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2011, Volume 25 Issue 04 Publication date: 26 April 2011 Previous Issue Next Issue

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

WANG Zhanjie

2011, 25 (04): 1-6 ; DOI: 10.19491/j.issn.1001-9278.2011.04.001

Abstract ( 2320 )

This article discussed the development status about the output and export of the domestic plastics pipes industry during the eleventh five-year plan period. The problems of the plastics pipes industry were pointed out. Finally, the development goals and some suggestion of the plastics pipes industry during the twelfth five-year plan period were given.

Research Progress of Application of SiO₂ in Flame Retarded Polymers

LI Zhenhua WU Chunlei DUAN Xianjian LI Zhengfa ZHAO Qianmin

2011, 25 (04): 7-11 ; DOI: 10.19491/j.issn.1001-9278.2011.04.002

Abstract ( 2396 )

The research progress of application of SiO2 in flame retarded polymers was summarized in this paper. The flame retardancy mechanism of SiO2, the effects of SiO2 on the flame retardancy, mechanical property, and processing behavior of polymers were reviewed. The synergistic effect of SiO2 with other flame retardants was also explored. The potential vapor-phase mechanism of SiO2 based flame retardant was discussed. It was forecast that the non-halogen and environmentally friendly silicon-based flame retardant would develop rapidly in the future.

Research Progress in Poly (vinyl formal) Cellular Plastics

JIANG Yu WEI Fengjun

2011, 25 (04): 12-16 ; DOI: 10.19491/j.issn.1001-9278.2011.04.003

Abstract ( 2414 )

The properties and preparation of poly (vinyl formal) (PVFM) cellular plastics were reviewed in this paper. The factors influencing the properties of PVFM cellular plastics were particularly discussed, including the kinds of poly(vinyl alcohol), water content, formaldehyde content, and acid content. The molding methods of PVFM cellular plastics were introduced, including bubbling by foaming agent, mixing, and pore-forming agent. The main applications of PVFM cellular plastics were also introduced such as clean and cosmetics, filtering and damping, medical and biological carrier, and degradable materials.

Biodegradable Shape Memory Polymers and Their Application in Biomedical Engineering

MENG Qianni ZHU Guangming XU Shuogui

2011, 25 (04): 17-21 ; DOI: 10.19491/j.issn.1001-9278.2011.04.004

Abstract ( 2451 )

The latest advances in biodegradable shape memory poly(lactide acid), polycaprolactone, and polyurethane were reviewed. The shape memory mechanisms, including phase transforming, physical or chemical cross-linking and phase separation were discussed in briefly. The applications of biodegradable shape memory polymers in drug release, medical instrument, surgery seam, and bone tissue engineering were introduced and discussed. In addition, their trends of development in the future were prospected.

Study on Isothermal Crystallization Kinetics of In-situ Compatibilized PA6/PE-HD Blends

WANG Zhongqiang HU Guosheng ZHOU Xiumiao

2011, 25 (04): 22-27 ; DOI: 10.19491/j.issn.1001-9278.2011.04.005

Abstract ( 1968 )

The isothermal crystallization behavior of in-situ compatibilized polyamide 6/high density polyethylene (PA6/PE-HD) blends was studied using differential scanning calorimetry. The isothermal crystallization kinetics was analyzed using Avrami equation. The calculated Avrami index n was between 2.19 and 3.70, which demonstrated that the crystallization of PA6/PE-HD blends was growing three-dimensionally, which was confirmed by polarized optical microscopy observation. The equilibrium melting temperatures of PA6/PE-HD blends were obtained from Hoffman-Weeks method. With the addition of PE-HD, the size of PA6 spherulites became smaller obviously, which indicated that PE-HD played a role of heterogeneous nucleation.

