Materials and Properties
HE Hezhi, XU Li, YANG Yike
Abstract (
745 )
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A prestress technique together with film stacking was adopted to prepare the carbon fiber （CF）?reinforced polycarbonate （PC） laminates. The tensile strength of the resultant laminates applied with different prestress levels was measured. The tensile fracture morphology of the laminates was characterized with scanning electron microscopy， and the alignment of CF in the PC matrix was observed using an optical microscope and a camera. The result indicated that the alignment of CF was improved with an increase in prestress level. The tensile strength of the laminates showed an increasing rend at first and then a decrease with an increase in prestress， and it increased by 10.66 % and 11.78 % compared to the lowest parts on both sides. However， the tensile modulus showed no relationship with the prestress.
LI Suyuan, LIU Huipeng, GONG Shun, HUANG Guotao, LI Yucai, WU Xin, DENG Jianping, PAN Kai
Abstract (
920 )
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988
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This paper reported a study on the effect of addition amount of foaming agent on the ethylene?vinyl acetate copolymer （EVA） foaming materials modified with thermoplastic polyamide elastomer （TPAE）， and the foaming performance and mechanical properties of the resulting EVA/TPAE foaming materials were also investigated at a fixed mass ratio of EVA to TPAE of 100 to 5. The results indicated that the foaming materials foamed more fully at a mass ratio of foaming material to foaming agent of 100 to 3， leading to a uniform cell size. The obtained foaming materials could meet the requirement of the shoe materials for mechanical strength. At this mass ratio， the foaming materials exhibited good comprehensive performance， suggesting a good application prospect in the shoe market.
LIU Chuan, XU Miaojun, WANG Jingchun, LI Bin
Abstract (
635 )
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515
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Silicone rubber （SR） composites were prepared by the incorporation of expandable graphite （EG）， followed by curing with peroxide， and their flame?retardant performance and combustion behavior were investigated. The results indicated that the SR composites containing 5 phr EG reached a UL 94 V?0 rating in the vertical burning tests， and their limited oxygen index value reached 33.0 vol%. The cone calorimeter test resulted demonstrated that the addition of EG suppressed the release of heat and smoke effectively. The mechanism of flame retardant was studied， which indicated that the EG distributed on the materials surface expanded completely and generated a heat insulation layer. Meanwhile， the inner EG expanded to a certain extent and produced a sufficient thermal conductive path to dissipate the heat of materials. Consequently， the SR composites were endowed with excellent flame retardant performance due to the introduction of EG.
RUAN Fangtao, XIA Chenglong, ZHANG Baogen, CAO Ye, LIU Zhi, XU Zhenzhen, ZHANG Jincao
Abstract (
780 )
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386
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Aramid?filament?wrapped carbon fiber bundles were prepared using a covering method， and wrapped carbon?fiber?reinforced epoxy resins were prepared by means of a vacuum?assisted resin?transfer?molding method. The axial compressive properties of the resultant composites were measured using an electronic universal testing machine， and the effects of aramid?filament?wrapped parameters on their axial compressive fracture mode and compressive strength were investigated. The experimental results indicated that the aramid filament wrapping could improve the compressive strength of the composites. The compressive strength of the composites increased gradually with an increase in the density of the aramid filament. Compared to the unidirectional covering， the biaxial covering of the aramid filament could further improve the axial compressive strength. The number of reinforcing fiber bundles also affected the fiber buckling state， resulting in a further improvement in compressive strength.
