Materials and Properties
HAO Chunbo, XIAO Dajun, LIU Quanzhong, ZHENG Shusong, WANG Chun, LI Chunhui, YAO Xiuchao
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620 )
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In this study， high⁃flowing and high⁃impact polystyrene （FHIPS） was prepared through a continuous bulk polymerization process. The effect of the addition amount of mineral oil on the melt flow rate and mechanical properties of the as⁃prepared FHIPS was investigated， and its microscopic and macroscopic properties were comparatively studied with those of foreign standard products. The results indicated that the melt flow rate of FHIPS gradually increased with an increase in the addition amount of mineral oil. Compared to the similar foreign product of FHIPS （HIPS425TVL）， the FHIPS prepared in this work exhibited the same physical properties along with a higher melt flow index.
WANG Zehui, WANG Zhenjun, WANG Xiaofeng, YANG Bo, LI Shuai
Abstract (
500 )
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To understand the effect of raw materials on the mechanical properties of polyurethane grouting materials （PGMs）， a series of solvent⁃free and environmentally friendly PGMs were prepared using polyester polyol （polyether polyol） and isocyanate as main raw materials together with surfactants， catalysts， cross⁃linking agents， and foaming agents as additives. The properties of the as⁃prepared PGMs， including the characteristics of functional groups， cellular structure， and compressive strength， were characterized by using Fourier⁃transform infrared spectroscopy and scanning electron microscopy， etc. The results indicated that the addition of 10 % polyester polyol increased the content of the benzene ring in the system， resulting in an improvement in the compressive strength up to 1.09 MPa. The optimum proportion of PGMs was determined to be polyether polyol 90 phr， polyester polyol 10 phr， triethylenediamine 0.6 phr， dibutyltin dilaurate 0.6 phr， surfactant 2.0 phr， triethanolamine 4.0 phr， water 2.5 phr， and blowing agent monofluorodichloroethane 9 phr according to the polyol mass in the units through calculating the loadings of the raw materials.
WEI Daidong, LI Huizhi, ZENG Juanjuan, ZHAO Chuanguo, LI Shiqiang
Abstract (
598 )
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In this work， a vegetable oil⁃based （ESOD） polyol with a high hydroxyl value was obtained through a ring⁃opening reaction between epoxidized soybean oil and 2，2⁃bis（hydroxymethyl）propionic acid using a solvent⁃free method. To fabricate an anti⁃graffiti and self⁃cleaning coating， the ESOD polyol， mono⁃hydroxy⁃terminated polydimethylsiloxane （PDMS⁃OH）， and hexamethylene diisocyanate trimer were employed as a polyol component， a low surface energy component， and a curing agent， respectively. The as⁃prepared biobased coatings look very smooth and transparent. With incorporating only 1 % of PDMS⁃OH， the resulting coatings exhibited outstanding anti⁃graffiti and self⁃cleaning performance. The droplets of water， coffee， rice vinegar， hexadecane， or peanut oil could slide off from the surface of the coa⁃tings without leaving any wetting footprints. Graphite powders， clay powders， and orange pigment powders could be efficiently removed by dripping water. Impressively， the coatings presented good wear resistance. Even after subjected to 1，200 cycles of writing and erasing with an oil⁃based marker pen， the coatings still exhibited a good ink shrinkage ability due to easy easing of ink traces.
WU Feng, HAN Shuo, CHEN Shihong, WANG Xiangdong
Abstract (
596 )
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The effects of pyromellitic dianhydride （PMDA） dosage， foaming temperature， and the pressure⁃dropping rate on the formation of open⁃cell foams were investigated. The results indicated that the PET open⁃cell foams with a foa⁃ming rate of 35 times and an opening rate of 96.3 % could be prepared at a foaming temperature of 216 ℃ and a PMDA dosage of 0.6 phr together with a high pressure⁃dropping rate. Polytetrafluoroethylene （PTFE） and organic modified montmorillonite （MMT） were introduced into the PET open⁃cell foams during the preparation process. PTFE and MMT presented a heterogeneous nucleation effect to reduce the size of the cell and widen the foaming window temperature of PET open⁃cell foams. The PET open⁃cell foam with a smaller cell size （10~100 μm） and an almost foaming rate of 40 times was successfully fabricated within a wider foaming temperature window of 222~228 ℃. The open⁃cell foam could absorb various petroleum products such as gasoline， diesel， kerosene， light crude oil and heavy crude oil. The oil absorption behavior of the open cell foams with a high open⁃cell rate was investigated. The open cell foams exhibited a good absorption capacity along with a high open⁃cell rate of around 8~30 g/g.
