WEN Bian-ying
2007, 21 (4):
1-6;
Abstract (
202 )
PDF (5994 KB)(
92
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The preparative methods and application of gradient polymeric materials are reviewed. The gradient polymeric materials were prepared by either mass or energy transportation methods. The former occurs in processes like diffusion in solution, interpenetrating，phase transition, and sol-gel, the latter was carried out with electric, radiant，magnetic, electric-chemical energy and potential energies.The techniques in preparation such as interface polymerization, co-extrusion and static spray were also introduced.
ZHAO Ji-jie, SU Si-ling, BAI Da-wei, YAIeG Bin
2007, 21 (4):
7-12;
Abstract (
438 )
PDF (6035 KB)(
250
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Advances in improving the heat resistance of biodegradable poly ( lactic acid) ( PLA)were reviewed in this article. Several technologies, such as adding nucleating agents, blending with polymers with high glass transition temperature, introducing crosslinked structure, and reinforced by fiber or nano-particle were proved effective for enhancing the heat resistance of PLA, which enlarged field of application in textile, food packaging, and engineering plastics. Some commercial grades of heat resistant ploy(lactic acid) were introduced.
XU Jun, , YAO Pei, ZHU Chen
2007, 21 (4):
13-19;
Abstract (
341 )
PDF (5568 KB)(
144
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PP/PET/EPDM-g-GMA blends were prepared via reactive melt blending. The morphology of the blends was analysized using SEM and image processing software, which confirmed that the compatibility of PP and PET was improved by EPDM-g-GMA，Isothermal crystallization of the blends were observed using polarizing microscope, it was found that the dimension and distribution of the spherulites became finer via using nucleating agent. The dimension of PP spherulites decreased with the inclusion of PET. EPDM-g-GMA not only compatibilized but also toughened the system, making the impact strength increased from 2 .2kJ/mzto6 .5kJ/m2 and the tensile modulus increased by 38 .6%compared with neat PP. The tensile strength decreased with increasing PET content, YP/PET/EYDM-g-GMA had no obvious effect on this property.
FENG Yue-xia, YIN Ning, ZHAO Yu-hua, LI Qi-f eng, WANG JUN-wei, KANG MAO-qing, WANG XIN-kui
2007, 21 (4):
20-24;
Abstract (
327 )
PDF (3997 KB)(
125
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Polycarbonate diol (PCDL) was synthesized using 1，6-hexanediol (HD) and dimethyl carbonate(DMC) in the presence of calcined Mg/Al hydrotalcite as a catalyst.The properties of casting polyurethane elastomers (CPUE) made from PCDL were studied. CPUE made from PCDL exhibited better mechanical properties and heat resistance compared with polyether type elastomers. Meanwhile it was more resistant to hydrolysis than polyester type elastomers.
LIU Xi-jun, JIANG Zhao-hua, ZHU Wen-ming, QI Ying
2007, 21 (4):
25-30;
Abstract (
319 )
PDF (5249 KB)(
116
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It aconic acid grafted polyethylene(PE-HD-g-ITA)was prepared via melt grafting through twin screw extrusion. The grafting was confirmed using FTIR, and the effects of concentrations of monomers and initiator on the graft ratio and melt flow rate of PE-HD-g-ITA were studied. The PE-HD-g-ITA was introduced into PA6/PE-I} blends through twin screw extrusion. The impact strength of the PA6 /PE-日I)blends containing PE-HD-g-ITA was 1 .7 times higher than neat PA6. SEM showed that the interface between PA6 and PE-日D became smeared and the dispersion phase size significantly reduced，which indicated an effective compatilization. DSC showed PE-HD-g-ITA did not affect the melt point ( Tm ) of both phases , whereas the degree of crystallinity for PA6 phase decreased slightly，that for PE-HD phase increased obviously.
NIAN GUANG-nan, LI HAI-dong, CAI HONG-guang, ZHANG CHUN-yu, ZHANG XUE-quan
2007, 21 (4):
31-34;
Abstract (
261 )
PDF (4309 KB)(
82
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Polyethylene with a broad molecular weight distribution was prepared using hybrid catalysts in presence of montmorillonite nanocomposites forming a composite in situ. The exfoliation of the layeyed silicates in the composites was confirmed by XRD and TEM observation. The broad molecular weight distribution characteristic for the composites was revealed by the GPC profile (MW/Mn=7 .23)，which was mainly due to different response to hydrogen regulation for active sites generated by hybrid catalysts. The composite gave rise to an elongation at break of 900%and a tensile strength of 40 MPa.
YANG Le, LIANG Jun, YANG Wei-min, DING Yu-mei, YANG Gao-pin, SU Zhi-biao
2007, 21 (4):
35-38;
Abstract (
216 )
PDF (4327 KB)(
102
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Temperature difference blending (TDB) was applied to the preparation of PP/TLCP in situ reinforcement composites. Scanning electron micrographs (SEM) revealed that the deformation of TL-CP from droplets to fibrils in PP/TLCP system was affected by the content of the TLCP. While the loading of TLCP approached 30%，TLCP fibrils took preferred orientation in both skin and core of the composites. The tensile strength and modulus increased with increasing content of TLCP (below 20%) at a cost of decreasing elongation at break.
