Materials and Properties
AN Lihong, TU Yi, ZHANG Guizhen
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Uniaxially stretched poly（ethylene⁃co⁃tetrafluoroethylene） （ETFE） films were prepared to investigate the impact of processing parameters on their properties. The crystallinity， mechanical performance， and optical transparency of the films were characterized as functions of stretching temperature， stretching ratio， and heat⁃setting temperature. The results indicated that the stretching process promoted stress⁃induced crystallization， with the stretching ratio being the primary factor governing the increase in crystallinity， while the stretching temperature had a comparatively minor influence. The optimum stretching conditions， a ratio of 3 and a temperature of 120 ℃， produced a film with a crystallinity degree of 35.6 %， tensile strength of 106.4 MPa， longitudinal tear strength that was 1.9 times higher than the pristine film， and 90.1 % transmittance. Heat⁃setting at 220 ℃ for 5 minutes was determined to be optimal， resulting in additional increments in crystallinity degree （3.8 %） and tensile strength （9.3 MPa）. Further extension of the heat⁃setting duration proved ineffective in enhancing the film properties.
XIE Mingdong, QIN Liu, SI Daoxing, LIU Jiaxin, YANG Weimin
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Rigid open⁃cell polyimide （PI） foam was synthesized from a precursor based on 3，3'，4，4'⁃oxydiphthalic anhydride and 4，4'⁃oxydianiline. The precursor was first foamed under a vacuum atmosphere and subsequently heated to 350 ℃ in air to complete imidization. The chemical structure， thermal properties， microstructure， and mechanical performance of both the precursor and the final foam were comprehensively characterized using nuclear magnetic resonance， Fourier transform infrared spectroscopy， differential scanning calorimetry， thermogravimetric analysis， mercury intrusion porosimetry， scanning electron microscopy， and mechanical testing. The foaming process was also investigated. The results indicated that the foam was fully imidized and exhibited a density ranging from 45 to 57 kg/m³， an open porosity of 95.32 %， and a specific surface area of 7.267 m²/g. The pore size distribution was predominantly between 20 and 200 μm， and the microstructure presented a three⁃dimensional sheet⁃like network where the sheets were mutually adherent. The foam demonstrated a compressive stress at 10 % strain of 16.19 kPa and maximum bending strength of 300.73 kPa. These properties are comparable to those of other polyimide foams of the same type.
XU Chenglong, WANG Yu, LI Guo, XIE Linsheng, MA Yulu
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This study investigated the unstable flow behavior of ultra⁃high molecular weight polyethylene （PE⁃UHMW）/high⁃density polyethylene （PE⁃HD） blends during capillary extrusion. The surface morphology of extrudates， including pure PE⁃UHMW， pure PE⁃HD， and their blends， was analyzed to characterize flow instabilities at various extrusion temperatures. Key phenomena examined include the critical shear rate for the onset of oscillatory distortion and melt fracture， as well as pressure oscillations and wall slip beyond this critical rate. The results indicated that the extrusion morphology evolved through a sequence of shark skin， oscillatory distortion， and global melt fracture. At an extrusion temperature of 260 ℃， severe pressure oscillations occurred at a shear rate of 116 s⁻¹， accompanied by a dynamic stick–slip transition at the melt–wall interface that induces oscillatory distortion and wall slip. Furthermore， increasing the extrusion temperature delayed the onset of unstable flow， expanding the shear rate range for oscillatory distortion from 116~522 s⁻¹ to 152~686 s⁻¹.
LI Xuehua, WU Wei, CHENG Hao, HE Miao, SHENG Honghang
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10 )
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This paper reports an investigation on the preparation and mechanical properties of hybrid composites reinforced with a plain glass fiber fabric and metal mesh， using an epoxy resin matrix （mixed at a mass ratio of 100∶30 with its curing agent）. Samples were fabricated using vacuum⁃assisted resin transfer molding. The effects of metal mesh pore size and the number of metal mesh layers on the composite properties were evaluated through tensile and flexural testing. Experimental results demonstrated that the incorporation of a metal mesh significantly enhanced the mechanical properties. A pore size of 2 mm × 3 mm was found to yield the optimal improvement in both tensile and flexural performance. Consequently， composites with this specific mesh size were selected for further study on the effect of layer count. Data analysis revealed a distinct trend： while the tensile properties gradually decreased with an increasing number of metal mesh layers， the flexural properties were progressively enhanced.
