Materials and Properties
LAI Jinmei, GUO Zhaoyan, RU Yue, QI Guicun, CAI Chuanlun, SONG Zhihai
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This study investigates the use of maleic anhydride⁃styrene alternate copolymer （MSL） to develop weathering⁃resistant polypropylene （PP）. The relative molecular weight， mechanical properties， and yellowing index of MSL⁃modified PP were evaluated before and after UV⁃accelerated aging. The results indicated that at 0.1 wt% MSL， the material retained mechanical properties post⁃aging equivalent to those modified with commercial hindered amine light stabilizers （HALS）. The MSL particles （≈400 nm in size） achieved homogeneous dispersion within the PP matrix. UV light was reflected while absorbing and re⁃emitting low⁃energy blue light， synergistically reducing UV⁃induced degradation. Even minimal MSL loading significantly enhanced the weatherability of the substrate， demonstrating its efficiency as a cost⁃effective UV stabilizer. These results position MSL as a promising additive for durable PP applications in outdoor environments.
JIN Yucheng, WANG Jingfan, ZHAO Shicheng
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32 )
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To address the sagging resistance of HDPE100S， this study introduces a blending strategy utilizing low⁃density polyethylene （PE⁃LD）， leveraging its long⁃chain branching characteristics. The impact of PE⁃LD incorporation on the rheological and anti⁃sagging properties of HDPE100S was systematically evaluated using melt flow index， capillary rheometry， and rotational rheometry. The experimental results indicated that the addition of PE⁃LD had negligible impact on the melt flow rate （MFR） of HDPE100S. Significant increases in processing torque， zero⁃shear viscosity， and relaxation time were observed， indicating enhanced melt elasticity and sagging resistance. Differential scanning calorimetry analysis further elucidated the influence of PE⁃LD on the crystallization and melting behavior of HDPE100S. These results demonstrate that PE⁃LD acts as an effective rheological modifier， improving the anti⁃sagging performance of HDPE100S without compromising its flowability during processing.
XIN Hua, ZHANG Tai, CHEN Qiqi, YANG Le, LIU Ruijuan
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This study investigates the friction and wear behavior of fused deposition modeling （FDM）⁃fabricated polyetheretherketone （PEEK） under physiologically simulated lubrication conditions， with a focus on the influence of printing angles on wear volume and mechanisms. After 2 million wear cycles， the average wear factors for samples printed at XY⁃0 ° （0°）， XY⁃30 °， and XY⁃45 ° are （5.929±1.047）×10⁻6， （4.702±0.989）×10⁻6， and （4.575±0.655）×10⁻6 mm³/（N·m）， respectively. Specimens printed at horizontal angles of 30 ° and 45 ° demonstrate superior wear resistance. Regarding wear mechanisms， the surface morphology of FDM⁃PEEK remains broadly consistent across printing angles. Morphological observations revealed arc⁃shaped scratches and fracture⁃induced delamination， while morphological analysis identifies fish⁃scale⁃like wear patterns. These features correlate with abrasive， fatigue， and adhesive wear mechanisms. The findings aim to advance the application of FDM⁃PEEK technology in prosthetics design and manufacturing， offering novel strategies to support the development of personalized medical solutions.
HE Lang, LIU Jianglin, YANG Dongdong, LIANG Jianguo, ZHAO Runtian, WANG Zhihui, LI Xiaodong, CHEN Zhanchun
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Four distinct screw configurations were evaluated for fabricating polyamide 6 （PA6）/carbon fiber （CF） composites. The impact of screw design on material uniformity was systematically assessed by characterizing residence time distribution， fiber length retention， and dispersion homogeneity. The results indicated that the slotted screw elements not only extended material residence time significantly but also induced divergent flow paths and elongational mixing， enhancing fiber dispersion. The 30° kneading block generated peak shear stress， effectively refining carbon fiber length through intensified mechanical action. The slotted⁃thread configuration improved composite uniformity by 52 % compared to the baseline design， demonstrating superior fiber alignment and matrix⁃fiber integration. This study underscores the critical role of screw geometry in tailoring shear intensity and flow dynamics to achieve high⁃performance PA6/CF composites.