HE Wei, LIAO Gong-xiong, J IN Ke-jia, WANG Jin-yang, JIAN Xi-gao
2007, 21 (4):
39-43;
Abstract (
268 )
PDF (4006 KB)(
86
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Blends of poly(phthalazinone ether sulfone ketone)(PPESK ) and polyarylate ( PAR)were prepared via melt mixing. The miscibility, processability, and thermal/mechanical properties of the blends were investigated using dynamic mechanical thermal analysis (DMTA)，scanning electron micro-scope ( SEM )，and thermogravimetric analysis(TGA).DMTA revealed the partial miscibility of the blends. PAR strongly promoted the processability of the blends, however, reduced their thern}al stability.
LI Li-ping, LI Bin, TANG Fei
2007, 21 (4):
44-47;
Abstract (
323 )
PDF (2740 KB)(
144
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The effect of glass fiber (GF)，flame retardant ( Mg-MPP )，and EPDM-MA on impact fracture behavior of PA66 was studied through impact testing. The individual stages of impact event, such as crack initiation and propagation, were analysized. PA66 and PA66/GF were mainly controlled by the crack initiation stage, the value of DI being 0 .660 and 0 .675 respectively, exhibiting a brittle fracture.Mg-MPP and EPDM-MA had pronounced effect on the crack propagation phase, the value of DI being 0 .833 and 0.883 respectively, indicating the increase of ductility.
XUE FENG
2007, 21 (4):
48-53;
Abstract (
225 )
PDF (3543 KB)(
90
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Reactor blends of PE-HD/poly(ethylene-co-1-butene) with broad or bimodal molecular weight distribution for large hollow containers were synthesized in a two-stage slurry polymerization process.The mechanical and rheological properties of the blends were measured. It showed that the density, melting point decreased and the environmental stress cracking ( ESCRFSo)increased with increasing 1-butene content in the blend. The stiffness of the blends depended on the degree of crystallinity. A balance of the mechanical and processing butene content and the weight ratio of properties could be obtained by adjusting hydrogen added, the 1butene onents and the weight ratio of components.
HUO Yin-lei, ZHANG Xin-changHUO Yin-lei, ZHANG Xin-chang
2007, 21 (4):
54-57;
Abstract (
390 )
PDF (2777 KB)(
100
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This paper studied the relationship between mechanical properties and density of expanded polystyrene and polyethylene. Theenergy-absorption increased with increasing strain, and the energy absorption efficiency increased with increasing stress. At constant stress the plot of energy absorption efficiency against densityexhibited a parabola-like curve with a maximum, which provided an effective way for the choice of foam materials.
CUI Hai-long, QIN Li-jie, J IAO Hong-wen, CHEN Hu-sheng, XU Wen-gao
2007, 21 (4):
58-63;
Abstract (
303 )
PDF (4001 KB)(
140
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PE-LD, m-PELLD,and EVA were compared as agricultural film in their weathering resis- tance.The mechanical properties of m-PE-LLD were better than PE-LD and EVA, however, the haze of EVA was lower than PE-LD and m-PELLD.The aging behavior was tested with tensile property reservation.Theagricultural films made ofm-PELLDand EVA exhibited a higher reservation in elon gation at break but a lower in tensile strength than that of PE-LD.
ZENG Jun, WANG Xiao-qing, JI Jun-hui, SHI Fens-hui, YAN Qing
2007, 21 (4):
64-68;
Abstract (
319 )
PDF (4027 KB)(
198
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Poly(butylene succinate)(PBS)microcapsules were prepared via emulsion solvent evapora- tion process, with different amount of pigment loading. The dian meters and morphology of microcapsules were characterized uisng SEM, TEM and particle size distributio in analyzer. Colorimeter and fluorescent photometer were used to measure the chroma and fluorescence. It was found that microcapsules showed regular morphology and dispersibility, when the ratios of pigmen t to PBS were 1:1, 2:1 and 3 :1( due to product M,M2,M3). The mean diameter of M1, M2, M3 was 12.3 μm, 10.5 μm and 12.5 μm, respectively. The pigment in microcapsules( M1, M2, and M3) was more vivider than pure powder of pigment, and their fluorescence was still maintained.
JIA Li-ya, LIU He-ping, DU Zhong-jie, ZHANG Chen, LI Hang-quan
2007, 21 (4):
69-72;
Abstract (
368 )
PDF (4139 KB)(
108
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Silica was modified with hexamethyldisilazane and hexamethyltrisiloxane(D3) via dry method. The influence of pre-treatment temperature on gel time and mechanical properties of modified silica filled polydimethylsiloxane system wasstudied.Modified silica was examined by Fourier transfor- mation infrared spectroscopy(FTIR)，X-ray photoelectron spectroscopy(XPS),and dispersion in sol vent. The mechanical properties of modified silica filled polydimethylsiloxane system were also investi- gated. The results reveal that Me3Si-and-Me2Si moieties were grafted on the surface of silica. When pre-treatment temperature was increased, the gel time of silica filled polydimethylsiloxane system increased and mechanical properties decreased. With silica content increasing, the tensile strength and stress at 100 % elongation increased.