Study on Properties of CPVC/MBS Blends and Effect of MBS on Gelation Degree

WANG Yanfang XU Baoliang TENG Mouyong LI Yan

2011, 25 (04): 28-32 ; DOI: 10.19491/j.issn.1001-9278.2011.04.006

Abstract ( 1937 )

The gelation and rheological property of chlorinated poly(vinyl chloride)/methyl methacrylate-butadiene-styrene copolymer (CPVC/MBS) blends were studied using differential scanning calorimetry and HAAKE rheometer. The mechanical properties, thermal properties and microscopic structure of the blends were also investigated. It was found that MBS could effectively improved processing performance of CPVC as it promoted the plastication and the gelation degree of CPVC. During the mixing of CPVC and MBS in the HAAKE rheometer, the equilibrium torque and temperature greatly increased while plasticizing time reduced. When the dosage of MBS was 6 phr, the blend displayed the optimal comprehensive properties.

Curing Kinetics of Epoxy Resin/Modified Nano-carbon Black Composites

ZHOU Hongjun YIN Guoqiang WU Wanshuang GE Jianfang LIN Xuan

2011, 25 (04): 33-37 ; DOI: 10.19491/j.issn.1001-9278.2011.04.008

Abstract ( 1972 )

The influence of modified nano-carbon black on the non-isothermal curing behavior of epoxy resin was studied using differential scanning calorimetry. It showed that the modified nano-carbon black decreased the initial curing and peak temperature of epoxy resin. The dependence of the activation energy on conversion rate was determined using the isoconversional method of Ozawa-Flynn-Wall. The kinetics parameters of the curing process were determined with Malek method. A two-parameter (m, n) autocatalytic model was found to be appropriate to describe the kinetics of the epoxy resin, the predicted results agreed well with the experiments.

Study on Preparation of Poly(lactic acid) Toughened by SEBS-g-MAH

LIU Mimi WEI Fayun ZHANG Yu

2011, 25 (04): 38-41 ; DOI: 10.19491/j.issn.1001-9278.2011.04.009

Abstract ( 1967 )

Poly(lactic acid) (PLA) and SEBS-g-MAH were mixed using a HAAKE rheometer. The mechanical properties, rheological properties and the microstructure of the obtained blends were investigated. It was shown that the tensile strength of the blends decreased, and the elongation at break increased with increasing SEBS-g-MAH content. When the loading of SEBS-g-MAH was 30 %, the impact strength of the blend was 2.5 times that of neat PLA. The melt viscosity of the blends decreased with increasing SEBS-g-MAH content. SEM showed that the MAH groups on the interface compatibilized the two components.

Effect of Nano-silica on Crystallization Behavior and Properties of PET

KONG Zhiming LUO Chunming TANG Anbin

2011, 25 (04): 42-45 ; DOI: 10.19491/j.issn.1001-9278.2011.04.010

Abstract ( 1932 )

Nano-silica was modified with hexamethyl disilylamine, which was introduced in polyethylene terephthalate (PET) during its synthesis process. The effects of nano-silica on the crystallization behavior, mechanical and electrical properties of PET were studied using Fourier transform infrared spectrometer, thermogravimetry, and scanning electron microscope. It showed that the surface modification reduced the aggregation of nano-silica resulting in finer dispersion. When the content of SiO2 was 0.1 %, the tensile, flexural, and impact strengths of the composites were 12.8 %, 14 %, and 11.4 % higher than those of neat PET, respectively. When the content of SiO2 was 1 %，the crystallization rate was the fastest. With the content of SiO2 increasing from 0.25 % to 1 %, the dielectric constant decreased and the volume resistivity increased gradually.

Preparation and Properties of Polyamide 6/Nitrile Rubber Blends with Oil Resistance

SUN He GUI Yu MU Yang ZHANG Huixuan

2011, 25 (04): 46-49 ; DOI: 10.19491/j.issn.1001-9278.2011.04.011

Abstract ( 2026 )

Polyamide 6/nitrile-butadiene rubber (PA6/NBR) blends were prepared via melt blending from PA6 and different types of NBR. The mixing torque, mechanical property, and solvent resistance of the blends were studied. With increasing content of rubber phase, the melt viscosity and swelling ratio increased, while tensile strength decreased. Infrared spectra showed that there were chemical reaction between NBR and PA6 under high temperature and high shear rate. With increasing content of nitrile, the equilibrium torque and tensile strength of PA6/NBR blends increased, solvent resistance reduced.

