Current Issue

2012, Volume 26 Issue 09 Publication date: 26 September 2012 Previous Issue Next Issue

Research Progress on Inorganic Tin Compounds Flame Retardants for Poly(vinyl chloride)

2012, 26 (09): 1-5 ; DOI: 10.19491/j.issn.1001-9278.2012.09.001

Abstract ( 1477 )

Research progress on inorganic tin compounds flame retardants for poly(vinyl chlorde) in recent years were reviewed. Flame-retardant mechanism of inorganic tin compounds flame retardants was also introduced. Finally, the trend of the development of inorganic tin compounds flame retardants was briefly explored.

Absorbing Properties of Rare Earth Elements and Other Non-rare Earth Doped Barium Ferrite

2012, 26 (09): 6-10 ; DOI: 10.19491/j.issn.1001-9278.2012.09.002

Abstract ( 1365 )

In this paper, the waveabsorbing mechanism of barium ferrite was introduced. The development of waveabsorbing properties of barium ferrites doped by rare earths, rare earth composites and other non rare earth materials was discussed. Finally, an outlook was given on the future development of them.

Development of nano-silica modified polypropylene composites

2012, 26 (09): 11-16 ; DOI: 10.19491/j.issn.1001-9278.2012.09.003

Abstract ( 1280 )

With abundant hydroxyl groups on the surface, nanosilica (nanoSiO2) was easy to react with organic polymers containing functional groups. It could improve the compatibility with polypropylene (PP) matrix and make nanoSiO2 dispersed more uniformly. Recent advances in PP/nanoSiO2 composites were introduced. The modified methods including surface treatment of nanoSiO2 particles and adding compatibilizer were reviewed. The impact of nanoSiO2 particle structure on the permeability, flame retardancy, electrical conductivity of matrix polymer was also discussed.

Variation of Mean Molecular Weight of Thermoplastic Polyurethane in Synthesis

BAO Yongzhong

2012, 26 (09): 17-21 ; DOI: 10.19491/j.issn.1001-9278.2012.09.004

Abstract ( 1333 )

The bulk steppolymerizations among 4,4′/2,4′diphenylmethane diisocyanate, polytetramethylene ether glycol, and 1,4butylene glycol were carried out in a torque rheometer, in the presence of a Bi/Zn composite catalyst or catalystfree, leading to a thermoplastic polyurethane (TPU). The mean molecular weights of TPU sampled during synthesis process were measured using gel permeation chromatography, and were correlated with the reaction rate constant, time, and catalyst concentration. The change tendency of molecular weight of TPU with time was well simulated and explained.

Synthesis and Characterization of Biomedical HMDI-based poly(carbonate-urethane) elastomers

Chengke YU

2012, 26 (09): 22-27 ; DOI: 10.19491/j.issn.1001-9278.2012.09.005

Abstract ( 1235 )

Biomedical poly(carbonateurethane) elastomers were synthesized from 4,4′methylene dicyclohexyl diisocyanate(HMDI), 1,4butanediol(BDO), and polycarbonate diol (PCD) through melting prepolymer method. The relationship between microphase separation structure and properties was analyzed using infrared spectrography (IR), differential scanning calorimeter (DSC), dynamic mechanical thermal analysis (DMTA), gel permeation chromatograph (GPC), mechanical property test, hydrolysis performance test, and cytotoxicity test. The casted poly(carbonateurethane) elastomers without carcinogenic degradation product 4,4′methylenedianiline(MDA) generation, had adjustable mechanical properties, good resistance to hydrolysis and excellent biocompatibility, and thus a great potential for application as a longterm implanted stable biomedical material.

Preparation Non-halogen Flame Retarded PE-LD/EPDM by Dynamic Vulcanizing

2012, 26 (09): 28-31 ; DOI: 10.19491/j.issn.1001-9278.2012.09.006

Abstract ( 1314 )

Owing to the mechanical properties decreased obviously when polymer were filled with high loading inorganic flame retardant, halogen-free flame retarded PE-LD/EPDM was prepared by dynamic vulcanizing method. Sulfur, DCP and phenolic resin were selected as vulcanizer for preparing dynamic vulcanizing PE-LD/EPDM materials, results showed that sulfur was the best vulcanizer and the proportion of EPDM/S/TMTD/DM/ZnO/AO was 40/1.6/2/1/0.5/0.5. Comparing with the material by simple blending, the mechanical and flame retardant properties of materials by dynamic vulcanizing improved remarkably. When PE-LD filled with 45% inorganic flame retardant, the material filling with 20% EPDM and preparing by dynamic vulcanizing had the best combination properties, tensile strength、elongation at break and impact strength was 9.59 Mpa、293.6 % and 36.5 KJ/m2 respectively, limited oxygen index was 29.1, the vertical combustion level reached UL94 V-0.

