最新刊期
卷 33 ， 期 8 ， 2020
- 摘要：Since the outbreak of Coronavirus Disease (COVID-19), masks can effectively prevent the spread of virus, which is not only a crucial weapon for preventing the virus, but also an indispensable anti-epidemic material in the process of resuming production. On the premise of ensuring safety, the reuse of masks is of great significance to alleviate the contradiction between supply and demand in the market and avoid the waste of resources. Commonly used disposable nonwoven fabric masks are divided into inner, middle and outer layers. The middle layer is an isolation filter layer, which is a key layer for protection. The material used is ultra-fine polypropylene melt-blown nonwovens (Abbreviated as PP film). In the production process, the PP film usually needs to be charged by corona polarized charging, so as to use static electricity to adsorb viruses and virus-containing particles to achieve a protective effect. And the more stable the charge, the stronger the adsorption capacity, the higher the blocking efficiency. Therefore, research on the mechanism of blocking and charge stability is the key to reusable masks. This paper systematically summarizes the effects of electret process, charge decay process and the structure of PP on the surface charge, mainly including charging voltage, charging temperature and time, storage environment, PP crystal structure and fiber structure, etc, aiming to provide guidance for the design and production of reusable masks.关键词：Polypropylene melt-blown nonwovens;Electret;Electrostatic adsorption;Electric charge
- 17
- |
- 18
- |
- 5
发布时间：2022-08-31 - 摘要：Long chain-based aliphatic polyamide (LCPA) refers to polyamides whose number of methylene groups between two neighbor amide groups on the main chain is more than or equal to 10. Compared with traditional short-chain polyamides, LCPA has lower density of amide groups in molecular structure, which makes it have lower water absorption, breaking elongation, rigidity and toughness balance, dimensional stability and molding performance. Therefore, it is widely used in automotive hoses, electronics and other fields. In the past three decades, LCPA materials have been developed rapidly, based on the development of LCPA monomer preparation technology synthesized by bio-fermented resources with independent intellectual property in China. The research on the preparation and modification technology of LCPA has become an important research direction for LCPA-based engineering plastics. This paper firstly gives a brief overview of LCPA. And then it starts with the preparation methods of LCPA monomer. Next, the paper introduces the preparation methods of LCPA polymer, classifiedly including their suitable monomers, their advantages and disadvantages. Finally, it reviews the progress of LCPA’s application modification in the last four years, mainly including high-performance and functional modification, and the prospect is also given. These contents have played a certain reference role in the selection of LCPA synthesis methods and suitable modification methods for different properties and functions in the future.关键词：Long chain-based aliphatic polyamide (LCPA);Preparation methods;Modification;Functionalization;Research development
- 19
- |
- 11
- |
- 0
发布时间：2022-08-31 - 摘要：The influence of the contents of butadiene repeating units (0~24.3%(mol)) on the properties of trans-1,4- Poly(butadiene-co-isoprene) copolymer rubber (TBIR) were invested. The results showed that, the thermo stability of TBIR molecular chain improved with the increase of the contents of butadiene repeating units. The scorch time and optimum curing time were slightly delayed, the crosslinking density increased slightly. The crystallinity of TBIR vulcanizates was greatly weakened until it disappeared. TBIR vulcanizates with 0% (mol) and 8.5% (mol) butadiene repeating units showed strong and tough tensile deformation behavior, the higher tensile strength and modulus, the lower elongation at break. TBIR vulcanizates with 16.3% (mol) and 24.3% (mol) butadiene repeating units showed tensile deformation behavior of typical vulcanized rubber, the lower tensile strength and modulus, the higher elongation at break. The rolling resistance and heat built-up of TBIR vulcanizates decreased obviously, the wet-skid resistance, abrasion resistance, rebounce and ageing resistance improved significantly with the increase of the contents of butadiene repeating units. TBIR with higher contents of butadiene repeating units have better devil triangle properties for high performances tyre.关键词：Trans-1,4-poly(butadiene-co-isoprene) copolymer rubber;High performances tyre;Tread stock;Devil triangle;Wet-skid resistance;Rolling resistance