WANG Suwei, HU Ping, ZONG Huzeng, XUE Ping
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To address the high density and low toughness of conventional wood⁃plastic composites （WPCs）， this study employed chemical foaming technology to introduce a microcellular structure into the material. Subsequent crack passivation and other methods were applied to achieve simultaneous enhancement and toughening， thereby facilitating high⁃performance applications of WPCs. Using azodicarbonamide （ADC） and sodium bicarbonate （SBC） as foaming agents， the influence of their pyrolysis behavior on cellular morphology was investigated through thermal stability analysis. Formula optimization was further conducted to examine the effect of gas production rate on the mechanical properties of the composites. The results indicated that， compared to SBC⁃based foam masterbatch， ADC foaming agent compounded with zinc oxide was easier to yield a “fine and dense” microcellular structure. At an optimal dosage of 1 phr， a microporous structure with an average cell size of 71 μm and a cell density of 2.7×10⁴ cells/cm³ was achieved. The corresponding impact strength， tensile strength， and flexural strength of the composite reached 6 kJ/m²， 9.7 MPa， and 22.1 MPa， respectively.
XIONG Yihuimeng, QIAN Lijun
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7 )
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This paper comprehensively reviews recent research advances and developmental trends of polyborosiloxane （PBS） worldwide， with a focus on its synthetic strategies， functional mechanisms， and application progress in multifunctional composites. Finally， the paper proposes future research directions and potential applications of PBS.
HU Yutao, ZHANG Lun, QIAO Mengjiao, MA Ke, SONG Hongqin, WANG Li, WAN Caixia
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Conventional polyethylene （PE） membranes show promise as substrates for ultrafiltration and reverse osmosis membranes but are limited by poor hydrophilicity， low porosity， and consequently low water flux. To address these issues， this study investigates the effects of pore expansion via stretching and hydrophilic modification on the pore structure and water flux of PE membranes. Pore structure was tailored through a stretch⁃expansion process， which increased porosity and pore size while reducing pore tortuosity， thereby enhancing filtration efficiency. Additionally， hydrophilic modification was achieved by crosslinking the membrane with a sodium polyacrylate coating. The modified membranes maintained a high bovine serum albumin （BSA） retention rate while demonstrating significantly improved water flux. The results indicated that a stretch ratio of 2 yielded optimal membrane properties， with porosity increasing to 80% and pore tortuosity decreasing to 1.6. The stretched and coated PE membranes exhibited markedly enhanced hydrophilicity， water flux， and BSA retention compared to unmodified PE membranes. The modified PE porous membrane can be directly applied as an ultrafiltration membrane and also provides a smooth， suitable surface for interfacial polymerization， making it a promising substrate for reverse osmosis membranes.
YANG Sen
Abstract (
8 )
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Glass fiber⁃ and carbon fiber⁃reinforced antistatic polyamide 66 （PA66） composites were prepared via melt blending. Halogen⁃free flame⁃retardant antistatic PA66 composites were subsequently fabricated by incorporating aluminum diethylphosphinate （ADP） and melamine polyphosphate （MPP） into the antistatic matrix. The mechanical， electrical， and flame⁃retardant properties of the composites were systematically characterized. Results indicated that the tensile strength， flexural strength， flexural modulus， and impact strength increased with higher carbon fiber content. A composite containing 10 wt% carbon fiber and 20 wt% glass fiber exhibited favorable economic efficiency and antistatic performance. MPP was found to synergize with ADP， substantially reducing the required ADP content. With the addition of 13 wt% ADP and 2 wt% MPP， the flame⁃retardant composites achieved a UL⁃94 V⁃0 rating at thicknesses of 3.2 mm， 1.6 mm， and 0.8 mm， along with a limiting oxygen index of 34 %.
