Materials and Properties
SONG Renda, WU Gaojian, CHEN Junxiang, ZHANG Youchen, YANG Weimin, XIE Pengcheng
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665 )
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The microcellular foam composites with a fiber structure were prepared using polypropylene （PP）， poly（ethy?lene terephthalate） （PET）， and carbon nanotubes （CNTs） as raw materials. The in?situ formation of PET continuous fiber in the granulation stage was realized through changing the internal flow channel of the laminator. The crystalline pro?perties， apparent morphology， electromagnetic shielding effectiveness （EMI SE）， and tensile properties of the obtained composite materials were characterized using differential scanning calorimeter， scanning electron microscope， vector network analyzer， and universal testing machine. The results indicated that the composites containing 2.5 wt% PEG achieved optimal electromagnetic shielding performance， presenting the optimal in?situ fiber forming and microcellular foaming effects. This is beneficial to the construction of a conductive network based on CNTs. The microcellular foaming materials exhibited an EMI SE of 29.84 dB， and their mechanical properties were related to the fiberizing effect. The better the fiberizing effect， the stronger was the ability to bear external forces.
YU Zhixing, LI Yingcheng, WANG Hongxue, PANG Xinlei, WANG Yuyao
Abstract (
562 )
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A series of laser direct structuring （LDS） alloys based on polyamide 6 （PA6）， polycarbonate （PC） and their composite materials were prepared using a melt extrusion method. The thermal properties， solvent resistance， and mechanical properties of the LDS alloys were characterized， and their fracture mechanism was investigated. The reliability and safety of the resultant materials used for the manufacture of mobile phone components was also verified. The results indicated that the LDS alloys had special thermal properties and rheological behaviors. The PA6 component improved the solvent resistance of the alloys， while the PC component increased the heat resistance of the alloys. With an increase in the PA6 content， the notched impact strength， elongation at break， tensile strength and modulus， flexural strength and modulus of the LDS alloy all decreased at first and then increased. The LDS alloy with pure PC showed a ductile fracture， whose fracture mechanism was attributed to the formation of shear bands resulting from the external force and network structures. The LDS alloys with pure PA6 and PC/PA6 exhibited a brittle fracture， and their corresponding fracture mechanism was ascribed to the formation of a “sea?island” structure based on two phases， crazing caused by shearing fracture， and cavitation effect. The LDS alloys had excellent laser activation and electroless plating functions， and the copper/nickel plating layer displayed high reliability and safety. The alloys developed in this study were suitable for manufacturing the circuits of devices with a heterostructure.
HENG Yue, XUE Nanxiang, CHEN Zhuangxin, LEI Caihong, XU Ruijie
Abstract (
1098 )
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Two types of polyethylene （PE） with relatively different molecular weights were blended with paraffin oil （LP） separately to form two blending systems. The effects of temperature and LP content on the dynamic rheological behavior of the blend systems as well as their compatibility and microporous structure were investigated using rotating rheometer， polarizing microscope， differential scanning calorimeter and scanning electron microscope. The results indicated that the energy storage modulus， loss modulus， complex viscosity and relaxation time of PE/LP blend decreased with an increase in temperature and PL content. The compatibility between the two phases in the blend system is strongly associated with to the molecular weight of PE. The Cole?Cole curve based on the PE1 with a low molecular weight and LP system is semicircular， and the slope of the Han curve is 1.36. There is no monotectic point in the phase diagram. When the Cole?Cole curve based on the PE2 and LP system with a larger molecular weight has linear characteristics， the Han curve presented a slope of 1.2. There is an obvious monotectic point in the binary phase diagram， corresponding to the PE mass fraction （φm） of 46 wt%. This indicated that the compatibility of the former system was better than that of the latter one， and however both blend systems were molten homogeneous at a high temperature. The PE1/LP blend system was mainly involved in the solid?liquid phase separation. When the mass fraction of PE is lower than φm， the liquid?liquid phase separation mainly occurred in the PE2/LP system， resulting in a "honeycomb" porous structure.