JIANG Sen, WANG Liyan, CHEN Yanming, ZHANG Le, ZHAI Guifa
Abstract (
594 )
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502
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Poly（butylene succinate） （PBS） and its copolyester with 2?methyl?1，3?propanediol （MPO） （PBMS） were synthesized through direct esterification?melt polycondensation. The chemical structure and molecular weight of the resultant PBS and its copolyester were characterized by Fourier?transform infrared spectrometry， nuclear magnetic resonance spectrometry （1H?NMR）， and gel permeation chromatograph， and their thermal performance was valuated by differential scanning calorimetry， simultaneous thermal analyzer， and melt flow rate tester. The structural characterization results indicated that there were repeating structural units of butanediol succinate （BS） and 2?methyl?1，3?propanediol succinate （MS） in the main chains of the copolyester molecules. The content of MS was almost the same as that of MPO added in the synthetic process， confirming the successful synthesis of the PBMS copolyester according to our design strategy. The weight?average molecular weights of PBS and PBMS were determined to be 7.87×104~8.75×104 g/mol. Thermal analysis results indicated that the glass?transition temperature of PBMS gradually increased with an increase in the MPO content but its melting temperature decreased gradually. Moreover， the non?isothermal crystallization capability of PBMS weakened gradually and its degree of crystallinity decreased from 74.57 % to 49.42 %. The thermal degradation temperature of PBMS was higher than 400 ℃ without any change with a variation of MPO content. As the content of MPO increased， the melt index of PBMS increased gradually. Compared to pure PBS， PBMS exhibited better melt fluidity at the same temperature.
WANG Qingsong
Abstract (
779 )
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534
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This study reported the development of polypropylene （PP） matrix composites containing 30 wt% short glass fiber， in which all of the ingredients were used under the control of the odor and volatile organic compounds （VOC） from resources. The raw materials and additives with an odor grade less than grade 3 were selected preferentially according to the odor test standard of Volkswagen PV3900. Several types of low?odor maleic?anhydride?grafted polypropylene （PP?g?MAH） as a compatibilizer used for the composites， together with different antioxidant systems and different odor absorbents obtained from the current market were investigated studied. According to the results from the third?party inspection institution， the material obtained from the optimal formulation achieved an odor level of below grade 3， and its VOC level was also better than the current standards required by the automobile industry. Its total VOC content was reduced to 3 188 μg/m3， which is far below the standard requirements of 5 000 μg/m3. The material also achieved tensile strength of 106 MPa， bending strength of 151 MPa， notched Charpy impact strength of 11 kJ/m2， non?notched impact strength of 55 kJ/m2， and a thermal deformation temperature of 145 oC at 1.8 MPa. These properties can meet the requirements of some automotive products.
LIU Guangyuan, ZHAI Qianchao, WANG Fengwu, WANG Yihui, ZHENG Debao, CHEN Xiangying, ZHANG Zhongjie
Abstract (
677 )
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583
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Di?butyl maleate （DBM） and maleic anhydride （MAH） as a polar monomer were grafted onto high?density polyethylene （PE?HD） though melt extrusion with a twin?screw extruder using diisopropylbenzene peroxide （BIBP） as an initiator. The PE?HD?g?（DBM?co?MAH） copolymer containing binary polar monomers was prepared as a compatibilizer， and its chemical structure was characterized using Fourier?transform infrared spectrometry. The effects of the mass ratio of monomers and the initiator concentration on the melt flow rate and grafting rate of the compatibilizer were investigated. An adhesive resin was prepared through melt extrusion of the resultant compatibilizer with PE?HD， linear low?density polyethylene， and poly（ethylene?vinyl acetate） resin， and its toughness， strength， and adhesion of the adhesive resin were evaluated by adjusting the mass ratio of matrix resins and the compatibilizer amount. The results indicated that DBM and MAH could be grafted onto PE?HD with the initiation of BIBP. The grafting rates of compatibilizer were 0.73 wt% for DBM and 0.76 wt% for MAH at a mass ratio of DBM to MAH of 1 to 2. When 10 % compatibilizer was added into the adhesive resin， its properties were optimal and could meet the requirements of the adhesive resin for steel wire pipe according to the national standard.
