Materials and Properties
WU Xiran, JIA Zhixin, LIU Lijun, LI Jiqiang, ZHAO Chuantao, CHEN Bojie
Abstract (
131 )
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Glass⁃fiber⁃reinforced polypropylene was used to prepare integrated over⁃molding products. The significant factors affecting tensile strength and bending strength of the molded products were investigated by an orthogonal experiment， and the influence of process parameters on their mechanical properties was analyzed. Furthermore， the tensile and bending failure modes of the molded products under different process parameters were discussed， the microscopic morphology of their failure section was observed， and the correlations between their molding process and microstructure and mechanical properties were established. The results indicated that the significant factors affecting the tensile strength included the preheating temperature， holding pressure， and mold temperature. The significant factors affecting the bending strength were the preheating temperature， holding pressure， and melt temperature. The bonding strength between organic sheets and injection molding materials and the degree of fiber⁃resin bonding of the organic sheet were the main factors affecting the mechanical properties of the molded products.
AN Jingjing, ZHANG Haoyu, LIU Xianhu, SHAO Chunguang
Abstract (
57 )
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1008 )
With the rapid development of economy， the problems of greenhouse gas emissions and energy consumption have become increasingly serious. In order to reduce energy consumption and promote green and low carbon developments， it is urgent to develop the efficient energy⁃saving and cooling materials. In recent years， thermoplastic polyurethane elastomer （TPU） has attracted more and more attention as a potential high⁃performance energy⁃saving cooling material. Starting from the structural design of energy⁃saving cooling materials， this paper reviewed the energy⁃saving cooling mechanism， preparation methods， and application scenarios of TPU⁃base film materials， summarized the advantages of energy⁃saving cooling by using TPU⁃based film， and looked forward to its development prospects in future.
LI Yajiao, LI Ning, QIU Siyuan, CHEN Yuanmin, WANG Wenhao, SUN Jingyao
Abstract (
51 )
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147
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1030 )
CS （chitosan）⁃， polyvinyl alcohol⁃， hyaluronic acid⁃， polyacrylamide⁃based hydrogels were prepared by using a blending method. Through comparing these hydrogels with the Slime hydrogel and deionized water， the thermal management performance of different hydrogels in the direction of heat insulation and heat preservation was investigated， and the hydrogel materials with excellent thermal management performance were selected in the scenarios at the temperatures with a less difference between the two sides. The results indicated that the CS⁃based hydrogel had the most excellent thermal insulation， thermal water locking， and flame⁃retardant performance. It could be used as a thermal management material in the scenarios at the temperatures with a less difference between the two sides. The thermal insulation mechanism of the CS⁃based hydrogel was also analyzed.
LI Changjin, LIU Wenlong, YANG Weimin, GUO Zifang, LI Haoyi
Abstract (
51 )
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To address the challenges in refining polyethylene （PE） fibers and realize the preparation and applications of ultra⁃fine PE fibers and their membranes， a type of low⁃density PW （PE⁃LD） ultra⁃fine fibers and their nonwoven fabrics were successfully produced through improving the traditional melt⁃blown process by modifying the melt⁃blown die and introducing an electrostatic field. The effects of electrostatic field strength and distance on the morphology， web structure， and diameter distribution of the nonwoven fabrics were investigated. Furthermore， the differences in filtration， hydrophobicity， and mechanical properties of the nonwoven fabrics before and after introducing the electrostatic field were compared. The results indicated that the average fiber diameter decreased from 9.82 μm to 8.07 μm with an increase in the electrostatic field strength， and the fiber diameter distribution became narrow. This improved the filtration efficiency of the nonwoven fabrics. At a flow rate of 32 L/min， the highest filtration efficiency reached 73.65 % at a filtration resistance of 19.1 Pa. In addition， the hydrophobic performance of the nonwoven fabrics was enhanced with an increase in the electrostatic field. Such an electrostatic spinning method is suitable for the continuous preparation of high⁃viscosity melt micro⁃nano fibers and their nonwoven fabrics. The obtained products presented broad application prospects in the markets such as filtration materials and packaging.
