最新刊期
卷 34 ， 期 8 ， 2021
- 摘要：The preparation of thermal conductive polymer materials can provide new ways for the application of organic polymer in the fields of light-emitting diodes, electronic packaging materials and engineering materials, etc., aiming to further expand the application scope of polymer materials. Based on the introduction of the preparation of heat-conducting polymer materials, this paper reviewed the development of new heat-conducting polymer materials, including the intrinsic plastic and thermoplastic heat-conducting polymers, as well as the packed heat-conducting polymer filled with metal particles and their oxides, nitrous compounds and carbon materials, etc.. The application scope of these polymers is summarized, the thermal conductivity mechanism of thermal conductivity polymer materials is discussed, and the future research and development direction of these polymers is also prospected.关键词：Heat conducting polymer;Packed polymer;Electronic packaging materials;Synthetic
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发布时间：2022-08-30 - 摘要：The iPP of adding β nucleation agent to pure isotactic polypropylene, the crystallization particles are small, the crystallization rate is fast, the crystallization temperature is high, transparency is good, and the mechanical properties is improved. As structural materials and engineering materials, iPP are widely used in chemical industry, packaging materials, automotive materials and household electrical appliances,therefore, the study of iPP β nucleation agents has become a hot topic in recent years. The nucleation mechanism and the types of nucleation agents were reviewed about small molecule and polymer β nucleation agent of iPP, the advantages and disadvantages of the various β nucleation agents were analysed, the effect of β nucleation agent on the crystallization properties was elaborated and the future development direction was discussed.关键词：Isotactic polypropylene(iPP);Crystallization;Nucleator
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发布时间：2022-08-30 - 摘要：Polypropylene carbonate (PPC) prepared by copolymerization of carbon dioxide and propylene oxide as raw materials is an environment-friendly material with great development prospects. Although it has entered industrialized production, its unsatisfactory thermal stability and mechanical properties limit the application of this type of material. At present, the properties of the polycarbonate material can be precisely controlled by introducing a third monomer in the copolymerization reaction to achieve chemical modification of PPC. This work systematically summarized the current research progress of PPC chemical modification, analyzed the influence of different third monomers on the mechanical and thermodynamic properties of PPC, and provided a theoretical basis for the chemical modification of PPC.关键词：Carbon dioxide;Epoxides;Terpolymerization;PPC;Monomer
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发布时间：2022-08-30 - 摘要：Taking the new non-pneumatic tire UPTIS as the research object, the Solidworks is used to establish the geometrical model, and the tire injection molding process is simulated and analyzed by Moldflow. Polyurethane (PU) was selected as the UPTIS material. And the PU material was measured by capillary rheological tester, DSC, DMTA, universal tensile equipment. The Cross-WLF equation was used as the rheological constitutive equation, and the parameters were obtained by fitting procedure according to the rheological curves. The influence of gate position and quantity on filling time, front flow temperature difference, warpage deformation were studied. The influence of melt temperature, mold temperature, pressure holding pressure and time holding pressure on molding process was studied by the orthogonal test method, and the molding process parameters were optimized.关键词：Non-pneumatic tire;Rheological constitutive equation;Orthogonal test;Injection molding;Simulation analysis
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发布时间：2022-08-30 - 摘要：A number of moisture-curable urethane prepolymers(MCPU)were synthesized by propyleneglycol(PPG), 4,4'-diphenylmethane diisocyanate (MDI-50),1,4-butanediol (BDO ),using Lauryl dibutyltin (T-12),2,2- dimorpholinodiethylether(DMDEE),self-made composite catalyst,respectively. Fourier transform infrared spectroscopy was used to characterize the assignment of hydrogen bonds of urethane carbonyl groups and urea carbonyl groups during natural ageing in MCPUs. In addition,the adhesion strength of the cured polyurethane adhesive was determined by tensile shear strength test. The result showed that natural ageing the number of hydrogen bonding urethane groups was raised with the decrease of free urethane groups, no significant relationship free urea carbonyl groups and hydrogen bonding urea groups. Total hydrogen bonding was increased by one kind of catalyst(T-12, DMDEE)nature ageing processes,at the same time microphase separation was promoted. Or reduced by self-made composite catalyst. The adhesion strength was correlation between total hydrogen bonding degree and hydrogen bonding urea groups.关键词：Moisture-curable;Polyurethane adhesive;Catalyst;Natural ageing;Hydrogen bond