Synthesis of P(AA-AM)/OMMT Superabsorbent Resin Under Signalmode Focusing Microwave Irradiation

2012, 26 (09): 32-36 ; DOI: 10.19491/j.issn.1001-9278.2012.09.007

Abstract ( 1107 )

Based on singlemode focusing microwave radiation and synchronized pneumatic gas cooling technologies, an aqueous solution polymerization of acrylic acid, acrylamide, and montmorillonite was carried out in a precision microwave organic synthesis system，and a super absorbent resin was obtained. Using the standard mode of the Discover precision microwave organic synthesis system，the factors that influence on liquid absorbency rate of the super absorbent resin were studied, including neutralization degree of AA, microwave irradiation time, microwave power, crosslinking agent dosage，initiator dosage and montmorillonite dosage. When microwave irradiation power was 150 W, radiation time was 60 s, neutralization degree was 75 %, mass ratios of m(AA)∶m(AM)∶m(OMMT) equal to 10.0∶2.5∶0.8, contents of crosslinking agent and initiator were 0.02 % and 0.7 %, the obtained P(AA-AM)/ montmorillonite possessed waterabsorbing abilities of 1520 g/g for pure water and 165 g/g for 0.9 % NaCl solution, respectively.

Study on Properties of Flame Retarded PC/Polyaluminosiloxane Composites

ZHOU Wen-Jun

2012, 26 (09): 37-41 ; DOI: 10.19491/j.issn.1001-9278.2012.09.008

Abstract ( 1302 )

A series of polyaluminosiloxane flame retardants was synthesized through cohydrolysis condensation reaction with varied R/Si and Ph/Me ratios. The influence of the polyaluminosiloxane on the mechanical properties and Vicat softening temperature of PC was investigated. It indicated that the addition of the polyaluminosiloxane had less effect on the flexural strength of the PC, and improved both the tensile strength and the notch impact strength of the PC. Especially, when 5 % polyaluminosiloxane was added to the PC, the notch impact strength of the PC was increased by 31 %. The Vicat softening temperature of the PC was also improved when 8 % or less polyaluminosiloxane was added.

Study on BN particles reinforced cyanate ester resin composites

2012, 26 (09): 42-46 ; DOI: 10.19491/j.issn.1001-9278.2012.09.009

Abstract ( 1142 )

Boron nitride (BN)/cyanate ester resin/glass fiber composites were prepared in order to enhance the properties. The effects of BN particles on the reaction activity of cyanate ester resin, mechanical properties, and heat resistance of the composites were investigated. It was found that BN particle had little influence on reaction activity of cyanate ester resin. Inclusion of 8 % couple agent treated BN particles resulted in 5 % and 36 % increase in the flexural strength and interlaminar shear strength, respectively. The addition of BN particles to the composites also increased the initial decomposition temperatures, heat resistance index, and thermal stability of cyanate ester resin composites.

Preparation and Characterization of Polypyrrole/Sepiolite

Zhi-hu Liu HU Xiao-Ping Chao-yang Wang Zhi-bing Fu Tao Lu

2012, 26 (09): 47-51 ; DOI: 10.19491/j.issn.1001-9278.2012.09.010

Abstract ( 1282 )

Polypyrrole/sepiolite (PPy/SEP) nanocomposites were prepared via insitu polymerization, using ferric chloride (FeCl3) and sodium dodecylsulfonate (SDS) as oxidant and dopant, respectively. Effects of the content of pyrrole, the polymerization time, and the amount of FeCl3 and SDS on the conductivity of the nanocomposites were investigated. The conductivity of the composite reached 2.15 S/cm when the content of pyrrole was 25 % (based on the mass of SEP), the polymerization temperature was 0 ℃, the polymerization time was 12 h, the mole ratio of FeCl3 and SDS to pyrrole were 2.3∶1 and 1∶5, respectively. The morphology and structure of the nanocomposite was characterized using transmission electron microscope (TEM), Fourier transform infrared (FTIR), Xray diffraction (XRD) and thermal analysis. It showed that PPy/SEP nanocomposite had a onedimensional coreshell structure and the surface of sepiolite was coated by amorphous PPy.