ZHU Nenggui, JIANG Tuanhui, LI Shengnan, SHEN Chao, ZENG Xiangbu, QIN Shuhao, GONG Wei
Abstract (
39 )
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There are some limitations in the application of ordinary polypropylene （PP）/basalt fiber （BF） foamed composites due to their poor foaming quality and toughness. In this study， maleic anhydride⁃grafted polyolefin elastomer （POE⁃g⁃MAH） was used as a compatibilizer to modify PP/BF composites， and the PP/BF foam composites were prepared at different contents of POE⁃g⁃MAH through a chemical foaming secondary mold opening process. The foaming quality and toughness of PP/BF composites controlled by POE⁃g⁃MAH were investigated by rheological， morphological， and mechanical measurements. The results indicated that the addition of POE⁃g⁃MAH improved the foam quality of the PP/BF foam composites. The composites exhibited optimal performance together with the best foam quality at a POE⁃g⁃MAH content of 6 wt%， and their foam cell size and density was 64.58 μm and 1.2×106 cells/cm3， respectively. Furthermore， the toughness of the PP/BF foamed composites was enhanced with an increase in the content of POE⁃g⁃MAH， demonstrating improved notch impact strength and fracture elongation. Specifically， the composite containing 6 wt% POE⁃g⁃MAH showed notch impact strength of 4.33 kJ/cm2， which increased by 84.25 % compared to the composite without POE⁃g⁃MAH.
FENG Shuo, ZHOU Shuyi, JIAO Yang, HU Miao, ZHANG Ruoxuan, JIN Yujuan
Abstract (
43 )
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103
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1024 )
In this paper， epoxy⁃terminated hyperbranched polyester （EHBP） were synthesized and then blended with poly（lactic acid） （PLA） and talc powders through melt blending to obtain PLA/talc/EHBP composites. The surface hydrophobic properties， crystallization properties， molecular structure， mechanical properties， thermal properties， and microstructures of the blends were characterized by contact angle measurement， differential scanning calorimetry， Fourier⁃transform infrared spectroscopy， universal testing machine， thermogravimetric analyzer， and scanning electron microscopy. The results indicated that the addition of EHBP reduced the degree of crystallinity of PLA. The compatibility between PLA and talc powders was best for the composites at a EHBP content of 2 phr. The addition of EHBP enhanced the mechanical properties and toughness of the composites. The composites obtained a significant improvement in the mechanical properties at a EHBP content of 2 phr， leading to an increase in elongation at break by 29.3 %， in impact strength by 49.8 %， and in tensile strength by 31.3 %.
CHEN Meng, LI Wenliang, ZHANG Tao, ZHANG Wencai, YANG Xiying
Abstract (
38 )
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To explore the anti⁃aging performance and mechanism of asphalt modified with rubber powder/SBS composites， a series of modified asphalts were prepared by incorporating 2 wt% SBS and 20， 25， 30， and 35 wt% rubber powders. The anti⁃aging performance of the modified asphalts after short⁃term aging and pressure aged vessel aging at different degrees was evaluated. The results indicated that the high⁃temperature rutting resistance of the modified asphalts was improved， and their penetration， ductility， elastic recovery， fatigue performance， and low temperature deformation resistance were deteriorated after aging. The deterioration degree decreased as the rubber powder content increased. The enhancement mechanism of anti⁃aging performance was analyzed by infrared spectroscopy. The variation ranges of carbonyl index， sulfoxide index， and infrared aging index of the aged asphalts became smaller with an increase in content of rubber powders， and the slope of infrared aging index equation decreased from 0.010 39 to 0.005 19. Rubber powders enhanced the anti⁃aging performance of the modified asphalts. The influence of the rubber powder content and aging time on the infrared aging index could be comprehensively evaluated by an infrared aging index prediction model. The k prediction model of low⁃temperature creep ratio （k） established by correlating the infrared aging index as a microscopic index with the k value as a macroscopic index was accurate and effective， and it could be used for rapid comparative analysis on the low⁃temperature anti⁃aging performance of the modified asphalts.
Processing and Application
YING Qihui, JIA Zhixin, GAO Lizhen, LIU Lijun, LI Jiqiang, WU Xiran, CHEN Bojie
Abstract (
59 )
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Integrated over⁃molding is based on a combination of hot press and injection molding processes. Owing to the different shrinkage rates of materials， the molded products formed a “bowl⁃shaped” structure with a concave center and warped sides after cooling and shaping. To investigate the preheating time of prepregs， mold temperature， melt temperature， injection speed， injection pressure and holding pressure， an orthogonal experiment was designed to analyze the influence of process parameters on the warping and deformation of the molded products. The results indicated that the preheating time had a significant effect on the warpage deformation， whereas the injection speed showed a smaller effect. Through the signal⁃to⁃noise ratio analysis， the influence of each factor on the warpage of composite products was followed by by an order of preheating time>holding pressure>injection pressure>melt temperature>mold temperature>injection speed. The optimal process parameters were obtained for manufacturing composite products with small warpage.