WEN Yuan, MAO Xianpeng, XU Kejie
Abstract (
1318 )
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This paper reported an investigation on the effect of sample thickness on tensile properties of polyethylene （PE）. Through the analysis of tensile tests of PE samples with different thickness， the thickness could generate a great influence on the strength， strain and tensile modulus of PE. However， there was no effect on the yield absorption energy per unit area. In the current design of plastic products， there have been hidden dangers with the tensile properties of PE materials and the thickness of products as two independent parameters.
XU Rongxia, WEI Gang, WEI Lilan, WU Jiecui, JIANG Yujiang
Abstract (
477 )
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492
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The effects of nano?SiO2 and its composites with polyamide 6 on the tribological properties of ultra?high molecular weight polyethylene （PE?UHMW） were investigated using electronic universal testing machine， M?2000 friction testing machine， electron and optical microscope. The results indicate that the friction coefficient and wear rate of PE?UHMW composites decreased at first and then tended to increase with an increase in the nano?SiO2 content. The composites exhibited the lowest friction coefficient and wear rate at a nano?SiO2 content of 2 wt%. When 8 wt% polyamide 6 was added into the PE?UHMW composite containing 2 wt% nano?SiO2， the composites obtained a low friction coefficient of 0.29 and a low wear rate of 0.33×10-9 g/（N?m）. The wear mechanism analysis indicated that the addition of nano?SiO2 could effectively inhibit the adhesive wear and plastic deformation of PE?UHMW， and PE?UHMW composite with appropriate nano?SiO2 and polyamide 6 can form a more uniform and compact self?lubricating transfer film， and the wear surface becomes more smooth and present a very slight abrasive wear characteristics.
ZHOU Wenxian, LI Mingquan
Abstract (
827 )
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1137
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The new dye?type polarizer and the iodine?type polarizer were systematically compared. The optical parameters of transmittance， polarization efficiency， hue and hue changes were analyzed after moisture test， high temperature test， xenon lamp UV aging test by using a spectrophotometer. The new high?durability dye?type polarizer was polarization efficiency of 99.7 % at transmittance 39 %. Compared with the traditional dye?type polarizer， there was a significant improvement. When the polarizers were placed in the instrument panel and executed the xenon lamp UV aging test. The hue change ΔEs of the new high?durability dye?type polarizers is 3.48， and the hue change ΔEs of the iodine?type polarizer was 19.63， which was obviously reddish brown. moisture resistance test at 85 ℃/85 %/1 000 h， the polarization efficiency of the new dye?type polarizers was still 99 %， and the iodine?type polarizer had completely depolarized and failed. The experimental results show that the new dye?type polarizing film has superior high temperature weather resistance， xenon lamp ultraviolet aging resistance， moisture resistance than iodine?based polarizing film， and meets the weather resistance of 105 ℃/1 000 h and 85 ℃/85 %/1 000 h. It is applicable to use at electric meters， automotive and other fields.
Processing and Application
SONG Lijian, ZHANG Youchen, ZUO Xiahua, ZHANG Zhenghe, AN Ying, YANG Weimin, TAN Jing, CHENG Lisheng
Abstract (
921 )
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505
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This reviewed the research progress in the heat transfer control of the soft?hard interfaces through self?assembled monolayers （SAM） in the microscopic viewpoint. The heat transfer mechanisms of SAM were introduced and its structure?thermal conductance relations were summarized systematically. The influential factors such as coverage density， length， and terminal functional group of the SAM on the interfacial thermal conductance were discussed. In addition， the current research status of SAM in the polymer?based thermal composites was introduced， and its future research directions of in interfacial heat transfer were prospected.
HE Yi, ZHAO Guanghui
Abstract (
667 )
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This paper repaired the latest research progress in the repairing and reinforcement of oil and gas pipelines using composites in recent decades. A qualitative and quantitative review was provided on the strengthening undamaged pipes， repairing cracked and volumetric pipes. Moreover， the existing problems and future research direction of composite materials for strengthening and repairing oil and gas pipeline were discussed.
