DING Juan-lin, L I Cheng-zhi
Abstract (
3255 )
The general situations of domestic poly(vinyl chloride)(PVC) industry and market in the year 2007 were introduced including the domestic supply and demand situation of calcium carbide, crude salt, and their effects on the related PVC production. The relationship between the industrial situation
and the national policy was discussed;a turning point in the caustic soda industry was expected in the near future. Some consideration was made on the environmental issues and sustainable development of domestic PVC industry.
ZHOU Qiang, XU Hui
Abstract (
2094 )
Toughening modification of poly(vinylidcnc chloride)(PVDC) resin includes chemical and physical methods. Chemical modification is resulted by introducing comonomers like vinyl chloride(VC)，glycidylmcthylacry(GMA)，or acrylonitrilc(AN);the physical toughening is caused by blending with clastomer or nanometer calcium carbonate. This paper mainly introduces the blending toughening system of PVDC with copolymer clastomcrs including ethylene-vinylacctatc (EVA)，methyl mctha-cylatc-butadiene-styrene(MBS}，or acrylatc(ACR).The development trends of toughening modification of PVDC arc also discussed.
YANG Qing-quan, GUO Zhao-xia, YU Jian
Abstract (
3947 )
This paper investigates systematically the effect and mechanism of talc on the micro-morphology, mechanical properties, heat-resistance and crystallization of PA66/PET alloy. The main conclulions arc as follows: addition of talc (5%一10%)and appropriate assistant agent induces a remarkable
increase in the mechanical properties of PA66/PET alloy; talc can dramatically reduce the size and size distribution of PET phase and plays a role of compatibilizer, this role owes to segmentation and barrier of talc on PET phase; talc decreases the △Hc of PA66 part and increases the △Hc of PET part;increases in strength，stiffness and heat resistance of PA66/PET alloy arc due to the strengthening of talc lamcllar on PA66 matrix and the interface between PA66 and PET, and the toughening effect of talc is related to the decrease in crystallinity of material and the improvement in the compatibility of PA66 and PET.
QIU Dun-rui, SUN Yu-feng, LI Shu-run, YANG Wan-tai
Abstract (
2954 )
Scanning electron microscopy(SEM)，differential scanning calorimctry (DSC) and mcchanical performance testing were used to investigate the compatibilization of polypropylene(PP)Polyamidc6(PA6)blends containing various polypropylene grafted malcic anhydride and vinyl acetate(PP-g-
MAH/VAc.SEM images indicated that the domains of PA6 dispersed in the PP/PA6/PP-g-(MAH/VAc) blends were significantly reduced to less than 5 μm.As 8%PP-g-MAH/VAc graft polymer with5.3%malcic anhydride-co-vinyl acetate was added as a compatibilizer in the blend of PP(80%)and Pn6 (20%)，its elongation at break, tensile strength，and notched impact strength reached 558%，60.88 MPa, and to 5.28 kJ /㎡，respectively. The improved compatibility in PP/PA6/PP-g-(MAH/VAc) blends was attributed to the formation of PP/PA6 copolymer by chemical reactions between anhy-
dridc of MAH in PP-g-(MAH/VAc) and terminal amino groups of PA6 during the melt mixing, as confirmed by FTIR results.
XU Guo-zhi, CEN Yin, YE Xiao-jun, LI Jie-tao
Abstract (
1953 )
The effect of carbon fiber contents on the conductivity of PE-HD based blends was studied.For the system of PE-HD/CF, the volume and surface resistivitics decreased from 6.16x10^14Ω*cm to 1.54x10^7Ω*cm and from 2.59x10^16Ωto5.74x10^9Ω, respectively. For the system of PE-HD/EVA/CF those values decreased from 1.91x10^13Ω*cm to 3.27xlO^15Ω*cm, and from 5.72x10^15Ω to 6.18x1O^8Ω, respectively. It showed that the addition of EVA could improve the conductivity of the composites. When the loading of CF was 5 phr, the volume resistivity exhibited a minimum. The degrey of orientation of CF increased with increasing its content, the volume and surface resistivitics alongthe machine direction decreased more obviously.
