Materials and Properties
LUO Jiawei, ZHOU Bing, WANG James H, JIA Qin
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286 )
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A multifunctional epoxy polymer was used as a chain extender for poly（butylene succinate⁃co⁃terephthalate） （PBST）， and the effects of chain extension condition on the properties of PBST/Talc（talcum powder） blends were investigated during the melt⁃phase reactive extrusion process. The chain extender dosage， reaction temperature， and screw rotational speed were studied as main factors. The primary influence factors and their interactions were identified through an analysis of variance. The results indicated that the influence of chain extender dosage is most significant， followed with a reaction temperature， whereas the influence of screw speed is less. The melting and crystallization temperatures of PBST decreased with an increase in the chain extender dosage， and meanwhile its molecular weight， melt viscosity， and thermal stability increased. The modified PBST compounds presented an increase in the breaking stress but a decrease in the breaking strain with an increase in the chain extender dosage. Response surface analysis indicated that the optimal chain extension condition was a chain extender dosage of 0.66 %， a reaction temperature of 200 ℃， and a screw speed of 300 r/min.
YANG Lian, JIANG Jing, JIA Caiyi, XIE Yuehan, WANG Xiaofeng, LI Qian
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276 )
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T he effect of compatibilizer on the nanofibril morphology， viscoelasticity， mechanical properties， and CFIM behavior of polypropylene （PP）/nylon6 （PA6） composite through a combination of in⁃situ fibrillation （INF） and chemical foam injection molding （CFIM） technologies. The results indicated that the addition of PP⁃g⁃MAH compatibilizer reduced the size of PA6 dispersion phase significantly， and PA6 microfibers were uniformly distributed in the PP matrix with an average diameter of about 265nm. The existence of a microfiber network structure and the synergistic enhancement effect of phase interface improved the mechanical strength of INF composites significantly. The tensile strength and impact strength of the composites are 26.2 % and 62 % higher than those of pure PP， respectively. Based on the CFIM experiment using the self⁃made endothermic⁃exothermic equilibrium chemical foaming agent， the INF composite foam product was prepared with a cell size of 62 μm and a cell density of nearly 5×105 cells/cm3. The as⁃prepared sample obtained a decrease in the weight by 12 %. Compared to pure PP foam， the composite foam exhibited an increase in the specific tensile strength and impact strength by 17 % and 46 %， respectively.
GAO Wei, XIONG Changyi, HAN Fei, KONG Nizao, YAN Yuanwei
Abstract (
219 )
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A type of thermal conductive and microwave absorbing dual⁃functional powders were designed with different ratios and particle sizes using aluminum oxide （Al2O3） as thermal conductivity powders， sendust （FeSiAl） as microwave absorbing powders， and dodecyltriethoxysilane （C12） as a modifier. The resultant dual⁃functional powders were filled in a silicone oil to prepare a thermal conductive and microwave absorbing pad， thus developing a series of thermal conductivity absorbing dual⁃function integrated materials. The results indicated that C12 generated a good lipophilic modification effect on Al2O3 and FeSiAl. The thermal conductive and microwave absorbing pad showed a thermal conductivity of 5.92 W/（m·K） at a Al2O3/FeSiAl mass ratio of 20∶80， exhibiting a good absorbing capability in the frequency range of 4.8~6.5 GHz. Ensuring a high thermal conductivity， the as⁃prepared powders were endowed with a wave⁃absorbing capability. Meanwhile， it is easy for the powders to be compressed and convenient for practical assembly applications， and their 50⁃psi compression stress reached a compression strain of 50 %.
LIU Shuai, ZHAO Zihao, YU Ying, YANG Jiaxin, ZHANG Yang
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211 )
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Polyaniline （PANI） was grown on the surface of carbon fiber felt （CFF） through in⁃situ chemical oxidative polymerization to obtain a core⁃shell structural composite. The composite was subsequently encapsulated with polydimethylsiloxane. The influence of reaction condition on the structure and properties of the resultant composite was explored. The results indicated that the PANI particles were uniformly decorated on the surface of carbon fiber， resulting in a color change from black to dark green. Contact angle and surface energy analysis indicated that the surface energy of the composite was greatly reduced after encapsulation， though there was no obvious difference between the CFF@PANI composite and CFF. The presence of the core⁃shell structure enhanced the interfacial and dipole polarization significantly because of the multi⁃interface structure and interfacial effects. A high dielectric relaxation behavior was achieved for the compo⁃site， thus improving its capacitance and voltage⁃sensitive effects significantly.
