最新刊期
卷 35 ， 期 8 ， 2022
- 摘要：Natural polymer flocculant has an extensive application prospect in water treatment because of its flocculation, non-toxicity and biodegradability. However, its flocculation effect is not ideal due to the lack of charge and poor solubility. It needs to be modified, such as etherification, graft copolymerization and so on. Various functional groups are introduced into its molecular chain to improve its flocculation or its charge, adsorption and sterilization. This paper summarizes the usual natural polymer based modified flocculants such as starch, chitosan, cellulose and lignin according to different modification methods, and summarizes the research progress of modified natural polymer based flocculants in China and abroad in recent years. At the same time, the preparation process of natural polymer based flocculant is briefly described, and the research direction of natural polymer based flocculant is prospected.关键词：Natural polymer;Modification;Flocculant;Water treatment
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发布时间：2022-09-09 - 摘要：Polyimide (PI) has been known as one of the special engineering plastics with outstanding comprehensive properties, and widely used in important technical fields such as aerospace, automobile manufacturing, microelectronics, etc., which however, due to the insolubility and infusibility, has serious issue in processing and molding, especially in the manufacturing of objects with high structure complexity. However, the emergence of "structure and performance control" 3D printing technology (also known as "additive manufacturing") uses digital model files as the basis to construct complex objects by layer-by-layer printing, which provides a new technological path for the development and application of smart manufacturing PI. In this paper, the research progress and development trend of 3D printing of PI are reviewed. The research progress of 3D printing thermoplastic PI and thermosetting PI based on melt molding, 3D printing photosensitive PI based on stereolithography and 3D printing PI based on extrusion is especially highlighted.关键词：Polyimide;3D printing;Thermoplastic;Thermosetting;Photocuring
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发布时间：2022-09-09 - 摘要：Nano drug-carrying system has become a research hotspot in the field of biomedicine in recent years because of its characteristics of improving pharmacokinetic properties, reducing toxicity, controlling dissolution, and targeting. Molecular simulation is a novel resource-saving prediction method that can be used to simulate the formation, behavior, and structure changes of nanoparticles under different conditions. The calculation results can help predict the materials required for experiments. This review introduces simulation methods at different scales, including all-atomic molecular dynamics (AAMD), Monte Carlo (MC), coarse-grained molecular dynamics (CGMD) and dissipative particle dynamics (DPD) methods, and the theoretical basis and the latest simulation progress are described.关键词：Molecular simulation;Nanomaterials;Drug carrier;Interaction
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发布时间：2022-09-09 - 摘要：Hydrogel is a three-dimensional network material composed of macromolecule polymers. It has advantages of biocompatibility, high environmental sensitivity, biodegradability and no pollution to the environment by using natural polymers and their derivatives. The application of natural polymer hydrogel in medicine, food, agriculture and environmental protection in recent years is reviewed in this paper. According to the different sources of materials, the classification of protein and polypeptide hydrogels, alga polysaccharide hydrogels, animal polysaccharide hydrogels, plant polysaccharide hydrogels, their modification, and the latest technology, functional properties and application fields of composite hydrogels were reviewed. Finally, the improvement direction and key application fields of natural polymer hydrogels in the future are prospected.关键词：Natural polymers;Hydrogels;Structures;Applications
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发布时间：2022-09-09 - 摘要：With excellent biocompatibility, biodegradability, good mechanical properties and excellent barrier properties, poly(vinyl alcohol) membranes are widely used in the fields of antibacterial and bacteriostatic, photoelectric devices, gas barrier, etc. However, it’s easy to be ignited and will release unsaturated aldehydes and ketones in the combustion process, leading to great safety risks during use, which limits its wide application. Therefore, it needs to suffer flame retardant modification treatment. In recent years, the development of nano-flame retardant materials in PVA flameretardant composite film is outstanding. The flame retardant effect of nano-PVA composite membrane with low load can be significantly improved. The flameretardants with different micro-morphologies and different flame-retardant systems have difference in PVA composites films. Based on the micro-morphology of nano-flame retardant fillers of PVA films and system of flame-retardant, the development and flame-retardant mechanism of PVA composite film are summarized from 2D nanomaterials (metal hydroxide, phosphorus, carbon, ceramic and clay) and non-2D nanomaterials, and the development trend of flame retardancy of PVA composite film is also prospected.关键词：PVA composite film;Flame retardancy;2D materials;non-2D materials