Study on Mechanical Properties and Thermal Stability on

2012, 26 (09): 52-55 ; DOI: 10.19491/j.issn.1001-9278.2012.09.011

Abstract ( 1224 )

Two epoxy resin systems （139S and BE188EL cured with hexahydrophthalic anhydride） were modified with 3glycidoxypropyl polyhedral oligomeric silsesquioxane cage (POSS) led to POSS/epoxy hybrid materials. The impact strengths of the two epoxy systems were increased by 57.45 % and 32.26 %, the flexural strength were increased by 9.23 % and 5.07 %，and the thermal residual weight increased by 50.19% and 20.16%. Meanwhile, the coefficients of thermal expansion was lowered.

Study on Properties of Polypropylene/Glass Fiber/Conductive

2012, 26 (09): 56-59 ; DOI: 10.19491/j.issn.1001-9278.2012.09.012

Abstract ( 1239 )

Conductive composites based on polypropylene (PP), glass fiber (GF), and conductive carbon black (CB) were prepared via melt extrusion process. The effects of the content of CB and GF on the electrical conductivity, mechanical properties, mould shrinkage, and crystallization behavior of the composites were studied. It showed that the addition of GF promoted the formation of CB conduction network and effectively decreased the percolation threshold. Meanwhile, the addition of GF resulted in a large improvement of stiffness and a remarkable decrease of mold shrinkage of the composites. The addition of CB and GF decreased the crystallization ability of PP.

Types and Application of Polypropylene Synthesized via Novolen Process

2012, 26 (09): 60-64 ; DOI: 10.19491/j.issn.1001-9278.2012.09.013

Abstract ( 1687 )

This article reviewed the characteristics of polypropylene resin based on Novolen process, the main domestic brands and manufacturers of the polypropylene were introduced. The applications of PP which was produced by Shenhua Ningxia coal group via Novolen process in fiber, injection molding, thermoforming, film, and extruded pipe were analyzed.

Design of an Improved Automobile Headlamp Lens

WU Daming

2012, 26 (09): 65-68 ; DOI: 10.19491/j.issn.1001-9278.2012.09.014

Abstract ( 954 )

A light guide plate with nonuniform arrangement was designed using an optical software LightTools. When the plate was in the automobile headlamp lens, it reduced the exit light divergence angle and increased the utilization rate of light energy, resulted in more uniform luminance distribution. This device could avoid the influence of external light on the driver in the night.

Preparation of Silicone/Titanium Dioxide Composites and Their Ultraviolet Protection Property

2012, 26 (09): 69-71 ; DOI: 10.19491/j.issn.1001-9278.2012.09.015

Abstract ( 1122 )

A series of silicone/titanium dioxide composites was prepared by adding titanium dioxide with a different concentration into organic silicone elastomer. The composites with thickness of 0.8 mm were obtained by a compressionmolding processing at 150 ℃. It showed that silicone/titanium dioxide composites had good effect of UV protection, but the strength and modulus of elasticity were reduced. The effect of UV protection and the elastic properties of the composites were related with the content of organic silicone elastomer in the emulsion.

Study on Properties of Microcellular PPS Foams Prepared by Microcellular Injection Molding

2012, 26 (09): 72-78 ; DOI: 10.19491/j.issn.1001-9278.2012.09.016

Abstract ( 1144 )

In this paper, microcellular polyphenylene sulfide (PPS) foam was prepared via injection molding using supercritical N2 (SCN2) as a foaming agent. Effects of mould runner, content of SCN2, and shot size on cell properties, relative density, mechanical properties, and dielectric properties of microcellular PPS foams were studied. It showed that the cell size was enlarged and the density was decreased with increasing mould runner. The content of SCN2 had little influence on the pore size, mechanical and dielectric properties, however, increased the density of the cells. Meanwhile, the shot size also played an important role in the properties of PPS foams. The lower shot size, the lower relative density, mechanical properties and dielectric constant of microcellular PPS foams were.