DU Haojie, ZHANG Ying, HUANG Jian, SUN Huali, XU Haiyun, ZHAO Xiaoying, XIANG Aimin
Abstract (
25 )
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Chlorinated polyvinyl chloride （CPVC） suffers from a narrow processing window and poor thermal stability. To address these limitations， this study first established suitable processing conditions based on CPVC's structural characteristics and pyrolysis mechanism， providing a foundation for subsequent compounding modification. The effects of Ca/Zn metal soap， methyl⁃tin， and TiO₂ on the thermal stability， plasticization behavior， and thermal decomposition of CPVC were then investigated. Torque rheology and plasticization analysis determined the optimal processing parameters for TiO₂⁃filled CPVC to be a temperature of 145 ℃， a shear rate of 45 r/min， and a processing time of 10 minutes， with TiO₂ found to promote rapid plasticization. Based on yellowness index and thermogravimetric⁃infrared analysis， methyl⁃tin significantly improved thermal stability， increasing the initial pyrolysis temperature from 240 to 250 ℃. Furthermore， torque rheological curves revealed that the thermal decomposition of pristine CPVC commenced at approximately 810 s， a process that was substantially delayed by the addition of methyl⁃tin. The results demonstrated that methyl⁃tin was a highly effective stabilizer for enhancing the long⁃term thermal stability of CPVC.
WANG Ji, BAI Wei, WU Wenhui, WANG Qingyin, WANG Gongying
Abstract (
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This study reports the synthesis of Al⁃MIL⁃53⁃OHx materials with varying hydroxyl group ratios and their application as catalysts in the production of poly（ethylene terephthalate） （PET）. The catalysts were characterized for their thermal stability and structure using techniques including Fourier⁃transform infrared spectroscopy， thermogravimetric analysis， X⁃ray diffraction， transmission electron microscopy， and N₂ low⁃temperature physisorption. The influence of key synthesis parameters， namely catalyst dosage， polycondensation time， and polycondensation temperature， on the intrinsic viscosity and molecular weight of the resulting PET was systematically investigated. The results demonstrated that the introduction of hydroxyl groups into the MIL⁃53 framework significantly enhanced catalytic activity， leading to a substantial reduction in the required reaction time.
Processing and Application
JIANG Zilong, MIAO Chao, ZHANG Zhen, CHEN Wei, RONG Xi, ZHANG Li'an
Abstract (
9 )
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This paper comprehensively analyzed development trends in the new energy vehicle （NEV） industry and explores the application prospects of novel chemical materials within this field. Key material categories examined include lightweight composites， high⁃performance polymers， recyclable and bio⁃based materials， and smart responsive materials. Furthermore， the review paper identifies prevailing challenges and limitations hindering the adoption of these advanced materials in NEVs. Corresponding strategic recommendations are proposed to foster higher⁃quality development and innovation within the industry.
LIU Shaogang, QIU Dandan, ZHANG Xianchao, WANG Xinyue
Abstract (
12 )
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The response surface method was used to investigate the effect of FDM parameters on the shape memory performance of PLA materials. These parameters include the number of top and bottom layers， filling rate， sample thickness， sample bending degree， sample printing direction， and deformation temperature. The shape memory performance is considered through two response variables： shape recovery rate and shape recovery time. Using the Box⁃Behnken design， high⁃order models were developed to calculate the optimum parameter combination with high accuracy compared to the experimental results. According to the results， the relative errors between the shape recovery rate of the sample and the shape recovery time with respect to the experimental results and model prediction results were 1.526 09 % and 2.390 3 %， respectively. The accuracy of the prediction model is good， which has certain reference significance for future research on 4D printing.
