Materials and Properties
XU Zixun, YUAN Jing, DU Xiyan, ZHANG Xinpeng, XU Jun, GUO Baohua
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186 )
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PBAT/polycarbodiimide （PCDI） and PBAT/carbodiimide （CDI） blends were prepared through melt blending using CDI and PCDI as anti⁃hydrolysis agents， and the effect of the content of anti⁃hydrolysis agent on the thermal， mechanical， molecular weight， and hydrolysis behavior of PBAT was investigated. The results indicated that PCDI exhibited a remarkable efficacy on enhancing the hydrolysis resistance of PBAT， resulting in a significant reduction in the content of carboxyl end groups from 28.2 to 0.4 mol/t when 1.5 wt% PCDI was incorporated. The PBAT samples without any anti⁃hydrolysis agents showed a hydrolysis weight loss of 7.54 wt% after hydrolysis at 70 ºC for 1 051 h. The hydrolysis weight losses of the samples containing 0.5， 1.0， and 1.5 wt% PCDI was 6.71 %， 4.34 % and 0.55 %， respectively.
ZHANG Weizhen, ZHANG Qi, LI Yuan, LU Yonglai, ZHANG Shijun
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135 )
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Polyamide 6 （PA 6）/carbon fiber composites toughed with epoxidized silicone rubber （ESR⁃5）/methyl silicone rubber （PDMS） compounding system were prepared through melt blending， and the effect of epoxy content on the mechanical properties， impact properties， heat resistance， and microstructure of PA6 composites was investigated. The results indicated that when there were 10 phr ESR⁃5 and 10 phr PDMS in the compounding system， the interface force between PA and silicone rubbers could be by in situ grafting reaction， thus enhancing the impact resistance and damage resistance of the composites. This resulted in an increase in the notched impact strength by 73.6 %， 178.0 % and 196.8 % at 23， -20， and -60 ℃， respectively， compared to the composites without toughening， exhibiting an excellent impact resistance in low temperature environment. This also minimized the impact of introducing elastomers to the reduction in the mechanical properties of the composite system. Meanwhile， the thermal stability of the composites was improved. The ESR⁃5/PDMS toughening system provides a feasible solution for the applications of carbon⁃fiber⁃reinforced PA6 composites in low temperature environments.
ZHANG Heng, LIU Hao, QIU Shouji, ZHANG Bing, WU Shuqing
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118 )
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In this article， TiO2 was surface modified by macromolecular polybasic acid （BA） and lauric acid （LA） and then used to whiten the PA6/GF composites through extrusion molding. The effect of modified TiO2 on the crystallization behavior and interfacial and mechanical properties of the composites were investigated. The results indicated that there was no significant influence on the improvement of mechanical properties of PA6/GF composites at an LA⁃modified TiO2 content of 3 wt.%. However， the composites with BA⁃modified TiO2 obtained tensile strength， flexural strength and notched impact strength of 109 MPa， 155 MPa， and 12.3 kJ/m2， respectively， which were higher than those of the composites with pure TiO2 by 11.1 %， 10.7 %， and 68.5 %， respectively. All parameters reached 85 % or more of the results for the composite systems with the same amount of ZnS.
DENG Jingqian, KONG Peng, HOU Dandan
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99 )
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Polystyrene/paraffin phase⁃change composite foam （EPSPW） was prepared through encapsulating paraffin into the pores of the foam using an emulsion⁃templating method. SEM observation indicated that the porosity of EPSPW ranged from 85 to 92 vol% and the pore size ranged from 3.5 to 10 μm with a narrow distribution. When the paraffin content was 30 wt%， EPSPW exhibited excellent shape stability without any leakage of paraffin， and its loading of paraffin was 33 times as great as its own mass. The leaching test results indicated that the mass loss rate of the sample was only 3 wt% at temperatures above the melting point of paraffin. EPSPW presented a melting enthalpy of 32 J/g， which was much higher than that of directly foamed phase⁃change foam materials （mostly around 15~20 J/g）. In addition， EPSPW exhibited good cycle stability over 50 heating/cooling cycles.
