最新刊期
卷 35 ， 期 11 ， 2022
- 摘要：Hydrogels possess great application potential in the fields of flexible electrodes and batteries, flexible sensors and soft robots. Usually, hydrogels freeze and become rigid, brittle, and non-conductive when the temperature decreases below the freezing point of water, severely limiting their use in this temperature range. To solve the weakening and failure of hydrogel at low temperature, the researchers designed and prepared a series of anti-freezing hydrogel materials through various methods. Ionic compounds and organic anti-freezing solvents play important roles in anti-freezing hydrogels system, ionic compounds could lower the freezing point of hydrogels and also provide the conductive capacity of hydrogels. A high concentration of solutes (e.g., ethylene glycol, glycerol) is introduced into hydrogels to depress the water freezing point,and the combination of ionic compounds and organic anti-freezing solvents is applied to produce anti-freezing hydrogel materials. The mechanical flexibility, conductivity of the prepared hydrogels at subzero temperature were studied and measured. The response function at subzero temperature of the resulting hydrogel-based flexible electronics, such as a capacitive sensor, a resistive sensor and an actuator, were explored and developed. Recent progress made in preparation, properties and applications of anti-freezing hydrogels is reviewed, the prepared method which includes various anti-freezing solvent media systems was discussed, and the challenges in anti-freezing hydrogels such as biocompatibility, toxicity of anti-freezing solvents will be expected to be met and resolved.关键词：Hydrogels;Anti-freezing;Flexible battery;Flexible sensor
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发布时间：2022-09-09 - 摘要：Epoxy resins possess excellent comprehensive performance. Epoxy systems with latent curing agent have favorable storage stability, and have huge application demand and commercial value in adhesives, coatings, electronic packaging, composite materials and other fields. There are many kinds of latent curing agents. According to the chemical structure, latent curing agents include dicyandiamide, hydrazide, anhydride, benzoxazine and amino acid compounds, imidazole and modified amine compounds, boron amine complex and diazonium salt, iodonium salt and sulfonium salt compounds. In order to guide the design and use of latent curing agents, in this work, the reported latent curing agents are divided into three catalogues according to their different latent mechanisms, namely heat dissolving, chemical modification and microencapsulation, and their research progress is summarized and discussed. Meanwhile, the current evaluation methods of latent performance of curing agent are summarized, including DSC and rheological behavior analysis. Finally, the advantages and disadvantages of the current latent curing agents are evaluated, and the trends of future work are highlighted. Nowadays, the methods for achieving the latent performance are complex, and it’s still difficult to well balance the latent performance and storage stability for the latent systems. In the future, the one-component epoxy systems with long storage life at room temperature, and high curing speed at medium and low temperature, and favorable performance after curing should be focused; and the latent systems combined with other functions such as high performance, toughening, flame retardancy, energy conservation and environment protection should also be the development direction.关键词：Latent curing agent;One-component epoxy resin;Chemical modification;Heat dissolving;Microencapsulation
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发布时间：2022-09-09 - 摘要：As a kind of energy storage devices, supercapacitors (SCs) have attracted widespread attention for their advantages of high power density, good charging and discharging efficiency, wide operating temperature windows, and a long cycle life. As an electrode material, polyaniline (PANI) has the advantages of multiple intrinsic redox states and high theoretical capacitance, which is conducive to improving the energy density of supercapacitors. However, due to the unsatisfied stability of pure polyaniline and poor processing performance, the introduction of transition metal oxides (TMOs) can promote the oxidation-reduction reaction, accelerate the speed of electron transfer, and effectively improve the specific capacitance and circulation stability of electrode materials through the synergistic effect of the two components. In this paper, the new progress of TMOs/PANI nanocomposites such as Ruthenium, manganese, nickel and cobalt involved supercapacitors is reviewed, and the conductive mechanism of TMOs/PANI nanocomposites is summarized and concisely discussed.关键词：Transition metal oxide;Polyaniline;Supercapacitor;Nanocomposite