GUO Weichao, XIN Xiaohang, ZENG Shanlin, GAO Xinqin, TANG Aofei
Abstract (
39 )
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During melt deposition molding （FDM） 3D printing， the outer outline of the printed model was firstly segmented from the inner region， and the inner and outer regions of the printed model were printed with different layer thicknesses. The inner region of the printed model was then segmented according to the stress distribution of the printed part. The variable density was filled according to the stress of each region. The results indicated that the proposed method could shorten the printing time by least 40% at least， reduce the surface roughness by 25%， and improve the printing efficiency. This ensures the printing accuracy of the side surface of the printed part. When the printed part was subjected to the same external load， the maximum stress of the printed part was reduced by 10% at least， their maximum displacement was reduced by 15% at least， and their mechanical properties were improved.
TANG Wenliang, YAN Jizhong, SHEN Limin, YANG Hong, WU Shengping, WANG GuoXing
Abstract (
36 )
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22 )
In this paper， a numerical simulation of polyethylene （PE） pipeline damages was conducted using the ABAQUS software by consideration of the synergistic effects of near⁃line pressure， ground settlement， pipeline internal pressure， buried depth， and ambient temperature. An orthogonal experiment was designed to investigate the impact of different factors on the pipeline damages. The results indicated that the pipeline experienced axial stretching and radial bending under the combined action of multiple factors， and the maximum Mises stress and maximum change rate occurred at the edge of the pressure occupied area. Through orthogonal analysis， it was found that when the near line occupying pressure and soil settlement around pipeline occurred simultaneously， the ground occupying pressure was the primary factor contributing to PE pipeline damage and the ground subsidence had a. limited influence.
CHEN Zhengnan, CHEN Binyi, HUANG An
Abstract (
36 )
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To investigate the optimum injection molding process conditions for the upper and lower covers of a socket， the Moldex3D software was used to simulate and compare three different feeding schemes. The latent four⁃point gluing was finally determined to be the best scheme. Subsequently， an orthogonal test method was used to explore the optimal injection molding process under this scheme. The results indicated that the factors affecting the warpage of the plastic parts was followed by an order of holding time>melt temperature>mold temperature>holding pressure. The optimum process parameters were determined to be a melt temperature of 200 ℃， a mold temperature of 45 ℃， a holding time of 25 s， a holding pressure of 55 %. After simulation verification， the maximum warpage value after optimization was determined to be 0.863 mm， which increased by 0.574 mm compared to that obtained under the initial process conditions. This result was optimized by nearly 40 %， and the product quality was effectively improved.
Additive
CHEN Yezhong, GONG Dejun, FU Xuejun, OUYANG Chunping, ZHANG Yi, YIN Yansheng
Abstract (
69 )
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Poly（butylene terephthalate adipate） （PBAT）， poly（lactic acid） （PLA）/calcium carbonate composites with different types of lubricants were prepared by using a melt blending method， and the effect of lubricant types on the mechanical and emissive properties of the composites was investigated. The results indicated that in addition to internal lubrication to enhance molecular chain slip， the introduction of stearate also triggered the localized breakage of the PBAT/PLA molecular chain. This resulted in an increase in the melting index but a decrease in the tensile properties and toughness of the films. The introduction of erucic acid amide， oleic acid amide， or ethylene bis stearamide （EBS） led to a slight decrease in the heat seal strength， and the introduction of stearyl ester salts improved the decrement rate in the heat seal strength. There was an increase in odor with the introduction of erucic acid amide or oleic acid amide， and the odor was further increased with the introduction of calcium stearate and zinc stearate. The total volatile organic compounds （TVOC） tended to increase with the introduction of lubricants， and the introduction of zinc stearate elevated the TVOC amount of the film by 40.2 %. Toluene， styrene， formaldehyde， acetaldehyde， and acrolein in the volatile organic compounds did not change significantly with the introduction of erucic acid amide， oleic acid amide， or EBS， whereas the introduction of stearate resulted in a significant rise in these categories.