DONG Jinghui, SANG Xiaoming, CHEN Zhen, YIN Weihao, JIANG Qian, CHEN Xinggang
Abstract (
510 )
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A series of phthalonitrile/carbon fiber composites were prepared using short⁃cut carbon fibers as a reinforcement agent， and the effects of the content and length of short⁃cut carbon fibers and the type of coupling agent on the mechanical properties of the composites were investigated using a universal testing machine and a dynamic thermomechanical analyzer. The results indicated that the composites obtained optimal mechanical properties and thermal stability when phenyltriethoxysilane was used as a coupling agent. Compared to the composites without a coupling agent， the composites modified with phenyltriethoxysilane exhibited an increase in the energy storage modulus by 22.2 % and in the characteristic temperature at a 5 wt% weight loss by 33.1 %. With an increase in the addition amount of carbon fibers， the mechanical properties of the composites showed an increasing trend at first and then tended to decrease. The composites obtain optimal mechanical properties at a carbon⁃fiber loading of 0.3 wt%. Compared to pure phthalonitrile resin， the composites achieved an increase in bending strength by 38.4 % and in bending modulus by 97.7 %. The composites exhibited higher bending strength and a higher energy⁃storage modulus at a carbon⁃fiber length of 6 mm than those at a fiber length of 3 mm.
ZHOU Xiangyang, LIN Yibing, XU Zixuan, GONG Genxiang, REN Min, YIN Guoqiang
Abstract (
506 )
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In this paper， PVA/starch composite membranes were grafted with dimethylaminoethyl methacrylate （DMAEMA） as a modifier. The composite membranes were endowed with a selective transmission function of CO2 gas through introducing tertiary amine groups. The CO2 transmission volume was optimized through exploring the relationship between the molecular structure and performance. Based on the characterization results from infrared spectroscopy， X⁃ray photoelectron spectroscopy （XPS）， atomic force microscopy， and permeability tests， the composites exhibited selective permeability to CO2 after grafting DMAEMA into starch. The CO2 transmittance of the DMAEMA⁃grafted starch increased by 28.03 times from 1.577 to 45.786 cm3/（m2∙24 h∙0.1 MPa） at a graft rate of 55.3 wt% and a copolymer amount of 1.5 wt%. The XPS results indicated a decrease in binding energy at 399.8 eV in N1s spectrum and an increase in binding energy at 401.8 eV after CO2 permeates the composite membranes. CO2 can react with tertiary amine groups on the composite membranes to realize an internal transfer. Therefore， the surface roughness of the composite membranes increased， and there was a transition from the curled state to the extended state for the molecular chains on the membrane surface， resulting in an increase in the contact with CO2.
GAO Qiqi, HAO Yanling, CHENG Long, SONG Xiaoshuang, WANG Shihui
Abstract (
506 )
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TiO2 nanoparticles were incorporated into corn starch to prepare a series of biodegradable starch/TiO2 nanocomposite films for food packaging through ultrasonic dispersion and solution casting. The effect of TiO2 nanoparticles on the mechanical properties， water vapor resistance properties and antibacterial activities of the nanocomposite films were investigated. Scanning electron microscope， infrared spectrometer and X⁃ray diffractometer were used to characterize the morphology and microstructure of the films. The results indicated that the compatibility of corn starch with TiO2 nanoparticles was enhanced at a proper addition amount of TiO2 nanoparticles due to the formation of molecular association. Compared to pure starch film， the nanocomposite films achieved an effective improvement in mechanical performance and vapor barrier property. The nanocomposite film containing 0.8 wt% TiO2 nanoparticles presented tensile strength of 7.54 MPa and water vapor permeability of 5.50×10-5 g/（mm·d）， which were 53.9 % higher and 23.5 % lower than those of pure starch film， respectively. The nanocomposite films exhibited a good antimicrobial capability and reduced transmittance of UV light.