ZHOU Ziyi, WANG Yangyang, SUN Tao, JIANG Wei, DONG Tungalag, YUN Xunyan
Abstract (
231 )
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A type of blending films based on poly（butylene adipate⁃co⁃terephthalate） （PBAT） and poly（lactic⁃co⁃butanediol itaconate） （PLBI） were prepared at different mass ratios through melt extrusion using a twin⁃screw extruder. The effect of PLBI content on the thermal performance， mechanical properties， and gas permeability of the blending films was investigated. The modified atmosphere packaging （MAP） system was designed on the basis of the gas permeability of material and the respiratory characteristics of strawberry. This MAP system was used for a strawberry⁃preserving experiment. The results indicated that the blended films achieved favorable mechanical properties at a PLBI content of 15 wt%. Through adjusting the blending ratio， the CO2/O2 penetration ratio of the blending films was reduced from 10.57 to about 3~7. Simultaneously， the water retention capacity of the blending films was enhanced. This makes the blending films more suitable for air⁃adjusted fruit and vegetable packaging. This packaging system can be used to extend the shelf life of strawberries up to 21 days under low⁃temperature storage conditions.
HE Songdi, LI Guanyu, CHEN Jiamin, WANG Chenyi, XU Jianping
Abstract (
172 )
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A ethylene⁃octene copolymer （OBC）/waste polystyrene （WPS） compatibilizing masterbatch was prepared through the Friedel⁃Crafts alkylation reaction. The effects of anhydrous AlCl3 dosage on the grafting rate of WPS and the properties of the masterbatch and the effects of the masterbatch dosage on the comprehensive performance of ethylene⁃propylene⁃diene rubber （EPDM） were investigated. The results indicated that WPS could react with OBC to form an OBC⁃g⁃WPS graft copolymer. There was no gelation at an anhydrous AlCl3 dosage of 0.4 and a WPS grafting rate of 25.3 wt%， resulting in the best comprehensive properties of the masterbatch. When this compatibilizing masterbatch was used for EPDM， the resultant rubber exhibited higher tensile strength， higher tear strength， and better heat aging resistance than pure EPDM vulcanized rubber， and its performance was also better than that of the EPDM containing the same amount of an OBC/WPS physical blend. Scanning electron microscopy indicated that WPS was uniformly dispersed in the vulcanized EPDM rubber with the addition of the OBC/WPS compatibilizing masterbatch.
SU Yuhang, ZHOU Yuhong, LIN Yuanzhi, MAO Jianquan, WANG Yongxiang, LIU Xiang, YU Li, KE Junmu
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250 )
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Three⁃layer glue⁃free composite films based on a PP/EVA/elastomer blending system were prepared through melt blending and cast co⁃extrusion using EVA as an adhesive layer and different elastomers as a compatibilizer for the PP core layer and adhesive layer. The resultant blending system was analyzed by means of mechanical tests， DMA tests， rheological tests， and scanning electron microscopy， and the properties of the composite films were investigated. The results indicated that there was an optimal bonding effect on paper when using the EVA containing 18 wt% vinyl acetate. The PBE elastomer exhibited a more significant improvement in the mechanical properties than POE. The glass transition temperature of PP and EVA increased gradually with an increase in the PBE content， and meanwhile the curvature of Cole⁃Cole also increased gradually， indicating that the compatibility between PP and EVA became better and better. When the content of PBE in the EVA adhesive layer was 30 wt%， the tensile strength of the composite films reached a maximum value of 29 MPa. The adhesive strength of the composite films with paper reached at maximum value of 9 N/15 mm at a PBE content of 20 wt%. The core layer and adhesive layer cannot be peeled off for the composite films at a PBE content of 25 wt%. The composite films are robust without delamination in this case. The optimal loading of PBE in the adhesive layer was determined to be 25 wt%.