ZHAI Yujiao, XIN Chunling, HE Yadong, YAN Baorui, QIAO Linjun
Abstract (
539 )
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Micro?foaming injection molding experiments were carried out using two gas injection methods， i.e.， a high pressure short time method and a low pressure long time method， with polypropylene and high?purity nitrogen as raw materials. In the experiment with the low pressure and long time as the gas injection method， the relationship between the cooling time and the probability of large bubbles on the product surface was investigated under the conditions of different melt temperatures， injection pressure differences and storage lengths. The results indicated that the probability of large bubbles appearing on the surface of the products obtained from the high?pressure short?time gas injection was high. This seriously affects the quality of products. The probability of large bubbles on the product surface was reduced significantly by using the low?pressure and long?term gas injection. The large bubbles on the product surface could be eliminated completely by prolonging the cooling time. In a certain range， the higher the melt temperature， the greater the injection pressure difference and the longer the storage length， the longer cooling time is needed to eliminate the large bubbles.
DENG Qian, SUN Yiting, MA Zifei, LU Zhen, LYU Donghao, XIAO Bo, LI Jixin
Abstract (
472 )
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Self?made epoxy cyclohexyl adipate （ACHD）?modified water?soluble polyester （MWPET） was prepared with terephthalic acid （PTA）， ethylene glycol （EG） and sodium isophthalic acid?5?sulfonate （SIPA） as main raw materials and epoxy cyclohexane adipate （ACHD） as a modifier， and it achieved an acid value of 9~14 mg KOH/g， a hydroxyl value of 85~110 mg KOH/g， and an intrinsic viscosity of 0.26~0.31 dL/g. The MWPET membrane with a thickness ≤45 μm and a gloss of about 100 Gu was further prepared. ACHD and MWPET were characterized using infrared spectrometer， nuclear magnetic resonance， and mass spectrometer. The pencil hardness， adhesion， water resistance， chemical resistance， and water absorption of MWPET membrane were analyzed. The analysis results confirmed the successful synthesis of ACHD. With increasing the ACHD content， the MWPET showed a decrease in glass transition temperature of decreased， its color gradually deepened， and its water solubility and water solution transparency became better at first and then tended to become worse； There was an enhancement in the hardness， water resistance and chemical resistance of the membrane， and its adhesion became stronger at first and then became weaker. The impact resistance seems to show no obvious change.
SUN Tao, YANG Qing, HU Jian, WANG Yangyang, LIU Bo, YUN Xueyan, DONG Tungalag
Abstract (
540 )
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Poly（lactic acid?co?glycolic acid） （PLLGA） was synthesized through one?step melt copolymerization using lactic acid （L?LA） and glycolic acid （GA） as raw materials， and its mechanical properties， crystallization properties and gas barrier properties were investigated. The crystalline characteristics of the PLLGA film were analyzed through Avrami equation using differential scanning calorimetry， and its mechanical and gas penetration performance were evaluated using a universal tensile testing machine and a differential pressure permeability meter through a differential pressure method. The results indicated that the introduction of GA generated a greater influence on the crystalline properties of the PLLGA film. GA could act as a nucleation agent to generate a nucleating effect on the PLLGA with a GA mole fraction of 4 %. The PLLGA film exhibited a faster crystallization rate than pure PLLA film， and its semi?crystallization time decreased. When the PLLGA had a GA mole fraction of 8 %， GA restricted the movement of the molecular chain， destroying the regularity between the copolymer molecules. This leads to a significant reduction in the crystalline properties of the PLLGA， making it in the amorphous state. With an increase in the mass ratio of GA， the PLLGA film presented a gradual decrease in tensile strength and elastic modulus， while its elongation at break increased significant. The elongation at break of the PLLGA with a GA mole fraction of 8 % reached 130.1 %， which was 21.3 times the value of pure PLLA film. In addition， the gas permeability of the PLLGA film decreased. Compared with the pure PLLA film， the O2， CO2， and N2 permeability of PLLGA film with a GA mole fraction of 8 % at 5 ℃ were reduced by 47 %， 41 %， and 39 %， respectively.