WENG Chengwu, ZHENG Yuying
Abstract (
710 )
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In this paper， a polyurethane sponge material with low temperature resistance and slow resilience was prepared using silicone modified polyether （Si⁃APEG） as a low⁃temperature resistant agent. The Si⁃APEG was synthesized through a hydrosilylation reaction of allyloxy polyoxyethylene ether （APEG） and polymethylhydrosiloxane with chloroplatinic acid as a catalyst. The effects of the Si⁃APEG dosage on the apparent core density， porosity， tensile properties， resilience and temperature humidity sensitivity index of the sponge were investigated. The results indicated that the foam structure of the sponge was ideal at an Si⁃APEG dosage of 10 phr， and its comprehensive mechanical properties were optimal along with the lowest hardness and resilience. Meanwhile， the temperature and humidity sensitivity index of the sponge was as low as 1.01， and its hardness was as low as 53 degree at -10 ℃. Therefore， the sponge could achieve optimal comprehensive performance at an Si⁃APEG dosage of 10 phr.
Processing and Application
CHEN Yu, ZHANG Chunhui, CUI Zheng, SUN Tongbing
Abstract (
646 )
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Flexible plastic packaging is conducted by using the complex materials obtained from combining two or more different film materials through adhesives. Flexible plastic packaging has widely used in the fields of food， daily chemical， medicine， industry， and agriculture， etc. As the world enters a low⁃carbon and sustainable era， single⁃materialization and single⁃material enabling technology， new inks， and environmentally friendly adhesive technologies have jointly constructed a low⁃carbon， zero⁃carbon， and carbon⁃negative technology innovation system， and they promoted the plastic flexible packaging industry to enter a low⁃carbon， circular and sustainable high⁃quality development period.
ZHAI Yongyi, LI Ruili, BU Yuhao, JI Yaru
Abstract (
696 )
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The octahedral UiO⁃66 was prepared by means of a solvothermal method， followed by modification through doping an Mg metal. To explore the optimal doping concentration， the Mg⁃UiO⁃66⁃n （n is molar ratio of magnesium to zirconium） adsorbent was prepared， and their morphology and surface properties were characterized using X⁃ray diffractometer， infrared spectrometer， and scanning electron microscope. The adsorption and dechlorination properties and adsorption mechanism of Mg⁃UiO⁃66⁃0.07 were investigated. The results demonstrated the successful fabrication of the Mg⁃doped UiO⁃66 adsorbent. The Mg⁃UiO⁃66⁃0.07 achieved the best adsorption effect at an adsorption time of 4 h and an adsorption temperature of 40 ºC. The Mg⁃UiO⁃66⁃0.07 gained a removal rate of 95.03 % at a solvent⁃to⁃oil ratio of 1/40 and could be recycled for reutilization 5 times. This adsorption process is a spontaneous chemical adsorption process， which conforms to a pseudo second order kinetic model.
LI Chuanmin, YANG Jianjun, LI Yang, WANG Luowei
Abstract (
618 )
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Taking the mixture of high⁃viscose polydimethylsiloxane （PDMS） and silicon carbide （SiC） powders as an example， the active mixing nozzle was designed and optimized through hydrodynamic simulation. The influence of different screw structures on the mixing effect of active mixing nozzle was analyzed through simulation. The bidirectional quad⁃screw structure was selected to explore the effect of structural parameters such as screw length， screw and cavity clearance on the mixing effect. The screw length and the gap between screw and cavity were determined to be 12 and 0.2 mm， respectively. The rotation speed and inlet speed of the structure were optimized， and the rotation speed and inlet speed were determined to be 60 r/min and as 1 mm/s， respectively. In addition， the structure can be mixed effectively under different material volume ratio based on the analysis results. Through printing samples， it was confirmed that the effective mixing of composite materials could be realized by using the active mixing nozzle.
