LIU Ji-san, LIANG Guo-zheng, ZHANG Zeng-ping, ZHANG Xuan, WANG Jiu-cheng,
2007, 21 (2):
1-4;
Abstract (
359 )
PDF (4471 KB)(
109
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The research work on poly(lactic acid)-polyethylene glycol) (PLA-PEG) block copolymers and its application as microsphere carriers were reviewed. The synthesis methods of PLA-PEG were described in details, including the polycondensation of lactide and PEG, the polycondensation of lactic acid and PEG, the polycondensation of lactide and ethylene oxide. The properties of PLA-PEG block copolymers and their applications in biomedical fields, such as drug delivery system, bone fixing, tissue repairing, and surgical mending~simply introduced. The prospect of these polymers was also discussed.
BU Ya-ping, WEND Yun-xuan, WANG Lan
2007, 21 (2):
5-9;
Abstract (
360 )
PDF (4598 KB)(
111
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The development in poly((3-hydroxybutyrate) (PHB) modification in resent years was summarued in this paper, including copolymerization with hydroxyvalerate ( HV)，grafted with malefic anhy-Bride(MA)，and blending with poly(propylene carbonate)(PPC)and starch. The mechanical properties, crystal behavior, heat stability, and hydrophile properties were reviewed. The future research trend was proposed.
LIU Xian-wei, LIU Zhi-meng, JIA De-min, JIANG Xin, ZHONG Chi-feng, LIU Yu-ping
2007, 21 (2):
10-14;
Abstract (
319 )
PDF (743 KB)(
119
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The research progress of phenolic resin composite for brake linings was reviewed on its chemical and blending modification and toughening. The resin was often reinforced with carbon fiber, aramid fiber, or potassium titanate fiber. The hybrid fibers are the developing trend for the reinforcement Safety，stability, long life, environmental protection, and zero noise are the developing direction of phenolic resin composite for brake linings.
ZHENG Bin, LI Bin, DAI Gan-ce
2007, 21 (2):
15-18;
Abstract (
330 )
PDF (4294 KB)(
90
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MAO Wei, TANG Song-chao, WANG Qing-hai, PAN Yong-kang, WANG Ting-lan
2007, 21 (2):
17-22;
Abstract (
272 )
Poly(lactic acid )(PLA)was prepared via solution method and was chain extended with methylenediphenyl diisocyanate in a twin screw extruder. The effect of different NCO/OH mol ratios on molecular weight, thermal characteristics, and mechanical properties was studied. It showed that it was feasible to prepare high molecular weight PLA by twin-screw chain extension. The viscosity-average molecular weight of PLA was increased from 9 .19X104to23.6 X 104 during the chain extending and the tensile strength became nearly 2 times higher.
MA Zhi-ling, WANG Jing-hui, LIU Lei, TANG Jian
2007, 21 (2):
23-26;
Abstract (
471 )
PDF (4021 KB)(
92
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The effect of carboxyled polypropylene (EPP) on the compatibility of polypropylene (PP)/brucite(BC) composite was discussed. SEM and rheological behavior tests indicated that EPP enhanced the adhesion and improved the compatibility between PP and BC. The appearance of absorption peaks at 884. 56 and 747.68 cm一1 proved that chemical reactions took place and produced carboxyled magnesium between EPP and BC. The experiments testified that on the one hand EPP reacts with BC through carboxyl，on the other hand PP segments of EPP and PP cocrystallize, so EPP is an effective compatibilizer of PP/BC composite. The property of PP/BC composites is obviously different that BC modified with smelting method and liquor method. XRD showed that liquor method made EPP intercalate the layers of BC and the testing of mechanical property and SEM showed that liquor method exceeded melting method.
AO Yu-hui , TANG Kai , XU Na , YANG Hai-dong , ZHANG Hui-xuan ,
2007, 21 (2):
27-30;
Abstract (
317 )
PDF (3906 KB)(
93
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POE was cross-linked using DCP. When the dosage of DCP increased from 0. 5 %0 to 5 .0%,the content of gel increased from 0 .8%to 12. 8%，and the melt flow rate decreased from2 .80 g/10 min to 0. 8 g/10 min. The crosslinked POE was blended with PP in a twin-screw extruder.The impact strength of PP increased moderately when the cross-linked degree of POE was lower. When she content of DCP exceeded 2. 0%。，the impact strength of PP/POE blends decreased obviously. SEM showed that with the increase of cross-linked degree of POE, the dispersion size of POE phase in PP/POE blends became larger. The morphology and impact property had good correlation.
