WANG Zhan-jie
2007, 21 (1):
1-7;
Abstract (
253 )
PDF (6439 KB)(
118
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With the fast growth of plastics pipes industry during the 10th Five-year-plan period, China has become one of the largest countries of production and application of plastic pipes. Much progress in the export and types, application areas, technological advances as well as standardization of plastics pipes has been made. Features of and problems in the plastics pipes industry were analyzed, and developing target,focus and strategy for it were proposed.
LI Ya-na, LI Shu-cai
2007, 21 (1):
8-12;
Abstract (
478 )
PDF (4615 KB)(
143
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Nowadays, approaches that can endow polymers with anti-infective properties mainly contain(a) mixing antibacterial agents in bulk polymers; (b) surface modification of polymers;(c) molecule-composition technique. In this article, the research and progress of different processing-type antibacterial polymers developed in the recent 5 years are reviewed. Special emphasis will be on the advantages and disadvantages of each technology.
LI Qian, YAN Hong-xia, FANG Fen, LEI Ping-sen
2007, 21 (1):
13-17;
Abstract (
353 )
PDF (4680 KB)(
160
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This paper reviews the main methods of toughening modification of bismaleimide resins, inchiding the introduction of rubbers, thermoplastic resins, allyl compounds, organic silicon compounds,and nanoparticles. The toughening modification mechanism was discussed. The studying status and development trend of modification of bismaleimide resins were probed.
LIU Xi-jun, ZHU Wen-ming, JIANG Zhao-hua, QI Ying
2007, 21 (1):
18-24;
Abstract (
363 )
PDF (5197 KB)(
125
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PP was grafted by itaconic acid or by itaconic acid and styrene via melt reactive twin screw ex- trusion, the products were studied using FTIR and thermal an alysis. The effects of concentration of monomers and initiator on the graft ratio and melt flow rate of gr afted PP were studied. The grafted PP was employed in PA6/PP blends as a compatibilizer and an im provement in impact strength was ob served. SEM indicated that the homogeneity of the compatibiliz hed PA6/PP blend was also improved. The size of the dispersion phase was significantly reduced, the in nterface became smeared. DSC showed that the crystallinity of PA6 component in the blends was decreas ed with the introduction of grafted PP.
DONG Xian-wing, LUO Ying, ZHANG Shu-ting, ZHANG Yong-ce, ZHENG Xiao-li
2007, 21 (1):
25-28;
Abstract (
224 )
PDF (5197 KB)(
132
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Electrical conductivity property and responsiveness to organic solvent vapors of poly( methyl methacrylate) /poly( ethylene glycol)/carbon black(PMMA/PEG(/CB) composites synthesized through in-situ polymerization were investigated. When the mass ratio of MMA/PEG was 8/1, it took only 20~30 min for the monomers to reach a conversion of 94 %. Afte r 8.5 wt% of carbon black was intro. duced, the composite gave a resistivity of 1.3 Ω cm. It was fou Ind that the electric resistances of the composites drastically increased by 104 times when the materials w were exposed to good solvent vapors of PMMAsuch as acetone, chloroform, and ethyl acetate, but only 140 times to poor solvent methanol. These results suggested that the composites could be regarded as a promising gas sensor.
WANG Bing-xi, LIN Meng-ping, LIN Hang
2007, 21 (1):
29-33;
Abstract (
276 )
PDF (4379 KB)(
138
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Modified carbon black was obtained bytreating N990 in CO2 at high temperature, and its PE HD composites were then prepared. Treated carbon blacks were characterized with BET, SEM and XPS. The effect of CO2 treatment on the structure and electric property of N990, as well as PTC prop- erties ofits compositeswereinvestigated.The results show that treated carbon black, as compared with the untreated one, keeps its original inner structure, but can increase its conductivity by more than 1 time nitrogen surface area by more than4times, new pores within 10~30A in size by more than 6 times on its surface,and decreases its surface oxygen by 36.6 %. Room resistivity of treated N990 com- posite can decrease by 0.6 to 3 orders of magnitude compared with that of the untreated one, though PTCintensity also deceases byzero to 60.1%.However, composites exhibiting low room resistivity and relative high PTC intensity can be attained by loading suitable weigh of treated N990.
ZHOU Hong-jun,
2007, 21 (1):
34-38;
Abstract (
330 )
PDF (4242 KB)(
96
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AminefunctionalizedPP(PP-g-NH2)was introduced into PP/nano SiO2, composites as a reac tive compatibilizer.Itshowed that the tensile strength, Young's modulus, and notched impact strength of the composites were increased at low nano-silica content. When 3 wt % epoxy functionalized nano-sil- ica and 10 wt% PP-g-NH2 were used, the tensile strength and notched impact strength of PP can be in-creased by 13 % and 87 %，respectively.
