CHEN Bin-yi, WANG Xiang-dong
Abstract (
2100 )
The important factors influencing the preparation of polypropylene/clay nanocomposites were discussed，including the nature of the polymer and clay, melt processing equipment and conditions. Low molecular weight and high M八H grafting degree of polypropylene were beneficial to intercalation，how-ever, once intercalated，high molecular weight and low MAH grafting degree were beneficial to the ex-foliation. The higher the canon exchange capacity(CEC) of the clay, the higher the degree of exfolia-tion was achieved. Twin-screw extruder constituted a good mean for the preparation of polypropylene/clay nanocomposites, which provide proper shear rate to obtain exfoliated structure. However, too high shear rate and too long resident time of the materials in the extruder may cause instability of the exfoliat-ed structure. In addition，an "electric melt pipe" equipped in the twin-screw extruder may promote the formation of exfoliated structure through its electric field. Processing parameters like loading sequence (direct blending or masterhatch method)，screw speed，barrel temperature, and the materials resident time all have impact on the structure of the nanocomposites, especially, high rotating speed of the screws and lower barrel temperature may enhance the exfoliation.
YANG Feng-xia, XU Guag-ri, WANG Tian-xi
Abstract (
2958 )
advances in predicting, optimizing, and controlling the location of weld-lines in injection-molded parts were reviewed.The mathematical model of weld-lines’formation in filling process was introduced. The analysis flow, predicting method and practical examples of the technologies such as numerical simulation, simulation combined with the theory of mathematics programming, valve- injection and the control technique of multi spruc feeding sequence for large injection parts wereintroduced in detail. Such simulation technology based on a combination of theory and mathematics programming had become a focus of research with increasing applications. Valve-injection and thecontrol technique of multi spruc feeding sequence for large injection parts can be successfully implemented to avoid weld-lines, and have wide application prospect in industrial practice.
SHEN Zhao-hong, WAND Rui一lan, WU Dong-liang, QIAN Xin
Abstract (
3245 )
Abstract:Differential scanning calorimctry (DSC) and wide-angle N-ray diffraction (W八ND) were usedin the characterization of crystallization behavior of uniaxially oricntded poly(lactic acid)(PI一八).In DSC experiment, two melting endothermic peaks were observed according to two crystal diffraction peaks at29 .9 0 and 31 0 in W八XD chart. It was found that orientation increased the degree of crystallinity andchanged PI一八’、crystal form. When temperature was above 110℃and the uniaxial stretch was more
than 4 times, some a crystal transformed to俘crystal. Talc could accelerate this process.!\ddition of 1 phr talc increased the degree of crystallinity from 18. 5%to 37.48%，and promoted the transforma-tion of crystal forms.
QIAN Li-jun, DONG Yu-ping
Abstract (
3184 )
Phosphorus-containing copolycsters were synthesized via solution polycondensation from 2-}6-oxide-6H-dihenz( c，c)(1，2) oxaphos-phorin-6-yl〕-dihydroxyphenylene, schacoyl chloride, and p-dihen-zoyl chloride. The structures and thermal behaviors were investigated by FT-IR，GPC, DSC, TGA，POM, and WXRD. The properties of the copolycsters can he adjusted by changing the mol ratio of scha-coyl to p-dihcnzoyl.八、the ratio was lower than 4:6，the copolycster was crystalizahle with a melting point about 355℃.When the mol ratio changed from 10/0 to 1 /9，the Tg increased from 30℃to172℃，the char yield at 600℃increased from 4.7%to 49.3%.
HU Li一hong, ZHOU Yong-hong, LIU Hong-jun, ZHANG Meng, LIU Xin
Abstract (
2248 )
Differential scanning calorimetry (DSC) was used to study the curing behavior of lignin phe-nolic resin ( LPF) at heating rates of 5 , 10 , 15，and 20℃/min between 25℃and 250℃.八11 the ini-tial temperature T;，peak temperature Tp，and final temperature T} of curing increased with increasing heating rate. The curing behavior of LPF was affected by the amount of curing agent. When the content of curing agent was 12%，the curing behavior of LPF was similar to that of neat PF, but with a greatly lower TN. Little change in reaction heat was observed by altering heating rate and amount of curing agent. The kinetic analysis was performed by means of Ozawa equation and activation energy was obtained as 85 .64KJ/mol.
