ZHANG Hong-juan, DING WU Gang, Xue-jia, ZHANG Nai-bin, WU Si-zhu
2007, 21 (3):
1-4;
Abstract (
298 )
PDF (4391 KB)(
82
)
As a new polyester resin, cyclic butylene terephthalate (CBT) possesses a variety of special properties including low processing viscosity, rapid forming, and no chemical releasing. It developed rapidly in recent ten years. The synthesis, structure, properties, application and research development of CBT were reviewed in this paper.
QU Xiao-hong, MA Xiao-yan, HU Zi-yan, CHEN Fang, ZHANG Qi-lu
2007, 21 (3):
5-9;
Abstract (
338 )
PDF (4969 KB)(
103
)
This article refers to the recent developments in computer molecular simulation technique applied in the research of nano material modified polymers.The applications include the study of nano materials's structure, mechanical properties, the interaction of modifiers and nano materials and the interface action of polymers}nano composites.
QIN Jiang-lei, LI Zhi-ting, GAO Jun-gang, RUN Ming-tao
2007, 21 (3):
10-15;
Abstract (
237 )
PDF (4300 KB)(
74
)
Melt rheological behaviors of the polypropylene/linear bimodal polyethylene( PP/PE-LB) blend were studied with capillary rheometer.Influences of composition, shear stress, and shearing rate on the melt rheological behavior were discussed. Non-Newtonian index( n) and melt flow activation en ergy of the melt were measured and the results showed that PP/PE-LB blends were pseudoplastic fluids.Melt viscosity of the blends increased with increasing PE-LB content. DSC and SEM showed that addi tion of PE-LB helped PP crystallize at higher temperatures. The addition of LBPE obviously increased the mechanical properties of PP. While the additions were 20 wt % and 40 wt %, the notched impact strength increased about 67% and 320%, respectively, however, at the cost of the tensile strength lowered by 7 % and 35 %, respectively.
LUO Xin, WU Lei, WANG Xiao-dong
2007, 21 (3):
16-19;
Abstract (
340 )
PDF (3027 KB)(
126
)
Thermoplastic polyurethane(TPU) was blended with three elastomers separately,ethylene propylene-diene monomer elastomer (EPDM)，polyethylene-co-1-octylene) (POE),and styrene buta- diene-styrene triblock copolymer(SBS)，via melt blending. The morphology, mechanical and rheologi cal properties were investigated. Scanning electronic micrograph revealed a bi-continuous morphology, in which the elastomer domain formed a network in TPU matrix, which enhanced the mechanical proper- ties.Such interlocked structure also increased the torques of the blending melts.
CHEN Zhi-cheng, SUN Shu-lin, XU Xin-yu, YANG Hai-dong, ZHANG Hui-xuan
2007, 21 (3):
20-25;
Abstract (
275 )
PDF (4404 KB)(
76
)
Acrylonitrile-butadiene-styrene copolymer( ABS) was reacted with maleic anhydride( MAH) to form ABS-g-MAH. FTIR showed that some of styrene-acrylonitrile-MAH( SAM) copolymer graftec onto the polybutadiene particles and the other ungrafted SAM existed as free copolymers. Both ABS and ABS-g-MAH were employed separately as a toughener ofPA6. Reological tests displayed that the torque values and temperature of PA6/ABS-g-MAH melts increased with increasing MAH contents. TEM ob servation showed ABS formed big domains in PA6 whereas ABS-g-MAH achieved a good dispersion. Compared with PA6/ABS blends,the brittle-ductile transition temperature of PA6/ABS-g-MAH blends shifted to lower temperatures and the toughness was higher. SEM showed shear vielding of PA6 matrix and cavitation of rubber phase were the major deformation mechanisms of PA6/ABS-g-MAH blends.
QI Xin-ping, ZHEN Wei-jun, LI Zhi-juan, LI Zhen-jiang, SONG Xiao-ling, HUANG Dong
2007, 21 (3):
26-29;
Abstract (
285 )
PDF (2804 KB)(
74
)
By melt intercalation，poly(vinylchloride)(PVC)/organoclay nanocomposite was prepared andcharacterized.The mechanical properties andthermal stability of the composites were studied. XRD showed that PVC/organoclay was an exfoliated nanocomposite. The tensile strength, elongation at break，andimpact strengthof nanocomposite were 34.7 MPa 12.3%，and 5.08 kjm2, respectively, compared withthose ofneatPVC32.53MPa5.4%，and4.07kjm2. However, the Vicat soften ing point of PVC/organoclay nanocomposite was not evidently increased.
ZHANG MIN-min, LU SHENG, HE MIN, ZHANG TIAN-shui, YU JIE, CHEN XING-jiang
2007, 21 (3):
30-34;
Abstract (
444 )
PDF (4140 KB)(
88
)
The effect of molecular weight and molecular weight distribution( MWD) on the properties of polypropylene(PP)was studied by addition of DCP. The reaction of DCP resulted in lower molecular weight and narrower MWD of PP, and the crystallization rate increased, the spherulite size decreased and β phase vanished, which improved the transparency. When the content of the nucleating agent(TM-3)and theDCP were 0.4%and 0.05%,respectively, the best transparency of PP was ob- served. However, the mechanical properties of PP decreased slightly with reduced molecular weight and narrowed MWD.