QIN Ya-wei , GUO Shao-hui , FENG Jia-chun, LIU You-yi
2007, 21 (2):
31-35;
Abstract (
278 )
PDF (3780 KB)(
185
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The non-isothermal crystallization of polypropylene containing a rare earth β-nucleating agent was studied using differential scanning calorimetry (DSC) at several different cooling rates. When the dosage of β-nucleating agent was 0， 1 wt，over 90%of β-crystallite was obtained. The non-isothermal crystallization kinetics was analyzed using methods of Jeziorny and Mozhishen. It showed that β-nucleating agent increased crystallization temperature, though the rate of crystallization decreased.
GONG Wei-guang, XIN Zhong
2007, 21 (2):
36-39;
Abstract (
310 )
PDF (2878 KB)(
78
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Brominated polystyrene (BPS) was prepared in the presence of Al-based complex catalyst by bromination of commercial grade polystyrene (PS) with element bromine in a halo-hydrocarbon solvent.The structure and properties of BPS were studied using IR, NMR，elemental analysis, and TG. The effects of the composition of complex catalysts and reaction conditions (reaction temperature and reaction time) on properties of BPS were discussed. When the bromination was catalyzed with SbCl3-Al, a weight percent of bromine in BPS around 66%一69%was achieved, which loss only 5%of weight until 370℃.When blended with PET, the limited oxygen index of the latter increased from 21%to 26. 5%.
WANG Jian-hua, LIU Ji-hong, LI Ming-yu, LEI Chao-min, ZHONG Sheng
2007, 21 (2):
40-44;
Abstract (
226 )
PDF (4086 KB)(
93
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The non-isothermal crystallization behavior of polyamide 612 at different cooling rates was studied by means of differential scanning calorimeter(DSC).The non-isothermal crystallization data of DSC was treated with the methods of Jeziorny, Ozawa, and Mo Zhi-shen. The peak temperature of crystallization of polyamide 612 moved from high to low temperature, the half-width of crystallization peak became larger, the half-time of crystallization reduced with increasing cooling rates. The comparison among the three treatment methods revealed that Ozawa method was not suitable to describe the non-isothermal crystallization kinetics of polyamide 612，Jeziorny method was substantially suitable and Mo Zhi-shen method was best. The activation energy of non-isothermal crystallization of polyamide 612 evaluated by Kissinger method was 293 .0 ICJ /mol.
CHEN Xiao-yuan, LU Ai, WANG Gang, YU Xue-jiang
2007, 21 (2):
45-48;
Abstract (
288 )
PDF (4132 KB)(
83
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The dynamic rheological and mechanical behaviors for polysulfphone(PSF)/olyphenylene sulfide (PPS) blends were studied, and relationship between compatibility and mechanical properties eras analyzed. It was indicated that the fluidity of blends was improved with PPS adding, and viscosity of blends descended with increasing content of PPS and ascending temperature, but independent of shear rate .PSF/PPS blends presented a two-phase structure with interactional interface to certain extent, and its compatibility depended on the proportion of blends. So a well compatibilized PSF/PPS ( 3 /'7 ) blend presented promising general mechanical properties. Especially impact strength of the blend went up by 64 percent as compared with that of neat PPS.
LIU King-xue, XU Gui-lian, PAN Xiang-jiang, WU De-zhen, HE Wei-feng
2007, 21 (2):
54-58;
Abstract (
255 )
PDF (4126 KB)(
77
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ZHANG Ping, ZHOU Nan-qiao, LI Bing, CAO Xian-wu, WANG Ming-yi
2007, 21 (2):
59-63;
Abstract (
376 )
PDF (4071 KB)(
120
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YAN Li, ZHOU Guo-fa, GUO Ji-lin, ZHOU Yong-fei
2007, 21 (2):
64-68;
Abstract (
276 )
PDF (3684 KB)(
80
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WANG Yang-dong, WANG Zhen-hua, XU Guo-zhi
2007, 21 (2):
67-72;
Abstract (
239 )
PDF (4085 KB)(
97
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A new anti-dripping coating for agricultural films was developed, which can be applied on the film by surface spraying. The preparation method of anti-fogging acrylic coating was introduced. The effect of fluorine surfactants on the anti-fogging property was investigated. Using the optimal formulation, the light transmittance of the coated film showed little change while the haze degree decreased from 17 .3%to 9 .45%，the contact angle decreased from 86 °to 30 °.