WANG Haolin, ZHU Xiangzhe
Abstract (
519 )
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321
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The solid conveying section of a common cone and two double cone screw extruders was simulated using the EDEM software. The motion state and distribution law of PE?HD particles in a conical twin?screw extruder were analyzed. The parameters of mass flow rate， filling rate， average speed， average pressure， average shear stress and torque of three conical screw extruders were investigated comparatively， and the solid conveying mechanism of ordinary and double conical screw extruders and the corresponding influence factors were discussed. The results indicated that compared to the ordinary conical twin?screw extruder， the twin?conical screw extruder exhibited relatively smaller axial velocity changes， stronger pressure building capacity， and higher volume filling. This is suitable for the processing of shearing?sensitive materials.
CHEN Tengfei, MO Qimian, ZHANG Shixun, CAO Wei
Abstract (
570 )
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331
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A series of rotary rheological experiments were conducted for high?impact polystyrene （PS?HI） under different temperatures to analyze the precision of conventional obtained from usually used viscous models. Then， a flow theory based on Phan?Thien Tanner （PTT） model was established and the corresponding algorithm was constructed to study the viscoelastic characteristics of rubber?like state PS?HI. Both theoretical and numerical results indicated that the Cross and Carreau?Yasuda models could describe the rheological characteristics of PS?HI better compared to other viscous models. The viscoelastic PTT model exhibited a significant improvement in precision， indicating that PS?HI presented some elasticity in the rubber?like state.
BAN Dongdong, WANG Danhua, LIU Kui, LI Yanan, LI Han, DAI Yahui
Abstract (
612 )
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461
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A numerical simulation was conducted on the flow field and mixing properties of half intermeshing co?rotating/counter?rotating wavy twin?screw elements and intermeshing co?rotating/counter?rotating routine twin?screw elements using the Polyflow? CFD software. The mixing performance of the two elements was investigated comparatively using the shear rate， mixing index， first characteristic value of inelastic stress tensor， residence time， time?averaged mixing efficiency， segregation scale， and other characteristic parameters. The simulation results indicated that the wavy twin?screw elements exhibited better mixing properties.
Additive
LI Mengqi, CHEN Yajun
Abstract (
807 )
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650
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This paper reviewed the research progress in the flame retardancy of poly（lactic acid） with nanomaterials in recent five years. These nanomaterials include metal organic framework material （MOF）， graphene， nano montmorillonite， bio?based nano flame retardants， carbon nanotubes， and so more. The preparation methods， properties， and mechanism of the nano flame retardants were summarized， and their future development trend was prospected.
XU Weihua, ZHENG Yu, SHEN Xiangyang, ZHANG Yan, LIU Juwen, YAN Shijing
Abstract (
672 )
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418
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The phosphorus?silicon synergistic flame?retardant epoxy resins were prepared separately by using two types of polyhedral oligomeric silsesquioxane （POSS） combined with 9，10?dihydro?9?oxa?10?phosphaphenanthrene?10?oxide （DOPO）?based organophosphorus flame retardants （D?bp）， and their flame retardant， thermal properties， mechanical， and dynamic mechanical properties were investigated. The results indicated that the phosphorus?silicon synergistic flame retardant epoxy resins obtained a UL 94 V?0 rating at a phosphorus content of only 0.25 wt%. The epoxy resins exhibited a peak heat release rate of 313.9 kW/m2， total heat release of 118.2 MJ/m2， and average effective combustion heat of 23.1 MJ/kg， which decreased by 66.6 %， 41.4 % and 26.9 % respectively when the Phenyl?POSS was compounded with D?bp. The combination of Epoxy?POSS and D?bp could simultaneously improve the flame retardant， thermal， mechanical， and dynamic mechanical properties of phosphorus?silicon synergistic flame retardant epoxy resins， indicating excellent comprehensive performance.