Standard and Test
HU Fa
Abstract (
49 )
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27
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A series of polypropylene （PP） films containing antioxidant 1010 and antioxidant 627A were separately prepared. The antioxidant content of the films was determined by microwave extraction and liquid chromatography. Eight different food simulants were employed to simulate water⁃based foods （pH>4.5）， acidic foods （pH≤4.5）， alcoholic foods， and fatty foods. The migration of antioxidants to food simulants was investigated at three different temperatures and five different times. The results indicated that the migration levels of the two antioxidants to water， 3 wt% acetic acid， and 10 vt% ethanol as three simulated substances were below the detection limit. When the simulated substance was n⁃hexane， both antioxidants could reach the maximum migration amount quickly. Antioxidant 1010 has a strong interaction with PP molecules to bind well with the matrix. Its overall migration was relatively small did not migrate even in alcoholic foods below 40 ℃. Moreover， its migration in the high⁃concentration alcoholic and fatty foods was significantly lower than that of antioxidant 627A.
Plastic and Environment
YANG Qing, CAI Jiafeng, GU Weihua, PENG Shengjuan, ZHAO Jing, BAI Jianfeng
Abstract (
46 )
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The development of modern industry has caused a sharp increase in the use of plastic products. Waste plastics are difficult to degrade naturally due to their high hydrophobicity and chemical inertness. Under the background of carbon peak and carbon neutrality， sustainable management of plastic waste is urgent. Biodegradation is one of the best environmentally friendly methods for treating plastic wastes. Extensive researches have focused on identifying microorganisms and enzymes with plastic degradation capabilities in recent years. In this paper， six common plastics and their recent research progress in biodegradation were reviewed. The characterization methods of plastic degradation were summarized and their degradation mechanisms were discussed.
YAO Jianmin, BI Xinyuan, LI Ruizhen, YAO Yuanyuan, LIU Zhao, YANG Ruiping, JIANG Lina
Abstract (
45 )
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A ultra⁃thin fully biodegradable water permeable mulching film with a thickness of 0.006 mm±0.000 2 mm was developed by combining polycarbonate propylene， polybutylene adipate terephthalate， anti⁃aging polycarbonate propylene ester， strong coupling water permeable auxiliary agent， and anti⁃UV agent， and its blowing temperature and processing conditions were optimized. The results of performance analysis indicated that the longitudinal/transverse tensile load， breaking nominal strain， and right⁃angle tearing load of the film was 2.92 N/1.90 N， 195 %/522 %， and 0.9 N/1.1 N， respectively. Its safe and effective service life was greater than 86 d， and its water vapor permeability was lower than 370 g/（m2·24 h）. All these indicators could meet the performance requirements for 0.01 mm film according to the national standard GB/T 35795—2017. In addition， the film had a function of air permeability and water permeability with an air permeability rate of 60 s/（23 ℃·100 mm·100 mm·20 g） and a water permeability rate of over 15 000 g/（23 ℃·m2·24 h）. Its alkaline degradation rate was also greater than 8.5 g/（23 ℃·10 g·48 h）. This type of film not only has excellent performance but also reduces the consumption by 40 % per unit area compared to the 0.01 mm fully biodegradable mulching film.
Machinery and Mould
QIN Xiaoyu, ZHU Xiangzhe, CHEN Bohan, WANG Yuyu
Abstract (
46 )
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In this paper， a parallel differential tri⁃screw extruder with a speed ratio of 1/5/5 was designed. This tri⁃screw extruder has a geometric structure and asymmetry of rotational speed. To explore the unique flow field characteristics， the designed tri⁃screw extruder was compared with the parallel differential tri⁃screw extruder with a speed ratio of 1/1/5 and the differential twin⁃screw extruder with a speed ratio of 1/5. The results indicated that， compared to the traditional extruders， the parallel differential tri⁃screw extruder exhibited a unique complex particle trajectory along with the appearance of a phenomenon of "secondary flow" shown by a circumferential velocity field in the meshing zone appears due to the particularity of the structure and the different speeds. This makes the material in the runner reciprocate together with an increase in the residence time of the material in the runner. These results were conducive to the mixing of materials. When calculating the mixing performance parameters of three sets of parallel differential screw extruders， the parallel differential tri⁃screw extruder with a speed ratio of 1/5/5 were found to have better mixing performance.