Study on Naphthol Modified Phenolic Resins

WU Jiangtao QI Shuhua LI Chunhua LI Meiling

2011, 25 (04): 50-54 ; DOI: 10.19491/j.issn.1001-9278.2011.04.012

Abstract ( 1949 )

Phenolic resin was modified with naphthol forming an environment-friend material. The structure and heat resistance of phenolic resin were studied using Fourier transform infrared spectroscopy and thermogravimetry, and the kinetic parameters of thermal degradation were calculated with Kissinger and Flynn-Wall-Ozawa methods. The thermal degradation of phenolic resin could be divided into two stages. The modification with naphthol improved the heat resistance of the phenolic resin. When the mass fraction of naphthol was 10 %, the tensile, flexural and impact strengths increased by 2.46, 1.62 and 1.34 times based on neat phenolic resin, respectively. Meanwhile, the volume and surface resistances reached orders of 1014.

Relative Molecular Weight and Distribution, Crystallization and Mechanical Properties of PP Powders with Different Particle Sizes

TIAN Yaozhu WANG Song QIN Jun YU Jie LUO Zhu

2011, 25 (04): 55-58 ; DOI: 10.19491/j.issn.1001-9278.2011.04.013

Abstract ( 1987 )

Molecular weight and distribution, crystallization behavior, and mechanical properties of polypropylene (PP) powers with different particle sizes were studied using differential scanning calorimetry and gel permeation chromatography. It was found that the molecular weight and distribution, crystallization temperature, crystallization rate, nucleating ability, and mechanical properties of PP were all obviously influenced by initial particle sizes of PP power. PP powers with small particle sizes had higher number-average molecular weight, wider molecular weight distribution, and higher melt flow rate. With decreasing particle sizes of PP powers, crystallization temperature, initial crystallization temperature, initial crystallization rate, and nucleating ability increased, tensile and impact strengths decreased, and spherulits became more uniform and finer.

Study on Preparation and Foaming Extrusion Behavior of PLA/OMMT Nanocomposites

MA Pengcheng WANG Xiangdong LIU Bengang LI YIng CHEN Shihong ZHANG Yuxia XU Guozhi

2011, 25 (04): 59-64 ; DOI: 10.19491/j.issn.1001-9278.2011.04.014

Abstract ( 1897 )

Polylactic acid(PLA) /montmorillonite(OMMT) nanocomposites was prepared by melt intercalation, the composite morphology structure, mechanical properties, thermal properties and dynamic rheological properties were characterized and tested, and foaming extrusion behavior of the composites was studied. The results showed that by melt intercalate different amounts of OMMT with PLA, different "intercalation" and "peel" structure can be formed; OMMT additive amount of 3% can improve the mechanical properties and thermal performance of PLA; OMMT can enhance the melt strength of PLA and also played the role of a nucleating agent in foaming extrusion process and diffusion of blowing agent in the PLA melt can be reduced, thereby enhancing the effect of PLA foaming extrusion.

Study on Highly-filled and Over-thickness Radiation Protection Materials

HE Peng GUO Zhentao ZHANG Long LI Tiejun KANG Xingchuan ZHENG Jinmei LI Shufeng

2011, 25 (04): 65-68 ; DOI: 10.19491/j.issn.1001-9278.2011.04.015

Abstract ( 1967 )

Based on rich hydrogen polyethylene with highly filled neutron absorber-boron compound, highly-filled and over-thickness radiation protection materials were prepared. The effects of melt flow rate of polyethylene and content of B4C and GdO on mechanical properties and shielding properties were studied. The effects of different molding process on the material characteristics were discussed. It showed that using powder of low density polyethylene with high melt flow rate and boron compound with a proper particle size, through proper processing condition and improved moulds, highly-filled and over-thickness radiation protection materials were produced with excellent mechanical properties and good quality of appearance. The neutron shielding factor was more than 6, and gamma shielding factor was more than 8.