HE Mingfeng, WANG Ke, WANG Qiyang, YANG Xiao, GUO Hong, HU Boyang, LI Baoan
Abstract (
330 )
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Graphene oxide was modified with vinyl trimethoxysilane containing matrix?like groups， and then functionalized graphene （F?GE） was reduced through a one?pan method. The thermal conductive polyvinylidene fluoride （PVDF）/F?GE composites with excellent interface properties were prepared using a solvent?casting method. The modified state， microstructure， thermal conductivity， and mechanical properties of the obtained composites were investigated using infrared spectrometer， scanning electron microscope， thermal conductivity tester， and electronic tensile testing machine. The results indicated that the dispersibility of the F?GE was enhanced greatly， and its compatibility with the PVDF matrix was improved significantly. The thermal stability， tensile strength， and thermal conductivity of the composites were significantly increased. When the content of F?GE was 20 %， the composite achieved a thermal conductivity 2.08 W/（m·K）， which was 845 % higher than that of pure PVDF ［0.22 W/（m·K）］. However， the PVDF/GE composite only showed an increase in thermal conductivity by 409 %. Meanwhile， the composites maintained good mechanical properties and thermal stability， and their tensile strength reached 112.6 MPa. The composites also exhibited a melting point of 171.3 ℃ and a thermal decomposition temperature of 471 ℃， which were higher than pure PVDF by 5.5 ℃ and 7 ℃， respectively.
ZHANG Xuemin, HOU Lin, FENG Jinmao, YAO Zhongliang, ZHONG Mingqiang
Abstract (
402 )
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This paper reported a study on the natural aging behavior of buried polyethylene （PE） water supply pipelines in service of 7~12 years in Taizhou， China. The variations of unsaturated groups， chain scission and branching， carbonyl index， hydroxyl index of the PE pipelines in service and the thermal stability， molecular weight， oxidation induction time， microscopic morphology， yield strength and tensile modulus of the pipes with different service times were investigated using infrared spectrometer， differential scanning calorimeter， and scanning electron microscope， etc. The results indicated that during the service of buried PE water supply pipelines， the pipes were in the physical aging stage within the first 7 years in service under the protection of antioxidants， and their microstructure and mechanical properties were basically unchanged. After servicing for 7 years， the pipes entered the chemical aging stage， and the content of unsaturated groups and characteristic peaks of chain scission increased gradually. The thermal stability and mechanical properties of the pipes were improved due to a crosslinking reaction. After servicing for 9 years， the degree of oxidation increased sharply， the auto?oxidation reaction was enhanced， the content of the carbonyl increased， the chain scission became the main reaction， the thermal stability and mechanical properties decreased rapidly， and a great number of cracks formed on the surface of the pipes. By nonlinear fitting the antioxidant depletion time curve， the depletion time of antioxidant in the pipes was calculated to be 24.08 years in the service state.
LI Qiwei, WANG Cuicui, ZHENG Haijun, CHEN Jihe, WANG Ge, CHENG Haitao
Abstract (
447 )
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The polypropylene （PP）?based composite reinforced with 30 wt% bamboo powders （BP） was prepared through six?cycle extrusion using a twin?screw extruder. The effect of recycle times on the rheological， mechanical， and foaming properties of the BP/PP composite was investigated. The results indicated that with an increase in the cycle number of extrusion， the apparent viscosity of the composite increased at first and then tended to decrease， but its mechanical pro?perties showed an opposite trend. The apparent viscosity decreased by 23.75 % after extrusion for six time. Compared to the original composite， the composite extruded six times showed a decrease in tensile strength by 17.08 % and in strength by 31.18 %. With an increase in the cycle number of extrusion， the composite showed a change in cell distribution from uneven to uniform， and its cell size became uniform gradually. Moreover， the distribution of BP tended to be uniform in the cell wall， and BP became short rods and granules instead of long fibers.