YU Bao-Gang, LU Lin-Gang, DONE Xi-lin, GAO Wei-ying, YANG Shou-Sheng
Abstract (
2206 )
A novel flame rctardant 1，3，5一tri(5，5-dimcthyl-1,3-dioxacyclophosphorinane phosphonatc) benzene(FR) and APP were introduced into polypropylene, and the combustion properties of the com-
positc were studied using limiting oxygen index(LOI)，UL94 test, and cone calorimeter test. Itshowed that FR with APP improved the LOI values and UL94 combustion properties, prolonged igni-tion time, and reduced the heat release rate and CO, COZ concentration in smoke. The synergistic effects were prominent. The LOI reached 29.6%and UL94 reached V-0 when 15%FR and 10% APP were added to polypropylene.
JIANG Xue-liang, ZHANG Yin-xi
Abstract (
3157 )
The non-isothermal crystallization behavior of dynamically cured polypropylene(PP)/epoxy(EP) blends compatibilizcd with malcic anhydride grafted PP(PP-g-M八H) was studied with difFcrcn-tial scanning calorimetry. The experiment data were treated with Ozawa and Kissinger equations, the
crystalline structure of PP in the blends was also studied. It showed that the cured epoxy particles acccl-crate the crystallization of PP component. The non-isothermal crystallization kinetics of both neat PP and PP in the blends can be well approximated by Ozawa equation, and the kinetic constant K(T) of PP in blends was higher than that of neat PP.八ccording to Kissingcr'、method，the crystallization acti-vation(OF_)of PP in the blends was lower than that of neat PP, and a minimum of OF_ was observed at an epoxy resin weight concentration of 20 phr. Polarized optical microscopy showed that the size of neatPP spherulites was obviously larger than those in blends.
ZHANG Wei, ZHANG Li一Ye
Abstract (
2805 )
Long-chain branching poly(lactic acid)(PLA)was prepared via electron beam irradiation of linear PLA，whose rhcological behavior was characterized using dynamic shear testing.At low-frequency region，the long-chain branching PLAexhibited higher elastic shear modulus G} and lower loss angle
tangent tan } than the corresponding linear one. The melt strength increased with increasing content of bifunctional monomer (BDDA)and/or radiation dose. It also found that poly(L-lactic acid)(PLLA) was more sensitive to electron beam than poly (D一lactic acid)(PDLLA).
JI Xiao-li, XU Guo-cai, WANG J un
Abstract (
3144 )
Epoxy/nano Si3}4 composites were prepared and their properties were investigated. The uni-form dispersion of nanoparticles in epoxy matrix was observed via TEM. When the loading of surface treated nano-Si3}4 was 3 wt%，the impact，tensile, and flexural strengths of the composites were in-
creased by 14S%,241%，and 2SS%，respectively; the electrical breakdown voltages under八C and DC were increased by 249%and 146%，respectively. The dielectric loss factor tan } and the dielectric constant s of nanocomposites were decreased.TG determination showed a better heat-resistance for the nanocomposites. The improvement in these properties was discussed with a model of "kernel- transition-al shell" structure.
SHEN Feng-lei, CAO Qing-hua, XU Shi一hua
Abstract (
1907 )
Silica sol was introduced into polyamide acid and a polyimidc(PI)silica(SiO2)hybrid film was obtained after amidization of PAA.The influence of silica content on clement composition，chemical structure, crystal structure, and morphology of the hybrid film was determined using EDS, FT-IR，XRD, and八FM. During imidization, random inorganic silicon-oxygen network was formed.Size of SiO2 particle increased with increasing SiO2 content. When Si02 content was lower than 5 wt%，the size of Si02 was less than 50 nm, which was increased to 200 nm via coagulation when the SiO2 content
reached 7 wt%.
GAO Yong, LU Ai, HUANG Yi一Gang
Abstract (
2125 )
The parameters affecting the damping property of rigid polyurethane foam (RPUF) were in-vcstigatcd.It showed that the damping factor increased with increasing porosity and cros、一linking dcnsity.八t the same porosity, the damping factor increased with increasing filler content. When the content
of nano-CaC03 was 5 vol%，the loss factor was above 0 .04 between一20一100℃.
ZHOU Guo-Fa, HU Quan-Lian
Abstract (
3145 )
In order to formulate the controlling model of the gas assisted controlling unit, experiments on the influence of processing parameters in the ga、一assisted co-injection molding were investigated in this paper. It showed that the gas packing time and gas delay time affected the gas penetrating pattern
appreciably, but not the melt at the core layer. With increasing gas packing time, the gas penetrating depth and width increased，with increasing gas delay time, gas penetrating depth increased，the gas penetrating width reduced，however, the instability of gas penetrating flow and finger appearance were observed.
