Materials and Properties
LEI Jingfa, HU Jibo, LIU Tao, WU Wenqi, Shen Zhaoyang
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226 )
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In this study， both universal material testing and high⁃speed tensile testing machines were used to measure the static and dynamic tensile mechanical properties of the poly（vinyl chloride） （PVC）/thermoplastic polyurethane （TPU） blends by using two molding methods and six blending ratios. The molding methods and blending ratios were optimized according to the fracture elongation and Shore hardness of the blends. The stress⁃strain data were obtained in a wide strain⁃rate range of 0.001~700 s-1， and microscopic characterization was carried out up on the cross⁃section of the tensile samples. The results indicated that the molded material obtained higher fracture elongation， and it achieved maximum fracture elongation at a PVC/TPU mass ratio of 90/10. The Shore hardness meets the hardness range of the soft tissue material of the test dummy （Shore 40~70 A）. The PVC/TPU （90/10） blends exhibited a significant strain⁃rate effect under both static and dynamic loads. The Zhu⁃Wang⁃Tang′s and Sherwood Frost′s equations were employed to construct a constitutive model for the blends， and a comparative investigation indicated that the Sherwood Frost′s equation had better fitting effect. The topography analysis indicated that under static and dynamic loads， the blends exhibited a typical brittle fracture without significant phase separation. As the strain rate increased， the cross⁃section became rough gradually and produced voids and small cracks.
GUO Minghai
Abstract (
249 )
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To improve the rigidity⁃toughness balance of high⁃impact copolymerized polypropylene with high melt flow rate （IPC⁃J）， the ethylene content and the ethylene content in ethylene propylene rubber （EPR） were increased to 12.4 wt% and 54 wt%， respectively， by combination with the high⁃impact copolymerized polypropylene （IPC⁃H） technology. Meanwhile， the molecular segment structures and aggregation morphologies of IPC⁃J， IPC⁃H， IPC⁃1， and IPC⁃2 were investigated. The results indicated that the EPR content of IPC⁃J increased from 19.4 wt% to 22.8 wt%， its weight average molecular weight （Mw） decreased from 2.0×105 to 1.9×105 g/mol， its intrinsic viscosity increased from 1.80 to 1.86 dL/g， its molecular weight distribution index increased from 8.9 to 10.7， and the maximum Mw of EPR increased from 1.1×106 to 1.2×106 g/mol， compared to those of IPC⁃H. The relatively longer ethylene crystalline chains with a greater amount were beneficial to enlarging the dispersed particle size. This resulted in a transformation of the maximum proportion region from 0.3~0.6 to 0.6~0.9 μm， which promoted higher impact strength of 11.0 kJ/m² at 20 ℃ and 5.7 kJ/m² at -20 ℃. The rigidity⁃toughness balance of the IPC with a high melt index were fully optimized through increasing the ethylene content and the ethylene content of EPR， according to the production technology for 300⁃kt/a polypropylene without changing the Ziegler⁃Natta⁃type catalyst system.
CAO Hui, TANG Jing, REN Weitao, ZHOU Qiong
Abstract (
251 )
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A series of metal organic framework （MOF） materials based on zirconium 1，4⁃carboxybenzene （UiO⁃66） were prepared， and their adsorption properties for heavy metal ions were comparatively investigated. The poly（ether sulfone）/poly（ether imide）/modified MOF composite membranes were then prepared， and the effect of MOF content on the adsorption and permeability of heavy metal ions was compared for the as⁃prepared membranes. The results indicated that UiO⁃66⁃NH2 exhibited the best adsorption performance for heavy metal ions among the prepared MOF materials， and its retention performance for heavy metal ions was optimal at a loading of 15 wt% in the composite membranes.
HAO Wenbo, TANG Shi, SU Tingting, WANG Zhanyong
Abstract (
205 )
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Three types of esterified starches with different contents of straight chain were prepared by mixing formic acid with three natural starches at a certain proportion， including cassava esterified starch （EM）， corn esterified starch （EN）， and waxy esterified starch （EW）. The structural properties of the as⁃prepared esterified starches were characterized and analyzed using Fourier⁃transform infrared spectroscopy， wide⁃angle X⁃ray diffraction， scanning electron microscopy， and thermogravimetric analysis. The changes in the mechanical properties of PBS/esterified starch blends were further analyzed. The result indicated that the starches exhibited a hydrophobic property after esterification， and their hydrophobic degree increased with an increase in the amylose content. The crystal structure of the starches was damaged by the incorporation of the esterified starch. The crystalline degree of the starches was proportional to the content of amylose， and their heat loss rate increased proportionally with an increase in the amylopectin by a factor of EM （237 ℃） > EN （235 ℃） > EW （231 ℃）. The hydrogen bond interaction between the molecules of the starches decreased， resulting in an improvement in the thermoplasticity of the starches. Moreover， the esterified starch with a high content of amylopectin has a good plasticizing effect.