Effect of DTBP on Extrusion Foaming of Polystyrene by Supercritical CO2

2012, 26 (09): 79-82 ; DOI: 10.19491/j.issn.1001-9278.2012.09.017

Abstract ( 1197 )

Effect of DTBP on the behavior of XPS foaming with supercritical CO2 was studied. It was observed that when the DTBP content was higher than 0.5 ％, the weight average molecular weight of PS decreased sharply, accompanied by a decrease in melt viscosity. When the mold temperature was 112 ℃, the mold pressure was 4 MPa； DTBP content was lower than 0.3 ％, the apparent density of XPS foam decreased remarkably. A higher DTBP content could slow down such decrease. The introduction of DTBP caused modules, compressive and flexural strengths increased, but the flexural modulus decreased.

Application of Phosphorus-silicon Flame Retardant in Intumescent Flame Retarded Polypropylene

2012, 26 (09): 83-87 ; DOI: 10.19491/j.issn.1001-9278.2012.09.018

Abstract ( 1099 )

An intumescent flame retardant system formulated with a phosphorussilicon compound (EMPZR), ammonium polyphosphate (APP), and melamine polyphosphate (MPP) was introduced into polypropylene (PP) via blending. When the mass ratio of APP/MPP/EMPZR was 15/10/15, the limited oxygen index of the composites was increased to 33 %, and the burning grading reached UL94 V0. The tensile, bending, and impact strengths of the composites were no less than plain polypropylene. Thermogravimetry analysis up to 600 ℃ showed that the char residue of the composites was 21.14 % which indicated a good synergistic effects of EMPZR with APP and MPP.

Influences of Lanthanum Stearate/Calcium Adipate/Zinc Adipate Costabilizer on Thermal Stability of PVC

Xiaoqian Liu GAO Jun-Gang Jianbo Yang Baofa Zang

2012, 26 (09): 88-92 ; DOI: 10.19491/j.issn.1001-9278.2012.09.019

Abstract ( 1516 )

In order to improve the thermal stability of PVC, a novel organic calcium/zinc stabilizer was prepared from calcium adipate and zinc adipate and use lanthanum stearate as a costabilizer. Influences of Ca/Zn ratios and lanthanum stearate on the thermal stability of PVC were studied. Congo red testing method, thermogravimetric analysis, dynamic rheology, dynamic mechanical analysis, and mechanical property were determined. When Ca/Zn mass ratio was 1/4, the Congo red time reached the maximum time of 86 min. When lanthanum stearate was added and the mass ratio of Ca/Zn was 2/3, the Congo red time reached the maximum of 135 min, and the impact strength of the sample was increased by 30 %. However, the introduction of lanthanum stearate decreased the storage modulus, loss modulus, and tanδ of PVC.

Design of Injection Mould with Hot Runner for Notebook Computer Display Frame

REN Changchun Yong LU

2012, 26 (09): 93-97 ; DOI: 10.19491/j.issn.1001-9278.2012.09.020

Abstract ( 1178 )

A hot runner injection mould for notebook computer display frame was designed based on the process and structure of the frame. The analysis of parting surface, the gating system, the side corepulling mechanism, exhaust and the cooling system of the mould was carried out and a reasonable mould structure was determined. The sophisticated design of the hot runner, the slider and the slanted ejector pin not only increased the quality of the product and labor capacity, but also reduced the machining cost of the product. An idea for the injection mould design of similar parts was given.

Design of Reacting Twinscrew Extruders for Melamine Foams

2012, 26 (09): 98-101 ; DOI: 10.19491/j.issn.1001-9278.2012.09.021

Abstract ( 1566 )

Aiming at the technological requirements and difficulties of continuous production of melamine foams, the industrial production processing was determined by experiment, and the specifications of reacting twinscrew extruder for melamine foams was determined by calculation. In order to meet the demands of quick homogenization of different viscosity components and quick removal of the reaction enthalpies, the special barrels and elements for reacting twinscrew extruders were designed. The technological processing and design of reacting twinscrew extruders were proved to be feasibility by industrial production.