TONG Qi-yong, LI Guang-ji
Abstract (
3170 )
Thermally conductive and clectroinsulating polypropylene(PP)composites were prepared with a twin-screw extruder using different mesh of talc as filler. The effect of particle size, which varied between 3 .6 μm and 50μm, on the thermal conductivity, volume resistivity, mechanical properties,and crystallization behavior of the PP/talc (70/30) composites was investigated.As the talc particle size became smaller, the tensile and flexural strength of the composites increased firstly and then decreased，while the thermal conductivity decreased firstly and then increased.The composite containing 12μm talc exhibited the maximum tensile and flexural strengths, 29.92MPa and S2.S8 MPa, which arc 5.5%and 12.8%higher than those of neat PP, respectively. The composite filled with 50μm talc gave rise to the maximum thermal conductivity, 0.3237W/(m*K)，which is 32.7%higher than that
of neat PP. When a mixture of 12μm and 30μm talc(1/1)was used，the thermal conductivity of the composite was 0 .3184W/(m*K)，which is higher than that of the composites when either single talc was used .In addition，all the volume resistivitics of the PP/talc composites were higher than10^8Ω*cm
HE Yu-xin, MA Jian-zhong, ZHANG Li, ZHANG Yu-qing
Abstract (
3534 )
A new type of graft copolymer EVA一g-PU was prepared;the grafting of polycthcr-polyurethane prepolymer onto EVA backbone was confirmed by FTIR and 13C-NMR characterization.Mechanical testing showed that the tensile strength and elongation at break of EVA一g-PU was far supcrior to neat EVA.Dynamic mechanical thermal analysis (DMA)showed that the storage modulus of EVA一g-PU increased with increasing PU prepolymer content. Thermal gravimetric analysis(TGA) testing showed that the introduction of PU prepolymer also increased the thermal stahilitics of EVA一g-PU copolymers.
LIU Chun-lin, ZHOU Ru-dong, DING Yong-hong, WU Dun
Abstract (
4626 )
The non-isothermal crystallization behavior of POM and POM/TPU blends were investigated by differential scanning calorimetry (DSC).The Jeziorny, Ozawa, and Mo methods were employed to analyze the DSC data. The results showed that the width of the crystallization peak was broadened，the
crystallization temperature(Tc) decreased with increasing cooling rate.At the same cooling rate, Tc of the blends was higher than that of neat POM. Jeziorny method could well he used to treat the nonisothermal crystallization. It showed that TPU increased the crystallization rate, decreased the half crys-tallization time(t1/2)，and changed the nucleating mechanism during crystallization of POM. However,Ozawa method did not fit the polymer blends, because it ignored the influence of secondary crystalliza-tlon.
TANG Hai-han, LIU Yong, YANG Wei-min, DING Yu-mei
Abstract (
2304 )
In-situ composites of poly( ethylene tcrcphthalatc)(PET) and polypropylcnc(PP) were prc-pared using a twin-rotor continuous mixer. The effects of temperature, composition，shear rate, and rhcological behavior on PET fibrillation was investigated.The relationship between compatibility and
fibrillation was discussed. The influence of PET mass content on the tensile strength of the composites was also explored.It showed that the fibrillation of PET phase in the PP matrix improved the tensile strength of the composites.
