XU Ya-jun, YANG Wei, SHAN Gui-fang, XIE Bang-hu, YANG Ming-bo
Abstract (
2245 )
An introduction was given on various shrinkage process in injection molding，including the shrinkage before gate freezing，that of the part in mold during the cooling stage，and that after dcmoulding. The origin of the shrinkage was sorted to thermal contraction，crystal shrinkage，orientation shrinkage，negative shrinkage，and post shrinkage. The effects on the shrinkage of PP parts were discussed，including molecular characteristics，blending，compounding，and nucleation.The influence of injection parameters，such as including injection temperature，molding pressure，molding time，mold temperature，cooling time，filling speed，and part thickness were also summarized. In the end，the methods of controlling the shrinkage of PP in production process were also referred.
OU Bao-li, LI Du-xin
Abstract (
3035 )
The latest research developments of the polyamidc 6/ polypropylene/ nano-montmorillonitc nanocompositcs were reviewed，with their preparations，static/dynamic mechanical properties，morphology, and rhcological properties discussed. The future work in this field should be focused on the developing functional nanocompositcs and exploring the enforcement and toughing mechanisms of inorganic nanoparticlcs.
YANG Chun-bai
Abstract (
3136 )
The production and processing technology of rigid polyurethane foam and its application in architectural field were reviewed. The foaming technology was mainly applied to external-wall interior insulation，sandwich thermal-insulating，and external-wall exterior insulation. Technology process for external-wall insulation was discussed in detail. The development trend of rigid polyurethane foam was forecasted.
ZHAN(s Yi, YU Jun-rong, MIN Hui-ling, HU Zu一ming
Abstract (
4337 )
Poly(methylmethacrylate/methylacrylate)/organ-montmorillonitc(P(MMn-Mn)/OMMT)nanocompositcs were used to modify poly(vinyl chloride)(PVC)by blending. The compatibility，thermal stability，the dynamical mechanical，tensile and impact properties of the compound were investigated by scanning electron microscope(SEM)，thcrmogravimctric analysis (TGA)，dynamic mechanical thermal analysis(DMA)， tensile and impact test. P(MMA-MA)/OMMT nanocompositcs and PVC exhibited good compatibility，the thermal stability, storage modules，glass transition temperature，and mechanical properties of the composites increased with increasing of nanocompositc content. When the mass ratio of the nanocompositcs and PVC was 20/100，the temperatures of 10%weight loss and glass transition increased by 17. 4℃and 4. 7 ℃ based on neat PVC. The addition of the nanocompositcs also improved the mechanical properties of PVC. The compound showed a set of optimal mechanical properties when the mass ratio of the nanocompositcs and PVC was 30/100，with the tensile and the impact strength being enhanced by 34. 7%and 21.1%，respectively，compared with neat PVC.
WANG Liu-yang, LU Wen-hua
Abstract (
2866 )
Non-isothermal crystallization kinetics of polypropylene/polypropylene grafted
2-acrylamido-2-mcthylpropancsulfonic acid(PP-g-AMPS)at different cooling rates was studied using differential scanning calorimctry. Jcziorny and Mo methods were used to analyze the DSC data. It showed that both methods described the crystallization behaviors successfully. AMPS side chains did not change the crystallization behaviors obviously，however，increased the crystallization rate. The crystallization activation energy of grafted PP was increased.
WU Xue-sen, WANG Wei
Abstract (
2167 )
PLA and crosslinkcd starch were blended using a rhcomctcr to form a blend，glycerin was used as a compatibilizcr. It was found that tensile and flexural strengths of the blend decreased with increasing starch content，however, the crosslinking of starch somewhat depressed such decreasing. When the loading of crosslinking agent in starch was 6 phr，the mechanical properties were optimal. SEM showed that the crosslinkcd starch was well compatibilizcd with PLA.
ZHANG Dong-liang, QIN Zhi-feng, XIA Lei
Abstract (
3816 )
Through dispersion of nano-Ti()z in an aqueous PVA solution with supersonic vibration，PVB/nano-TiO2 composites were prepared. The microstructure，morphology，and properties of the composites were studied using FT-IR, UV-VIS, DSC, TG, and AFM. The nano-TiO2 was well dispersed in PVB. The mechanical properties were improved obviously by nano-TiO2，the elongation at break was increased by 6 times based on neat resin.Mcanwhilc，the composites showed excellent shielding to the ultraviolet ray. The heat-resistance of the composites was also improved.