DUAN Kaige, CHEN Xiaodie, NI Jia, MEI Zhenwei, ZHOU Chaoxi, YE Xiaoping, ZHU Hui, YU Dongming
Abstract (
237 )
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In this study， high⁃density polyethylene was selected as a base resin， and a suitable photoinitiation system was selected to prepare ultraviolet （UV）⁃crosslinked high⁃density polyethylene （PE⁃Xe）. The formula was optimized and the process was explored. The penetration of ultraviolet light was systematically tested. At the same time， the effects of the amounts of photosensitizer and crosslinker， the power of UV lamp， and line velocity on the crosslinking degree of the PE⁃Xe materials were studied. The results indicated that the penetration ability of ultraviolet light reached 9.5 mm. When the addition amounts of photosensitizer and crosslinking agent was 0.7 wt%， and the UV lamp power was 500 W， the crosslinking degree of the PE⁃Xe material reached over 75 %. The prepared pipe exhibited good pressure resistance， excellent mechanical properties， and a crystalline degree of over 40 %， and its oxidation induction time at 200 ℃ was greater than 20 min.
KONG Dejin, LIAO Xu, LI Nanxi, LEI Jingyi, LIU Kuo, LI Hongfei, TANG Wufei
Abstract (
225 )
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Chitosan （CS） was mixed uniformly with poly（vinyl alcohol） （PVA） and gelatin （GEL） at different mass ratios， and the resulting solution was dumped onto a plexiglass plate by using a solution⁃casting method to obtain a series of CS/PVA/GEL blend films. The structure of the blend films was characterized by infrared spectrogram analysis， ultraviolet spectrum analysis， water contact angle， and so on. Their thermal stability， flame retardancy， oxygen permeability， preservation， mechanical properties were investigated. The results indicated that the blend films exhibited the best comprehensive performance at a CS/PVA/GEL mass ratio of 10/3/7.
ZHAO Hanyang, YAN Ge, YANG Yong, JI Xiaona, WANG Xin, LIU Wenyan
Abstract (
192 )
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Thermoplastic polyurethane （TPU） elastomers have been widely used in the storage and transportation of petroleum products due to their excellent wear resistance and solvent resistance. During the storage and transportation processes of jet fuel， The TPU equipment has to face various complex transportation environments. In such processes， the TPU hoses may be affected by the dual effects of jet fuel and ultraviolet radiation. If this impact causes their thermal characteristics to no longer meet the demand and results in an economic loss and environmental problems. Therefore， the impact of jet fuel on the thermal performance of TPU during storage and transportation cannot be ignored. In this study， differential scanning calorimetry and thermogravimetry analysis were conducted to investigate the thermal performance of the TPU treated with jet fuel and UV irradiation. The results indicated that a long⁃term immersion in jet fuel led to an increase in the glass transition temperature and a decrease in the thermal stability of TPU. After treatment with jet fuel， the TPU samples exhibited an exothermic peak at 150 ℃ as a result of the presence of crystallization.
WANG Han, LIANG Jinhua, GAO Zhenguo, JIANG Wei, ZHOU Hao
Abstract (
288 )
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To investigate the effect of the introduction of self⁃healing epoxy microcapsules on the mechanical properties and repairability of resin⁃based composite materials， a repair system consisting of in⁃situ polymerized epoxy microcapsules and phthalic anhydride as a latent curing agent was incorporated into the mixture of E51⁃type epoxy resin and modified polyetheramine curing agent， resulting in the formation of self⁃healing epoxy resin⁃based composite materials. The shear viscosity of the mixing system was analyzed， and the mechanical and repairing performance of the composite materials were investigated. The results indicated that the increase of the content of self⁃healing components resulted in a decrease in the mechanical properties of the composite materials but an increase in their healing efficiency. However， the tensile strength of the repaired composite materials did not show a linear increment. Through comprehensive analysis on the experimental results， the optimal choice was determined to be a self⁃healing component ratio of 3/2 and a microcapsule content of 8 wt% for the composite materials. Under these conditions， the resultant composite material exhibited tensile strength of 15.32 MPa and post⁃repair tensile strength of 10.13 MPa， presenting a healing efficiency of 66.12 %.