LI Bo, GONG Jun, JIN Xueyi, MENG Xiaoyu
Abstract (
534 )
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261
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In this paper， two surface modification methods， acid treatment and polyethyleneimine （PEI） grafting， were employed to modify multi?walled carbon nanotubes （MWCNTs）. The resultant acid?etched MWCNTs （a?MWCNTs） and PEI?grafted MWCNTs （PEI?MWCNTs） were melt blended with polyamide 11 （PA11） to obtain the PA11/a?MWCNTs and PA11/PEI?MWCNTs composites. Their microscopic morphology， dispersibility， thermal stability， crystallinity and mechanical properties were investigated using scanning electron microscope， thermogravimetric analyzer， infrared spectrometer， and differential scanning calorimeter. The results indicated that the PA11/PEI?MWCNTs composites exhibited much better performance. When the content of PEI?MWCNTs was 3 wt%， the composites achieved tensile strength of 62.7 MPa and a Young’s modulus of 1 017 MPa， which are higher than pure PA11 by 37 % and 65 %， respectively. In addition， their degree of crystallinity increased by 14.6 %.
Processing and Application
LI Yongqing, YANG Xiaolong, CHEN Wenjing, YAN Xiaokun, MA Xiuqing
Abstract (
583 )
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To study the effects of modifiers and high?density polyethylene （PE?HD）/organo?modified montmorillonite （OMMT） composites on the intercalation and exfoliation of montmorillonite， a molecular dynamics method was employed to simulate the arrangement of different loadings of octadecyl trimethyl ammonium chloride cations （OTAC+） in the montmorillonite （MMT） and its influence on the intercalation of OMMT. A material model for the PE?HD/OMMT composites was constructed， and the MS Perl script was written to extract the interaction energy among OTAC+， MMT and PE?HD to study the effect of the barrel temperature of the twin?screw extruder on the exfoliation of MMT at 463 K. The simulation results indicated that the MMT slices appeared as lateral?monolayer， lateral?bilayer， and pseudotrilayer in sequence with an increase in the loading of OTAC+. Meanwhile， the increase of the OTAC+ loading resulted in an increase in the layer spacing of MMT， and however MMT was not exfoliated. In the simulation time of 90~95 ps， the interaction energy between the top and bottom of MMT in the PE?HD/OMMT composite model varied from -24.53 to 3.54 kcal/mol， indicating the successful exfoliation of MMT， leading to an MMT layer spacing of 91 ? at that time.
LIU Zhen, YU Yun, ZHANG Menghang, YIN Liuye, DUAN Yufei, HOU Guixiang
Abstract (
431 )
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Ricinoleic acid?based polyamine （COAPA） was synthesized as a curing agent using castor oil and three ethyle?ne four amine as raw materials and then was mixed with gallic acid epoxy resin （GAER） to form a whole biological cu?ring system. The curing process of GAER/COAPA composite system was investigated using a nonisothermal DSC method. The optimum mass ratio of GAER to COAPA was determined to be 7：3 for the curing system， and the optimum curing temperatures were obtained. The activation energy and kinetic parameters of curing reaction were obtained by fitting and calculation using the Kissinger equation together with the ?esták?Berggren autocatalytic model. The pro?perties of the cured GAER system were compared with that of the bisphenol?A epoxy cured system. The results indica?ted that the average activation energy of the GAER/COAPA system was 62.28 kJ/mol. When the conversion rate of cu?ring reaction was less than 60 %， the curing kinetics conformed to the ?esták?Berggren autocatalytic model. Compared to the bisphenol?A epoxy thermoset， the gallic acid epoxy thermoset exhibited a lower thermal decomposition temperature and a higher carbon residue rate at 800 ℃， and its tensile strength and flexural modulus were lower， the flexural strength and glass transition temperature were also slightly higher.