WU Dong-sheng, YANG Qi, WANG Lin-chum, JIANG Yao-gui, GAO Ling-qiang
Abstract (
3018 )
Two special mastcrbatchcs were made by blending epoxy resin(EP>，polystyrene(PS>，and ethylene-propylene-dicnc monomer(EPDM)or acrylic acid grafted ethylene-propylene-dicnc monomer (EPDM-g-nn)， which were separately used in the PS/EPDM blends as a compatibilizcr.
While both compatiblizcrs improved the impact strength of PS/EPDM blends，the EPDM based one gave rise to an increase of 109%，compared with the plain blend. The EPDM based compatibilizcr made EPDMdispersed finer in PS matrix，resulting in more plastic deformation in the notch surface than EPDM-g-nn based one. When the curing agent content was 15%一20%，the best compatibilization was achieved，evidenced by the lowest toluene extraction mass.
ZHOU Qun, HU Bo-xing, HE Qi-hui
Abstract (
2983 )
Cyanatc ester resin (CE) was modified by hydroxyl-terminated polybutadicnc(HTPB>.The reactivity between the components and the properties of the system were studied using Fouricr transform infrared spectroscopy(FT-IR >，DSC-TG, atomic force microscope(AFM).It showed that the flexibility of the blends was increased without a loss in the thermal stability. When the content of HTPB is 25%，the impact strength of the blends was close to 19 kJ/m2.
CHENG Feng-mei, CHEN Da-jun
Abstract (
3157 )
Polyethylene(PE) was blended with hollow glass beads. The effect of various processing parameters on the properties of the blends were investigated, including the surface treatment of glass beads, toughness and crystallinity of the matrix，diameter and content of glass beads, using scanning electron microscope，polarizing microscope, and mechanical property testing. It is obvious that the silane coupling agent was beneficial to the dispersion of glass beads in the matrix. In order to achieve a high toughness of the blends, the matrix should possess an initial toughness above 5.0kJ/m2.The impact strength of composites is 38.0kJ/m2, When the Glass Bead content is 25% , diameter is 2.5μm .
Tian Hua, Yang Biao, Xu Guozhi, Lin Yi
Abstract (
4004 )
A biodegradable material was prepared by blending corn starch with polyvinyl alcohol (PVA), water, and glycol. With 25phr of PVA and 30 phr of water, the tensile behavior underwent a brittle-ductile transition, the tensile strength and elongation at break increased from 25.80MPa and 1.11% for neat corn starch to 31.78MPa and 6.24%. When borax and glycol were added, the tensile strength and elongation at break were further increased to 36.26MPa and 11.71%, respectively.
HUANG Ying-zhu, XIN Chun-ling, FU Zhong-yu, HE Ya-dong
Abstract (
2270 )
Differential scanning calorimeter was used to characterize the non-isothermal crystallization of polypropylene/ultra high molecular weight polyethylene (PP/UHMWPE) blends, with the data analyzed with Ozawa、Mo Zhishen, and Kissinger methods. Extrusion foaming experiments on PP/UHMWPE blends were carried out on a self-made super critical liquid foam equipment. It showed that in presence of UHMWPE, the crystallization activation energy of PP decreased, the crystallization rate decreased, and PP began to crystallize at a higher temperature with the addition of UHMWPE. The existence of macromolecullar chain of UHMWPE and entanglement with PP obstructed molecullar chain of PP into the lattice,so the crystallization temperature increased and the crystallization temperature range broadened, which resulted in obvious improvement of foam performance of PP. When the content of PE-UHMW was 5 phr, the obtained apparent density of the extrudate was 0.038g/cm-3.
ZHAOJian
Abstract (
2769 )
L27(313) experiments were performed in order to determine an optimum condition for minimizing the volumetric shrinkage in multi-cavity injection molding part of polypropylene (PP). It showed that the mold temperature and packing time had the greatest influence on the volumetric shrinkage. Based on a standard analysis of variance(ANOVA), it was found that the relative significance of the factors on the volumetric shrinkage was in the descending order: packing time, mold temperature, melt temperature, and packing pressure. Using the optimized level of factors, the volumetric shrinkage was decreased by 21.46％.
XU Wang-ding, QIAN Xin
Abstract (
2263 )
The iso-thermal blend process of two polymer melts in HAAKE mixer were numerically 3-D simulated using FEM software POLYFLOW. The mixing mechanism of PE-LLD/SBS melts in HAAKE mixer was revealed by analyzing position, rotating speed, ratio of disperse phase, and temperature. The simulated data was agreed well with experimental results.