YAN Cheng, LI Lulu, CHEN Tianhuan, GUO Shuai, YU Kejing
Abstract (
202 )
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A polydopamine coating was first formed on the surface of ultra⁃high molecular⁃weight polyethylene （PE⁃UHMW） fibers， followed by an in⁃situ growth of ZnO nano⁃arrays grown on the fiber surface using a hydrothermal method. The aspect ratio of ZnO obtained from the PEI⁃mediated synthesis and the interfacial properties of PE⁃UHMW fibers before and after modification were investigated， and the enhancement mechanism was revealed. The results indicated that the growth of ZnO nano⁃arrays did not affect the thermal stability and crystallinity of the fibers， and there was less damage to the fibers. The system obtained the highest aspect ratio of ZnO at a PEI concentration of 3 mmol/mL. The interfacial bond strength and interlaminar shear strength of the fibers were enhanced by 63.6 % and 70.14 %， respectively， after the modification.
ZHANG Zhiqi, WANG Xiangdong, LIU Haiming, CHEN Shihong
Abstract (
280 )
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Biobased polyamide 56 （PA56）/polyamide 66 （PA66） blends were toughened by using polyamide elastomer （MH2030）， and then a series of bio⁃based polyamide blend foams were prepared through a supercritical CO2 intermittent foaming technology. The effect of MH2030 content on the crystallization， rheological， mechanical properties， and foaming behaviors of the PA56/PA66/MH2030 blends was investigated. The results indicated that the introduction of MH2030 improved the viscoelasticity and foaming performance of the blends， leading to a shift of the crystallization peak toward a high temperature. This may be due to the nucleating effect of MH2030 on the crystallization of the blending system. The addition of MH2030 also increased the toughness of the blends but reduced their rigidity. The blend containing 20 wt% MH2030 exhibits the highest impact strength， which is 30.4 % higher than that without MH2030. The foaming behavior and compression performance of the blend foams were investigated. The blend form containing 10 wt% MH2030 exhibits a higher cell density and better matrix mechanical properties. In this case， the blend foam obtained micro⁃size pores with a smaller cell size of 19.24 μm and higher compressive strength of 0.71 MPa， which was 29.1 % higher than that of the non⁃toughened PA56/PA66 blend foam.
LAN Qing, HOU Xinyi, LI Yifan, PAN Kai, ZHOU Jiaju, HUANG Danmeng, HUANG Haobing
Abstract (
268 )
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Ground calcium carbonate was modified through water grinding and polymerization modification to fit the application in poly（vinyl chloride）（PVC） pipes， and its structure and performance were investigated by using particle size analyzer， thermogravimetric analyzer， infrared spectrometer， pendulum impact testing machine， universal tensile testing machine， colorimeter， and gloss meter. The results indicated that the surface coating modification of calcium carbonate with polyvinyl acetate could be performed through in situ polymerization in calcium carbonate slurry. Compared to conventional stearic acid⁃modified calcium carbonate， polyvinyl acetate⁃modified calcium carbonate exhibited better appearance and mechanical properties in the PVC application. This is due to the fact that polyvinyl acetate can better enhance the compatibility between calcium carbonate and polyvinyl chloride.
ZHANG Yi, HUANG Yating, WEI Yongbao, TANG Wei, QIAN Lijun
Abstract (
225 )
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The pyrolysis and combustion mechanisms of polypropylene （PP） containing different flame retardants were investigated by using a reactive force field method. The pyrolysis reactions and flame retardancy of block copolymers （PAPO⁃MP） and blends （PAPP/MPP） were compared through the simulations in a molecular level. The results indicated that the difference between the calculation and the experiment in the mass residual yield was less than 2.1 %. The activation energy of the reaction decreased from 200.16 （pure PP） to 154.64 （PAPO⁃MP） and 159.14 kJ/mol （PAPP/MPP）. This indicated that there was a prior response in the thermal decomposition of flame retardants to protect the substrate. Furthermore， the gas molecules decreased by 10 % for PAPO⁃MP and 17.5 % for PAPP/MPP. The P—O—P structure facilitated the generation of macromolecular agglomeration， thus reducing the toxic gases and improving the char residue. Moreover， the potential energy of the system was reduced by 11.6×103 kcal/mol with the addition of PAPO⁃MP compared to PAPP/MPP. In this case， the block copolymers exhibited a better stability.