TIAN Xin, CHEN Xiao-feng, ZHOU Chang-lin, LEI Jing-xin
Abstract (
3853 )
Effect of ultraviolet light (UV) irradiation on the structure and properties of PVC was studied by means of FT-IR，UV spectrum, SEM, GPC, stress-strain curves, yellow index, and water contact angle tests, etc. With the increasing UV irradiation time, the molecular weight of PVC increased to a maximum then decreased，polydispersity index increased from 1.771 to 1.919.The carbonyl groups and the conjugated double-bond sequences were generated on PVC chains. Surface of PVC samples became coarse, lots of cracks formed and enlarged，yellowness index increased from 40.7%to 90.28%，and the color turned to dark gradually. The weight loss of PVC samples increased to 0. 22%during UV ir-radiation.At initial UV irradiation，the contact angle to water decreased from 63.3to 55 rapidly and then leveled off to about 50 .The tensile strength of PVC samples increased slightly from 55 MPa to a
maximum 57 MPa and then decreased，while the elongation at break decreased from 35.5%to 11.8%with UV irradiation time.
CAI Yong-hong, SUN Xiao-hui, QU Jin-ping
Abstract (
2933 )
Based on dissipation mechanism of shearing power, a theoretical model for vibrating shear flow was formulated and new method for calculating the dynamic viscosity of polymer melts was proposed in this paper. Using the method，the dynamic viscosity of Maxwell fluid in simple vibrating shear
flow was found in accordance with results using a traditional method. The prediction ability of the method was discussed based on the superposition of vibrating shear flow onto the steady flow. The limi-tations of the model for the superposed flows were found and the causes were analyzed.Results of rhco-ogical experiments showed a good agreement with the theoretical prediction in a bound of small amplituck.
HUA Dong-Shuan, GAO Jun-Gang, QIN Jiang-lei
Abstract (
2692 )
The rhcological behavior of linear low-density polyethylene (PE-LLD)/ethylene-silsesquiox-anc(E-POSS)blend was investigated using a capillary rhcometer. Influences of composition of the blends, shear rate and shear stress on melt apparent viscosity were discussed. ion-Newtonian index(n)，swell ratio, conventional yield stress, breaking strength，and breaking extensibility of the blends at different contents of E-POSS were measured.It showed that the PE-LLD/E-POSS blends were pscu-doplastic. When the content of E-POSS was lower than 3%and the temperature was below 160℃，the melt viscosity was lower than that of neat PE-LLD; while the viscosity was higher when the content and temperature became higher. The blends exhibited maximum mechanical properties when the mass frac-tion of E-POSS was 3%.
JIN Yang-fu, QIAN Xin, LV Xun, HU Xiao-dong, YU Qing-ping
Abstract (
3812 )
Based on the relationship between the structure and performance of car dashboards, the filling process in the gas-assisted injection molding of car dashboards was simulated using CAE software Mold-f low/MP I，and the part quality was predicted.According to real production conditions, the processing
parameters of gas-assisted injection molding for car dashboards were optimized.The experimental results showed that the gas penetrated through the melt polymer commendably under the conditions of optimum processing parameters, and the quality of car dashboards could satisfy the client’s requirements .
LIU Dong-lei, XIN Yong
Abstract (
1936 )
According to the flow character of polymer melt in cavity, the molding mechanism in the rapid heat cycling molding(RHCM) was studied.How to enhance the reproductive ability to cavity,eliminate processing defects, such as weld mark, dark mark, flow mark, sliver mark, fibre on surface,and how to eliminate the difference in color were discussed.It was found that just because of the high melt temperature the polymer melt could flow smoothly and joins fully, resulted in lower shrinkage and thus ensured the higher quality of the parts.
CAI Zhao-hui
Abstract (
2621 )
High-density polyethylene (PE-HD) film was prepared on a casting machine, and was treated by irradiation. The effect of irradiation on the structure and performance of the PE-日D film was invcsti-gated. It indicated that the toughness decreased slightly with increasing irradiation dose while the tensile and tear strengths increased. When the dose of irradiation increased from 1 Mrad to 6 Mrad，the tensile strength of MD increased from 20.5 MPa to 23.2 MPa, which of TD increased from 18.1 MPa to 19.5 MPa; the tear strength of MD increased from 11.8 mN to 17.2 mN，which of TD increased from 8 .3 mN to J.3 mN;the elongation at break changed slightly. When the dose of irradiation reached 8 Mrad，the mechanical properties were further improved.However, at higher doses, the mechanical properties decreased obviously. The content of the gel increased，which decreased the melt flow rate.