ZHANG Lin, LIANG Guo-zheng, HE Shao-bo, ZHANG Zeng-ping
2007, 21 (3):
35-39;
Abstract (
283 )
PDF (4345 KB)(
65
)
In this paper carbon nanotubes (CNTs) were separately treated with dense HCl, dense HNO3，bromic acid, HNO3，H2SO4-HNO3 and K2Cr2O7-H2SO4, in order to increase the reactionof CNTs/BMI/BA svstemand interfacial interaction between resin and CNTs. XRD and TEM were used to characterize the structure of carbon nanotubes. The influence of CNTs/BMI/BA on the reaction characteristics was studied using DSC and mechanical properties of the composites were also investigated with CNTs treated by different acids. It was found that the CNTs treated with mixture of HNO3-H2SO4(4#CNT) enhanced the reaction of BMI/BA/CNTs system and greatly improved the mechanica properties of bismaleimide resins.When the contents of 4# CNT in the BMI/BA resin were 1 wt % anc2wt %，the impact strength increased by 16.92 % and 23.06 %, the flexural strength increased by 7.61 % and 6.47 %，respectively, based on those containing neat CNTs.
WANG Yan, SHU Wen-xiao, BIRO Yong-zhong, HUANG Zhi-ming, WENG Zhi-xue
2007, 21 (3):
40-43;
Abstract (
202 )
PDF (2647 KB)(
73
)
Poly(vinyl chloride)(PVC)/hydrotalcite nanocomposites were prepared via suspension poly merization of vinyl chloride in presence of 10-undecenonate intercalated hydrotalcite. The structure of obtained nanocomposite and influences of hydrotalcite on the thermal stability and the smoke density during combustion were investigated. It showed that a part of vinyl chloride was intercalated into the layers of hydrotalcite and copolymerized with 10-undecenonate in situ. Hydrotalcite particles were par- tiallyexfoliated and dispersed in polymer matrixin the nano-scale. The thermal decomposition tempera- ture and time increased as the weight fraction of hydrotalcite increased, indicating the improvement of thermal stability of PVC. Nanosized hydrotalcite particles exhibited an effective smoke-suppression function on PVC. The maximum smoke density decreased 40% when the weight fraction of hydrotal- cite was 1.25 % in the nanocomposite.
WANG Pei-zhang, SONG Cong-yu, WANG Lan
2007, 21 (3):
44-48;
Abstract (
412 )
PDF (4180 KB)(
79
)
The crystallization，rheological, and mechanical behaviors of a series of starch were investigat- ed.Itindicated that the rheological and mechanical properties of the starch were not dependent on the degree of crystallinity and crystal formbut on the molecular weight and the content of the straight- chain.Recrystallization was observed during the standing period, which resulted in the change of the crystal form and the decline of the mechanical properties. Moisture would promote, and glycerol would depress the rate of recrystallization.
ZENG Tai, ZHU Ji, WEN Yao-feng, ZHANG Jie, SHEN Kai-zhi
2007, 21 (3):
49-52;
Abstract (
254 )
PDF (4070 KB)(
113
)
IPP injection samples are prepared by self-made vibration injection mold in different tempera- turepressure and vibrate frequency.WAXD methods were used to study the development and transi tions of different crvstalforms insurface laver. When melt temperature was 230C crvstal formed whose contentincreased with increasingvibration frequency and vibration pressure. Tensile strength in- creases with the vibration pressure.The elongation at break may be decreased by vibration of low fre- quency,however increased by high frequencyones.The orientation of a-crystal was characterized with polefigures. At low vibration frequency,low temperature and high vibration pressure, the normal of (040) plane of IPP orientated in Mdirection, while in the opposite condition in N-direction.
LIU Dong-lei, SUN Ling, XIN Yong
2007, 21 (3):
53-57;
Abstract (
178 )
PDF (3891 KB)(
77
)
This article emploved the response surface methodology( RSM), combined with CAE tech-noloeyand analysis of varance theory (ANOVA) to establsh an ontimization model. which describes the relationship betweenthe mainprocessing parameters and thin wall part quality. The processing pa- rameters were optimized using the genetic algorithm (GA) A case study showed that the method was effective and feasible.