Processing and Application
FENG Jingming
Abstract (
159 )
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A composite isolator was proposed for the used in power equipment and then formed through over⁃injection molding using polyurethane and thermoplastic polyurethane elastomers as raw materials. Taking the isolation of a compressor as an example， the composite isolator was designed， and the dynamic stress analysis of the designed composite isolator was simulated by using the simulation software of the company to provide a guide for the design. Finally， the results from the durability⁃comparative experiment of the composite isolator and rubber isolator preliminarily indicated that the composite isolator exhibited better durable performance and lighter weight than the rubber isolator.
LI Mingkun, LIN Rongtao, ZHANG Yong, LIU Peiru, LIU Kai
Abstract (
201 )
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During the rainy season， rain will affect the direction of the radar wave emitted by the radar detector embedded in the acrylonitrile⁃styrene⁃acrylic acid copolymer （ASA） grid， resulting in misreport. The purpose of this work is to explore the influence factors of automobile ASA grille material to improve the attenuation performance of radar wave and to reduce the risk of misreport by radar from the perspective of material optimization. The results indicated that the content and type of acrylate segment in the ASA material were the key factor， and the ASA powders with a high acrylate content and a small rubber particle size exhibited better attenuation performance of radar wave.
YANG Chaoyong, GUO Jinqiang, WANG Fuyu, ZHANG Yuxia
Abstract (
226 )
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The in⁃situ fibrillation films based on poly（adipic acid/butylene terephthalate） （PBAT）/poly（lactic acid） （PLA） blends were prepared by extrusion blowing through adjusting the extrusion process conditions such as die temperature and traction speed. The results indicated that PLA tended to form fibers in PBAT/PLA blend system with an increase in the traction speed at lower die temperature. The formed fibers tended to refine with an increase at first and then a decrease in the crystallinity. The longitudinal tensile strength and tensile modulus of in⁃situ fiber formed films also increased at first and then tended to decrease. The effect of PLA in⁃situ fibrillation was the most obvious in the blend at a die temperature of 150 ℃ and a traction speed of 5.0 m/min. Meantime， the longitudinal tensile strength and modulus of the films reached 40.0 and 723.9 MPa， respectively. Their tensile strength was 20 % higher than that of pure PBAT， whereas their tensile modulus was much higher than that of pure PBAT.
Additive
SONG Zirui, LIU Baijun, ZHANG Mingyao
Abstract (
266 )
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In this study， acrylonitrile⁃butadiene⁃styrene copolymer （ABS） grafting copolymer latexes with core/shell mass ratios of 60/40 and 70/30 and different initiator dosages in the grafting process were prepared through emulsion grafting polymerization. The effects of the shell thickness of ABS and the dosage of waterborne antioxidant on the thermo⁃oxidative aging properties of the ABS grafting copolymers were systematically investigated. The effect of the dosage of water⁃based antioxidant on the mechanical performance and apparent properties of the ABS obtained from melt blending was also investigated. Meanwhile， the effects of waterborne antioxidant and shell thickness on their mechanical and apparent properties were studied. The results indicated that a thinner shell resulted in poorer thermo⁃oxidative aging performance of the ABS grafting copolymers. Both the impact strength and apparent properties of the ABS grafting copolymers were influenced by their shell thickness. When the addition amount of waterborne antioxidant was below 1 wt%， a higher dosage of waterborne antioxidant led to a higher the oxidation induction period and oxidation induction temperature for the ABS grafting copolymers. When 0.75 wt% waterborne antioxidant was incorporated， the heat resistance and oxygen aging of the ABS grafting copolymers reached a high level. The addition amount of waterborne antioxidant did not affect the mechanical properties of the ABS grafting copolymers， but influenced their apparent properties such as whiteness and yellow index significantly.