XU Li-dan, XIANG Ai-min, ZHENG Yi-zhu, ZHOU Honk-fu
2007, 21 (1):
39-42;
Abstract (
252 )
PDF (3993 KB)(
97
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Continuous carbon fiber reinforced polyamide 6(CFRPA6) composites were prepared through pultrusion melt immersion method. The properties of composites were investigated with the changes of carbon fiber’s content andlength.Theresult showed when the length of carbon fiber was increased from2~4mm(short CF)to 8~10mm (long CF), the tensile strength, flexural strength and hardness were enhanced by 25.70 %,31.65%,3.10%,respectively. When CF content was 15 %, the impact strength of long CF reinforced PA6 was 16.25% higher than that of short CF reinforced PA6. When CF content was3%，the water absorption of long CF reinforced PA6 was 15.66 % lower, compared to short CF reinforced PA6, while the linear expansibility was hardly affected by the length of CF. With increasing of carbon fiber content, impact strength was decreased, while tensile strength, flexural strength, hardess, water absorption and imear expansibiltv were still improved steadily.
WU De-feng, ZHANG Yi-sheng, ZHANG Ming, WU Lan-feng, DAI Hong-li
2007, 21 (1):
43-47;
Abstract (
311 )
PDF (3953 KB)(
102
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Blends of poly(phenylenesulfide)/polycarbonate( PPS/PC) were prepared via melt mixing The crystallization processoftheblends was characterized using DSC and XRD. It showed that the PPS/PCblends presents the typical partially compatible phase morphology. PC component inhibited the crystallization of PPS.This inhibition became stronger with increasing PC contents. However, the pres- ence of PC component did not change the crystalline structure of PPS.
LI Mei, LI Zhi-qiang
2007, 21 (1):
48-51;
Abstract (
443 )
PDF (2453 KB)(
126
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Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) was studied in this paper. poly( 3-hydroxybu tyrate)possesses a narrow melting range, a high crystallinity, large spherulite sizes and brittle fracture, which limited its application.When copolymerized with 4-hydroxybutyrate, several properties were im proved.With increasing the amount of 4HB, melt flow rate decreased from 20.7g/10 min to 8.9 g/10 min viscosity number increased 1.8 times, melting range was widened to T=150~170 ℃，and crystallinity decreasedfrom 11.57 % to 5% and spherulites were no longer observed. In addition, the tensile strength decreasedfrom 13.5to7.9MPa,elongation at break increased from 796 % to 1 020 %,glass temperature was increased from-7.29℃to-3.17℃，which is beneficial to processing.
LI Jing-qing, TIAN Xiao-wing, SHENG Jing
2007, 21 (1):
52-58;
Abstract (
297 )
PDF (5583 KB)(
101
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Time sweep investigation ofthe static rheological behaviors of polypropylene(PP), polystyrene(PS)and their blends were carried out at low shear rates. The viscosity of neat PP and PS decreased linearly with time mainly due to thermal degradation. For the PP/PS alloy, the viscosity in-creased first and subsequently decreased. The first increase of the viscosity could be attributed to the in-terlockofthe phase structure and the later decrease was for the same reason of the homopolymers.
ZHENG Guo一qiang, WANG Song-jie, YANG Wei, HUANG Li
2007, 21 (1):
59-63;
Abstract (
346 )
PDF (5421 KB)(
158
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Morphology of the gas-assisted injection molded polycarbonate/polyethylene(PC/PE) blend was investigated employing scanning electronic microscope(SEM). Although the gas-assisted injection molded parts have the skin-core structure as the conventional injection molded parts do, the morphology evolution of PC phasein the gas-assisted injection molded(GAIM) part and the conventional injection molded(CIM)part showed completely different characteristics. The deformation and distribution of PC phaseGAIM parts are extremely sensitive to melt temperature. On the basis of morphological descrip tion, the effects of the molding temperature on the mechanism of the PC phase deformation and distribu- tion are also discussed.
ZHOU Bo, CHENG Min-lian, YU Qiang, MENG Jun
2007, 21 (1):
64-68;
Abstract (
391 )
PDF (4062 KB)(
111
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Blends of PE-HD/PA6/EVOH and PE-g-MAH as a compatibilizer were blow molded to barri er containers, the effects of composition and processing conditions on rheological and barrier properties were investigated. The laminar structure of the container section was observed using scanning electron microscopy.EVOH acted as the second compatibilizer, which interacted with PA6, thus increased the melt viscosity and improved processingstability. The optimal processing condition was set agtempera ture between225and230℃，the rate of screw rotation 30 rpm, and the blending time 3 min.
XIN Yong, LI Shuang-lin, ZHOU Xin
2007, 21 (1):
69-72;
Abstract (
269 )
PDF (4229 KB)(
99
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This paper focuses on the impact between injection molding process and the injection molded products.By introducing the expert experiences and knowledge, obtaining design knowledge in the field and transforming them into production rules form which is accepted by the CLIPS, the plastic defects knowledge database isbuilt, and CLIPS knowledge inference engine is utilized to conduct the inference of the knowledge, which gets the cause of defects and the corresponding solutions. Finally an inference example is applied and the utility of the system is shown.