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发布时间：2022-09-09 - 摘要：Polyvinylpyrrolidone-semi-interpenetrating network-polycaprolactone/poly(lactic acid) (PVP-semi-IPNPCL/ PLA) hydrogels were prepared through free radical polymerization of N-vinyl pyrrolidone (NVP) in ethyl acetate solution of PCL and PLA. Three kinds of PVP-semi-IPN-PCL/PLA hydrogels were prepared with the hydrophobic to hydrophilic ratio of 1∶9, 3∶7, 5∶5, respectively. Carbamazepine-succinic acid (CBZ-SUC) cocrystal was prepared through evaporation method. PVP-semi-IPN-PCL/PLA hydrogels were used as drug vector for CBZ-SUC cocrystal delivery. The CBZ-SUC cocrystal loading and in vitro release abilities of PVP-semi-IPN-PCL/PLA hydrogels with different hydrophobic to hydrophilic ratios were studied. CBZ-SUC cocrystal loaded hydrogels were prepared with the drug loading capacity of 17%, 19%, 21%, encapsulation efficiency of 71%, 83%, 89%, respectively. The in vitro release of CBZ was studied in pH 6.8 PBS solution at 37℃, and the results show that the release profiles of hydrogels loaded CBZ cocrystal were better than those of CBZ cocrystal without hydrogels vector. The 3∶7 hydrogel loaded CBZ cocrystal has the highest cumulative release amount, which reached about 70% when dissolved for 96 h. The results of this study show that PVPsemi- IPN-PCL/PLA hydrogels are capable of loading and control release of CBZ-SUC cocrystal. The combination of pharmaceutical cocrystal and hydrogel drug vector can restrain the solution mediated phase transition of cocrystal, which can be an effective way to improve the dissolution behavior and bioavailability of poorly soluble drugs.关键词：PVP-semi-IPN-PCL/PLA hydrogel;Drug vector;Pharmaceutical cocrystal;in vitro release
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发布时间：2022-09-09 - 摘要：In this paper, ultrathin cryo-section of the five kinds of different modifed rubbers and elastomers and one kind of blended elastomer were observed by transmission electron microscope and scanning electron microscope, to explore the suitable ultrathin cryo-section temperature and related technical parameters of different nano-modified polymers, and to analyze the relationship between ultrathin cryo-section temperature and glass transition temperature. At the same time, electron staining method was also used for the blend of silica modified butadiene rubber-polyvinyl chloride-chlorinated polyethylene. The study provides a reference for studying the ultrastructure of polymer materials with different properties and selecting suitable ultrathin cryo-section temperature and electronic staining method.关键词：Nano-modified;Polymer;Ultrathin cryo-section;Transmision electron microscope;Scanning electron microscope
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发布时间：2022-09-09 - 摘要：According to new policy on the promotion of ethanol gasoline, the original domestic production capacity of about 18 million tons of methyl tertiary butyl ether (MTBE) is facing a life and death decision, and a large amount of downstream isobutylene resources need to find another way out. The development of high activity polyisobutene high-tech can alleviate the dual pressure of low utilization rate of isobutene and oil quality upgrade, and promote the sustainable development of carbon IV industry chain of refining and chemical enterprises. In this thesis, water (H2O)/dichloroethylaluminium (EADC)/2,2-dichlorodiethyl ether (CEE) was used as the initiating system to investigate the characteristics and laws of polymerization and to explore the method for preparing HRPIB with high conversion and high α-exo-olefin content.关键词：Cationic polymerization;Exo-olefin structure;Isobutylene;High activity
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发布时间：2022-09-09 - 摘要：The physical and chemical changes of the components in the preparation process of the dissolution and precipitation system polyethylene catalyst used in the slurry process were studied. The dissolution process of the system was explored. For the first time, dynamic light scattering was used to dynamically track the dissolving liquid. Combined with characterization methods such as scanning electron microscopy and liquid nuclear magnetism, it was proven that magnesium chloride-ethanol (MgCl2-EtOH) microcrystals were formed during the dissolution process. The precipitation process of the catalyst was also analyzed, finding that there was a two-phase structure in the catalyst that is the crystalline phase dominated by magnesium chloride and the amorphous phase dominated by titanium alkoxide (Ti(OC2H5)nCl4-n ). This study deepens the understanding of the catalyst and lays the foundation for its further optimization and the development of new catalyst systems.关键词：Slurry Process;Dissolution and precipitation;Ethylene polymerization;Ziegler-Natta catalyst
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发布时间：2022-09-09 - 摘要：In order to understand the development status and research trend of key preparation technologies of metallocene poly-α-olefin (mPAO) base oil in the world, combined bibliometric method and patent analysis, with the help of visualization software VOSviewer, using web of science core database and incopat Patent database, papers and patents related to mPAO technical process by the end of 2020 were searched for analysis, a keyword co-occurrence map was drawn, and the planning and layout of related fields at home and abroad were sorted out to analyze current research hotspots and development trends. The results show that mPAO technical research field is relatively new, belonging to the frontier technology in the a draw keyword field, and is still in a period of rapid development; from the distribution of research institutions, there are great differences at home and abroad, foreign research is relatively mature, mainly concentrated in the United States and Japan; domestic research is scattered, and has not yet formed a core research institution. On this basis, it is predicted that the global demand for mPAO with high viscosity index and low pour point will further increase. The research and development of mPAO synthetic lubricating oil and its process will become one of the development directions of advanced lubricating base oil in the future.关键词：Metallocene poly-α-olefin;mPAO;Bibliometric;Patent analysis;Research trend