WANG Chen, HUANG Hanyi, WANG Tianyi, ZHANG Chenyun
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8 )
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This paper reports an investigation on the influence of three key slicing parameters， printing orientation， extrusion temperature， and infill density， on the impact resistance of material extrusion （MEX） 3D⁃printed polylactic acid （PLA） models. Using Charpy impact testing and an orthogonal experimental design， the process parameters were systematically evaluated and optimized. The results indicated that printing orientation significantly affected impact resistance， with the highest strength observed for the xzy orientation， followed by xyz， and the lowest for the zyx orientation. Furthermore， impact strength increased concomitantly with higher extrusion temperatures and greater infill density. Analysis of the parameter effects revealed that infill density exerted the greatest influence on impact resistance， followed by printing orientation， and then extrusion temperature. An optimized parameter set was identified： xzy printing orientation， an extrusion temperature of 210 °C， and 80 % infill density. The models printed with these parameters achieved a peak impact strength of 6.89 kJ/m²， representing the best performance observed in this study.
WANG Hai, ZHOU Wen
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9 )
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This paper presents a statistical analysis of the research and development landscape for biaxially oriented polypropylene （BOPP） capacitor films. The study examines the number and trends in patent applications， the overall patent landscape， sources and geographical distribution of technologies， legal statuses， and technology development pathways. The analysis offers insights into the industrial development of BOPP capacitor films， with a specific emphasis on the evolution of Toray Industries’ patent portfolio and its strategic approaches to patent protection in this field.
CHEN Libin, SUN Tengjiao
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In this study， carbon fiber⁃reinforced nylon gears were fabricated via fused deposition modeling and their wear life was optimized. Utilizing a response surface methodology design， the effects of five key process parameters， including layer height， infill density， raster angle， printing speed， and nozzle temperature， were investigated. The grey wolf optimization （GWO） algorithm was then employed to determine the optimal parameter set for maximizing wear performance. RSM analysis revealed that layer height， infill density， raster angle， and nozzle temperature were significant factors， whereas printing speed had an insignificant effect. Significant interactions were observed between layer height， infill density， raster angle， and temperature. Furthermore， only the second⁃order effects of infill density and raster angle were found to be significant. After 100 iterations， the GWO algorithm predicted an optimal wear life exceeding 40 hours. The corresponding optimal parameters were a layer height of 0.2 mm， an infill density of 89 %， a raster angle of 45 °， a printing speed of 72 mm/s， and a nozzle temperature of 278 ℃. Experimental validation under these conditions yielded a wear life of 41.41 hours， confirming the model's accuracy and the effectiveness of the GWO⁃based optimization approach.
CHENG Debao, LI Zhaoyong, WEI Chiyi, XIANG Lubing, ZHAO Xiaoying, XIANG Aimin
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This study presents the development of a novel non⁃metallic， multilayer composite pipeline designed for hydrogen transport. Constructed primarily from high⁃molecular⁃weight polyethylene， the pipeline features a four⁃layer structure： an inner tube， a barrier layer， a reinforcement layer， and an outer protective layer. This design effectively mitigates hydrogen embrittlement， a critical limitation of metallic pipelines， while simultaneously overcoming the low⁃pressure resistance and high gas permeability of conventional polymers. The inner and outer layers are composed of polyethylene resin， the barrier layer combines aluminum foil with a blend of ethylene⁃vinyl alcohol copolymer and modified linear low⁃density polyethylene， and the reinforcement layer consists of high⁃tenacity polyester yarn. The resulting structure exhibits high mechanical strength， excellent flexibility for coiling， superior barrier properties， and long⁃term durability. This work provides a safe， efficient， and lightweight pipeline solution that supports the growing infrastructure needs of the hydrogen energy sector.
Additive
ZHANG Zheng, CHEN Le, LI Jie, DUAN Shun, LI Changjin, LI Fangquan
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9 )
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This review introduces several common photo⁃induced antimicrobial agents， detailing their respective mechanisms of action and exploring their potential applications in medical protective materials. The discussed agents include titanium dioxide （TiO₂）， zinc oxide （ZnO）， and other photoactive compounds that exhibit antibacterial and antiviral properties under light irradiation. By elucidating the relationship between material structure， photocatalytic activity， and biological efficacy， the review paper aims to support the rational design and development of advanced light⁃driven antimicrobial protective equipment for use in healthcare and public settings.