Study on Self-adhesive Mechanism of PVC Films

FAN Shuangyu WANG Peizhang

2011, 25 (04): 69-72 ; DOI: 10.19491/j.issn.1001-9278.2011.04.016

Abstract ( 2377 )

Self-adhesive poly (vinyl chloride) (PVC) films were prepared via casting molding. The effects of content of plasticizer dioctyl phthalate (DOP), variety and content of thickening agent, film thickness, surface roughness, surface tension, and precipitate on the bonding strength of PVC films were studied using digital high resistance meter, atomic force microscopy, video optical contact angle measuring instrument and Fourier transform infrared spectroscopy. It was found that the bonding strength of PVC film increased with increasing plasticizer content. The addition of thickening agent significantly improved the self-adhesive of PVC films, in which terpene resin was the best. Self-adhesive of PVC films was influenced by surface energy of the films in question.

Effect of Coagulation Bathes on Morphology and Properties of Polyurethane-based Semi-IPNs

LV Haining ZHAO Shumei HONG Junyan CHEN Qiaoyu LI Yuzhou

2011, 25 (04): 73-76 ; DOI: 10.19491/j.issn.1001-9278.2011.04.017

Abstract ( 1746 )

Poly-N-isopropylacrylamide was introduced into the solution of polyurethane forming a semi-interpenetrating polymer network (semi-IPNs), and the semi-IPNs were cast into different coagulation baths. Fourier transform infrared spectroscopy and scanning electron micrograph were employed to characterize their structure. The swelling behavior and tensile properties of the semi-IPNs were also tested. It showed that the semi-IPNs films had better mechanical properties and more uniform structure than the films based neat polyurethane. The semi-IPNs films formed in water had better properties than in alcohol and isopropanol, and had higher temperature sensibility.

Effect of Novel Intumescent Retardant on Flame Retardancy of ABS

LIU Yi YI Jiangsong CAI Xufu

2011, 25 (04): 77-82 ; DOI: 10.19491/j.issn.1001-9278.2011.04.019

Abstract ( 2013 )

A novel intumescent flame retardant (IFR), containing ammonium polyphosphate (APP) and poly(hexamethylene terephthalamide) (PA6T), was prepared for acrylonitrile-butadiene-styrene copolymer (ABS). It was found that when the contents of APP and PA6T were 25 % and 5 %, respectively, the limiting oxygen index of ABS/IFR system reached 29 %, but only UL-94 V-1 rating was passed. Thus, Al(H2PO2)3 was incorporated into ABS/APP/PA6T system as a synergistic agent. It was found that 2 % addition of Al(H2PO2)3 caused PA6T/APP/PA6T(70/23.3/4.7) to pass V-0 rating of UL-94 test. Meanwhile, the TG curves indicated that PA6T was effective as a charring agent and there was a synergistic reaction between PA6T and APP, which promoted the char formation of ABS/IFR system. The residual char after the limiting oxygen index test was characterized using Fourier transform infrared spectra. It showed that P-O-C bond was formed in the residual char, indicating the cross-linking reaction occurred. Furthermore, scanning electron microscopy revealed that both ABS/APP/PA6T(70/25/5) and PA6T/APP/PA6T/Al(H2PO2)3(70/23.3/4.7/2) formed uniform and compact intumescent charred layers.

Experimental Study on Bond Behavior of BFRP Bars Embedded in Concrete by Beam Test

ZHOU Junlong LI Binghong JIANG Shiyong SHI Qianhua HU Xianqi

2011, 25 (04): 83-88 ; DOI: 10.19491/j.issn.1001-9278.2011.04.020

Abstract ( 1999 )

The beam test method was used to investigate the bond behavior between BFRP bar and concrete. Fourteen BFRP bar and 2 steel bar beam specimens were prepared and tested. It was found that the loading process of BFRP bars could be identified as four steps: minor slippage, normal slippage, accelerated slippage, and descending approach. With constant embedment length of BFRP bars, the bond strength increased with increasing concrete strength. With constant concrete strength, the bond strength decreased with increasing embedment length of BFRP bars, meanwhile the failure patterns changed from slippage to rupture of BFRP bars. The diameter of BFRP bars has little effect on the bond strength. At the same bar diameter, embedment strength, and the concrete strength, the bond strength of BFRP bars was close to that of steel bars. The bond behavior of BFRP bars was greatly influenced by the surface deformation conditions of BFRP bars.