NI Zhuo, NIU Ke
Abstract (
3016 )
This work presents the effect of di(3，4-dimethyl) dihenzaldchyde sorhitol (DMDBS) on the crystallization behavior of polypropylene (PP).The contents of DMDBS in PP were 0.1%，0.3%，0 .5%，0.7%，and 0.J%.Various techniques including FT-IR, DSC, WAXD, polarized light microscopy, etc. were employed to investigate crystal structures and thermal properties for the samples.
Extensive experiments demonstrated that DMDBS acted as an effective a form nucleating agent for PP，resulting in smaller spherulite size, higher crystallization and melting temperatures, and higher trans-parency of the samples.
HOU Song-tao, CAI Zhi, XIN Zhong, MENG Xin
Abstract (
3396 )
Four different benzofuranone/1010/168 ternary complex antioxidants for polypropylene (PP) had been studied via comparing their melt flow rate after multiple extrusions and oxidation induction time (OIT).Aftcr 5 times of extrusions at 250℃，the PP sample containing 1%of 5一tcrt-butyl-7-methyl-(3-methoxyphenyl)-3H- benzofuran-2-one(ANBF2)/1010/168 system exhibited the smallest flow rate and the longest OIT, and thus the highest thermal stability.At the same loading of 1010 and 168，the stabilizing effect of八}BF2 was compared with Irganox HP-2225.Even when the loading of ANBF2 was one third that of HP-2225，the stabilizing effect of the former was still better than the latter.
LIANG Li-i, LUO Xue-Gang
Abstract (
1819 )
The effects of photosensitizers on the mechanical properties of polyethylene mulching films were studied systematically under real field conditions by single and orthogonal factor experiments. The experimental results indicated that the ferric stcarate played a major role in accelerating the photodegra-
elation of polyethylene. Ferrocene was less sensitive than ferric stcarate. When used alone, nickelN，N-dibuty dithiocarbamate could retard the aging of polyethylene, while used with ferric stcarate could prolong the induction period and accelerate the degradation of mulching films later. However, when it was used with ferrocene, the degradation period was longer than that used with ferric stcarate.
WANG Xu, ZHANG Hui一ping, YAN Xiong
Abstract (
2360 )
The purpose of this paper is to investigate acoustic emission (AE)characteristic of ultra high molecular weight polycthylene/low density polyethylene (PE-UHMW/PE-LD) laminates during tensile damage process by means of correlation analysis and principal componentanalysis. The result of experi-
mcnt reveals strong correlation between AE parameters. For example, the correlation coefficient betwecn duration time and counts of [0] is 0.976，while that between amplitude and counts of[90] is 0 .8.According to principal component analysis, the first principal components of [0] and[90] reflect
the character of time domain，such as rise time and duration time, and the second principal components of them reflect the character of frequency domain，such as peak frequency and frequency centriod. The principal component score of[90] shows different damage modes, such as the onset of interface crack- ing, the growth of interface cracking and the fracture of interface, each possessing different scores.
LONG Zhi一bin, ZHANG Ya-qin, LUO Bing, ZHAO Feng, Han Ya-nan
Abstract (
2125 )
The screw axial force of a screw segment was simulated using POLYFLOW software. The recult indicated that screw axial force is fluctuated with screw rotation，various with the screw configuradons and operating conditions. The screw axial force of intermeshing co-rotating twin screw extruder was measured by strain experiment of drawbars. Experimental results show that the screw axial force is composed by static pressure force of the die and additive force along the screw, the ratio of additive force along the screw to static pressure force of die ranges from 0.4 to1.6
