Materials and Properties
JIANG Guo, LU Wanxia, ZHANG Shuidong
Abstract (
771 )
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Anhydrous zinc acetate （ZA）-modified thermoplastic starch （TPS） and tartaric acid （TA）-modified TPS were prepared through a twin?screw extruder and then designated as TPS?ZA and TPS?TA， respectively. The rheological behavior， morphology and mechanical properties of poly（propylene carbonate） （PPC）/TPS composites were investigated. The results indicated that compared to ZA， TA could help to improve the dispersibility of TPS in the PPC matrix. The mechanical properties of the composites were increased with the addition of TPS-TA at low contents. The PPC/TPS composites achieved optimal performance at a TPS-TA dosage of 10 wt%. The tensile strength of the composites increased up to 8.11 MPa from 5.70 MPa of pure PPC， and their characteristic temperature at 5 % weight loss also increased 31.7 ℃.
TANG Shi, ZHAO Jingjing, SU Tingting, WANG Zhanyong
Abstract (
1067 )
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Modified thermoplastic starch （TPS） was prepared through a torque rheometer using different sources of starches as raw materials and propylene glycol as a plasticizer. The resultant thermoplastic starch was characterized with X?ray diffraction， thermogravimetric analysis （TGA）， water contact angle and scanning electron microscopy. The results indicated that there were four types of thermoplastic starches containing granular and granular fragments， in which the proportion of thermoplastic cassava starch was higher. The torque of starch reached an steady state in the carbohydrate process in an increasing order of cassava starch （23 N·m） > corn starch （21 N·m） > potato starch （17.8 N·m） > waxy corn starch （15.2 N·m）. This result is directly related to the amylose ratios among these different starches. According to the infrared analysis result， there was a different hydrogen bonding capability between the different types of starches and plasticizer. Waxy corn starch exhibited the strongest bonding， which was consistent with the TGA results. The four types of TPS presented an increase in the level of hydrophilicity in an order of thermoplastic cassava starch （75.9 °）>thermoplastic corn starch （69.2 °） > thermoplastic potato starch （67.9 °） > waxy corn starch （64.9 °）.
WANG Conglong, HAN Shuo, ZHANG Yihui, CHEN Shihong, WANG Xiangdong
Abstract (
644 )
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259
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Polyether sulfone （PES） foams were prepared through a batch?foaming method using supercritical CO2 as a foaming agent， and their homogeneous nucleation behavior during the foaming process was investigated with talc and SiO2 as heterogeneous nucleating agents. The results indicated that the foaming parameters were determined to be a temperature of 200~230 °C， an optimal immersion pressure of 20 MPa， and an optimum soaking time of 3 h for the intermittent foaming method. The pore diameter of unmodified PES foams was less than 10 μm， and their pore density was 109~1010 /cm3 with a thicker pore wall. SiO2 was found to show a more obvious heterogeneous nucleation effect than Talc. Under the foaming conditions of 210 °C， 3 h， 20 MPa， PES foams achieved a diameter of 0.77 μm and a cell density of 4.16×1011 cells /cm3 in the presence of 0.9 wt% SiO2.
LU Zhangxiang, SONG Ge
Abstract (
663 )
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To study the effect of a variety of reinforcing fibers composed of only non?metallic mixtures on the friction and wear properties of resin?based friction materials， the friction materials were prepared by adding carbon fiber and aramid pulp fiber through a hot?pressing sintering technology using the cashew?nut?shell?liquid?modified phenolic resin （CNSL） as a matrix. The friction and wear performance of the friction material under different braking conditions was investigated using a ring block friction and a wear tester equipped with high?speed steel. The wear morphology of the friction materials was analyzed with scanning electron microscopy. The results indicated that the friction material （P3） containing 4 vol% glass fiber， 10 vol% carbon fiber and 3 vol% aramid pulp fiber exhibited high hardness than the friction material （P1） at the corresponding fiber contents of 7， 4 and 6 vol% and the friction material （P2） at the corresponding fiber contents of 1， 7 and 9 vol%. Under the different braking conditions， the sample P1 had the largest friction factor， the sample P3 had the second， and the sample P2 had the smallest. The relative wear rates of the samples P3 and P2 were similar and relatively stable， which were about 1 ~ 1/5 of that of the sample P1. The sample P3 exhibited the best tribological performance. The wear form of friction material and mating material was determined to be mainly abrasive wear.