Plastic and Environment
MENG Kun, CAO Jinpeng, ZHANG Yanjun, WANG Erlong, CHEN Minjian
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9 )
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This paper provides a concise review of the current status and recent research progress in waste plastic recycling. The review highlights significant achievements in both mechanical and chemical recycling technologies. Furthermore， it identifies critical challenges that urgently need to be addressed and offers a perspective on the future development directions for the field.
Machinery and Mould
BI Chao, ZHAO Chong, WU Mingjun, JI Yao, TENG Zurong, ZUO Shibo, YIN Deju
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This paper reports a screw configuration analysis algorithm designed for large⁃scale twin⁃screw extrusion systems. By leveraging a performance database of screw elements， the algorithm identifies material conveying characteristics to determine the filling state within the extruder. Based on this filling state， it evaluates key operational metrics under specified processing conditions， including： filling degree and pressure distribution， shear⁃induced plastication capability， material backpressure and torque load， drive power consumption， and specific mechanical energy input. The algorithm is applied to analyze a typical screw configuration used in a ϕ380 mm twin⁃screw extrusion granulation unit for polyethylene. The findings provide a robust theoretical foundation for the systematic development and optimization of screw configuration analysis in large⁃scale extrusion processes.
LI Linghua
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8 )
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This paper reports the structural analysis and injection mold design for a split⁃type air conditioner indoor unit base. A novel mold with ejector mechanisms integrated into both the stationary and moving halves was developed. To facilitate the release of long， high bars and counteract vacuum formation during mold opening， an ejector mechanism was specifically designed for the stationary mold. Various complex features on the part necessitated multiple specialized mechanisms： a slant⁃pin⁃driven slider was designed for the external rib and bottom wall features； a double⁃bevel⁃wedge⁃driven slider was implemented for the undercut on the bottom wall； and additional sliders were employed to demold the V⁃shaped groove above the vent and the three undercuts below it. For the small cylindrical hole in the upper right corner and the outlet pipes on both sides， which have high draft angles， differently structured angle⁃pin mechanisms were designed. An angled⁃lifter mechanism was utilized for the ribs within the vent. To ensure high⁃quality molding， a hot runner system with a cylindrical gate was adopted. Furthermore， a conformal cooling channel layout was designed to maintain uniform mold temperature.
FENG Chao, WANG Shunguo, ZHU Jian
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This paper provides a comprehensive review for the application of 3D printing technology in the field of mold manufacturing. Based on current technological trends and limitations， future directions for the development of intelligent mold manufacturing systems are proposed.
Review
WANG Yong, SUN Xiaojie, WANG Rong, SUN Miaomiao
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9 )
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This article offers a comprehensive and systematic review for recent advances in the modification of poly（glycolic acid） （PGA）， with a focus on copolymerization and blending strategies. The review examines the design of block and random copolymers and discusses how different copolymerization systems influence the crystallinity， mechanical properties， and degradation behavior of PGA. Additionally， the review highlights recent work on blending PGA with other polymers， emphasizing methods to improve toughness and enhance processability through physical blending.
HE Linfei, PENG Panpan, YANG Jianjun, WU Qingyun, WU Mingyuan, ZHANG Jian'an, LIU Jiuyi
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This paper provides a comprehensive review in polyvinyl butyral （PVB） resin， focusing on its structure， properties， applications， synthesis mechanisms， and recent advances in synthesis technologies. The research progress in PVB synthesis was analyzed from multiple perspectives， including the application of novel catalysts and dispersants， innovations in reactor design and production technology， as well as the integration of artificial neural network models and algorithms for process optimization and guidance. This review offers valuable insights that can guide future production and research efforts aimed at developing high⁃performance PVB resin.