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发布时间：2022-09-09 - 摘要：Mind map is an effective note-taking method for helping students understand and remember the course contents. Considering the wide range and complexity of the course of polymer composites, mind map can be of great help in the learning process. How to guide students to use mind map correctly and build their own knowledge system during learning, this paper discusses the relevant teaching principles and strategies and shares some of our practices. The principle of independence ensures the effectiveness of this teaching method and avoids becoming a mere formality; The principle of stratified teaching is conducive to helping each student achieve good learning results according to the characteristics of students' thinking mode at different levels.关键词：Polymer composites;Mind map;Independence;Stratified teaching
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发布时间：2022-09-09 - 摘要：A comprehensive experiment was designed to prepare drug-loaded fiber membrane containing paeonol and using polycaprolactone as carrier by electrospinning. The experiment involves the preparation and characterization test of drug-loaded fiber membrane. The drug-loaded fiber membrane was prepared by electrostatic spinning technology, which was characterized by Infrared spectrometer (IR), scanning electron microscope(SEM) and X-ray diffraction(XRD). Through this experiment, the students can understand the preparation methods and characterization techniques of nanofiber membrane, master the principle and operation technology of IR, and understand the principle and sample preparation method of large instruments such as SEM and XRD. The experimental project covers multiple knowledge points, highly comprehensive, easy to operate. It can be used as a comprehensive experimental project for undergraduate majors such as polymer materials and engineering, pharmaceutical engineering, etc., to cultivate students' comprehensive experimental skills and innovative ability, and to arouse their interest in scientific research.关键词：Comprehensive experiment;Electrostatic spinning technology;Film material;Paeonol
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发布时间：2022-09-09 - 摘要：The COVID-19 epidemic has brought a severe test to the chemistry experiment teaching. This article takes Polymer Materials and Engineering as an example to analyze the main difficulties in the traditional offline experimental teaching mode under special circumstances.Proposed the countermeasures of "offline+remote virtual simulation 'integrated’" teaching mode. We not only hope to break the limitation of time and space through the construction of simulation platform to build a ubiquitous "Cloud Lab" , but also hope to overcome the shortcomings of simulation experiment teaching through offline experiment teaching.关键词：Special circumstances;Chemistry experiment teaching;Remote virtual simulation;Integrated teaching mode;Cloud Lab
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发布时间：2022-09-09 - 摘要：Organic chemistry experiment is an important part of basic chemistry experiments for polymer materials and engineering, and the scientific and reasonable performance evaluation system is the key link in experimental teaching. This paper analyzes the existing problems and drawbacks in the current organic chemistry experiment evaluation system. A new organic chemistry experiment evaluation system has been established, starting with the construction of a teaching resource bank, a test questions bank, and a procedural evaluation plan. The implementation effect shows that the new evaluation system can not only increase students’ enthusiasm for participating in the experiment, but also test the real learning effect of students, cultivate students’ hands-on ability in the experiment process and the ability to analyze and solve problems. At the same time, it has laid a solid foundation for subsequent learning in polymer professional courses.关键词：Polymer materials and engineering;Organic chemistry experiment;Process assessment;Evaluation method
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发布时间：2022-09-09 - 摘要："Materials Structure and Performance" is a course to study the relationship between the hierarchical structure of polymer materials, their molecular motion and physical and mechanical properties. In view of the characteristics of the course of "Materials Structure and Performance" , we analyze its current situation and the existing issues and put forward the teaching reform idea of "innovation via foundation and scientific research from practice" . That is to say, from the perspective of mind mapping and the combination of theoretical and experimental teaching, the abstract polymer physics theory becomes visualization and the foundation is consolidated. According to the major national needs and practical application cases, topic discussion caused inverted classroom is utilized to improve the students’ critical thinking and the skill of analyzing and solving problems, which will provide a good guidance for innovation academic research of polymer materials.关键词：Structure and performance;Polymer physics;Teaching reform;Mind mapping;Inverted classroom
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发布时间：2022-09-09 - 摘要："Modern Research Methods and Testing Technology of Materials" is a compulsory core course for materials major with strong theory and practicality. Focusing on the connotation of Emerging Engineering Education and the demand for talent cultivation, on the basis of fully understanding the deficiencies in the course construction and teaching, practice and exploration in the construction of the curriculum system, such as the optimization of teaching content, the diversification of teaching methods (virtual simulation technology application, online and offline integration, interactive teaching methods, etc.), moral education training and optimization of the assessment mechanism. Fully stimulate students' interest in learning, consolidate their professional basic knowledge, and cultivate high-quality materials professionals with stronger practical ability, innovation ability, and international competitiveness.关键词：Emerging engineering education;Modern research methods and testing techniques of materials;Virtual simulation technology;Course construction;Education teaching reform
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发布时间：2022-09-09
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