YANG Wenjie, HE Jiawen, ZHU Hanbin, WANG Sisi, LI Xiping
Abstract (
464 )
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Poly（lactic acid） （PLA）/graphene nano?platelet （GNP） composites were prepared by melt blending with different GNP contents， and their micromorphologies， mechanical properties， rheological behaviors and foaming properties were investigated. The results indicated that GNP presented a good dispersion in the PLA matrix. Compared to pure PLA， the composites exhibited an improvement in tensile strength and stiffness by nearly 20 % at a GNP content of 3 wt%. In addition， the movement of PLA chains was restricted with gradually increasing the GNP content. This enhanced the viscoelasticity of composite melts significantly， which was beneficial to the PLA foaming. Owing to the heterogeneous nucleation of GNP， the composite foams presented a large foaming ratio more than 30 times， and their compressive strength and modulus increased by 2.5 and 7 times， respectively.
ZHAO Xingmin, ZHAO Jianping, YAN Jizhong
Abstract (
1218 )
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401
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An artificial accelerated aging method was adopted to simulate the photo?oxygen aging process of high?density polyethylene （PE?HD） pipes and butt fusion joints under the natural sunlight. A UVA?340 standard fluorescent ultraviolet lamp was used to simulate the aging process in the two cycle modes of light and condensation at different temperatures of 50 ℃， 60 ℃ and 70 ℃. Infrared spectroscopy was also conducted to analyze the chemical structures of the aged pipe and joint samples. The results indicated that with an increase in aging time， the joint showed higher peak intensity for the olefin and carbonyl absorption in the joint than that in the pipe due to the increase of the photo?oxidation aging degree. Meanwhile， the oxidation induction time of pipes and joints were measured with different aging time at different temperatures. The oxidation induction time and the relationship between natural sunlight and fluorescent ultraviolet lamp irradiation were fitted by means of the kinetic curve linearization method， and a life prediction model for the natural light aging of high?density polyethylene pipes was proposed. The results indicated that the lifespan of PE?HD butt fusion joints exposed to the natural environment was 33.76 % shorter than that of the pipes at room temperature.
LI Lu, LIU Feixiang, LUO Huiling, CHEN Guohua
Abstract (
844 )
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The graphene and other carbon nanomaterials were mixed and ground with solvents and various additives to prepare a stable graphene composite conductive paste. This conductive paste was sprayed on the surface of acrylonitrile?butadiene?styrene copolymer （ABS） to provide excellent electrical conductance for ABS， followed by an electroplating treatment. To improve the bonding force between the graphene coating and the surface of ABS， different surface treatments were carried out for the ABS， which included the matte， organic solvent micro?corrosion and chemical roughening methods. The results indicated that the surface roughening treatments resulted in the formation of micropores on the plastic surface， leading to an enhancement in hydrophilicity. The chemical roughening method also produced some hydrophilic groups on the plastic surface， thus greatly improving the adhesion of the graphene coating. The ABS/graphene system presented good electrical conductance with a resistance range of 0.3~5 kΩ. The products obtained from electroplating exhibited good metal luster， and their coating layers were intact and not easy to fall off.
Processing and Application
HUANG Zhichao, LUO Qiang, LAI Jiamei, LIU Shuaihong
Abstract (
719 )
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To study the influence of the position of glass fiber （G） layer on the impact damage degree of carbon fiber （C） composite panel， the impact tests were carried out for the ［CC］2s， ［CCCG］s， ［GCCC］s and ［CCGC］s composite plates using a drop weight impact test machine under the conditions of 15 J and 25 J impact energy， and the curves of contact force， energy and displacement as a function of time were obtained. A water immersion ultrasonic C?scan system was used to inspect the surface and internal damages of the composite plate after the impact tests. The results indicated that under the same energy impact， the growth rate of contact force of the ［GCCC］s composite plate was higher than those of the other three types of composite plates， and the peak value of contact force was also larger than those of the other three kinds of composite plate. There was no significant difference between the maximum displacement of punch acting on the ［CC］2s， ［CCCG］s， ［GCCC］s and ［CCGC］s composite plates under an impact of 15 J energy. However， the glass fiber appeared on the outer surface of the composite sheet under the 25 J energy impact， and the displacement of the punch was the smallest. This indicated that the impact resistance of glass fiber was improved remarkably with an increase in impact energy. In addition， the damage area of glass fiber on the surface was smaller than those of the other three composite sheets， indicating that the toughness of glass fiber was higher than that of other composite plates due to its better capability to inhibit damage diffusion.
