

Abstract ( 1978 )

Kneading blocks were a introduced into regular intermeshing counter-rotating twin-screw extruder to enhance its mixing performance. PE-HD/PS blends were mixed with this equipment and the resulted morphology and diameter of dispersed phase (PS) were investigated using SEM. It showed that the kneading blocks did improve the mixing power and the thickness of the kneading disc and staggering angle had impact on the mixing effect.