PENG Bo, GUO Shao-yun, LIU Zhi-minig
2007, 21 (4):
73-76;
Abstract (
308 )
PDF (3977 KB)(
70
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By the aid of ultrasonic vibration, a novel propylene based plastomer (DP)/nano-SiOz composits was prepared by means of melt blending. The effects of ultrasonic wave on morphology, dynamic mechanical properties, and crystallization properties of the composite were studied. Ultrasonic vibration promoted the dispersion of nano-SiO2 in DP matrix, thus increased the storage modulus and decreased of loss modular. In addition, the presence of nano-Siq increased the crystallization temperature, however,the crystallization enthalpy decreased
ZHANG Qing, BA Xin-wu, BAI Li-bin
2007, 21 (4):
77-81;
Abstract (
192 )
PDF (3840 KB)(
70
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Polypropylene was melt grafted with 2-trimethyla immonium ethyl methacrylate chloride(DMC)and styrene(St). When the content of initiator ( dicumyl peroxide, DCP) was 0.6 phr, molar ratio of DMC and St was 1:1, a maximum grafting of DMC was achieved. The tensile and impact strength of the grafted PP were similar to neat PP. During cry istallization, the nucleation density and the total crystallization rate of the grafted PP were larger, the half time of crystallization ( t1/2) was shorter and the crystallization temperature( Tc) was higher than neat PP.
YAO ZHAN-hai, YIN JING-hua , SONG YONG-xian, SONG CHUN-yu
2007, 21 (4):
82-86;
Abstract (
180 )
PDF (4013 KB)(
78
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Reactive type dropping agent containing β double bond(βS) was synthesized. Polyether tetrols(PETO)and maleic anhydride(MAH) were used as sta art materials, p-toluene sulfonic acid as catalyst and hydroquinone as inhibitor. The effects of monomer ratio, amount of catalyst and reaction time on conversion were studied. FTIR and H1-NMR were used to confirm the chemical structure of βS. The conversion of the products was calculated based on the resicdual fraction of MAH. The conversion of the reaction was higher than 95 %, and yield higher than 90 %. The films of PE-LLD-g-βS were pre- pared. The dripping durability of PE-LLD-g-βS film and common dripping film at 60 ℃ were 76 days and 17 days, respectively.
LUO Ying, DONG Xian-ming, ZHANG Shu-YANG Zhao-zhang, DENG Guo-zhi
2007, 21 (4):
87-90;
Abstract (
209 )
PDF (4278 KB)(
134
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By means of soapless emulsion polymerization, graft polymerization of styrene(St) onto the surface ofalkyl nanoTiO2 was carried out, resulting in composite particles with TiO2, core and a polymer shell.Polystyrene(PS)ischemically attached onto the nanoparticles by a double bond introduced during the pretreatment with a coupling agent. Through analyzing the reaction mechanism, the emulsion poly- merization site was found to besituatedatthe TiO2 surface. The factors affecting the grafting yielding o PS on the particles were also investigated, including monomer concentration, emulsion agent content, and reaction time, an optimum grafting reaction condition was determined. The structural characteris-tics of the grafting polymers can betailored by changing the reaction conditions. This provided possibili-ties for optimizing the structure-property relationships of polymer composites filled with the modifiec nano-TiO2 particles in the future works.
YU Jie, DU Pe-hua, LUO Zhu, HE Min, JIANG Guan-sen ,
2007, 21 (4):
91-95;
Abstract (
254 )
PDF (4162 KB)(
83
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The effect of strain rate(v) on the tensile behavior of PBT was studied. As the loading rate grew, the fractography transformed from ductile to brittle. The flat region ratio(Ap/Ao)increased rapidly with increasing loading rate initially and leveled off at 1000 mm/min. The study also showed that the roughness of fracture surface(Rs) increased linearly w ith strain rate according to Rs=2.10-4.72x10-4v. The yield stress( σy) increased rapidly with increasing strain rate and leveled off at 1000 mm/min. And the relationship between the yield stress and the strain rate was consistent with Eyring theory, and could be explained by the molecular chain sliding mechanics.
YAO ZHAO-fu, JIN ZHI-ming, DU-NING
2007, 21 (4):
96-102;
Abstract (
202 )
PDF (5027 KB)(
70
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The melting behavior of the plastics in iniection and extrusion screws was discussed and com-pared.The influences of processing conditions and screw structure on the melting behavior were studied. The position of melting delay and the axial temperature difference along injection screws were deter mined and correlated with processing conditions like back pressure, rotation rate, temperature, and reservation time. Proper structures for screws with high efficiency were suggested