LIU Bangyi, WANG Guangwei, SU Yingxia, SUN Bo
Abstract (
42 )
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A patented technology of micro hole laser engraving on the front bumper was adopted in the Geely Galaxy E8 car. In this technology， some elements such as sound， light， and electricity were added to obtain the world's first mass⁃produced integrated luminous front face， solving many problems such as inconsistent front bumper colors and multiple parts that require grille design for a car luminous front bumper. The feasibility of the integrated luminous front face was demonstrated from several aspects such as laser engraving sequence， laser engraving background color， laser engraving size， different post⁃processing methods， and different colors of paint. The results indicated that adopting front side laser engraving was superior to the back side laser engraving technology， which could avoid the problems of difficult shading and low qualification rate due to a requirement for spray painting on both sides. Adopting a substrate exposure scheme was more optimal to avoid adding primer even if primer was not used to directly laser engraving onto the substrate. Each of spraying and baking increased once， which increased the difficulty of construction， lowers the product qualification rate， and posed a higher cost risk. The micro hole laser engraving technology was superior to large hole laser engraving， which avoided the problem of large hole laser engraving. The laser engraving features were obvious， and there were black shadows on the boundary of the laser engraving features. Moreover， the exposed substrate was prone to yellowing after being light resistant. The 3⁃coating and 1⁃baking process cannot be used according to the requirement for design scheme of the front micro hole laser engraving. Wet paint can cause blurred laser engraving boundaries， and the 3⁃coating and 3⁃baking process consumes a lot of energy and is also complicated. Therefore， the 3⁃coating and 2⁃baking process is preferred， and all paint indicators can meet the requirements. Different colors of paints， differences in pigments and paint formulations， and demand to adapt to laser engraving parameters can also lead to differences in paint adhesion.
WANG Yousi
Abstract (
48 )
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45
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To address the problems of large size of turnover baskets， long manufacturing period for molds， small demolding angle of products， high demolding resistance， and difficult ejection， an unconventional idea for mold design was proposed. A new mold structure was designed by abandoning the mold feet and ejector pin plate parts. A four⁃side sliding block core extraction was used with an oil cylinder， and an innovative design scheme was adopted to use the fixed mold pull rod and pull plate to pull out the product for secondary demolding through a mold opening distance， solving the problem of turnover basket demolding. Such a new mold structure design provided a precise selection for subsequent processing and manufacturing. This design scheme adopted a structural design of hydraulic cylinder pushing out the slider and fixed mold opening stroke distance to pull out the product， simplifying the mold structure and greatly reducing the overall size of the mold. A precision numerical control equipment was used in mold manufacturing to ensure the accuracy of the manufactured molds. This also shortened the mold manufacturing cycle and greatly reduced the mold costs. The mold was operated smoothly in actual production together with a reasonable and reliable mold structure and stable product quality， and it achieved good economic and social benefits in the market.
Review
LIU Wenlong, ZHOU Xiang, LOU Shuang, MA Xiuqing, LI Haoyi, LI Changjin, YANG Weimin
Abstract (
53 )
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This paper expounded the refinement mechanism of fiber diameter in the melt⁃blown process and discussed the influence of melt⁃blown process parameters on the preparation of ultrafine fibers， mainly including melt⁃blown air flow， temperature， melt extrusion capacity， and receiving distance. The general rules and principles of the effect of process methods on the attenuation of fiber diameter were summarized. Finally， the action modes of the mold type on the fiber diameter were introduced. Furthermore， the innovative design of traditional molds or their combination with the electrostatic technology based on the melt⁃blown technology will become an effective way to realize the refinement of melt⁃blown fibers to the nanoscale.
2025, 39 (5):
123-131;
Abstract (
26 )
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141
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β-Cyclodextrin is the cyclic glucose-type oligomer extracted from starch， and its external hydrophilicity and internal hydrophobicity form a unique 'microenvironment'， which makes β-cyclodextrin gain a wide range of material compatibility. With the ability to be compounded with various types of materials， β-cyclodextrin can form nanomaterials with different functions. The purpose of this paper is to present an overview of research progress in the applications of β-cyclodextrin nanomaterials in adsorbing harmful substances， such as heavy metal ions， dye molecules， and antibiotics， in wastewater and soil and to look forward to the development prospect of β-cyclodextrin nanomaterials in future.
Review
LI Wenzhuo, QIU Munan, WEN Bianying
Abstract (
73 )
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As the global automotive industry actively pursues environmental protection and low carbon， new energy vehicles have become the core development trend due to their unique energy configuration and usage characteristics. Compared to traditional vehicles powered by internal combustion engine， the functional components of new energy vehicles play a crucial role in constituting critical performance parameters， including range， driving experience， and safety， and meanwhile there is a higher demand on the used materials. Polymers exhibit important application values in the functional components of new energy vehicles due to their advantages， such as easy processing， low cost， and modification. This paper reviewed the research progress in the development and applications of polymers in the functional components of new energy vehicles， including power batteries， thermal management systems， control， and drive systems， etc.， and also prospected the future development of polymers in new energy vehicles.