SHI Heng-chong, LI Bin
2007, 21 (2):
73-76;
Abstract (
388 )
PDF (3973 KB)(
145
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(PE-HD/SEBS)-g-MAH was prepared by means of a torque rheometer and was employed as a compatibilizer in PE-HD/wood flour composites. FT-IR confirmed that malefic anhydride ( MAH) was grafted onto PE-HD/SEBS. During the reaction, the torque of the rheometer increased with increasing content of malefic anhydride and dicumyl peroxide. Styrene could promote the rate of reaction between MAH and PE-HD/SEBS. The mechanical properties of PE-HD/wood flour composites were obviously enhanced with (PE-HD/SEBS)-g-MAH.When the content of (PE-HD/SEBS)-g-MAH was 2 wt%，tensile and flexural strengths of the composites reached 25 .9 MPa and 34 .8 MPa, respectively. The notched Izod impact strength reached 5 .081}J /m'`.SEM showed that (PE-HD/SEES)-g-MAH obviously improved the compatibility of PE-HD/wood flour composites.
HUANG Nian-hua, XIONG Qi, LI Zhi-hua, ZHANG Qiang, TANG Sheng-bin
2007, 21 (2):
77-81;
Abstract (
353 )
PDF (3918 KB)(
81
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JIANG Chun-hua, ZHONG Gan-ji, XU Xiang-bin, LI Zhong-ming
2007, 21 (2):
82-85;
Abstract (
368 )
PDF (2666 KB)(
91
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ZHANG Wen-long, DAI Ya-jie, LIU Kuo, CHEN Yu
2007, 21 (2):
86-89;
Abstract (
328 )
PDF (2807 KB)(
92
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In this paper,a new test method for anti-fogging performance of greenhouse film of polyethy lene basedon the determination of surface tension was proposed. The relationship between the surface tension andtime of invalidation was formulated. A critical surface tension(34x10-3N/m) was set, below whichthe film was considered as invalidating During the test, the film was immersed in hot wa- terat 50℃ and the time lasted for the surface tension of the film decreased below the critical value was measured,which was considered measure of the time of invalidation.
TANG Guang-li, JIA Ming-yin, XUE Ping, WU Wei-ping, ZHU Fu-hua
2007, 21 (2):
90-95;
Abstract (
378 )
PDF (4531 KB)(
88
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A novel solid conveying theory，double-flight driving theory(TGL theory), was proposed based on the model of arcplates.The key idea was to avoid circumferential shear to the solid plug and to make thetranslating from friction drag conveying to positive conveving in solid conveying zone. Through motion analysis and force analysis of the solid plug for the lKV single screw extruder, it was found that the driving forces from screwflank and feeding seeve flank were the reason of the motion of solidplug.The friction forces between solid plugand barrel surface and that between solid plug and screw surface constituted the resistance force.The boundary condition for avoiding circumferential sheal to the solid plug could be solved through the determination of coefficient k.
LIU Xiao-ming, XIE Lin-sheng, MA Yu-lu, Wen-feng
2007, 21 (2):
96-103;
Abstract (
299 )
PDF (5135 KB)(
83
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In this page, through simulation of the 3-D isothermal flow in mixing section of two-rotor continuous mixer-ECM30，thedistribution of axial velocity, shear stress,and mixing index were ob-tained, based on which the dispersive performance of tworotor continuous mixer in terms of axial veloci tyshear stress and mixing index were estimated. Compared the results from simulation about flow field of different rotors and inserted blocks, the influence of structure of rotor and inserted block on dis-persing performance in mixing section of two-rotor continuous mixer ECM30 was found as follows the shear flow increased and the elongation flow decreased with decreasing length of rotor convergence sec-tions, the shear flow and tension flow decreased with increasing angle of rotor. With the height of in- serted block increased, the backflow, shear flow increased, and tension flow decreased.
