最新刊期
卷 34 ， 期 9 ， 2021
- 摘要：Microwave devices based on tunable materials are one of the focuses of current dielectric application research. Typical applications include phase shifter, antenna beam control, resonator, filter, voltage controlled oscillator, matching network and tunable power distributor, etc. Tunable capacitor is the core of tunable microwave devices. Based on the comparison of the structural properties of capacitors, this review systematically discusses the relationship between the structure and dielectric tunable properties of various materials including biopolymers, metal-organic frameworks, ceramicpolymer composites, liquid crystals and fluoropolymers. The results show that fluoropolymers can be promising candidate materials for many new applications due to their mechanical flexibility, ease of processing and light weight. This article can also offer help for various microwave applications in material selection and other aspects.关键词：Tunable microwave device;Dielectric tunable material;Capacitor;Composite material;Polymer
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发布时间：2022-08-30 - 摘要：Polycaprolactone is a nontoxic and controllable synthesis of the molecular weight of polymer materials, while has good biocompatibility, different polymer compatibility and biodegradability advantages. Therefore, polycaprolactone is widely used in biomedical, industrial and daily life. With the continuous development of precision medicine concept and modern manufacturing technology, polycaprolactone is manufactured into a variety of structures to achieve controlled drug release, in order to improve the effectiveness of drugs in disease treatment and reduce its side effects. In this study, the research progress of polycaprolactone on microspheres, fibers, micelles and hydrogels drug carriers are reviewed based on the preparation technology, the advantages and disadvantages of different carrier preparation methods have been analyzed, and the future development direction of polycaprolactone as drug carrier material is prospected. The purpose of this study is to provide some references for the research of polycaprolactone controlled release carriers.关键词：Controlled release of drug;Polycaprolactone;Preparation process;Carrier structure;Targeted drug delivery
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发布时间：2022-08-30 - 摘要：Conductive polymers are one of the main categories of electroactive polymers that have been proved to be ideal materials for fabricating artificial muscles. Artificial muscles based on conducting polymers exhibit many superior characteristics, such as lightweight, low power driving, micro-machining, and biocompatibility. These characteristics make a significant contribution to their wide application in the fields of the biomedical devices. Although a large number of studies have been carried out on the construction of conductive polymer artificial muscle in the past, few reviews have been published. The driving mechanism and factors affecting the driving performance of conductive polymer artificial muscle, as well as their biomedical applications, are discussed in this review. Furthermore, some suggestions on the challenges it faces are proposed.关键词：Conductive polymers;Artificial muscle;Actuator;Polypyrrole
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发布时间：2022-08-30 - 摘要：With the forbidden of the nondegradable plastics, degradable materials gradually walk into people's vision. Poly(lactic acid) (PLA) is a new type of degradable materials belongs to polyester, its application is more and more extensive in many areas. The disadvantages of PLA, such as high brittleness, slow crystallization speed, low melt strength and poor thermal stability, can be improved by modification. However, copolymerization, blending and other modification methods also lead to the lack of composite transparency of PLA after modification. This paper reviews the research progress of transparent PLA composites in recent years. The effects of crystallization regulation, cellulose modification, acrylate modification and other organics methods on the transparency of PLA composite are introduced, and the development prospect of transparent PLA is prospected.关键词：PLA;Transparency;Composite
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发布时间：2022-08-30 - 摘要：Magnetorheological elastomer (MRE) is a kind of magnetorheological materials, its unique solid properties give it excellent mechanical properties. Researchers have successively studied the mechanical properties, mechanical models, electrical-magnetic properties of MRE, including theoretical model analysis, numerical simulation analysis, test data comparison, force-electromagnetic coupling analysis, etc. This paper introduces the latest research status of mechanical properties of MRE, including shear properties, tensile and compressive properties, micro and macro mechanical property models, and the practical applications of MRE in aerospace, biomedicine, civil engineering and mechanical engineering. Finally, the development potential and challenges of MRE are prospected.关键词：Magnetorheological elastomer;Shear performance;Tensile and compressive properties;Microscopic model;Macroscopic mechanical model