ZHANG Si-deng, DING Yong-hong, LI Jin-chun, YU Qiang
Abstract (
2323 )
Effects of particle size and content of calcium carbonate, the type and dosage of dispersant resin, and processing temperature on the rhcological behavior of the heavily loaded calcium carbonate masterbatch were investigated using a rotating rhcometer with parallel plate geometry. Two "shear thinning" regions were observed from the rhcological curves, with one in the low shear rate region being attributed to the collapse of interface combination between the filler and resin, and the other being related to the di、一entanglement and orientation of polymer chains in the high shear rate range. The zero shear rate viscosity of the masterbatch was much larger than that of PE-LLD and increased rapidly with increasing filler content and/or decreasing particle size. The apparent viscosity in high shear rate region showed little change with filler size, but dramatically decreased with the addition of dispersant resins.The flow activation energy of the mastcrbatch was 25 .7KJ/mol，close to that of PE-LLD.
LI Bing, ZHOU Nan-qiao, WEN Sheng-ping
Abstract (
3814 )
Using a home-made dynamic simulation foaming extrusion equipment，experiments of PS micro-foaming were carried out with different temperature, pressure, and force fields. Microccllular structure of PS was obtained at 8 MPa. The temperature necessary for producing open-cells was found to be
150℃，160℃，and 165℃for pressures of 16 MPa,12 MPa, and 10 MPa, respectively. The addition of a vibration force field improved the cell nucleation.八t the same time, the vibration lowered the opcncell temperature. The open-cell temperature would be lower when the amplitude and frequency wereimproved.
XIAO Li一ren
Abstract (
1985 )
The experimental methods such as artificial accelerated weathering, outdoor exposure, andlandfill in natural soil were conducted to test the aging and degradation properties of PE film containingrarer earth photosensitizer, CaC03，and a biologically activating agent. Characterizations with SEM，
TG-IR，and Ubbclhode viscometer showed that the rare-earth photosensitizer promoted the light-induced oxidative degradation of the PE film. The incinerable and degradable PE film possessed thecnvi ronmcntal-，photo-，and biological-degradability.
YANG Hua-lin, DENG Fang, LI Yong, SHI Jun-you
Abstract (
3013 )
The optimum of the structure of plastics parts may prevent the disfigurement, reduce the cost, and increase the efficiency.八、tructural architecture and knowledge management system was established including various processing parameters such as concavo-convex profile, taper, wall thick-ness, reinforcement plate, hole design method，etc. Classic design cases were also provided.Designing reports and check list can be generated automatically and reserved for reuse.
CHANG Xiao-rong, ZHANG Yong, CHEN Shi-an
Abstract (
2146 )
Two kinds of dispcrsants，Altfona 3050 and ALTFONA 3020 were introduced into polypropylene(PP) /carbon black(CB) composites to improve the dispersion of CB. When the contents of CB and Altfona 3050 were 8 phr and 2 phr, respectively, the composite gave a volume resistivity of 1 .08 X 10 cmwithout a loss in tensile strength. Scanning electron microscope(SEM) showed that Altfona 3050 couldpromote the dispersion of CB in a nano-scale in PP.
MA Zhi-ling, L I Hong-en, HAN Jie
Abstract (
2889 )
The influence of silane coupling agent KH-550 and KH-560 on the structure and properties ofpolypropylene(PP)/intumcsccnt flame-rctardant(KDIFR) composites was studied. X-ray diffraction(XRD)indicated that KDIFR promoted the formation of俘一form PP，which was strengthened by KH-550，but weakened by KH-560.SEM showed that the adhesion between KDIFR and PP was enhanced by the silanes. POM showed that the size of the spherulites of PP and the dispersion of KDIFR particles became more uniform with the increasing silane content. The mechanical properties of the composites were also improved.八recipe of PP/KDIFR/KH-560二70}30}5 was found to be optimal，the impact and tensile strengths were increased by 24. 2%and 9. 6%，rc}spectivcly, compared with neat PP/KDIFR eompcasites. The flame retardancy of the eompcasites was also improvcxl when silane was added.
WANG An-xin, XUE Ping, JIA Ming-yin
Abstract (
2019 )
The preparation and compatibilization technique of immiscible polymer blends from plastics wastes were reviewed in this paper. The blending technologies including grinding, extrusion，injection，and compression moldings and the related equipments were introduced.The compatibilization of PP/PVC blends by introducing a third component was discussed in detail. Some suggestions were made forthe development of the recovery and utilization of commingled waste plastics.
XU Zhi-juan, LIN Xue-chun, LIN Feng, LIU Wu
Abstract (
3006 )
The movement characteristic of a mould with complicated core-pulling mechanism was analyzed. The required movement of this mold can not be realized on a regular injection molding machine.The hydraulic and control systems of a regular injection molding machine was modified to meet the re-
quirement. The existing controlling components including core-pulling, core blowing, and cavity blowing, as well as internal and external hydraulic systems were fully employed，the in-core and out-core of core-pulling mechanism could be completed in one process of mould opening or closing.