HUANG Wei, LIU Hesheng, HUANG Xingyuan, ZHANG Wei, KUANG Tangqing, CHEN Zhongshi
Abstract (
444 )
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A square cross?sectional pipe was injection?molded through an overflow water?assisted injection molding method using short?glass?fiber?reinforced polypropylene as a raw material. The effects of process parameters such as melt injection temperature， water injection delay time and water injection pressure on the macro phenomenon were investigated， and the penetration behavior of high?pressure water in the square pipe was analyzed. The results indicated that with an increase in melt injection temperature， the residual wall thickness of the right?angle side and the inclined side of the square tube tended to decrease. However， when the temperature was too high， the pipe tended to shrink， and the hollow area of the pipe section was increased. The shape of the cross section was consistent with the shape of the high?pressure water penetration front， presenting an ellipse shape. However， the roundness of the cross section decreased gradually. The residual wall thickness of the pipe decreased with an increase in water injection pressure， and the hollow area of the cross section increased. With an increase in the water injection pressure， the shape of the cross section was gradually consistent with the cavity structure， presenting a rectangle shape. When the injection delay time increased， the residual wall thickness of the pipe tended to increase， the hollow section became smaller， and the pipe section was consistent with the penetration front of high?pressure water， presenting an ellipse shape. Compared to the other two parameters， the injection delay time showed less influence on the square pipe， and there was little influence on the circumference ratio roundness of the cross?section.
JIN Qingping, YI Jianming, GAO Yonghong, CAO Nannan, DENG Siyuan
Abstract (
486 )
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In this study， the mechanical properties of glass fiber reinforcement polymers bars （GFRP） were investigated after subjected to dry?wet cycles and static immersion of alkaline solution for different days， and the reduction law of mechanical properties was analyzed. Based on the life prediction formula of durability of GFRP， a strength reduction model for the GFRP with a diameter of 20 mm subjected to the alkaline solution was obtained through linear fitting， and the model was used to predict the variation trend of long?term tensile properties of GFRP. The results indicated that the tensile strength of GFRP decreased significantly with an increase in the duration time of dry?wet cycles in the alkaline solution. The strength reduction mainly occurred in the first 90 days， and the GFRP with a diameter of 20 mm showed a faster initial strength reduction than that with a diameter of 25 mm. After a certain period， the reduction became slower， and however the stress?strain relationship was almost same. There was a size effect on the long?term alkali resistance of GFRP， being associated with the action mode of the alkaline solution.
REN Lihui, LI Fuzhu, WANG Yun, DAI Yachun, YANG Hui, XU Zhenying
Abstract (
496 )
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To improve the injection molding quality of a commode chair panel， a grey relational comprehensive evaluation model based on the TOPSIS was proposed by combining the TOPSIS with a grey relational analysis. The gating system of a plastic part was first optimized and determined， and then the orthogonal experimental design was carried out. The mold temperature， melt temperature， injection time， holding pressure and holding time were selected as experimental factors to simulate and analyze the warpage， shrinkage index and volume shrinkage of the plastic part as evaluation inde?xes using the Moldflow software. According to the orthogonal test data， the weight coefficients of each evaluation index were determined using the CRITIC method， and the multi?objective optimization was transformed into the single objective one using a grey relational comprehensive evaluation method based on the TOPSIS to obtain an optimal combination of process parameters. The experimental results indicated that the volume shrinkage of the plastic part after optimization was reduced by 14.6 %， its shrinkage mark index was reduced by 43.3 %. The warpage deformation was basically the same as that before optimization， and the overall quality of the plastic part was improved significantly.
YANG Yuxuan, LIU Zhaogang, ZHAO Jingang, HUANG Xubo, CHEN Mingguang, HU Yanhong, WU Jinxiu, FENG Fushan
Abstract (
418 )
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A lanthanum 2，3?pyrazinedicarboxylic acid （2，3?LPDA） rare earth thermal stabilizer was synthesized using 2，3?pyrazinedicarboxylic acid as a ligand together with lanthanum nitrate and ammonia water， and its molecular formula was analyzed through infrared spectroscopic characterization and elemental and thermal analyses. The thermal stability of 2，3?LPDA and its compounding system with other auxiliary heat stabilizers like zinc stearate， calcium stearate， and pentaerythritol were investigated through a static thermal stabilization experiment. The effect of thermal stabilizers on the plasticization and mechanical properties of PVC were evaluated. The thermal stability mechanism of 2，3?LPDA was analyzed. The results indicated that the molecular formula of 2，3?LPDA was determined to be La2（C6N2O4）2（NO3）2·3H2O. When the compounding ratio of 2，3?LPDA to zinc stearate to pentaerythritol was set as 2∶1∶2， the thermal stabilization time of PVC reached 44 min and its processability and tensile strength was improved significantly. The presence of 2，3?LPDA could depressed the dissociation of the C—Cl bond in PVC and absorbed the Cl- produced by the degradation of PVC through a combination with rare earth ions to form LaCl3. This effectively inhibited the degradation of PVC， resulting in a good thermal stability.
