最新刊期
卷 36 ， 期 9 ， 2023
- 摘要：Twisted structures exisit widely in natural living bodies and inanimate substances, and through a large number of studies, it has been found that it is widely present precisely because such twisted structures help to improve the properties of materials, which in turn can achieve rich biological functions. By mimicing the natural twist structures, researchers have developed a number of twisted fibers for a variety of applications. During the twisting process, the fiber will twist and deform to generate a twisting moment, and the internal structure of the fiber is tightly hugged and becomes tighter while being helical-oriented. As a resuct of torsion, the internal structural of the fiber changes adding some very unique and outstanding properties in terms of mechanical properties, thermal effects and electrical properties. Therefore, twisted fibers have attracted extensive attention from researchers, and have been applied in multiple fields. This review paper mainly introduces the preparation mechanism of twisted fibers. The latest research progress of twisted fibers in the fields of artificial muscle, refrigeration and power generation is reviewed, and the further research development and application prospect of twisted fibers are prospected.关键词：Twisting;Twisted fibers;Torsional refrigeration;Artificial muscles
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发布时间：2023-07-26 - 摘要：Fused filament fabrication (FFF) is one of the most widely-used polymer-based additive manufacturing technologies, with advantages of high raw material utilization, simple working principle, and low cost. However, nowadays FFF technique tends to be used to fabricate prototypes rather than final products, especially in industrial area, since it produces polymer parts with weak interlayer interfaces and therefore anisotropic mechanical properties due to its later-by-layer manufacturing principle. During FFF process, neighbour layers weld at the interface through surface wetting, molecular diffusion and entanglement, highly depending on the thermal profiles experienced by the deposited polymer strands. To this end, the in situ external field-assisted FFF techniques have been developed, aiming at promoting the welding behaviours between adjacent layers during the FFF process, with the help of thermal and force fields and their combination external fields, which in turn improve the mechanical properties of the FFF parts. This paper firstly summarizes the state-of-art of the modeling and experiments devoted to exploring the interlayer welding behaviours of amorphous and semicrystalline polymers during FFF process. Then, various thermal, force and their combination external field-assisted FFF techniques are presented, from aspects of the principles and their effects on the mechanical properties of the FFF parts. Finally, the challenges and prospects of the thermal/force-assisted FFF technology are discussed from the perspectives of materials, processes, and devices, and the development and application of FFF technique are emphatically analyzed.关键词：In situ external field assistance;Fused filament fabrication;Polymer materials;Mechanical properties
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发布时间：2023-07-26 - 摘要：In this paper, the preparation and application of paraffin-based/polymer, inorganic and polymer-inorganic hybrid shell microcapsules were mainly introduced, and the advantages and disadvantages of the above microcapsules were summarized. The wall materials of paraffin/polymer shell microcapsules include melamineformaldehyde resin, urea-formaldehyde resin, melamine-formaldehyde-urea resin, urethane resin, acrylic resin, etc. The wall materials of paraffin-based/inorganic shell microcapsules include silica, titanium dioxide, calcium carbonate, and zinc oxide, etc. The wall materials of the paraffin/polymer-inorganic hybrid shell consist of melamine-formaldehyde resin, melamine-formaldehyde-urea resin, acrylic resin, etc., which are compounded with inorganic particles such as titanium dioxide and silicon dioxide. The future development direction and application prospect of paraffin-based microcapsule phase change materials have been prospected in order to provide a reference for future research.关键词：Paraffine;Microcapsules;Wall material;Encapsulation rate;Enthalpy value
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发布时间：2023-07-26 - 摘要：Aramid nanofiber (ANF) is a new type of nano-reinforced material with excellent properties such as high aspect ratio, high surface energy and high thermal stability. It can be combined with polymer materials to enhance the mechanical and thermal properties of the polymer. However, there are still shortcomings in the preparation methods of ANF that make it difficult to produce on a large scale, and effectively combining it with polymer materials remains a challenge. This paper summarized the common preparation methods of ANF, introduced the application of ANF in the field of polymer composites, and prospected the application research of ANF in the field of polymer materials.关键词：Aramid fiber;Aramid nanofiber;Polymer composite material;Polymer reinforced