LIU Fang
Abstract (
73 )
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In this paper， five methods of sampling pretreatment were adopted to obtain the cross section of a commercial food⁃packaging composite film， and its layer structure and material compositions were analyzed by using scanning electron microscopy （SEM）， energy dispersive X⁃ray spectroscopy， and Fourier⁃transform infrared spectroscopy. The results indicate that the composite film was composed of five layers， including a polyethylene terephthalate （PET） layer， an inorganic pigment/polyurethane （PU） adhesive/aluminum⁃metallized layer， a PET layer， a PU adhesive layer， and a polyethylene layer in sequence. By observing the cross sections obtained from five sampling pretreatment methods using SEM， it was found that the composite film showed a small layered cross section when sampling with the steel and diamond knifes of an ultra microtome or an ion milling device， exhibiting an ideal morphology with a well⁃defined layer structure. In summary， an appropriate method can improve the successful rate greatly for obtaining an ideal film cross section. This is very significant for the quality inspection as well as the research and development of ultra⁃thin metal⁃coated multilayer films.
YANG Qinglin, ZHOU Song, LI Canran, YU Wenda, LUO Yumei
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125 )
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Toughened polyphenylene ether/polyamide 66 （PPO/PA66） blends were prepared through twin⁃screw extrusion and injection molding using maleic anhydride⁃grafted styrene⁃ethylene⁃butene⁃styrene copolymer （SEBS⁃g⁃MAH） as an impact modifier. Their water absorption， mechanical properties， melt flow performance were investigated and their crystallization behavior and fractured morphology were studied by differential scanning calorimetry and scanning electron microscopy. The results indicated the toughness and tensile strength of PPO/PA66 blends decreased significantly in the presence of PPO due to poor interfacial adhesion between PA66 and PPO. Owing to the energy absorption caused by SEBS⁃g⁃MAH as well as an improvement in the compatibility between PA66 and PPO， the addition of 10 phr SEBS⁃g⁃MAH into the PPO/PA66 （30/70） blend resulted in an increase in the tensile strength， elongation at break and impact strength by 23.95 %、81.58 % and 157.39 %， respectively. The PPO/PA66 （30/70） blend obtained better comprehensive properties with the addition of 10phr SEBS⁃g⁃MAH， and it achieved relative maximum toughness at the SEBS⁃g⁃MAH loading of 18phr. The PPO/PA66 （30/70） containing 10phr SEBS⁃g⁃MAH present a water absorption of 0.61 %. This result decreased by 55.88 % Compared to the water absorption （1.36 %） of pure PA66. PPO enhanced the crystal formation of PA66 in the bends， whereas SEBS⁃g⁃MAH inhibited its crystal formation of PA66. Both PPO and SEBS⁃g⁃MAH improved the melt processability of PA66.
HOU Wenjie, YANG Na, REN Jianfei, GAO Dahai, GUO Gaiping, DAI Yuhua
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113 )
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In this study， cellulose acetate porous membranes with an adjustable structure and a high water flux were prepared by using cellulose acetate as a raw material， acetone as a solvent， and water as a non⁃solvent. Carboxyl groups were introduced for selective separation of protein through the oxidation of tetramethylpyridine oxide/sodium bromide/sodium hypochlorite. With a porosity of 92.5 % and a water flux of 1 655.7 L/（m2·h）， the cellulose acetate porous membranes exhibited optimal comprehensive performance at a cellulose acetate concentration of 10 wt%， a coagulation bath temperature of 10 ºC， and a non⁃solvent water content of 30 wt%. After oxidation， the cellulose acetate porous membrane obtained an adsorption rate of 2 806.1 mg/g for lysozyme at pH 6.
SU Yuhang, LIN Yuanzhi, MAO Jianquan, WANG Yongxiang, LIU Xiang, YU Li, KE Junmu, CHEN Yishi
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120 )
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The composite structure of a three⁃layered matting and heat⁃sealing film was designed by selecting suitable polyethylene （PE） and polypropylene （PP） as visual layer materials and adding micron SiO2 into the core layer to improve the haze of the film. The film was prepared by using a three⁃layer co⁃extrusion casting method， and its properties were investigated. The results indicated that PE⁃HD and copolymerization⁃type PP could be combined to form the best matting material. With an increase in the PE⁃HD content in the visual layer， the PE⁃HD/PP hybrid system obtained an improvement in the impact strength， storage modulus， and loss modulus， indicating a reinforcing and toughening effect on the film. This also， accelerated the crystallization rate of the PE⁃HD/PP hybrid system and promoted the haze formation of the film. The film showed a haze of 80 % and a gloss of 7.8 % at a PE⁃HD content of 40 wt% in the visual layer along with an optimal matting effect. The film also presented the highest tensile strength of 29.5 MPa and the highest elongation at break of 64 % at a micron SiO2 content of 3 wt% in the core layer. The film obtained a light transmittance of 58.8 %， and its haze increased to 82.3 %.