LI Pei-yao, SONG Guo-jun, YIN Lan-lan, WANG Li, QI Feng
2007, 21 (1):
73-76;
Abstract (
293 )
PDF (3960 KB)(
113
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PoyethylencPE)/OMMT nanocomposites were prepared via melt extrusion without using a compatibilizer.Transmission electron microscopy(TEM) confirmed that an exfoliated structure of OMMT wasobtained.Thegas permeationtests showed that the oxygen penetration in the nanocompos-ite film decreased by 37%. The vacuum degree holding times of nanocomposits bags increased from one to eighteendays.The crystallization behavior andthermostability of the nanocomposites were also stud ied using DSC and TGA.
WANG Lan, CHENG Guo-hu, JI Bin-bin, ZHAO Jun-hui
2007, 21 (1):
77-80;
Abstract (
293 )
PDF (3860 KB)(
112
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The bicomponent-grafted polypropylene was prepared by using of a twin-screw extruder; the grafted reaction was characterized by FT-IR.Theinfluence of the content of initiator and monomer on the melt flow rate, meltstrength and anti-sagging ability were studied, and the extrusion foaming was also investigated. Results show that the melt strength and antisasging ability were increased. and the performance of the foam was improved effectively.
HE Yang, HUANG De-hua, XIAO Li-qun, HUANG Rui
2007, 21 (1):
81-85;
Abstract (
290 )
PDF (3960 KB)(
109
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Effect of a rare earth β-nucleating agent(WBG)on the properties of isotactic polypropylene (iPP) was studied by polarizing microscope(PLM), differential scanning calorimetrv( DSC), and wide-angular X-ray diffraction( WAXD).The results showed that the addition of small amounts of WBG to PP induced the proportion of β crystals. The relative content of β-phase was up to 57 % in a PP containing 0.2% ofthe WBG. The Izod impact strength of homopolymerization PP was increased 1.48 times, and heat deflection temperature rose 11~33℃，when small amounts of WBG was added. The samples showed the optimal properties when the beat treatment at 100 ℃. A slow cooling rate benefited the for mation and perfect of pcrystals. The photos of PLM showed a new phenomenon that β crystals grew up with leaflike form in the center and covered with B-spherulites which formed some small and anomalistic interface,some central β crystals impenetrate each other.
YOU Rui-yun, LIN Lang, XIAO Li-ren, CHEN Qing-hua
2007, 21 (1):
86-90;
Abstract (
355 )
PDF (4157 KB)(
118
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Calcium oxide and rare earth metal photosensitive compound were used as fillers to prepare the environmentally degradable CaO/PEfilm.The film was subjected to artificially accelerated and natura exposure agings, and subsequently the environmental degradability was characterized using FTIR, TG- IR, and SEM.Itshowed that the CaO/PE film had both photo and thermal-degradability. In addi- tion, the CaO/PE films discharged little poisonous gases when incinerated.
ZENG Wen-hui, ZHOU Jie-min
2007, 21 (1):
91-94;
Abstract (
330 )
PDF (4156 KB)(
98
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The numerical method was applied to correct the experimental thermal conductivity and spe-cific heat of poly(methyl methacrylate) measured via quasi-steady state plate method. In the correction. the step-by-step method was used.The calculation was ended until the temperature difference and tem perature rise speed rate of the calculated curves match the relative data of the experimental curves. The correction amplitude of the thermal conductivity and the specific heat is 1.7 % and 2.8 %,respective- ly,and the corrected data was in the recommended range of relevant references.
ZHAO Wei-zhe, YAN Bao-rui, GUO Yi-chong
2007, 21 (1):
95-98;
Abstract (
395 )
PDF (3831 KB)(
228
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Evaluating the transfer function,thedynamic relation between the pressure in the die and the speed of the screwis necessary to studythe pressure close-loop control svstem in a single screw extrud-er.The transfer function ofasingle screwextruder was evaluated via mechanism analysis. It showec that thetransfer function of single screw extruders is a proportional component by the experiment testing method.Using theresultsand thetransfer functions of other components in the close-loop control sys tem，amathematical model in theclose-loop control system of the extruder could be formulated.
OU Di-sheng, ZHOU Xiong-xin
2007, 21 (1):
99;
Abstract (
359 )
PDF (3989 KB)(
93
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Aimed to the premature failure of the tri-thread near a slot for releasing stress of a tie-bar of a plastic injection machine, this paper analyzed the stress distribution of the tri-thread and its adjacent slot of a tie-bar with finite element method in ANSYS software, and built up a parameter optimum model ac- cording to the geometry characteristic of the adjacent slot of the tri-thread end of a tie-bar. A multi-ob- jective function was used to reduce the maximum stress of a tri-thread and to control the maximum stress and the minimum machining allowance ofits adjacent slot of a tie bar.Through the multi-objective opti- mization of the parameters of a tie-bar under the condition of one-way tension, the maximum stress on the root near the slot of the tri-thread of a tie-bar decreases 55 percent. Under the condition of deflective load,its maximum stress decreases 21.4 percent.Under the condition of one-way tension, the maximum stress of the slot of a tie-bar increases 26.5 percent in comparison with the average one-way tensile stress.It demonstrates that the optimum method can make the slot play a better role on releasing stress.