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发布时间：2022-08-30 - 摘要：Polycarbonate (PC)/Polylactic acid (PLA) composite porous membrane structure of double components PC and PLA were prepared by quenching method under Hexafluoro-isopropanol(HFIP) as co-solvent and methanol as nonsolvent. The effects of factors, such as HFIP concentration, quenching time, quenching temperature and PC/PLA mass ratio, on the morphology and structure of the porous membrane were investigated. The optimum conditions were: 6g/mL HFIP concentration, 2h quenching time, 0℃ quenching temperature and 1/1 PC/PLA mass ratio. A possible mechanism was proposed. The results show that: the quenching phase separation under non-solvent and the pore formation rate of solvent evaporation successively correspond to the liquid-solid and liquid-liquid two-phase processes respectively, which are directly controlled by solution viscosity and surface tension. Under the suitable experimental conditions, the layered porous structure with uniform pore size distribution and good penetration are obtained. Whereas, Other conditions can be a large size and irregular hole broken structure, or a single layer and uneven hole structure, or be lamellar and only a few isolated holes dense structure.关键词：Polycarbonate;Polylactic acid;Porous membrane;Quenching
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发布时间：2022-08-30 - 摘要：In this work, a novel nanometer acrylonitrile-styrene-acrylate co-polymer based on MAP-POSS (POSS-ASA) was synthesized via seed emulsion polymerization, then the PVC/POSS-ASA nanocomposite were prepared. The plastic behavior and rheological behavior of PVC-POSS-ASA were investigated. The influences of composition on balance torque, plastic time, and non-Newtonian index (n) of PVC-POSS-ASA melts were discussed. The dynamic mechanical properties, mechanical properties, and morphology were determined. The results showed that the plastic time decreased but melt viscosity increased with increasing POSS-ASA content. The storage modulus of blend also decreased with increasing POSSASA content. When POSS-ASA content was only 1%(wt), the impact strength and tensile strength was 3.3kJ/m2 and 12.2MPa higher than that of pure PVC, respectively. POSS-ASA can be used as an efficient impact aid and process aid for PVC.关键词：Poly(vinyl chloride);Acrylonitrile-styrene-acrylate;POSS;Dynamic;Mechanical properties;Rheological behavior
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发布时间：2022-08-30 - 摘要：The water-based intumescent fireproof and anticorrosion coatings for steel structure were prepared, in which the water-based silicone modified acrylic resin was used as the film forming material, and ammonium polyphosphate, melamine, pentaerythritol and expandable graphite were used as intumescent fireproof system, and aluminum tripolyphosphate, zinc phosphate, aluminum silver paste were used as anticorrosion system. The fire resistance of the coating was tested by high temperature simulation and thermal analysis method. The corrosion resistance of the coating was tested by salt spray test chamber and electrochemical workstation. The surface morphology and characterization of the coating were analyzed by SEM and X-ray diffraction. The results showed that when the mass fraction of resin was 50% and the mass ratio of fire prevention system to anti-corrosion system was 2.78, the coating had the best fire prevention and anti-corrosion performance, the expansion ratio of carbon layer was up to 7.9 and the fire resistance time is up to 65min. There was no obvious corrosion in the neutral salt spray test for 30 days, and the corrosion current was as low as 1.38μA.关键词：Coating;Intumescent fire retardant;Anticorrosion;Water-based;Steel structure
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发布时间：2022-08-30 - 摘要：Viscosity method is one of the commonly used methods to characterize the molecular weight of polymer. It has the advantages of convenient operation, simple equipment, high experimental accuracy, wide range of molecular weight application, and it has been widely used in industrial production and scientific research. The experiment project of "Measuring the molecular weight of polymer by viscosity method" is an important item in the experiments of polymer physics. The traditional viscosity teaching experiment is only to determine the molecular weight of polymer separately without considering its influencing factors. The experiment content is single and lacks of systematicness. In this paper, the traditional confirmatory experimental item is transformed into comprehensive one through the design and expansion of the original experiment content. It is helpful for students to understand the principle and application of the viscosity method more deeply, understand the formation mechanism of different polymer crystalline forms more vividly, and stimulate their enthusiasm for learning, and have a good teaching results.关键词：Viscosity method;Confirmatory experiment;Comprehensive experiment;Teaching reform