JIANG Fangxin, LI Xianhua, TIAN Qingtao, WANG Limin, LI Peixun, DU Jiangtao
Abstract (
173 )
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In recent years， the retard⁃bonded pre⁃stressed technology has become popular in the pre⁃stressed structures thanks to its excellent characteristics. The key material for the retard⁃bonded pre⁃stressed technology is the retard⁃bonded pre⁃stressed steel strand， and the technical principle is to bond the steel strand with the surrounding concrete through an adhesive solidified in the steel strand. Therefore， the bonding and anchoring properties of the structure are improved. At present， there are few researches on the curing evaluation index of the adhesive in academic and engineering circles. In this paper， four common curing indexes of the cured adhesives were studied， including shore hardness， tensile shear strength， compressive strength， and bending strength. The results indicated that the corresponding curing time was close to each other when the four curing indexes of the adhesive reached maximum， indicating that the four curing indexes were consistent. The maximum values of shore hardness exhibited the smallest dispersion coefficient of 0.013， and the characteristic value at a shore hardness of 80 D presented the best curing evaluation index for the complete curing of adhesives.
Plastic and Environment
SUN Jishu, PENG Junbo, ZHANG Min, GUO Yanfang
Abstract (
166 )
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To verify the applicability of waste oil for the recovery of asphalt aging performance， a composite waste oil regeneration agent was prepared by means of a response surface method using waste oil， C9 petroleum resin， and dioctyl adipate as raw materials. To avoid the volatilization and aging of lightweight components during the mixing process of recycled asphalt， a warm mixing agent was introduced to reduce the mixing temperature and obtain performance protection of recycled asphalt. At the same time， the regeneration effect of the recycled agent on the aged asphalt and the protective effectiveness of the warm mixed agent were investigated. The results indicated that the defects of poor low⁃temperature ductility of aged asphalt were recovered. The recycled asphalt exhibited a better resistance to high⁃temperature deformation than base asphalt. After warm mixing， there were more viscous components in the recycled asphalt. This resulted in superior low⁃temperature rheological performance. The regenerant supplemented the aromatic compounds of the aged asphalt effectively. The small molecular oil substances in the warm mixed recycled asphalt were well protected， and the generation of large molecular matter groups during the secondary aging was controlled.
Machinery and Mould
LIN Gaoming, ZHANG Guohui, ZONG Huceng, WANG Chongyang, HE Youfeng, WANG Suwei
Abstract (
192 )
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To solve the problem of human⁃machine interaction and manual operation in the charging process of polymer⁃based high⁃viscous slurry， a vertical spiral extrusion⁃charging process was adopted to obtain a continuous loading of energetic slurry. Based on analyzing the characteristics of the high viscous slurry， the screw configuration and barrel structure were simulated and optimized. The results indicated that pineapple head mixing element not only improved the particle⁃mixing effects but also caused hidden dangers such as a rise in high shear and high temperature. Therefore， this mixing element is not suitable for the stable and safe transportation of a high⁃sensitivity slurry. Meanwhile， the blocking effect of the flow channel was significantly reduced by setting the size of the die and the cone angle of the barrel to be Φ30 mm and 1 °， respectively. This could weaken the hidden dangers such as high pressure and high temperature to ensure process safety.
Review
ZHANG Zheng, LI Fangquan, LI Jie, LI Changjin, GUO Min, WANG Ying
Abstract (
358 )
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This paper reviewed the research progress in polyamide （PA） and its applications for medical health materials， including the PA⁃based sutures， medical catheters and balloon， denture materials， antibacterial materials， 3D⁃printed medical materials， medical bone growth scaffolds， drug⁃delivery materials， and wound repair materials. Meanwhile， their application effectiveness and performance were discussed.
WU Ruonan, SHI Wenzhao, LU Shaofeng, LIU Jinshu, DONG Jiankun, CUI Junjie, ZHANG Ling
Abstract (
237 )
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This paper introduced the preparation methods of β⁃Cyclodextrin polymer（β⁃CDs）and reviewed the research progress in its adsorption mechanism and application effectiveness in the adsorption and separation of printing and dyeing wastewater pollutants such as anionic dyes， cationic dyes， heavy metal ions， and bisphenol. Meanwhile， the future development trend of β⁃CDs in research and applications was prospected.
CHEN Xiaoqing, LIANG Jiahao, XIE Wenyu, SHAO Weiming, WANG Ruzhen, FU Wen, CAI Yebin
Abstract (
271 )
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This paper introduced the construction and fabrication technology of photothermal evaporation membranes with different structural forms through electrospinning. The current application status of different electrospun photothermal fibrous membrane materials for solar interface evaporation was summarized， including carbon⁃based composite fibrous materials， metal plasmon composite photothermal fibrous materials， and semiconductor composite photothermal fibrous materials. Finally， the future direction in the research of photothermal evaporation membranes was prospected.