ZHU Kuilin, LYU Chong, GUO Lei, CHEN Yilin, HUANG Yifeng, ZHAO Peiqi, JIANG Xueliang, YOU Feng
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34 )
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NH2⁃CeO2/MAPP/PP/POE composites were synthesized through amino⁃functionalized CeO2 modification， incorporating maleic anhydride⁃grafted polypropylene （MAPP） as a compatibilizer to improve dispersion within the polypropylene （PP） matrix， and blending with polyolefin elastomer （POE）. The dielectric， thermal， and mechanical properties of the composites were systematically investigated. The results demonstrated that increasing the POE content elevated both the dielectric constant and dielectric loss of the composites. At a test frequency of 1 kHz and a POE mass fraction of 11 %， the NH2⁃CeO2/MAPP/PP/POE composite achieved optimal performance with a maximum dielectric constant of 4.23， accompanied by a dielectric loss of 0.0183 and elongation at break of 66.7 %.
ZHEN Qi, QIN Zixuan, ZHANG Heng, CUI Jingqiang, WANG Guofeng, CHENG Wensheng, LI Han
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37 )
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To enhance the mechanical performance of polylactic acid （PLA）⁃based melt⁃blown microfibrous materials for medical packaging， PLA/PCL@EBS melt⁃blown microfibrous samples were subjected to annealing. The structural morphology， crystallinity， and mechanical properties of the samples were systematically characterized. The results indicated that the annealing action reduced fiber diameter， with 72.0 % of fibers falling within a 6 µm diameter range at elevated annealing temperatures. Increasing the annealing temperature from 60 to 80 ℃ significantly improved crystallinity， rising from 5.1 % to 29.7 %. Concurrently， mechanical properties were enhanced： machine⁃direction and cross⁃direction fracture strengths increased from 16.4 and 3.4 N/5 cm to 30.9 and 8.4 N/5 cm， respectively， while top⁃break strength improved from 10.1 N/5 cm to 18.9 N/5 cm. Response surface methodology further revealed optimal mechanical performance at an annealing temperature of 70 °C and a duration of 30 minutes.
ZHOU Qi, LI Quan, LI Yajing, LIU Xinan, GU Xinchun, HUANG Shouying
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In this study， polylactic acid （PLA） was melt⁃blended with poly（propylene carbonate） （PPC） at varying composition ratios using a twin⁃screw extruder. The thermal stability， mechanical properties， water vapor barrier performance， and rheological behavior of the PLA/PPC blends were systematically analyzed via differential scanning calorimetry， universal tensile testing， water vapor transmission rate measurements， and rotational rheometry. The results indicated that phase separation occured between PLA and PPC when the PLA/PPC ratio exceeded 20/100. Despite this， the blends exhibited enhanced processing performance， improved water vapor barrier properties， and superior tensile strength. Notably， when the PLA/PPC ratio surpassed 50/100， all evaluated properties， including rheological behavior， barrier efficiency， and mechanical performance， demonstrated significant improvement.
Processing and Application
CHEN Yuanmin, ZHAO Mengyu, QIU Siyuan, LI Yajiao, WANG Wenhao, WANG Hao, ZHU Guangying, SUN Jingyao
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This study employs the operating principle of semiconductor⁃based resistive strain sensors to fabricate an intermediate conductive layer using two distinct methods： spatially⁃confined forced assembly and screen printing. Comparative analysis revealed that the sensor produced via spatially⁃confined forced assembly demonstrated superior suitability for pre⁃radiotherapy breathing training in patients. Under a maximum applied strain of 24 %， the sensor exhibited stable performance， with a fitted sensitivity of K=0.0015 V/mm and a repeatability of 96.67 %. Tensile testing at 10 % strain yielded a rapid response time （Tr≈137 ms）， meeting the requirements for real⁃time monitoring. Forward and reverse stroke output⁃input curve measurements further revealed a low return error （δH=1.06 %）， demonstrating the working stability of the sensor during prolonged operation. Finally， respiratory signals were successfully collected from ten individuals with varying chest circumferences， highlighting the clinical utility of the sensor in medical diagnostics and patient⁃specific respiratory monitoring.