FAN Wenxuan, XU Shuangping, JIA Hongge, ZHANG mingyu, QU Yanqing
Abstract (
180 )
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Three types of rigid⁃group⁃bridged polysiloxanes⁃modified ethylcellulose （EC） mixed membranes were prepared by using three bridged⁃polysiloxanes with different rigid groups of hexafluoroimide， naphthalimide， and fluorene as modifiers and EC as a substrate， through solution co⁃blending and coating. The three mixed membranes exhibited a good film formation ability， high mechanical properties， and good thermal stability. Compared to pure EC membrane， the three mixed membranes gained an improvement in the permeability of CO2 without sacrificing selectivity （CO2/N2 and CO2/CH4）. Especially， the naphthalimide bridged⁃polysiloxanes obtained a CO2 permeation coefficient of over 213 barrers， which is 4.9 times higher than pure EC membrane.
DONG Yapeng, ZHAO Tianjiao, WANG Meizhen, CUI Wenju, LIN Fuhua, WANG Bo
Abstract (
190 )
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The sodium salt of long chain fatty acid and sodium of arylamide fatty acid were compounded to form a compounding nucleating agent （SCAB）， and its effect on the crystallization and mechanical properties of polypropylene （PP） was investigated. The results indicated that the molecular structure of SCAB was not changed during its compounding process or at the processing temperature of PP， and its intermolecular aggregation state was significantly improved by the compounding process. The nucleated PP showed a significant increase in the crystallization rate， notch impact strength， and tensile strength with the extension of the carbon chain length of sodium salt of long chain fatty acid. The compounding did not affect the crystal growth mode of PP. Owing to the excellent dispersibility of SCAB in the PP matrix， a combination of SCAB with sodium stearate could refine the PP spherulites effectively and improve its crystal structure. This resulted in an increase in the crystallization rate of PP by 6.3 times， in the notch impact strength by 27.3 %， and in the tensile strength by 8.2 MPa.
MA Yiheng, WANG Jianyong
Abstract (
257 )
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In this paper， the effect of plasma surface modification of PTFE fibers was investigated through contact angle， monofilament pull⁃out， and peel strength measurements. The obtained samples were analyzed by means of scanning electron microscopy， Fourier⁃transform infrared spectroscopy， and X⁃ray photoelectron spectroscopy. The results indicated that the plasma surface modification of PTFE fibers promoted higher compatibility and higher adhesion between materials， thus resulting in better performance. The modified PTFE fibers showed an increase in the interface shear strength at first and then decreased with an increase in the time. Such an effect weakened gradually with an increase in the placement time， leading to a failure in the modification effect failed after 24 h.
ZHANG Huafeng, TANG Yujing, YANG Qifan, LI Shuhong, WANG Xiangdong
Abstract (
277 )
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Poly（butylene adipate⁃co⁃terephthalate） （PBAT）/cellulose composites were prepared through melt blending， and then the PBAT/cellulose foams were prepared using supercritical CO2 as a physical foaming agent through intermittent autoclave foaming under different operation temperatures. The crystallization properties， rheological properties， foaming properties， and compression resilience properties of the PBAT/cellulose composites and their foams were investigated. The results indicated that the introduction of cellulose promoted the crystallization of PBAT. With increasing the cellulose content， the cold crystallization peak of the PBAT⁃based composites shifted to a higher temperature at first and then to a lower temperature， and meanwhile the storage modulus and complex viscosity of the composites increased. The expansion rate of the PBAT/cellulose composite foams increased at first and then tended to decreases with an increase in the cellulose content. However， the composite forms presented a decrease in the cell density at first， followed by an increase and then a decrease. PBAT⁃g⁃GMA could act as a compatibilizer to improve the compatibility between PBAT and cellulose， which resulted in stable cell morphology and improved flexibility for the composite foams. The cell density， cell size， and expansion ratio of the composite foams were affected by the autoclave pressure relief temperature. When the PBAT/cellulose composite was soaked in supercritical CO2 at 130 ºC for 2 hours， the expansion ratio of the composite foams complex reaches 13.06 and their cell density reached 0.37×1010 cell/cm3 at an autoclave pressure relief temperature of 80 ºC and a cellulose content of 10 phr.
XIE Bo, TU Zhigang, ZHOU Xianjin, ZHAG Shangxian, XIONG Ligui, YANG Ting
Abstract (
242 )
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A high⁃performance biaxially oriented polypropylene （BOPP） film was developed using a special raw material formulation with a special processing technique， and its friction coefficient， heat shrinkage， and optical properties were compared with a standard BOPP film at four selected times on the 1st， 7th， 15th， and 30th days within 30 days. The results indicated that the developed film obtained an improvement in all aspects of performance. The film exhibited a low friction coefficient， high heat shrinkage， and excellent optical properties.