HUANG Yating, LI Lianliang, ZHANG Yi, TANG Wei, QIAN Lijun
Abstract (
895 )
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This paper reviewed the research progress in waterborne intumescent flame⁃retardant coatings for steel structure， and the mechanism of thermal insulation was analyzed. The classic expansion flame⁃retardant system， new synergistic flame⁃retardant systems， and methods for water⁃resistant improvement were introduced. Acrylic resin， epoxy resin， waterborne polyurethane， and silicone as well as their modification technologies were discussed. The synergistic effects of flame⁃retardant， fillers and nanomaterials were analyzed in detail. Finally， the future research direction of waterborne intumescent fire⁃retardant coatings for steel structure was prospected.
Plastic and Environment
YANG Min, WANG Ying, CHEN Lei, MA Huifang, YAN Guihuan, WANG Wenyu
Abstract (
1006 )
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In this paper， the sources and distribution of microplastics and their migration and transformation processes were introduced. The toxic effect of microplastics was analyzed and evaluated. Furthermore， the research progress in the removal technology of microplastics by means of coagulation， advanced oxidation， and membrane bioreactor technologies were reviewed. The potential risks to ecosystems and human health caused by microplastics were demonstrated. In addition， the advantages and shortcomings of current microplastics removal technologies were presented， and then the suggestions and outlooks for future research on microplastics were proposed.
Machinery and Mould
ZHANG Weihe, WEN Huangying, FENG Jing
Abstract (
503 )
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In this work，we designed a bicolor injection mold for the cover of an intelligent positioner according to its structural characteristics and test requirements. The mold structure was simplified， and the safety and stability of the mold ope⁃ration were improved by using a fixed mold side core⁃pulling mechanism. The auxiliary flow channel of ABS melt was formed by employing a process core. As a result， the melt could enter the cavity from the inner side through the submarine gate. This ensured the appearance quality of the molded products and realized the automatic bicolor molding. As the mold was put into production， the operation of the mold was confirmed to be safe and stable， and the quality of the molded products reached the design requirements. All of these indicated that the mold structure was advanced and reasonable.
Review
YANG Chen, TANG Xiaodong, LI Jingjing, FENG Xuefeng, CAO Yefei, GAO Zhiqiang
Abstract (
1109 )
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This paper introduced the synthetic mechanism and industrial production methods of bisphenol⁃A epoxy resin. The research progress in the synthesis technology of bisphenol⁃A epoxy resin by using one⁃ and two⁃step methods was reviewed. The one⁃step technology includes the addition of catalysts， alkali⁃fixing method， solvent method， sodium salt method， and atmospheric and vacuum azeotrope method. The two⁃step technology includes the two⁃step kinetics， usage of catalysts， and decrease of hydrolyzed chlorine. The problems existing in the synthetic technologies were analyzed， and the future development direction of the synthetic technology for bisphenol⁃A epoxy resin was prospected.
PU Chenlu, LI Gen
Abstract (
509 )
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In this paper， the possible food contaminants in food packaging and their analytical techniques were reviewed. These possible food contaminants include antioxidants， intentional additives， non⁃intentional additives， oligomers， and volatile odor substances. The qualitative analysis techniques for the contaminants cover the analyses of volatile organic compounds and non⁃volatile organic compounds. The surface analysis and quantitative analysis techniques were mainly introduced. This review paper can provide a technical reference for the quality control of food packaging and the supervision of food safety.
JIN Qingping, LIU Yundie
Abstract (
473 )
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In this paper， the durability of fiber⁃reinforced⁃polymer （FRP）⁃confined concrete columns was analyzed in seve⁃ral aspects including different corrosion environments， temperatures， and action modes. The retention rate of compressive strength of FRP⁃confined concrete columns was fitted under different factors， and the effect of the different factors on the mechanical properties of FRP⁃confined concrete columns was discussed. This paper can provide a reference for the subsequent durability research and practical applications of FRP⁃confined concrete columns.