ZHANG Xiangkai, WANG Zhimin, XIE Jianqiang
Abstract (
734 )
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This article reviewed the research progress in biomass curing agents for epoxy resins in recent years， which included biomass amine curing agents， biomass acid glycoside curing agents， and polyphenol， carboxylic acid and ester biomass curing agents prepared using cardanol， vanillin， rosin， lignin， and vegetable oil as raw materials. The structure， preparation method， synthesis route， and properties of the cured products obtained from biomass curing agents were introduced in detail. Finally， the development trend of biomass curing agents was summarized and forecasted.
YANG Xiaochun, YU Jing, ZHANG Qing
Abstract (
362 )
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N?ethylpiperazine?based phthalate was synthesized using phthalic anhydride and N?ethylpiperazine as raw materials， and then the obtained product was reacted with zinc chloride to prepare N?ethylpiperazinylphthalomide zinc （ZNEP）. Four types of composite heat stabilizers were obtained separately through compounding ZNEP with pentaerythritol， dimethylbenzoyl methane （β?diketone）， epoxy soybean oil， and phenyl diisooctyl phosphate， and their effect on the static thermal stability， dynamic thermal stability and thermal degradation process of PVC was investigated using the Congo red test paper method， thermal aging oven method， torque rheometer， and thermal gravimetric analysis. The results indicated that the PVC compounds achieved an optimum thermal stability at a mass ratio of ZNEP to pentaerythritol of 1∶2. The static and dynamic thermal stability times were determined to be 2 340 and 1 602 s respectively. Comparing to the PVC sample without heat stabilizer， the heat?stabilized PVC exhibited an increase in T5 %， T10 %， and Tmax， indicating that the composite heat stabilizer can effectively inhibit the thermal degradation of PVC.
Plastic and Environment
MA Jiasen, XUE Yongbing, GUO Qi, LIU Zhenmin
Abstract (
729 )
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This article reviewed the research progress in the modification of asphalts with asphalt polyethylene， polypropylene， polyvinyl chloride， polystyrene， ethylene?vinyl acetate copolymer， acrylic acid copolymer and other waste plastics as a modifier used alone and compounded with other materials in recent years. The plastic cracking and asphalt modification technologies with a promising development prospect were introduced， and meanwhile the relevant modification mechanisms were summarized， including swelling mechanism， separation mechanism， and storage stability mechanism. Finally， the future development trend in waste plastic?modified asphalts was prospected.
Standard and Test
REN Ping, ZHAO Jie, JU Ying, WANG Yu, SHEN Kangjun, LIU Shu
Abstract (
1523 )
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This article summarized 41 types of primary aromatic amines （PAAs） related to food contact materials in domestic and foreign regulations， standards， technical guidelines， and references and analyzed the source and migration risk of PAAs in food contact materials. Moreover， the differences in technical regulations of PAAs in China， the European Union， and South Korea before 2021 were compared. Based on these investigations， PAAs in food contact materials were mainly derived from azo colorants， aromatic isocyanates， and other additives， and they were detected from polyamide tableware， colored plastic products， and composite products， especially in polyamide tableware and kitchenware. The specific migration of all PAAs in plastic food contact materials and products has been restricted by the European Union. As a member of the European Union， Germany restricts the migration of PAAs from six high?risk materials such as plastic colorants and rubber. South Korea restricts the specific migration of 4，4’?diaminodiphenylmethane in epoxy resin and aniline， 4，4’?diaminodiphenylmethane and 2，4?diaminotoluene in polyamide plastics. China restricts the specific migration of toluene diamine in composite food packaging bags， m?phenylenediamine， 4，4'?diaminodiphenylsulfone in plastic re?sins， and the amount of PAAs used in colorants was also limited. The migration risk of PAAs in plastic food contact materials has received widespread attention at present in China. It is recommended that manufacturers pay much attention to the differences in domestic and foreign laws and regulations and strictly control the migration risk of PAAs in azo colorants， aromatic isocyanates， and other additives.