Processing and Application
JI Yaru, LI Ruili, ZHAI Yongyi, ZHANG Shibo
Abstract (
255 )
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The removal effectiveness of the MOF⁃808 material for organic chloride in a plastic cracking oil was studied in light of its excellent adsorption properties. The MOF⁃808 materials was prepared， and then the Zrx∶Fey@MOF⁃808 materials with different doping ratios were prepared by using a hydrothermal synthesis method. Four typical organic chlorides in the plastic cracking oil were selected to prepare a model oil， and the optimal x/y ratio was determined to be 1∶0.67 according to the removal rate of organic chlorides in the model oil. The optimal reaction conditions and reuse performance of adsorption dechlorination experiments were determined， and the corresponding adsorption mechanism was investigated. The results indicated that the as⁃prepared Zr1∶Fe0.67@MOF⁃08 adsorption material exhibited has good structure and stability. The removal rate of chloride in the model oil was as high as 97.66 % at an adsorption temperature of 50 ℃， an adsorption time of 2 h， and an agent/oil mass ratio of 1/40. The dechlorination rate remained to be above 85 % after repeatedly using the adsorbent for 6 times. The adsorption process conformed to a pseudo⁃second⁃order kinetic model， belonging to a spontaneous chemisorption process.
YIN Dashuai, ZHAO Yongqiang, HEI Ganggang, LI Zhibin
Abstract (
208 )
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Aiming at the problems in the complicated process and the difficulty to control the precision of traditional metal type screw rotor， a new injection⁃molding method with a screw rotor was proposed to replace the metal type rotor with a plastic material. The Moldflow software was used to analyze the injection molding of the tooth surface of the screw rotor using glass⁃fiber⁃reinforced nylon as a raw material. The depth of shrinkage and warping deformation were taken as quality criteria to screen and analyze 7 process parameters affecting the molding quality of plastic parts， and 3 process parameters that had the greatest impact on the 2 quality standards were determined. A response surface experiment was designed through the BBD experiment. The influence of injection process parameters such as melt temperature， holding time， and holding pressure on the shrinkage depth and warp deformation was studied. A polynomial regression response model for minimum shrinkage depth and warp deformation was obtained. Using regression model， the optimal combination of process parameters was determined to be a melt temperature of 281.0 ℃， a pressure holding time of 18.7 s， and a pressure holding pressure of 115.7 MPa. The results indicated that the values obtained from the numerical simulation and prediction with the model were similar along with errors of 3.75 % and 0.53 %， respectively.
CHEN Ping, LU Dan, LU Guangming, YUAN Chu, YU Ruilei
Abstract (
202 )
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This article focuses on polyamide materials T1 and B1， and uses two types of fungi to conduct anti mold tests on them. It conducts in⁃depth exploration and research on the failure mechanism during the co cultivation process of fungi and polyamide. Through infrared spectroscopy analysis， it was found that mold growth can absorb oxygen from the outside， which can cause the methylene on the polyamide molecular chain to break and react with it to form carbonyl groups， causing changes in the internal structure of the molecule. Through UV spectroscopy and nuclear magnetic resonance analysis， it can be seen that due to the presence of highly reactive methylene structures on the internal molecular chains of polyamide， the color of polyamide and mold will change during the co cultivation process. It will react with the outside world to generate methylene free radicals， further react with oxygen to generate hydrogen peroxide， and then isomerize to generate carbonyl groups. The carbonyl groups then combine with other active groups to produce carbonyl imines. As a result， the conjugated chains on the polyamide molecular chains will increase， and the maximum absorption wavelength will be seen in the visible light region， which is macroscopically manifested as the color change of the polyamide material. Thermogravimetric analysis shows that fungi can obtain nutrients from the surface of polyamide for reproduction， and the surface structure will undergo significant damage and changes. Mechanical performance tests have shown that mold can cause a decrease in the tensile， bending， and impact properties of polyamide materials， and the two types of mold can cause different degrees of attenuation.