Plastic and Environment
WAN Yi, LI Li, JU Chunyan, HAO Xuechun, LI Run
Abstract (
603 )
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658
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This study was based on the data related to the proportion of plastic waste in municipal solid waste， the delivering quantity of municipal solid waste， and the data of social and economic development in Urumqi City from 2008 to 2019. The annual output of plastic waste in Urumqi was analyzed using the multiple linear regression equation model， ARIMA model， and gray model， and the gray correlation model was used to distinguish the main influence factors. The results indicated that the annual output of plastic waste in Urumqi City exhibited a linear growing trend from 4.75×10? t in 2008 to 35.14×10? t in 2018. The analysis results of influence factors indicated that the per capital disposable income had the greatest impact on the annual output of plastic waste. On the other hand， the urban population generated the greatest impact on the generation of plastic waste when the level of environmental construction was the smallest. The ARIMA model was considered to be the best model to predict the annual output of plastic waste in Urumqi City. The prediction results indicated that the annual output of plastic waste in Urumqi City was going to reach 54.4×10? t， 82.63×10? t， and 124.91×10? t by 2025， 2030， and 2050， respectively. This may bring about some new challenges to the prevention and control of plastic waste.
Standard and Test
XU Xiaohui, ZHAO Jie, SHEN Kangjun, LIU Shu
Abstract (
587 )
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467
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Taking styrene migration amount as a test indicator， the migration of residual styrene in polystyrene cups to three types of food and alcohol simulants was investigated comparatively， and the suitable food simulants from the Chinese special food series were confirmed. The migration amount of styrene from the polystyrene cup to bean beverages， tofu， porridge， and 10 and 20 vol% alcohol was detected using headspace?gas chromatography. Meanwhile， the migration amount of styrene from the cup to 50 and 95 vol% alcohol was determined by high?performance liquid chromatograph. The results indicated that the migration amount of styrene in the bean beverages was between the migration amounts in 20 and 50 vol% alcohol. The migration amounts of styrene in tofu and porridge was closed to the migration amounts in 10 and 20 vol% alcohol， which were much lower than that in 50 vol% alcohol. According to the migration results， 50 vol% alcohol was recommended as a simulant for bean beverages， and 20 vol% alcohol as a simulant for tofu and porridge. These results provided a data reference for reformulating the national food safety standards.
PENG Jing, XIAO Da, WU Yingjiang, LI Bing, ZHANG Long, LI Zegang
Abstract (
828 )
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844
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This paper reported a comparative analysis on the domestic and international standards for plastic structured?wall drainpipes. Through a comprehensive comparison between the Chinese national standards and the international standards of plastics structured?wall drain pipes， the Chinese national standards was found to exhibit a higher quality requirement than the international standards. Combined with the development and application of novel plastics structured?wall drainpipes in China， it can be concluded that the industry of China has a preferable development and innovation.
Machinery and Mould
JIANG Jingwei, LIU Zhenfeng, ZHOU Guofa
Abstract (
531 )
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388
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Aiming at the industry common technical bottleneck in the control of the mixing uniformity and process reproducibility of polymer composites， the synergetic evolution law of the standard relative deviation （RSD） of powder mixing uniformity and process reproducibility with the inlet powder formula ratio， powder cohesive characteristics， and screw speed was simulated， The results indicated that the RSD was negatively correlated with the component content and screw speed， and it had a positive correlation with powder cohesive energy density. The mixing uniformity and process reproducibility of cohesive powders with an ultrafine particle size and an ultralow component content could be enhanced by increasing the screw speed. When the component content was less than 5 % and the energy density was less than 30 000 J/m3， the regulation of mixing uniformity and process reproducibility could be realized by increasing the screw speed up to 1 600 r/min. This can meet the requirement of technical index with a RSD less than 5 %. A regression model for the collaborative coupling correlation control between RSD and screw speed was constructed on the basis of this condition. The real?time online model predictive control of mixing uniformity and process reproducibility in the cohesive powder mixing process at an ultrafine particle size and an ultralow content could be realized by using a speed sensor， a variable frequency drive motor together with the collaborative coupling correlation control regression model. These results provided a technical support for solving the common technical bottleneck in the processing industry of polymer composites.