Huang Xiao-Yan, Li De-Qun
Abstract (
2551 )
According the characters of parts produced by gas-assisted injection molding, an algorithm of gas-channel mesh was formulated. Combining the manual setting of gas-channel path and automatic building of gas-channel node, semiautomatic generation of gas-channel mesh was realized. The algorithm was applied in CAE system, some case studies were used to verify that the generation was correct and reliable, which is prerequisite for numerical simulation of gas-assisted injection molding process.
JIN Xiao-yu, JIANG Hong-wei
Abstract (
2104 )
Into a flame retardant polypropylene composites containing poly (ethylene urea-formaldehyde) and ammonium polyphosphate, a small amount of magnesium stannat was introduced as a synergetic flame retarding agent. The flame retardant properties and the resultant char layers of the composites were studied through cone calorimeter, TG, FTIR, SEM, and EDX energy spectroscopy. The measured results showed that a loading of 1wt% magnesium stannate increased combustion residue, improved the quality of char layers, and led to higher efficiency of flame retardancy, in addition, the burning time with flame was prolonged from 415s to 805s. Upon loaded with 1wt% of magnesium stannate, for reaching a level of UL-94 V-0, the loading of flame retardant decreased from 32% to 28%, limited oxygen index rose from 33.4% to 35.1%, tensile strength of the composites increased from 24.3MPa to 26.0MPa, elongation at break increased from 23% to 45%, compared with devoid systems.
SONGShuai, LUOZhu, YUJie, TIANYao_Zhu, QINJun, HEMin
Abstract (
2178 )
Non-isothermal crystallization behavior of polypropylenes, neat and containing three types nucleating agent was studied using differential scanning calorimetry (DSC) with the data analyzed with Jeziorny method. It showed that all three nucleating agents increased the crystallization temperature and rate of PP, indicated by decreased t1/2 and increased Zc. The rosin type nucleating agent was proven to be the most effective. In addition, at same cooling rates, the presence of nucleating agent decreased the n value of PP.
WANG Yi-long, SHANG Lin-lin, HUANG Ming, SHENG Zhe-yang, HU Wen-hao
Abstract (
2096 )
Recycled PET drink bottle flakes were extruded with 30(experiment) and 90(industry) extruders with a same screw structure in order to study the effect of water content of the flakes on the intrinsic viscosity of the product. It showed that the intrinsic viscosity of PET from experiment extruder is lower than that industry one. When water content in flakes was 2.5% and 0.2%, industry extruder resulted intrinsic viscosities of PET product of 0.70 and 0.82 dL/g, respectively. If pyromellitic dianhydride extender was used, the intrinsic viscosity obtained from industry extruder was increased to 0.94 dL/g.
DENG Ke, BU Hai-tao, HONG Jian-cheng, LIU Xian-feng, WU Shi-jian
Abstract (
3029 )
The stress distribution, stress concentration position and stress concentration factor of the dumb-bell specimens during tensile testing were simulated with ANSYS. It showed that there was obvious region of stress concentration distributed at the circular arc, with a factor of 1.123.PS specimens were prepared by compression and injection molding. The tensile fracture process and fracture region of specimens were found agree with the simulate-analytical results. The compression molded dumb-bell specimens were homogeneous and isotropic, and fracture occurred on the circular arc transition, on which the stress concentration factor was the maximal. The injection molding dumb-bell specimens fractured on the straight portion far from the gate on which the thickness of the skin layer and the shearing layer were thin. And the influence of stress concentration was weak.
ING Jun-tao, XIE Lin-sheng, MA Yu-lu, LIU De-li, LU Ya-yun
Abstract (
2972 )
Statistical analysis was performed on the mixing process of polymer melts in a two-rotor continuous mixer using Polyflow software. Based on the 3-D isothermal time-dependent flow fields calculated at different rotational angles of rotors, dynamic mixing processes of polymer melts in the two-rotor continuous mixer were simulated through particle tracking analysis (PTA). By statistical treatment of 1000 particle trajectories, the resident time distribution, cumulative max-shear-stress distribution, and percentage of shear stress as a function of time were obtained. Furthermore，the influences of these parameters to the mixing performance in a two-rotor continuous mixer were analyzed.
Chen Qingpei, Yan Baorui, Yang Yuguang, Zhang Anzhen
Abstract (
3210 )
Based on National Instruments’ M-series data collection card, Signal Conditioning module, and Advantech IPC, a multi-function, multi-channel universal data collection system was developed. The software of the system employed Labview graphical programming language. Using opening configuration parameters, the universality of the system was greatly improved. The system exhibited characteristics of good interface, easy operation, and high measuring efficiency, as well as high measuring accuracy and good stability. It could be used to collect and monitor dynamic parameters of plastic injection molding machine.