SONG Yuexiao, ZHOU Guiyang, ZHANG Xiongwei, ZHOU Lixia, CHEN Yao, YANG Zheng, DENG Hangjun, LI Zihao, CAI Chenxi, YIN Hong
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97 )
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In this paper， homopolymerization was carried out to prepare polymethyl methacrylate （PMMA） by using methyl methacrylate （MMA） as a monomer and azobisisobutyronitrile as an initiator. The effects of the chroma of MMA， water， and inhibitor contents on the polymerization process and properties of PMMA were investigated. The results indicated that the chroma of MMA should be controlled at below 6 in order to meet a requirement of optical grade for PMMA. There was no direct influence of water content on polymerization. Considering the forming process of PMMA and avoiding the hydrolysis of PMMA， it was recommended to control water content below 500 mg/kg. When the inhibitor content was less than 10 mg/kg， there was little effect on the polymerization and properties of PMMA， and MMA could be directly used as a monomer for its polymerization.
Processing and Application
ZHANG Xun, LIU Xiang, FANG Mei, GUO Pan, FENG Yuezhan, HUANG Ming, LIU Chuntai
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The prepreg tape with dynamic reversibility and excellent mechanical properties were prepared by using bisphenol⁃A diglycidyl ether as a resin matrix， glutaric anhydride as a curing agent， carbon fiber as a reinforcement. The tensile， compressive， bending， stress relaxation， and creep properties of the composites after hot pressing were investigated. According to The mechanical test results， the solid modeling was conducted for the secondary bonding forming and integrated forming structure panel， and a finite element simulation analysis was carried out. The results indicated that compared to the traditional secondary bonding forming structure panel， the maximum deformation of the integrated forming structure panel decreased by 28.57 %， 28.57 %， 28.04 % and 8.27 % under tension， compression， bending， and impact conditions， respectively， at the same external load. When buckling instability occurred， the critical load of the integrated structure panel increased by 84.69 %， and its longitudinal strain at the maximum deformation at each angle was greatly improved， demonstrating excellent anti⁃buckling performance.
FENG Mengyao, XIN Chunling, REN Feng, ZHAI Yujiao, XU Wenchong, MA Chiyuan, MA Yufei, HE Yadong
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99 )
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In this paper， the warping defects appearing in composite laminates produced by fiber placement was addressed. A suitable characterization method was adopted and a non⁃contact visual measurement platform based on morphological principles was established to identify these defects. Through the design of different process parameters， the optimization for solving the detect problem was performed. The relationship between warping degree and tensile performance was explored to further optimize the warping defects. The experimental results indicate that the non⁃contact visual measurement platform could identify the warping degree accurately. The warping defects were reduced with an increase in the heat gun temperature from 300 to 500 ℃. There is a negative correlation between warping degree and tensile performance. The warping can be further optimized by heating the mold.
WANG Cheng, SU Yongsheng, RUAN Fangtao, ZHU Yiyang
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86 )
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An experimental study was conducted on the hole⁃making performance of carbon fiber⁃reinforced composites （CFRP） using a PCD tool under dry drilling and ultrasonic dry drilling conditions. The objective was to identify potential avenues for enhancing the cutting performance of CFRP and to optimize the efficiency and quality of hole⁃making for CFRP. In order to ascertain the efficacy of PCD conventional tools and PCD weaving tools in the context of dry drilling and ultrasonic dry drilling conditions， the holes were made in CFRP. The cutting force， hole entrance diameter size， hole external morphology， and tool surface adhesion were analyzed under different conditions. In the context of ultrasonic dry drilling， the fiber filaments were found to be more extensively broken， although the resulting hole diameter was typically large. Compared to the PCD conventional tool， the PCD structuring tool resulted in a reduction by 34.72% in the total cutting force and by 1.27 % in the relative error drop of the hole diameter. The surface quality at the entrance of the hole was superior under the PCD textile tool machining conditions， and ultrasonic dry drilling reduced the total cutting forces by 6.64% to 16.87 %. Compared to dry drilling， ultrasonic dry drilling generated a more pronounced effect on breaking up chips and could effectively inhibiting the generation of burrs at the entrance. In the context of ultrasonic dry drilling， PCD weaving tools could reduce the cutting force in comparison with conventional PCD tools. Similarly， when using PCD weaving tools， the cutting force could be effectively reduced compared to dry drilling.