TAN Lei, HUANG Xingyuan, WANG Han, PAN Liuwen
Abstract (
579 )
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398
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In view of a large temperature difference in the temperature distribution of the melting chamber， the heat transfer in the melting chamber of a hot?air melting waste plastic granulator was simulated by using the Fluent simulation software. By comparing the temperature distribution of the melting chamber with different inlet diameters， different inlet positions， and different inlet wind speed， the effects of inlet diameter， inlet position， and inlet wind speed on the temperature distribution of the melting chamber were investigated. An orthogonal experiment was performed to explore the optimal parameter components and distinguish the primary and secondary factors. The analysis results indicated that the temperature inside the melting chamber increased significantly with an increase in the diameter of the air inlet increases when using the controlled variable method. However， this temperature varied with a variation of the position of the air inlet. If the distance between the air inlet and the main shaft was too small or too large， the temperature distribution of the melting chamber was inhomogeneous. Only in the middle area， the temperature distribution of the melting chamber was more uniform， and there was no obvious change with an increase in the air inlet speed. Through the orthogonal experiment， the optimal parameter group was determined to be an air?inlet diameter of 120 mm， a distance of 47.7 ℃ between the air inlet and center 150 mm， and a wind speed of 2 m/s at the air inlet. It is concluded that the optimized scheme with an air?inlet diameter of 120 mm and an air inlet distance of 150 mm from the center should be adopted to avoid a large temperature difference in the melting chamber.
Review
CHEN Wenjing, YANG Xiaolong, HAN Shuntao, HAN Ying, MA Xiuqing
Abstract (
1251 )
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The paper reviewed the research progress in the modification methods of polyacrylonitrile materials in recent years， which include copolymerization modification， graft modification， blending modification， finishing method， and plasticization modification. The characteristics of different modification methods were analyzed， and the modification research direction and future development trends of polyacrylonitrile materials were prospected.
DONG Luqian, XU Fang, WENG Yunxuan
Abstract (
1257 )
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1434
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This paper reviewed the research progress in the modification methods of poly（glycolic acid） （PGA） from the aspects of hydrophilicity， cell compatibility， mechanical performance， melt strength， heat resistance， antibacterial properties， and degradation rates. Moreover， the applications of PGA in the fields of biomedical， food packaging， oil extraction， and agricultural production were also summarized.
LIU Wen, SHI Wenzhao, LIU Jinshu, LU Shaofeng, ZHOU Hongjuan
Abstract (
871 )
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The shape memory process and mechanisms of electro?active shape memory composites were introduced from macro to micro perspectives. The classification and research of electro?active shape memory composites were summarized based on different conductive fillers， including nanoparticles， continuous fibers， short?cut fibers， and composite fillers. The preparation methods including physical compounding， in?situ polymerization， and freeze?drying were analyzed briefly. The electrically induced shape memory composites were introduced according to their conductive mechanisms from three aspects of homogeneous conductor units， interface bonding between conductor and substrate， and conductive network structure. An overview on the phenomena of nanoscale conductive networks and ion channels in the microstructure was presented. Finally， the applications of electro?active shape memory composite materials in aerospace， biomedicine， smart textiles， and electronic semiconductors were discussed and their future development direction was prospected.
PENG Bo, XIAO Yunbin, GU Jiabao, CHEN Zijun, TANG Yanhuang, ZHU Gang, XU Huanxiang
Abstract (
850 )
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This paper reviewed the research progress in the preparation of polymer/graphene composites， and two emerging preparation methods were introduced emphatically. The structural and performance design of polymer/graphene functional composites were described in detail， and their future development direction was prospected. This review provided an important reference for the research and development of advanced polymer/graphene composites， promoting the comprehensive research and industrial applications of graphene.