Machinery and Mould
ZHANG Xiang, YAN Zhenhao, KONG Xiaoya, ZHU Jianxiao, GUAN Guotao, ZHAO Na, LI Qian
Abstract (
483 )
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To improve the plasticizing performance during the processing， the plasticizing process of disk screw micro?injection machine was numerically simulated through multi?physical field modeling using a simulation software， and the structure of disc screw was optimized. Theoretical analysis was first carried out on the structural parameters of the moving plate， and then simulation calculation and analysis were performed on the structure through changing the structural parameters. The influence of each parameter on the plasticizing performance was evaluated. Finally， an optimized structure of disc screw was designed through combining the effect of various parameters on the disc screw of plasticizing capability and considering the actual situation of the disc screw. The results indicated that the plasticizing performance of the disc screw micro?injection molding machine was improved significantly through using an optimized disc screw structure with a reduced groove width in the prototype structure to leave space to construct three screw grooves.
YANG Qinjie, LI Jiawen, LI Ming, CHEN Gang, LI Guangzhao, Peng Biyou, HAN Rui
Abstract (
835 )
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This review briefly introduced the basic principle and classifications of 3D printing technology， and the mechanism， advantages， and current problems of fused deposition modeling （FDM） technology were discussed. The state?of?the?art in FDM 3D printing devices was systematically summarized from two aspects of control methods， including temperature control， motion control， and path control and motion mechanism， including feeding mechanism， nozzle， and motion mechanism. Finally， the current challenges and problems in the FDM 3D printing equipment were proposed， the future development direction of FDM 3D printing equipment was prospected.
Review
LIU Yankuan, GU Zichen, WANG Zhiping
Abstract (
788 )
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528
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This article summarized the mainstream impregnation and processing technologies of continuous?fiber?reinforced thermoplastic prepregs at home and abroad， which included hot melting， solution impregnation， film stacking， blending， powder impregnation， and in?situ polymerization. The advantages and disadvantages of various technologies were compared in terms of raw materials， equipment， and processing procedures. The design and applications of thermoplastic prepreg forming molds were also discussed. The development status of thermoplastic prepregs was introduced. The preparation methods for the lightweight and diversified thermoplastic prepreg impregnation technologies， including three?dimensional continuous weaving technology， were also discussed. Finally， the development direction of preparation technology for thermoplastic prepregs in the future was analyzed and prospected.
QIU Hongbo
Abstract (
797 )
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109
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In this paper， the theoretical models of superhydrophobicity and the biomimetic mechanisms of natural superhydrophobic surface were introduced， and the construction methods of wood superhydrophobic surface at home and abroad were reviewed， which included stencil printing method， etching method， graft copolymer method， and sol?gel method. The advantages， disadvantages， and problems of different construction methods for superhydrophobic surface were analyzed. The application prospects of superhydrophobic wood were described. Finally， the challenges and prospects of the study on superhydrophobic wood were proposed．
TIAN Baozheng
Abstract (
523 )
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276
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This review introduced the flame?retardant mechanism of alkyl phosphinates and summarized the latest research progress in the alkyl phosphinate flame?retardant compound systems. These compound systems included the alkyl phosphinate and phosphorus flame retardants， nitrogen flame retardants， silicon flame retardants， carbon?based materials， inorganic metal flame retardants， and chain?extender?containing flame?retardant polymer. The development trend in alkyl hypophosphonate synergistic system was finally prospected.