- 9
- |
- 15
- |
- 0
发布时间：2022-08-31 - 摘要：Oil pollution is of great significance in environmental pollution. Therefore, the disposal of oily wastewater has become a worldwide challenge. At present, oil-absorbing materials are mainly composed of synthetic polymers, which is difficult to degrade to cause secondary pollution. As an inexpensive natural polymer, zein is an amino acid-based vegetable protein with biocompatibility and biodegradability.We found that zein can be used to prepare edible composites and controlled release materials. Herein, using sol-gel method, the zein-based polymer gel was prepared by zein and poly (vinyl alcohol) (PVA). With further surface modification by silane coupling agent and in-situ precipitation for introducing Fe3O4, the zein-based magnetic polymer gel was successively prepared. Its morphology and structure were characterized by FT-IR, SEM and TG. It indicated that the polymer gel had a multi-layered network structure and the contact angle was 132.77°. The modified gel has significant capabilities of oil-water separation and magnetic separation, which will provide efficient and environmentally friendly Environmentally friendly adsorption materials for water treatment and environmental protection.关键词：Natural polymers;Zein;Gel;Oil absorbing materials
- 10
- |
- 15
- |
- 0
发布时间：2022-08-31 - 摘要：A functional self-assembling peptide/sodium alginate reacted with calcium chloride to obtain a parallel active hydrogel microfibers by the hydrodynamic stretching, then the chitosan/calcium alginate/self-assembling peptide hydrogel microfibers are obtained through polyelectrolyte composite reaction. The application of the nanocomposite scaffolds in nerve regeneration is studied by SEM, cytotoxicity, the interaction between the matrixt and the neural stem cells. The results show that the nanocomposite scaffolds are highly regular and parallel and have good biocompatibility. Besides, the nanocomposite scaffolds can support the growth and differentiation of neural stem cells and can guide the directional growth of axons.关键词：Hydrogel microfibers;Self-assembling peptide;Sodium alginate;Chitosan;Nerve repair
- 12
- |
- 13
- |
- 0
发布时间：2022-08-31 - 摘要：Molecular dynamics simulations were conducted on bimodal polyethylene (BPE) in order to reveal the molecular mechanism of short-chain branching (SCB), especially the effects of branch content (BC), short-chain branching distribution(SCBD) and methylene sequence length (MSL) on BPE crystallization. This paper built two types of BPE models which were closer to the normal industrial BPE: SCBs evenly distributed on the long chain or on the short chains. Tran-rich phenomenon was observed during the early stage of crystallization. SCB placed on the long chain provoke a delay to the formation of precursor during the induction period as compared with the case of SCB placed on the short chains. The crystallization mechanism of BPE was dependent on the BC. When BC was lower than 5SCB/1000C, the crystallization state was a competitive state of nucleation process and crystal growth process. However, when BC was higher than 5SCB/ 1000C, the crystallization state was a crystal growth controlled state. The trans state population of BPE models was increased with the increase of MSL. Above 5 SCB/1000C, BPE models with SCB incorporated in the short chains show higher trans state population as compared with those with SCB incorporated in the long chain.关键词：Short-chain branching distribution;Bimodal polyethylene;Molecular dynamics simulation;Crystal nucleation
- 11
- |
- 12
- |
- 0
发布时间：2022-08-31 - 摘要：Proton exchange membrane fuel cell (PEMFC) is a clean and efficient green environmental protection power supply with broad application prospects. Membrane electrode assembly is the core component of PEMFC which directly affects the performance and commercialization of PEMFC. In this paper, the global patents in the field of membrane electrode assembly were taken as the research objects. The trend of patent application, the technical development trend and technical effect were analyzed by using patent and text analysis methods. The layout, technical characteristics, competitive advantages and technological trends of the main institutions in China and abroad were identified. Finally, this paper put forward some suggestions, such as attaching importance to the patent protection strategy, accelerating the research and development of key technologies, and effectively linking production, education and research.关键词：Proton exchange membrane fuel cell;Membrane electrode assembly;Proton exchange membrane;Gas diffusion membrane;Polymer
- 12
- |
- 14
- |
- 1