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发布时间：2022-08-30 - 摘要：In order to improve the working performance of the reentry aircraft, the carbon/carbon-silicon carbide (C/CSiC) composite test specimens were prepared using the chemical vapor infiltration process, and the test specimens were tested for strength and thermal shock resistance. The ablation tests were performed in the reentry flight environment, the ablation rate of the test specimens were measured, the ablation morphology of the test specimens were observed, and the ablation mechanism was analyzed. The results show that the bending and tensile strengths of the test specimens are 286.5MPa and 184.3MPa respectively, and the thermal shock resistance parameter is 42.4kW/m. The ablation rate of the stagnation point of the specimen is the largest, and the line ablation rate is 0.0445mm/s, and the mass ablation rate is 0.0472g/s. Because of the SiC in this area is consumed by gasification, the protection effect is not obvious. The ablation mechanisms are gasification and oxidation reactions. In the other area, the SiO2 produced by the reaction is precipitated around the specimens, thus effectively retarding oxidation reaction. On the whole, the material gives its outstanding mechanical properties and anti-ablative performance.关键词：Reentry;C/C-SiC Composites;Plasma;Ablation rate;Thermal shock
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发布时间：2022-08-30 - 摘要：Use of Origin software was introduced to the teaching and practice of reactivity ratios determination. By using Origin software, the nonlinear least-squares method, i.e. the NLLS method or the T-M method, becomes much more expeditious, and gives more accurate and objective reactivity ratio values compared to what abtained via the most frequently used F-R method, YBR method, or even K-T method. Meanwhile, the students’ awareness and ability of using modern tools will also be developed.关键词：Origin software;Copolymerization;Reactivity ratio;Calcutaltion;Teaching;Polymer chemistry;Practice;Awareness development;Ability training
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发布时间：2022-08-30 - 摘要：The virtual simulation technology, which is applied to the experimental teaching of polymer materials and engineering with strong practicality, is an important means for students to improve their ability of finding, solving and operating problems and cultivating high-quality innovative talents. The construction of virtual simulation experiment teaching project of thermal oxidation degradation and combustion process test of flame retardant modified polymer and its application in professional experimental teaching is discussed in this paper. Its teaching effect fully reflects the effectiveness of online experimental teaching and the compatibility with traditional experimental teaching mode. Meanwhile, the improvement direction of virtual simulation project construction has also been clarified, and the construction of all kinds of first-class experimental teaching courses is also promoted further. Therefore, virtual simulation experiment plays a positive role in enriching experimental teaching resources, cultivating students' experimental skills and promoting the quality of talent training.关键词：Virtual simulation;Polymer materials and engineering;Experimental teaching
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发布时间：2022-08-30 - 摘要：The anionic polymerization is very important in studying the course of polymer chemistry. The correct understanding the involved concepts of anionic polymerization, mastering living anionic polymerization mechanism dealing with anionic polymerization kinetics is of very importance for leaning anionic polymerization. In this presentation, the structural features of vinyl monomers, the essence of initiator initiating vinyl monomer, the polymerization rate, polymerization degree and distribution of polymerization degree were discussed carefully. According to the characteristics of the anionic polymerization mechanism, the monomer bond probability p and the total bond probability P are used to derive and analyze the polymerization degree and polymerization degree distribution of living anionic polymerization.关键词：Anionic polymerization;Rate of polymerization;Degree of polymerization;Distribution of polymerization degree
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发布时间：2022-08-30 - 摘要：In this paper, the problems and shortcomings of the engineering specialty in applied universities in terms of the goal, system and platform of innovation and entrepreneurship education were analyzed. Combined with the teaching objectives and contents of polymer major in application-oriented undergraduate colleges, taking the innovation and entrepreneurship activities of polymer major in Hunan City University as an example,the innovation and entrepreneurship education and professional education have the same goal and should be deeply integrated in the whole teaching process.The Progressive "456" innovation and entrepreneurship training system with multi-channel and multi-dimension was constructed and practiced.The system is composed of four training objectives ( "understanding, thinking, meeting and ability" ), five training approaches ( "cognition, simulation, follow, autonomous activities, typical case" ) and a six-dimensional platform ( "knowledge popularization, enthusiasm stimulation, promotion, project transfer, experience simulation and incubation" ). The practical results show that the system has a good effect on the cultivation of entrepreneurship and innovation ability of students majoring in polymer materials, and it is of great practical significance for the cultivation of students' creative ability in polymer specialty.关键词：Innovation and entrepreneurship education;Polymer;Industry-education integration;Progressive;Construction and practice
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发布时间：2022-08-30
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