BU Zehua, LI Shiyong, LIU Jinjun, ZHAO Haoyu, ZOU Jianan, LI Hongxia
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This study reported an investigation on a specific model of a blown film machine， considering the coupled interaction between its internal wind field and temperature field. A three⁃dimensional finite element model of the wind field was developed to analyze the characteristics of both the wind and temperature fields. Additionally， the research examines how the positioning of the flow⁃equalizing plate within the machine influences the pressure， velocity， and temperature distribution at the air outlet. The results indicated that increasing the height of the flow⁃equalizing plate led to minimal changes in the average pressure and velocity at the air outlet， with both parameters exhibiting a slight upward trend. Furthermore， the velocity distribution across the air outlet between static pressure boxes demonstrates an initial trend toward uniformity before transitioning to dispersion. Notably， the position of the flow⁃equalizing plate has negligible impact on both the air outlet temperature and the velocity distribution within individual static pressure boxes.
GUAN Hongyan, YANG Wenqiang, ZHANG Guoqiang
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38 )
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Based on the simulation method of CFD⁃DPM， we analyzed the particle flow state and the number of particles escaping from the water chamber of the underwater pelletizer under different inlet angles， and studied the average number of particles escaping from the water chamber within the same time change at different inlet angles， and then determined the optimal inlet angle of the water chamber by using the curve fitting method of cubic spline interpolation. The results show that when the inlet of the water chamber of the underwater pelletizer is set at 80° （the inlet of the prototype is rotated counterclockwise by 10°）， the average number of particles escaping from the outlet of the water chamber is the largest within the same time change.
CHENG Yuanyuan, HUANG Zhigang, XU Zhen, SUN Chenhao, WU Yuntao
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This article reported an investigation on the impact of various contact conditions on the changes in channel characteristics during the extrusion of polylactic acid （PLA） using an opposite⁃direction twin⁃screw extruder in non⁃isothermal issues. Three screw models， including complete meshing， partial meshing， and no meshing were constructed by a Solidworks® software， and corresponding numerical simulations were carried out by a Polyflow® analysis software. A comparative study was conducted on the pressure field， shear rate field， and viscosity field of the PLA fluid under different contact states of the three screw models. In the non⁃isothermal case， the complete meshing state exhibited high shear rates and moderate viscosity， which was consistent with the efficient extrusion of PLA. In conclusion， the extrusion effect of PLA in the complete meshing state was superior to the other two screw contact states under non⁃isothermal conditions.
SONG Yumo, DONG Lijia, LI Guosheng, WANG Jinxia
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This study focuses on power⁃law fluid dynamics within a three⁃dimensional single⁃screw model. Numerical methods were employed to analyze the flow behavior of power⁃law fluids， and the ANSYS Polyflow software was utilized to simulate their flow patterns in the 3D screw geometry. Dimensionless parameters were adopted to ensure the generalizability of the results. First， the relationship between screw throughput and pressure gradient under varying power⁃law indices was calculated to validate the simulation method’s accuracy. Subsequently， flow field characteristics， including velocity， shear rate， and viscosity profiles along the depth of the screw channel， were extracted and analyzed， with emphasis on their variations under different power⁃law indices and pressure gradients. The study concluded with key findings on power⁃law fluid flow dynamics. Notably， as the power⁃law index decreases， the pressure⁃driven flow field of the fluid intensifies， leading to diminished screw conveying capacity. This is reflected in the viscosity field： reduced viscosity near the upper and lower surfaces of the screw channel weakens the response of fluid to screw⁃induced propulsion， ultimately decreasing conveying efficiency and potentially inducing reverse flow.