CHEN Yeru, GUO Deyu, WEN Yuan
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80 )
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In this study， linear low⁃density polyethylene （PE⁃LLD） was selected as the substrate to prepare powder materials suitable for rotational molding process through melt blending using a twin⁃screw extruder， followed by processing with a mechanical mill. By controlling the feeding amount to control the thickness of the rotational molding products， five important factors were thoroughly investigated， which included the thickness of the rotational molding product， the melt flow rate （MFR） of the rotational molding material， the particle size distribution of the powder， the amount of carbon black added， and the furnace temperature of the rotational molding equipment. A systematic analysis was conducted on the minimum peak internal air temperature （PIATP） required to eliminate the pores in the product wall during the rotational molding process， the minimum peak internal air temperature （PIATI） required to achieve a yellowing index of 0 on the inner surface of the product， the optimal process interval （BPI） for rotational molding， and the comprehensive effects of low⁃temperature drop hammer impact strength （LTIS） within this interval. The results indicate that the temperature for eliminating pores was significantly reduced with an increase in the thickness and MFR of rotational molding products， and the BPI of rotational molding was significantly widened. Meanwhile， LTIS was improved with an increase in the thickness. A decrease in the particle size of powder material led to an increase in PIATP but a decrease in PIATI， narrowing the BPI range during rotational molding. The effect of carbon black on the range of PIATP， PIATI， and BPI was less. Moreover， the matrix LTIS slightly increased with an increase in the addition amount of carbon black. The increase of the furnace temperature of the rotational molding equipment resulted in a slow increase in PIATP but significant increase in PIATI， consequently expanding the range of rotational molding BPI.
HUANG Ke, ZOU Huajie, QIAN Zilong, LI Bingbing
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88 )
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Taking the rear trim strip of a certain type of car skin as the research object， feature point A on the strip was selected as the warpage observation point， and an “overflow loop” was added along the direction of the material flow at the buckle feature. Mold surface temperature， injection temperature， injection pressure， and pressure holding pressure were selected as the research objects to construct a four⁃factor four⁃level L16 orthogonal experiment. The range analysis was carried out upon 16 groups of data to obtain the most sensitive factors and levels as well as the optimal combination of process parameters. With the optimal combination of parameters， the warpage quantity at the point A reached 5 mm under all effects， which was 30 % lower than that under the tenth group of parameters. The optimal parameters were verified by experiments. The main injection parameters were determined to be a mold surface temperature of 128 ℃， an injection temperature of 330 ℃， an injection pressure of 48 MPa， and a holding pressure of 95 % of the injection pressure. After molding， the appearance of the product was uniform. There was no silver grain， wire drawing， and white injection defects. The feature point A looks smooth over the all transition of the product， meeting the test expectations. After molding， the product can meet the requirement of application. The results verified the accuracy of the Moldflow⁃2023 analysis software and the scientificalness of range analysis.
Additive
WU Benze, LI Bin, LEI Yuan, HUANG Shaojun, LYU Wenjun, YU Chuanbai
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81 )
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Four surface modifiers， NDZ⁃201， GR⁃A118， KH⁃550 and DPAK， were used to modify Sb2O3 particles by wet ball milling. The structure and morphology of Sb2O3 before and after modification were characterized by FTIR， XRD and SEM. ABS/DBDPE/Sb2O3 composite was prepared by extrusion granulation and injection molding. The effect of Sb2O3 modified by four surface modifiers of 2 % on the composite properties was studied. The results show that Sb2O3 modified by four surface modifiers has a certain effect on the comprehensive properties of the composite. After surface modification， the machinability of the composite is obviously improved. After modification， good flame retardancy and thermal properties are maintained， and all vertical combustion passes the UL 94 V⁃0 grade. After modification， the mechanical properties are improved in different degrees， and the impact properties are improved obviously. The NDZ⁃201⁃modified composite presented impact strength of 46.99 kJ/m2. This result is 36.01 % higher than the impact strength of unmodified composite. Moreover， the bending strength of the modified composite was also improved to some extent. NDZ⁃201 and DPAK exhibit good modification effect， facilitating an improvement in the machining and mechanical properties of composites.