Additive
NIU He, LYU Mingfu, ZHANG Zongyin, XU Yaohui, XU Wei, ZHANG Shijun, GUO Peng
Abstract (
164 )
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This article reviewed the application progress in the additives in poly（glycolic acid） （PGA） processing， including antioxidants， chain extenders， anti⁃hydrolysis agents， and inorganic particles.
Plastic and Environment
LIU Baoying, YANG Chenguang, ZHAO Meng, LI Qingzheng, WANG Lei, ZHAI Hua
Abstract (
225 )
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In this study， a plastic infrared sorting machine was used to conduct sorting tests on the normal polyethylene terephthalate （PET） plastic bottles with blue， white， and green colors as well as the other plastic bottles made from polycarbonate （PC）， polyethylene （PE）， and polypropylene under the dual⁃path excitation environment of visible and infrared light. Three common Retinex color enhancement algorithms were further utilize to identify the white⁃， blue⁃， and green⁃color PET bottles， and the recognition effect of plastic infrared sorting machines was investigated. The results indicated that there was no significant difference in the imaged images between PP， PC， and PET bottles with a white color under visible light. However， under infrared imaging， PP， PC， and PET bottles reflected green， purple， and blue light with significant differences. The HSV range value was expanded from 0~46 to 0~61， the background saturation was adjusted from 72 to 80， the missing proportion of white and blue PET bottles was reduced from 4.58 % to 1.26 %， and the misidentification rate of white bottles made from PP， PC， and PE was reduced from 3.88 % to 2.69 %. There was no impact on the misidentification rate of the PE bottle， maintaining a recognition rate of 100 %. The best removal effect was obtained through the MSR color enhancement algorithm with removal rates of 94.8 %， 95.83 %， and 95.83 % for the recognition of white， blue， and green PET bottles， respectively.
Machinery and Mould
YE Weiwen, CHEN Zhensen, JIANG Bingchun, WU Guangming
Abstract (
233 )
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According to the design requirements of a straight pipe mouth double shrink water chamber in the heat⁃exchange system， a detailed process plan was proposed to form the part using a thermoplastic composite based on the PA66 matrix and 30 wt% glass fiber （GF）. This plan included the plastic component characteristic analysis， structural design， working principle， and pre⁃deformation technology of products. The key technologies for the design of the water chamber and the pre⁃deformation of products were studied. Through multiple verifications， the optimal mathematical model for the nozzle water chamber product was designed， and corresponding injection molds were developed. The research results indicated that the structural design of the double shrink Ke slider achieved a significant improvement in the mold space utilization and plastic forming quality. This design makes the mold space more compact and improves the production efficiency. Meanwhile， the optimized structure reduces the molding defects of the plastic parts， ensuring the stability of product quality. By using the PA66/30 wt% GF composite and mold design scheme， the original metal parts were replaced by the plastic parts， which greatly reduced the processing and material costs. Such a lightweight design not only reduces the weight of the entire vehicle， but also improves the vehicle's endurance. This study provides an effective approach for the technological development and engineering practice in related fields.
Review
JIANG Qinyao, JIA Yuyao, YANG Shaozhe, WU Rong, BAI Wei, SUN Teng
Abstract (
235 )
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This paper reviewed the research progress in high⁃temperature⁃resistant modification of polycarbonate at home and abroad in recent years from two aspects： chemical and physical modifications.
DU Rong, LIN Tong, XIAO Hang, YIN Lyu, ZHANG Jin
Abstract (
232 )
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This paper reviewed the research status in the epoxy⁃based composite coatings with nano Fe3O4 powders before and after surface modification and the surface treatment methods for the dispersion of nano⁃Fe3O4 in the epoxy matrix. The latest research progresses in the epoxy/nano Fe3O4 composite coatings were summarized， including mechanics， corrosion resistance， friction， wear， and magnetic properties. Finally， the future perspectives of epoxy/nano Fe3O4 composites were prospected.
CAO Shuai, JIANG Tao, LIU Xiong, WANG Ying, LI Wenge, WU Xinfeng
Abstract (
302 )
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The heat transfer mechanism of thermally conductive MXene⁃based composites was introduced， and their preparation methods were reviewed， mainly including vacuum⁃assisted filtration， freeze⁃drying orientation， solution blending， self⁃assembly， and multilayer casting. The characteristics of the thermally conductive MXene⁃based composites were analyzed， the challenges they have to face were pointed out， and their development direction in future was prospected.