发布时间：2022-08-31 - 摘要："Golden Course" with depth, difficulty and challenge is an important factor to accelerate the construction of world-class universities and top disciplines. Based on massive open online course (MOOC) of "Fiber Chemistry and Physics" , the organic integration of four teaching modules that is traditional classroom theory teaching, independent learning of MOOC platform, flipped classroom and in-class experiment, is created. A comprehensive and objective "five process and one final" assessment system is constructed by combination of process assessment and summative assessment mode, and applied in the teaching practice. Implementation results show that the diverse evaluation mechanism can not only assess the learning effect comprehensively avoiding the phenomenon of "one examination determines the whole lifetime" , but also enhances the students' learning initiative and cultivates the ability of innovation in practice, and team cooperation. It is of great significance in the promotion of the construction of fiber chemistry and physics course and talent cultivation in light chemical engineering.关键词：Learning process assessment;Fiber chemistry and physics;MOOC;Ability cultivation
- 9
- |
- 11
- |
- 0
发布时间：2022-08-31 - 摘要：The introduction of curriculum ideological and political ideas effectively promotes the reform and development of higher education.It is an important task for institutions for higher education to introduce ideological and political contents into professional courses. It is important to guide students with correct values, shape their ideals and beliefs, and enhance their cultural confidence.This article has carried on the practice to the curriculum thought and politics in "Academic English for Polymer Materials" teaching. From professional vocabulary prefix root summary, polysemant, words with similar spelling, combining form one minute before class, the classic sentences from the Constitution of the Communist Party of China (CPC), Report to the 19th CPC National Congress, Xi Jinping’s important reports as well as in the Chinese traditional culture were introduced. The moral educations are naturally penetrated into the major courses. Lead students to persist to the correct political orientation, guide the student to set up the correct world outlook, the outlook on life and values.关键词：Academic English;Ideological and political education;Moral education
- 12
- |
- 12
- |
- 0
发布时间：2022-08-31 - 摘要：Based on the pain points of "Functional Polymer Materials" course, such as more knowledge points, strong interdisciplinary, and less class hours, which affect teachers' teaching quality and students’ learning effect, this paper proposed to join three teaching links of "before class, during class, and after class "from the perspective of interactive cultivation of" core knowledge points + learning interests", and make full use of the advantages of the online teaching platform of rain classroom to do a good teaching work of pre class preparation and post class consolidation. Meanwhile, the online and offline hybrid teaching reform of various teaching methods combination with offline diversified interactive classroom teaching can stimulate students' strong interest in learning and better grasp the core knowledge of the course. Thus continuously improve and raise the quality of teaching and learning effect of students.关键词：Core knowledge points;Learning interests;Hybrid teaching
- 11
- |
- 13
- |
- 1
发布时间：2022-08-31 - 摘要：According to the requirements of the standard for engineering education specialty certification, combined with the school's orientation and characteristics, Polymer Materials and Engineering Major of Wuhan Textile University has carried out comprehensive professional reforms and practice in the aspects of teaching quality management mechanism, professional training objectives, graduation requirements, training quality evaluation and continuous improvement, curriculum system and teaching staff. The advantages of scientific research was transferred to teaching,the process of personnel training was standardize, an integrated course following the engineering logic was built, the cooperation between schools and enterprises was promoted, the combination of courses and competitions was advocated, the teams of courses and teaching were built. The reforms have achieved good results in improving students' engineering practice ability, innovative spirit and humanistic quality.关键词：Engineering education;Professional certification;Professional comprehensive reform;Continuous improvement;Engineering practice ability
- 11
- |
- 13
- |
- 1
发布时间：2022-08-31
- Technical support is provided by Beijing Founder electronics co., LTD 京ICP备09064830号-19
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0