Standard and Test
ZHONG Shenghui, WANG Yaohua, WU Yanmin, MA Jingfen, RUAN Yulin, HU Zhun
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99 )
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The content of Irganox 3 114 in polypropylene was quantitatively analyzed by Fourier⁃transform infrared （FTIR） spectroscopy， and its characteristic absorption peak was determined at 1 695 cm-1. Meanwhile， the FTIR spectrum shows a quantitative absorption peak for PP at 4 059 cm-1 through comparing the infrared spectral information of Irganox 3114， PP， and PP/Irganox 3114 blend. By taking 1/A4059 as the thickness standardization factor， A1695/A4059 as the horizontal coordinate， and 3114 content as the vertical coordinate， the standard curve of Irganox 3114 was established. The results indicated that the content of Irganox 3114 had a good linear relationship with A1695/A4059， and its linear correlation coefficient was 0.999 28. The effect of thickness standardization factor was verified， and the sample thickness had no influence on the determination result of the content of Irganox 3114 over the experimental range. The relative standard deviation of this method is less than 1.30 % for the determination of Irganox 3114， and its precision is good. The absolute relative error of Irganox 3114 in standard substance is less than 3.27 %， and the accuracy of this method is higher.
Plastic and Environment
XIE Shishuang, WU Liang, HUANG Feng, ZHAN Yuzhou, RONG Xin, LI Xujuan, XU Xiangbin
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100 )
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The adaptability of fully biodegradable film in tobacco cultivation was investigated by field experiments and laboratory analysis， including Fourier⁃transform infrared spectroscopy， scanning electron microscopy， and 16SrDNA high⁃throughput sequencing， and its effect on microorganism diversity in soil was studied. The results indicated that the fully biodegradable film exhibited good degradation performance， moisture retention， and heat preservation in tobacco cultivation in the Guizhou area. The degradation of the film improved the soil microbial communities and its abundance. The microbial communities included Proteobacteria， Gemmatimonadota， Actinobacteria， Chloroflexi， Acidobacteria， Bacteroidetes， Verrucomicrobiota， and Firmicutes at the phylum level， and Streptomyces， Lysobacter， Nitrospirillum， Flavisolibacter at the genus level. Moreover， the other beneficial bacteria also increased. This can facilitate the soil carbon sequestrants and the nitrogen， carbon， phosphorus cycling.
Machinery and Mould
WANG Chaoyuan, CHEN Xin, LIN Zeng, QI Jihao, PANG Zhiwei, SHA Jin
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59 )
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Based on the two⁃dimensional analytical modeling for the single⁃screw metering section of an extruder， a cross⁃validation method was employed to construct an artificial neural network （ANN） model and optimize its hyperparameters to effectively map the complex nonlinear relationship between the working conditions and structural parameters of the extruder and the productivity and power consumption. A multi⁃objective optimization of the structural parameters of the screw metering section was proposed using the ANN surrogate model combining with the NSGA⁃Ⅱ （non⁃dominated sorting genetic algorithm Ⅱ） algorithm， and the structural parameters of the optimal combination of productivity and power consumption were obtained through the TOPSIS （technique for order preference by similarity to an ideal solution） method. The relevant work is of theoretical guidance significance for the intelligent design of the structural parameters of the single screw metering section.
Review
CHEN Xi, WANG Xiang, JIANG Chao, GAO Dali
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155 )
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This paper introduced the modification methods of polypropylene grafted with maleic anhydride （PP⁃g⁃MAH） and reviewed its research progress， focusing on the grafting methods and its characteristics. The applications of PP⁃g⁃MAH were also simply classified. It should be noticed that PP⁃g⁃MAH could be used as a compatibilizer， binder， and coupling agent to expand the application range of polypropylene. The utilization of composite grafting methods may become a key research direction to improve the properties of graft products in future.
WU Qimin, WANG Weimin, LE Deliang, LIN Zhonghua, PEI Kemei
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103 )
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This paper summarized the compositions and classification of epoxy resin cement mortar （ECM） repair materials， performance influencing factors， new modification technology， and performance characterization methods. The current status of the development of ECM was reviewed， and its trend was analyzed.
WANG Yu, ZHANG Yajun, ZHENG Yongbiao, GAO Cong
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88 )
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This paper introduced the research history and practical application of polymer gas⁃assisted extrusion technology， outlined the influence of different process parameters of gas on product quality during gas⁃assisted extrusion molding， briefly described the applications and development of computer simulation technology in gas⁃assisted extrusion， and provided a prospect for the research and practical applications of the gas⁃assisted extrusion technology based on the existing researches and technologies.
HAN Yufei, WAN Daxin, FANG Xiaotong, HU Jing
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77 )
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This paper reviews the research progress in photosensitive resins in recent years and summarizes the applications of UV⁃curable resins in the direct ink writing formation. The problems in the relevant research were also addressed.