ZHUANG JIAN, WANG MIN-jie, YU TONG-min, SONG MAN-cang
2007, 21 (3):
58-62;
Abstract (
279 )
PDF (3910 KB)(
72
)
Basedon a viscosity model of polymeric melt representing the rheological characteristics in mi-croscale,the influence ofmelt viscosityon the filling process in micro injection molding was investigated through analyzingthepressuredistributionsof ABS at different inlet temperatures in different mi- crochannels.Numerical simulation showed that the microscale viscosity was lower than the conventional oneand reduced with the decreasing characteristic dimension of microchannel section. In addition, the curves of melt velocity at the sectionofz=5 mm became more smooth with decreasing characteristic di mension of microchannel section
LI JI-quan, LI DE-qun, GUO ZHI-ying, LI ZHEN-hong
2007, 21 (3):
63-66;
Abstract (
196 )
PDF (4340 KB)(
78
)
This study presented a method to measure the warpage, in which the warping was character-ized by warping degrees and the rotation feature. An equation was formulated to estimate the warping degrees based on CAE simulation of the injection molding. The effectiveness of the method was con- firmed with a case study.
BAI Shi-bing, LIU Jing-lin, WANG Qi
2007, 21 (3):
67-72;
Abstract (
274 )
PDF (5724 KB)(
71
)
In this paper, the impact, friction and wear properties of POM were improved via blending with PEO. When PEO(molecular weight 5.0x105) content was 5%, the blend achieved a notched impact strength of 12.9kJ/m2 two-folds that of neat POM, and the friction coefficient and the wear scar width were 0.18 and 3.5 mm，about 50% and 35 % that of neat POM, respectively. It was sug gested that PEO form a surface lubricating layer on the blends and thus decreased the wear scar width and the friction coefficient.
BU HUA-ping, BAI YUN-hui, TAN HUI-min
2007, 21 (3):
73-76;
Abstract (
256 )
PDF (4380 KB)(
92
)
Low density polyethylene(PE-LD ) was blended with various inorganic nano particles and light stabilizer to enhance its resistance to photo-oxidative degradation in high altitude areas. Carbonyl index was determined using infrared absorption spectroscopy(IRS) and used as a characteristic of aging behavior. A small amount of .inorganic nano particles, such as SiOz and ZnO, played very good function for shielding ultraviolet(UV) light and inhibiting photo-oxidative degradation. These inorganic nano partides exhibited an obvious synergetic effect with light stabilizers. The effectiveness of the inorganic nano particles was in the order ofZnO> SiO2>Al2O3.
CHEN CHENG, LI BIN, ZHANG XIU-cheng
2007, 21 (3):
75-80;
Abstract (
321 )
PDF (4392 KB)(
77
)
In this article, Na-montmorillonite (Na-MMT) was modified by butyltriphenyl phosphoninm bromide ( BTPB ) and dodecyl triphenyl phosphonium bromide(DTPB).Sedimentation experiments showed that modified montmorillonite had better dispersibility and swelling property in organic solvent containing toluene and benzene. XRD and FTIR demonstrated that the quaternary phosphonium cationic had intercalated interlayer of montmorillonite and the interval distance of montmorillonite was obviously enlarged. TG curves show that the initial decomposition temperature of quaternary phosphonium modified montmorillonite rose by 102 C and 57℃，respectively, in comparison of that based on quaternary ammnnimm salt.
HUANG Yuan-lu, YANG Wei, NI Hai-ying, WANG Shao-hui, XUE Hong-fei, CHEN JUN
2007, 21 (3):
81-83;
Abstract (
320 )
PDF (2830 KB)(
95
)
Three compatibilizers,SEBS，poly(propylene-graft-styrene)(PP-g-PS), and Surlyn were emploved and compared in the blends of polypropylene/polystyrene. SEBS resulted in a great increase of impact strength,but a decrease in tensile strength. PP-g-PS also improved the compatibility and reduced the coalescence of the dispersed partides and the average particle size. In confrast. Surlvn resulted in moderate decrease of mechanical properties， no improvement in the compatibility was observed
LI CHUN, XIN ZHONG
2007, 21 (3):
84-88;
Abstract (
295 )
PDF (5782 KB)(
81
)
The effect of the loading and particle size of pearl shell powder on the mechanical properties of PPwas investigated.Whenthe content of pearl shell powder ( average particle size 3.4 um) was 10wt%，the tensile strength ofPP increased bv 2.81 %，flexural modulus by 21.34 %,and impact strength by 66.14%，compared wih neat PP. The improvement caused bv pearl shell powder was better than that by calcium carbonate and talc.
YUAN Guo-ding, SUN Ri-wen, WANG Yun, ZHANG Kai
2007, 21 (3):
89-93;
Abstract (
176 )
PDF (4020 KB)(
73
)
Simulation software MoldFlow was used to carry on the simulation to the different gate loca tion,andthecooling system of the magnetism therapy meter casing etc, and the injection pressure, clamping forceand weld line to the different gate location while filling were performed to analyze. Re-sults indicate that best gate location is in the outside of parts, and single gate. Several straight formulae cooling circuits were adopted to cool，and the disposed schemes were simulated. Results reveal that cool-ing result of scheme 2 is to be better, the most great difference in temperature of the core and cavity within 20℃，temperature profilesevenlyand makes pieces of deformation amount little. Finallly injec- tion experiment has been completed and high-quality products were obtained, which verified the rational- ity of the simulation.