SHA Jin, CHEN Xin, CHEN Dongping, MA Yulu, XIE Linsheng
Abstract (
623 )
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347
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In this study， a new strategy was proposed to fabricate various columnar microstructures on the glass surface through controlling the glass surface hydrofluoric acid etching process using the patterned poly（vinyl alcohol） （PVA） film. The electrohydrodynamic （EHD） technique was adopted to fabricate the cylindrical microstructures on the surface of the PVA film spin?coated on the glass surface. Followed by the hydrofluoric acid etching process， various primary microstructures were fabricated on the glass surface to tune the optical properties. The results indicated that the changes in the EHD induced voltage and the initial thickness of the PVA film could lead to differentiated cylindrical micropatterns on the PVA film. Furthermore， the changes in the etching time and concentration of hydrofluoric acid could lead to a variety of columnar microstructures on the glass surface， which dominated the optical properties of glass such as haze and transmittance. With the results obtained from this work， the application range of PVA film patterning technology in the manufacture of glass surface microstructures can be greatly expanded.
ZHOU Guofa, ZHANG Xinyu, FU Binyi
Abstract (
453 )
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The micro assembly interfacial damage deformation is one of the main bottleneck issues in the industrial application of advanced in?mold micro assembly technology. Aiming at this issue， the simulation technology of interfacial damage deformation was established for in?mold micro assembly molding. The results indicated that two types of interfacial damage deformation of depression collapse and viscous drag flying edge were easily induced near the surface of the leading edge for upstream micro assembly Interface. The interfacial damage deformation exhibited a parabola evolution law with the injection speed of the secondary molding process， which decreased at first and then tended to increase. This was positively correlated with the depression collapse driven pressure of thermal fluid solid coupling， the depression collapse?driven normal stress of viscoelastic support and the flying edge driven shear stress of viscous drag. However， it was negatively correlated with the evolution region thickness of continuous phase transition. The reduction of the thermal fluid solid coupling impact load and the thickness of continuous phase transformation evolution region is beneficial to the depression of the kinematic pair interfacial damage deformation.
GUAN Tianmin, LI Yu, ZHAI Yun, LEI Lei
Abstract (
731 )
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240
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Based on the actual stress condition of a rectangular ring structure， the sample structure was firstly modeled in a 3D mode， and then the model was imported into the simulation software to complete the static analysis under different stress conditions. The equivalent stress and deformation cloud map of the sample was obtained， and the stress concentration area of the sample was determined. The test samples with different deposition angles were processed by a melt deposition molding method. Tensile tests were carried out on these samples. The experimental results indicated that when the direction of force and deposition angle was 45 °， the fracture strength increased by 63.80 % corresponding to 0 ° and 32.81 % corresponding to 90 °. The relationship between the forming process and the anisotropy of mechanical properties was obtained. This provides a reference for the material forming process under specific working conditions.
MENG Hao, YUAN Meixia, HUA Ming
Abstract (
591 )
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361
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The melt deposition molding （FDM） 3D printing technology was used to form ABS parts of acrylonitrile （A） ? butadiene （B）?styrene （S）. The influence of nozzle extrusion temperature and layer height on the surface quality of the parts was investigated. According to the different extrusion temperature and layer height printing process parameters， multi groups of parts with the same shape and size were prepared. The surface morphology data of the parts were collected and analyzed by using the shape measurement laser microscope. The change trend of the surface parameters such as Sa、Sz、Str，etc with the extrusion temperature and the layer height was obtained. The flatness was measured and analyzed by using three?coordinate measuring instrument， and the variation trend of flatness error with extrusion temperature and layer height was obtained.The influence of temperature and layer height FDM process parameters on the surface quality of ABS printing parts was revealed The law of influence. The experimental results show that extrusion temperature and layer height have an important influence on the surface forming and surface quality of the parts. Under the same other conditions， the extrusion temperature of 230~240 ℃ makes the surface roughness of the products obtained by FDM process the best，and the flatness is the best at 210 ℃； the smaller the layer height， the better the surface roughness of the parts，and the larger the layer height， the smaller the flatness of the part.
SUN Dongbao, LU Qin, LU Xinyu, JIA Wangyi, CAO Shang
Abstract (
644 )
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PLA/rice husk powder wood plastic composites were prepared by a compression molding method with chitosan， silane?coupling agent and sodium hydroxide as modifiers. Their mechanical properties and water absorption of the composites were characterized， and their crystalline structures were analyzed with XRD. The results indicated that the composites exhibited a higher Rockwell hardness at a chitosan mass of 4 g， and their impact strength， bending strength， tensile strength， and water absorption increased by 22 %， 77 %， 48 %， and 40 % respectively. When the content of silane coupling agent was 2 g， their impact strength， bending strength and tensile strength increased by 32 %， 78 % and 61 %， respectively， but their water absorption decreased by 7 %. When the rice husk powders were treated with 6 g sodium hydroxide， the composites did not show a significant enhancement in mechanical properties， and their water absorption increased by 15 %. In summary， silane coupling agent has a good comprehensive modification effect on the composites， chitosan can better improve the mechanical properties of the composites， and NaOH is an excellent hydrophilic modifier.