NIU Zhong, WU Zunhong
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In this study， magnesium⁃aluminum layered double hydroxide （LDHs） was surface⁃modified by combining phenylphosphonic acid with octanamide to prepare modified LDHs （m⁃LDHs）. The effects of m⁃LDHs on the thermal stability， mechanical properties， wear resistance， and flame retardancy of PVC composites for badminton court surface layers were systematically investigated. The results indicate that the crystal structure of LDHs remained largely unchanged after modification. While unmodified LDHs restricted the motion of PVC molecular chains， thereby increasing the glass transition temperature （Tg）， the incorporation of m⁃LDHs significantly reduced due Tg to their internal lubrication effect. The surface⁃modified LDHs exhibited synergistic flame retardancy， effectively suppressing the combustion and decomposition of PVC， leading to enhanced static thermal stability and flame⁃retardant performance. At an optimal m⁃LDHs loading of 3 wt%， the composite achieved a stiffness⁃toughness balance in mechanical properties， with a 37.3 % reduction in friction coefficient compared to pure PVC. These results not only meet the safety specifications for polyvinyl chloride （PVC） sports flooring outlined in the Hebei Provincial Standard DB 13/T 2662—2018 but also preserve the elasticity， strength， toughness， and shock absorption required for badminton court surface materials. This effectively reduces muscle fatigue and micro⁃injuries during athletic activities， demonstrating significant potential for practical application in this field. However， excessive m⁃LDHs （>3 wt%） led to agglomeration within the PVC matrix， diminishing the modification effect.
Plastic and Environment
LI Zeyang, LIU Shu, YAN Chenglin, SUN Jie, TANG Lei, WEI Mengjuan
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This paper reviewed recycling methods for polyethylene terephthalate （PET） waste， covering both physical and chemical regeneration processes. The applications of recycled PET （rPET） in sectors such as textiles and food packaging were summarized， emphasizing its versatility across industries and significant market potential. The review also delineated structural and performance differences between PET and rPET， and elaborates on identification methods that leverage these distinctions through advanced chemometric techniques and machine learning models， as investigated in domestic and international research. Finally， future studies should prioritize cost reduction in chemical regeneration processes， development of higher⁃value⁃added rPET products， and the establishment of rapid， reliable identification protocols to enhance quality control and sustainability efforts.
FAN Zhaorong, GU Yaxin, LIU Yang, WANG Xiaodan, LIU Yunxue
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A paint residue modified high⁃density polyethylene waterproof board was prepared using high⁃density polyethylene （PE⁃HD） as a matrix resin， solid waste paint residue as a filling modifier， and silane coupling agent （KH⁃560） as an interface modifier. The effects of paint residue content and silane coupling agent dosage on the impermeability， mechanical properties， and thermal aging resistance of the composite material were studied. The experimental results indicated that the elongation at break of the modified PE⁃HD waterproof board decreased significantly with increasing paint residue content， and its tensile strength and contact angle exhibited an initial gradual increase at paint residue levels ≤ 4 wt%， followed by a sharp decline at higher concentrations. The thermal aging resistance of the modified PE⁃HD waterproof board remained largely unaffected by paint residue content. The addition of KH⁃560 improved fracture elongation， demonstrating its effectiveness in enhancing interfacial bonding between the PE⁃HD matrix and paint residue filler. This work highlights the potential of repurposing industrial paint residue into functional additives for polymer composites， offering a sustainable solution for high⁃performance waterproofing materials.
MA Hailong, DAI Mingxin
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This paper reviewed recent advances in the application of recycled plastic aggregates in cement concrete， and also examined the types of plastic aggregates and their effects on the key properties of cement concrete， analyzing their underlying mechanisms of action， with a focus on three critical aspects： physical properties， mechanical performance， and durability. Additionally， the cost⁃effectiveness， environmental implications， and current limitations of incorporating plastic aggregates into cement⁃based materials were discussed. These insights provide a foundational understanding of the practical advantages and challenges of using recycled plastics in concrete， offering guidance for future research and sustainable construction practices.
Machinery and Mould
QIU Siyuan, WANG Wenhao, CHEN Yuanmin, LI Yajiao, ZHENG Xiuting, XU Hong, WU Daming, SUN Jingyao
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Continuous roll⁃spatial confining forced network assembly （CR⁃SCFNA） innovatively reengineers the traditional flat⁃plate hot⁃pressing method into a dynamic “flexible roll⁃to⁃plate” process. By integrating the mechanical force of rollers with the intrinsic self⁃assembly behavior of fillers， CR⁃SCFNA synergistically drives the formation of a high⁃density filler network. The system employs a graded roller press that progressively compresses the composite material to align with the dimensional specifications of the limit plate. Experimental results demonstrated that applying forced assembly forces， specifically radial compression combined with orthogonal shear forces， enabled precise alignment and directional organization of fillers within the polymer matrix. This created a densely interconnected thermally/electrically conductive network. This breakthrough process significantly enhances the thermal and electrical conductivity of polymer composites， addressing the growing industrial demand for lightweight， high⁃performance materials in applications such as electronics， energy systems， and advanced manufacturing.