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发布时间：2023-07-26 - 摘要：In face of the energy crisis and global warming challenges, the development of cooling technologies without additional energy input or equipment assistance is of great practical importance. Daytime radiative cooling (DRC) has been proven to be an effective coping strategy, which depends on materials with a high reflection in the solar spectrum and high emission in the atmospheric window. Owing to the wealthy functional groups, high emission in the atmospheric window of polymers can be achieved. Various preparation techniques of polymers make the large-scale production of different application scenarios more potential. Therefore, polymer-based daytime radiative cooling materials (PDRC) are gaining more and more attention. This review firstly introduces the design principles of DRC materials including selecting materials with high reflection in the solar spectrum or high emission in the atmospheric window according to the absorption spectrogram, designing the material structure, and reducing non-radiative heat transfer to achieve the radiative cooling effect. From the perspective of structural design, the effects of the polymer/metal film laminated structure, polymer bionic structure, polymer/micro-nano-particle distribution structure, and porous polymer structure on P-DRC performance are discussed and emphasized in their advantages and disadvantages. Finally, the current status of P-DRC materials in building cooling and personal thermal management are reviewed, and their future development directions are foreseen.关键词：Polymers;Daytime radiative cooling;Structure design;Building cooling;Personal thermal management
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发布时间：2023-07-26 -
Application and Research Progress of Solid Linear Phenolic Resin in the Field of Integrated Circuits
摘要：Linear phenolic resin is the key functional material as the base resin due to excellent heat tolerance, reliability and electrical insulation in the field of integrated circuits. However, traditional phenolic resin has some problems such as poor stability, slow photosensitive speed, low transparency, resolution and mechanical strength, which increase the application cost and technical difficulty, and reduce the economic benefits of phenolic resin in the field of integrated circuits. Therefore, the traditional linear phenolic needs to be modified to resin for better application in the field of integrated circuits. In this review, the recent research status of linear phenolic resin in chip photoresist, electronic packaging and copper-coated plate was reviewed, the main methods of modifying linear phenolic resin were summarized and the development trend of linear phenolic resin was prospected, providing a reference for the research and development of high-performance integrated circuit application materials in the future.关键词：Linear phenolic resin;Chip photoresist;Electronic packaging;Copper-coated plate- 26
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发布时间：2023-07-26 - 摘要：Series of soluble polyimides (PI) gas separation membranes were successfully synthetized by using 3, 3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA), tolylene-2,4-diisocyanate (TDI), diphenylmethane-4,4'-diisocyanate (MDI) and 1,3-bis(2-isocyanato-2-propanyl)benzene (TMDXI). It is shown that the incorporation of TMDXI has a great effect on the solubility, fractional free volume (FFV), tensile strength, and thermal resistance of resultant PI membranes. The fracture behavior of PI membranes transforms from brittle fracture to ductile fracture, and the permeabilities of PI membranes increases for various gases attributed to introduced TMDXI moiety, and especially, the permeability for CO2 of the PI membrane containing 30 mol% TMDXI increases 144% in relative to the sample without TMDXI.关键词：Polyimide membrane;Solubility;Fractional free volume;Gas separation
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发布时间：2023-07-26 - 摘要：In this study, the dialdehyde microfibrillated cellulose/poly(vinyl alcohol) (DAMFC/PVA) composite hydrogels were investigated, with easily controlled mechanical strength. DAMFC/PVA hydrogels were prepared by the acetal reaction occurred between the aldehyde groups on the surface of DAMFC microfibers and the hydroxyl groups on the PVA macromolecular chains. Then the hydrogels were soaked in various salt solutions. Due to the acetal reaction, the reinforcement DAMFC and the matrix polymer PVA were connected by covalent bonds. Under the stress, the load could be efficiently transferred from the reinforcement to the matrix, so that the mechanical strength of the composite hydrogel was significantly improved. In addition, due to the salting out effect, the mechanical strength of the hydrogels was further improved by soaking in salt solutions. The anion species of the salt had a great influence on the mechanical strength. By regulating the content of DAMFC, the oxidation time of NaIO4 and the selection of anion in salt solution, the mechanical strength of PVA composite hydrogels can be regulated in a wide range to meet the needs of different applications.关键词：Poly(vinyl alcohol);Dialdehyde microfibrillated cellulose;Hydrogel;Salt solution;Mechanical Strength