Combustion Properties of Poly(vinyl chloride)/Nano Hydrotalcite/ZnO/MgO Composites

SU Hu BAO Yongzhong HUANG Zhiming

2011, 25 (04): 89-92 ; DOI: 10.19491/j.issn.1001-9278.2011.04.021

Abstract ( 1797 )

In this paper, poly(vinyl chloride)/nano hydrotalcite (PVC/HT) composites were prepared by in-situ suspension polymerization, which were further blended with ZnO and MgO. The combustion properties of PVC/HT/ZnO/MgO composites were investigated using cone calorimetry. It was found that HT, ZnO and MgO were well dispersed in PVC matrix. ZnO and MgO had the synergistic effect with HT on reducing the heat and smoke release rates during combustion. Compared to neat PVC, the peak heat smoke release rates of PVC/HT/ZnO/MgO(95/5/3/3) composite decreased more than 50 %, and the char yield was obviously increased. It was also found that tensile and impact strength of PVC/HT/ZnO/MgO composites were greater than that of PVC/ZnO/MgO composites.

Surface Modification of Flame Retardant Aluminum Hydroxide and Its Application in Polypropylene

ZHENG Bingfa XIN Mingliang MA Yujie XU Gai CHEN Mingcai

2011, 25 (04): 93-97 ; DOI: 10.19491/j.issn.1001-9278.2011.04.022

Abstract ( 2092 )

Aluminum hydroxide was modified with hydrogen silicone oil, and the influence of the loading of hydrogen silicone oil, time and temperature on the thermal stability and structure of aluminum hydroxide was characterized through thermogravimetry and Fourier transform infrared spectroscopy. The modified aluminum hydroxide was introduced polypropylene forming a composite, the mechanical properties and morphology of the fractured surface of which were studied. It was found the optical modification conditions were: the amount of modifier was 1.0 ％ of aluminum hydroxide, the modification time was 30 min, and the modification temperature was 80 ℃. The presence of hydrogen silicone oil not only improved the thermal stability of aluminum hydroxide, but also enhanced the mechanical properties of the composites.

Study on Measurement Method for Dynamic Density of Polymer Melts

HAN Ke LI Zenghe XU Hong WU Daming

2011, 25 (04): 98-101 ; DOI: 10.19491/j.issn.1001-9278.2011.04.023

Abstract ( 1849 )

A new measurement method for polymer melt density under different pressure and temperature was established. Based on the PVT theory of polymer melt, a melt flow rates tester was modified with a dial indicator for the measurement of the micro distance. With the modified instrument, polymer melt density can be measured under any pressure and melting temperature. By further analyzing the result, the data of the melt density was agreed with the free volume theory, i.e., the polymer melt density decreased with increasing temperature and increased with increasing pressure.

Pressure Distribution in Solid Section in Helically Grooved Feed Single-screw Extruders

PAN Long JIA Mingyin XUE Ping JIN Zhiping TANG Guangli

2011, 25 (04): 102-106 ; DOI: 10.19491/j.issn.1001-9278.2011.04.024

Abstract ( 1944 )

In the feeding sleeve several helical grooves were opened up. Regarding the materials between groove and channel as a solid-plug, the barrel and screw could be considered as an indivisible system to cooperatively push forward the materials in solid conveying zone. A mathematical model was formulated to consider the influences of the compressibility and the acceleration of the materials, the pressure and the velocity of the solid-plug in the down-channel were calculated. Finally, it is found that when the solid-plug was being carried by way of positive conveying, the peak pressure at the end of solid conveying zone was strikingly promoted and the materials could be stably extruded.