Plastic and Environment
FENG Yahui, PAN Shenglin, DAI Dongqing, ZHA Yanqing, YAN Wenxun
Abstract (
518 )
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This paper introduced the types and characteristics of energy consumption， reviewed the research progress in the energy consumption evaluation and improvement of polyethylene at home and abroad according to the comprehensive energy consumption and life cycle energy consumption， analyzed the current situation of polyethylene energy consumption standardization， and briefly introduced the regulatory applications of energy consumption evaluation of recycled polyethylene in cross?border field. The analytic results indicated that energy consumption evaluation based on life cycle exhibited great potential for the application in improving the scientific supervision of cross?border recycled polyethylene pellets and promoting the development of domestic green circular economy.
Standard and Test
LI Yafei, CHEN Wenge, LUO Shaofeng
Abstract (
593 )
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238
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This article analyzed the content of the US military standard for Cover material， Vehicle， Coated Tactical and Combat， Heavy?duty， Waterproof （MIL?PRF?32002D） and introduced the requirements for the basic properties， mechanical properties， physical and chemical properties， environmental adaptability and other main technical indexes of the envelop materials and corresponding test methods. Moreover， the paper also compared the PLA military standard for General Specification for Packing Envelope （GJB 2682?1996） with the US military standard， and analyzed the similarities and differences between them. The results indicated that MIL?PRF?32002D has more technical index items （22 items） with higher technical index requirements in general. A revision was suggested for the technical indicators of the PLA military standard （GJB 2682） by referring to the US military standards.
Machinery and Mould
LIU Qingdong
Abstract (
893 )
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459
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According to the structural characteristics and technical requirements of automotive plastic parts， we designed a mold with oblique core?pulling on the both sides of moving and fixed molds along the mold opening diagonally direction. This design resolved the problem that the core?pulling and demolding of the stepped hole was not parallel to the mold opening direction. The mould was designed with a two?step core?pulling mechanism equipped with a separable top clamp plate with the A plate on the fixed mold and a core?pulling mechanism equipped with a separable B plate with the support plate on the moving mould. Meanwhile， a sequential distance parting mechanism and an accompanying mechanism for the ejector were designed. The mold has been tested to meet the production requirements and has been applied for the mass production.
CHEN Hongtu, ZHANG Weihe
Abstract (
538 )
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In this work， we designed an injection mold for the fixing frame of vehicle according to the structural characteristics and test requirements. A bicolor forming process was adopted to meet the requirement for the aspect of the product. This also made the dimensional accuracy of the products reach a MT3 level （GB/T 14486—2008）. The mold realized fully automatic production through a secondary demolding mechanism. The economic benefit of the enterprise was greatly improved， and the mold test was successful at one time. The formed plastic parts meet the requirements for the drop test and the hot and cold impact test. This result proved that the mold structure was advanced and reasonable.
Review
FENG Xiping, ZHANG Shengyuan, LIANG Qun, WANG Bo
Abstract (
819 )
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This paper reviewed the research and application works of laser in?situ curing of thermoplastic composite materials at home and abroad. Summarized three aspects of laser in?situ curing mechanism research ， experiments ， and temperature field simulation. Discussed the latest development trend of laser in?situ curing technology at last.
HUANG Fei, WU Xianan, WANG Jian, YANG Weimin, XIE Pengcheng
Abstract (
901 )
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491
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This paper discussed the importance of PVT characteristics and test technology and introduced the development status of PVT test technologies. A direct pressurization technique （piston?die technique） and an indirect pressurization technique （confining?fluid technique） as two traditional technologies were first introduced. The improved technologies based on traditional test techniques were further introduced， which included a high cooling speed piston?die technique， a modified confining?fluid technique and an online technology based on processing and molding equipment. The state of the art in the development of PVT equations of state for polymers was also briefly described. In addition， the problems and future research directions of PVT characterization and test techniques were summarized.
FAN Xiaoling, XIN Fei, CAI Liyun
Abstract (
567 )
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481
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Metal organic frameworks （MOFs） have provided a new direction for the flame retardancy of polymer materials. Besides being used as flame retardants， MOFs can also be hybridized into organic and inorganic materials to achieve better flame?retardant properties. In this paper， the classification and synthetic methods of MOFs were briefly introduced， and the recent research progress in the flame retardancy of polymer materials was reviewed in terms of the aspects from the applications of modified and unmodified MOFs in polymers to their flame retardant mechanism. The application perspective was summarized and prospected.