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发布时间：2023-07-26 - 摘要：Ten single-template molecularly imprinted polymers (SMIP) and eight mixed-template molecularly imprinted polymers (MMIP) were synthesized by non-covalent bond precipitation polymerization using plant growth regulator as template, methacrylic acid (MAA) as functional monomer and ethylene glycol dimethyl acrylate (EGDMA) as crosslinking agent. The effects of the dipole moment, oil-water partition coefficient (lgP), acid-base ionization constant (pKa), H bond acceptors, polar surface area and molar volume of the template on the imprinting effect was studied. Molecular dynamics simulations of all-component prepolymerization mixtures for MMIP have been employed to investigate the mechanistic basis for template selective recognition in these systems. The results showed that the dipole moment, lgP and pKa of the template were positively correlated with the imprinting factor (IF), specificity parameters (SP) and binding capacity (Q) of the SMIP synthesized by UV-initiated polymerization at 4 ℃, and the lgP and pKa of the template were positively correlated with the IF, SP and Q of the SMIP prepared by thermal initiation polymerization at 60 ℃. MMIP synthesized by UV-initiated polymerization at 4 ℃ using 4-chlorophenoxyacetic acid, uniconazole and 1-naphthylacetic acid as mixed templates obtained better co-imprinting effect than single template imprinting, even though the concentration of each template was only 1/3 of that of single imprinting. Which has the best selectivity for 4-chlorophenoxyacetic acid, uniconazole, 1-naphthylacetic acid, paclobutrazol, triadimefon and thiazolone. The binding capacity of the MMIP for these target PGRs is 1.77, 1.78, 2.79, 1.62, 2.88 and 5.39 times of that of corresponding non-imprinted polymer (NIP), respectively, and the total binding capacity is 10.93 μmol/g, which can be used for the extraction and separation of these PGRs. In molecular imprinting preassembly systems, complexes can be formed not only between the same template but also between different templates. The binding between some templates can hinder their binding with functional monomers, resulting in a weakened imprinting effect. The combination of other templates can enhance their binding with functional monomer, so as to enhance the imprinting effect.关键词：Plant growth regulator;Molecular imprinting;Template properties;Mixed-template;Imprinting effect
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发布时间：2023-07-26 - 摘要：In 2022, the Organic Polymer Materials Discipline of Department of Engineering and Materials Science in the National Natural Science Foundation of the People’s Republic of China optimized the research direction and key words under the discipline code, added the research direction reflecting the new trend, enriched the key words under each research direction, made the research direction and key words more comprehensive and reasonable, and contributed to a more efficient, scientific, and fair fund evaluation.关键词：Organic polymer materials discipline;National Natural Science Foundation of China;Research direction;Key words
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发布时间：2023-07-26 - 摘要：In order to cultivate new age talents with the ability of engineering practice and innovation, the project takes the large-scale and design-oriented experiment of polyester synthetic as the carrier, and adopts the techniques of 3D modeling, digital simulation, virtual reality and so on. The virtual simulation experiment of polyester synthesis with "One Centre-One Ring, education-oriented" was designed and established. Taking students’ individual learning as the center, through the teaching contents and methods of hierarchical progressive and closed-loop learning, students can complete their study in "disassembling" , "playing" , "imitating" and "creating" , and stimulate their interest in learning, cultivating students’ innovative thinking and engineering practice ability, giving full play to students’ initiative, helping to improve the quality of experimental teaching.关键词：Virtual simulation;Personalized learning;Experimental teaching;Polyester synthesis
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发布时间：2023-07-26 - 摘要：Since the concept of "polymer" was established in 1920’s, polymer science and industry have grown enormously and prosperously, and human mankind has entered a new era featured with polymer materials. Polymer materials play critical roles in various fields such as people’s necessities in daily life, national security, and cutting-edge technologies. As the biggest country in manufacturing in the world, if we want to lead in the field of polymer material in the future, the key is to cultivating the top professionals from university, who have both a genius talent and a great moral character. The major of polymer materials and engineering in the department of polymer science and engineering at Zhejiang University has a typical interdisciplinary feature crossing science and engineering. Based on the teaching reform on the core required course "Polymer Chemistry", this paper summarizes the accumulated experiences from exploration and practice during the building of the major, and discusses two basic problems in the talent cultivation of professionals with the interdisciplinary feature: one is the construction of the curriculum system which aims to cultivate professional talents with integrated knowledge of science and engineering; the other is the execution of teaching practice which aims to input morally sound values to students as the first priority. The authors hope that their accumulated experiences and thoughts from teaching will play an inspiring role in the cultivation of talents in the field of polymer materials and engineering.关键词：Polymer science and engineering;Polymer chemistry;Course building;Combination of science and engineering;Interdisciplinarity
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发布时间：2023-07-26
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