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发布时间：2022-08-30 - 摘要：Applied course is an important part of college curriculum system, and the improvement of its teaching quality is an inevitable requirement for the regional economic development. The principles of polymer materials and engineering with a strong theoretical significance and practical value is one of the foundation courses of "polymer materials and engineering" . The content is difficult to learn, and it is important to make students grasp the major content in a limited class. In the teaching process, open teaching method could be used for the students to fully participate in the learning and improve the efficiency for teaching and learning. The points of open teaching method including: (1) making the students know the content of the course in advance through sending course outlines to them; (2) providing students with alternative listening content by introducing autonomous selection mechanism; (3) introducing classroom competition mode and teaching abstruse theoretical knowledge through the competition.关键词：Applied course;Polymers;Open;Teaching;Competition
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发布时间：2022-08-30 - 摘要：In order to effectively carry out the ideological and political work throughout the whole process of postgraduate education, achieve the curriculum ideology and politics and ideological and political courses in the same direction. The advantages of its curriculum ideology and politics, implied ideological elements and mapping points were explored, according to the characteristics of the course content of the postgraduate professional basic course "Polymer Materials" , which is closely related to the national defense industry, daily life and the sustainable development of the ecological environment. Teachers cleverly integrate ideological and political elements into the teaching through three ways of "fusion, transmission, and leadership" . Combining case analysis, group discussion and student participation in question and answer, an interactive teaching mode was established to enhance the pertinence and effectiveness and educate students from various angles.关键词：Curriculum ideology and politics;Polymer materials;Ideological elements
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发布时间：2022-08-30 - 摘要：It is of great significance for the implementation of the fundamental task of "establishing moral in cultivation" to promote the construction of "curriculum ideological and political education" in specialized courses. Take "Basics of Polymer Material Processing Molds" as an example, ideological and political contents in course based on engineering education accreditation were explored, and they were integrated into the specialty knowledge system. In order to realize the integration, the teaching methodology of Internet plus and project-team were applied. Moreover, the evaluation system facing both specialty training target and ideological & political target was established to evaluate the teaching quality. The evaluation was dynamic and developing to highly effectively improve all the steps through teaching process.关键词：Ideological & political in courses;Teaching reform;Evaluation system
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发布时间：2022-08-30 - 摘要：In the course of polymer physics, several curves involving molecular motion of polymer (such as straintemperature curve, modulus-temperature curve, modulus-time curve, modulus-frequency curve, and mechanical losstemperature curve, etc.) have a great correlation. We explain these important curves in series, focusing on the clarification of their internal connection, and the emphasis of the knowledge points required for these parts of the contents. This will help students fully understand the characteristics of molecular motion and better grasp the relationship between the structure and performance of polymer. Students deepen their understanding and memory, and develop comprehensive thinking skills. This article sorts out and summarizes the relevant contents related to these important curves.关键词：Polymer physics;Teaching;Molecular motion
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发布时间：2022-08-30 - 摘要：The microstructure of the copolymer determines its performance. Therefore, it is very important to accurately characterize and distinguish the microstructure of the copolymer. This article systematically summarizes and discusses the experimental methods for distinguishing random copolymer and block copolymer, random copolymer and mixed homopolymer, and block copolymer and mixed homopolymer, which enriches the teaching content of copolymerization and makes the students understand polymer synthesis and characterization more deeply.关键词：Random copolymer;Block copolymer;Mixed homopolymer;Copolymerization
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发布时间：2022-08-30
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