LI Qingan, ZHANG Weihe
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This work presents the development of a large⁃scale injection mold incorporating sequential valve⁃gated hot runner （SVGHR） technology. There are two key challenges addressed， which included high clamping force and demolding complexity. A two⁃stage ejection system resolved excessive clamping force on the horn mesh structure and facilitated reliable part release. Integrated support columns within the part geometry eliminated the deformation caused by inclined ejector pin forces during demolding. SVGHR control ensured uniform filling of the large mold cavity， mitigating flow⁃related defects. A multi⁃channel cooling system with 24 interconnected circuits， including through⁃type， angled， and baffle⁃cooled wells， achieved rapid， balanced cooling through optimized vertical/horizontal routing. Production trials confirmed the dimensional accuracy of molded parts meeting MT3 standards according to the national standard GB/T14486—2008. Cycle time was reduced by 10 % compared to conventional molds.
CHENG Yue, ZUO Guilan
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A two⁃plate hot runner mold was designed for manufacturing the lower support plate plastic component of air conditioning outlets in new energy vehicles. The mold design faced two primary challenges： first， the complex geometry of the part complicated the configuration of the gating system， and second， the presence of numerous irregular structural features hindered automatic demolding. To address these challenges， CAE analysis was employed to optimize the mold’s gating system and contour cooling layout. The final design adopted a hybrid cold⁃hot composite gating system， utilizing a rectangular side gate with initial dimensions of 8 mm×2 mm. For cooling， 11 ϕ12 mm pipes were arranged in a contour configuration， with an initial inlet water temperature of 25 ℃. Optimization results confirmed that the injection pressure within the mold cavity remains below 28 MPa， warpage deformation of the plastic part is controlled under 2.275 mm， and the injection cycle is maintained below 30 seconds. The dimensional accuracy of the part meets the MT4⁃MT5 grade standard. To resolve demolding difficulties， the design incorporated four slider mechanisms and six lifter mechanisms for automated part ejection. Notably， an innovative cross⁃type lifter mechanism was developed， featuring a sliding lifter seat driven by an angle pin. This modification reduced the movement resistance of the angle rod and enhanced the mechanism’s durability. Critical design parameters include a sliding seat angle pin inclination （α）=12 °， a angle rod ejection angle （β）=9 °， and a sliding seat groove guide angle （θ）=15 °. These optimizations ensured reliable demolding performance while meeting stringent cycle time and precision requirements.
Review
TU Zhu, MA Huixia, LI Lanpeng, ZHOU Feng, WEI Zhiyong
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This review introduced the degradation properties of biodegradable polyester plastics in seawater and summarized key seawater⁃degradable polyester materials reported to date. The review further explored variations in the degradation behavior of these polyesters in marine environments and discussed material modification strategies， focusing on polymer types and underlying degradation mechanisms. Finally， considering the current challenges in designing seawater⁃degradable polyesters， the review provided targeted recommendations and insights to guide future research and development in this field.
NING Dingyi, ZHAO Tianjiao, DONG Yapeng, WANG Meizhen, HAO Xinyu, WANG Bo
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This paper addresses the limitations in crystallization behavior and mechanical properties of polylactic acid （PLA） stemming from its inherent molecular chain structure. Recent advancements in blending modification strategies for enhancing the crystallization and mechanical performance of PLA， as reported in domestic and international studies， are comprehensively reviewed. Key approaches include elastomer modification， polymer alloy blending， inorganic material reinforcement， nanoparticle incorporation， bio⁃based material integration， nucleating agent optimization， chain extender⁃based modification， and synergistic multi⁃component systems. To advance this field， prioritizing the use of biodegradable or bio⁃based fillers in PLA blends was proposed while improving interfacial compatibility. Furthermore， future research should focus on developing low⁃cost， PLA⁃compatible modifiers and eco⁃friendly compound systems. Such innovations represent a critical pathway to achieving high⁃performance PLA materials through sustainable blending modification techniques.