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发布时间：2022-09-09 -
Effect of None Rubber Components on Relationship between Structure and Performance of Natural Rubber
摘要：Natural rubber (NR)includes about 3 wt%~7 wt% none rubber components (NRCs). It is the NRCs that have transferred the structure of NR from linear to supramolecular by the means of non-covalent interactions such as hydrogen bonding, ionic bonding. The above unique structure has given irreplaceable properties such as strain induced crystallization, modulus self-recovery after shearing and good adhesion to metal compared with Isoprene Rubber (IR). Because of the above properties, NR has widely used in aviation tires, engineering tires, tank roadwheels, air springs and other extreme service conditions. In this article, we make a systematic and comprehensive summary of this field based on effects of NRCs on relationship between supramolecular structure and performance of NR. The species, content and methods for determining content of NRCs have firstly introduced; three aspects are discussed in more detail: the structure of modified end groups of polymer, the mechanism for supramolecular structure and the relationship between the structure and performance. Meanwhile, the future direction of development is discussed as well.关键词：Natural rubber;None rubber components;Protein;Phospholipid;Supramolecular network aggregation structure- 33
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发布时间：2022-09-09 - 摘要：Fiber reinforced polymer (FRP) has been widely used in marine engineering, aerospace engineering, civil engineering and other fields due to its lightweight, high strength and corrosion resistance. However, the inherent flammability of matrix resin makes FRP undergo complex physical and chemical changes in high temperature (fire) environment, resulting in a decrease in mechanical properties. The decrease in strength and stiffness may lead to structural deformation and collapse, resulting in property losses and even casualties. Therefore, it is very important to study the mechanical properties of composite at elevated temperatures to ensure the fire safety of composite structures. The experimental and theoretical research results of high-temperature mechanical properties of FRP at home and abroad were reviewed. Several models for predicting the loss in the mechanical properties are described. Firstly, The similarities and differences of the existing test methods were compared and analyzed. Secondly, the test results of high temperature mechanical properties of composite materials are briefly introduced. The effects of matrix resin type, composite interface, reinforced fiber type and coating method, and fireproof coating on high-temperature mechanical properties of composite were analyzed and summarized. Finally, the direction for further research in the future was prospected.关键词：Resin matrix composite;Fire;Elevated temperature;Mechanical properties
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发布时间：2022-09-09 - 摘要：In recent years, non-degradable plastics have been restricted to use. Research and industrialization of completely biodegradable materials are becoming a hot topic. In this paper, the considerable factors for the design in biodegradable plastic formulas were briefly introduced. Plastic resins and additives usually used in biodegradable plastic compound were summarized. Different processing methods used for biodegradable plastic modified compound were analyzed. Suggestions for biodegradable plastic compound design were illustrated.关键词：Biodegradable plastics;Compound;Modify
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发布时间：2022-09-09 - 摘要：Acrylic acid-ethylene glycol monovinyl polyglycol ether copolymer (AA-g-EPEG) is a graft copolymer, which is currently mainly used as a dispersant for cement concrete and other powder materials. This copolymer has been evaluated using a small molecule simulation method that concludes the calculation and analysis of copolymerization performance. Acrylic acid-isobutenyl polyethylene glycol copolymer (AA-g-HPEG) is used as the control group. The calculation of copolymerization performance mainly includes comonomer reactivity ratio and monomer activity, copolymer composition, as well as the sequence distribution of copolymers. A comparative test was conducted for the effect of the two copolymers synthesized under optimized conditions on the performance of concrete. The results show that the theoretical results of the copolymers have a great positive correlation with the performance tests. Copolymer composition and copolymer sequence distribution are the most important factor affecting copolymer performance.关键词：AA-g-EPEG;AA-g-HPEG;Monomer activity;Copolymer composition;Copolymer sequence distribution;Concrete
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发布时间：2022-09-09 - 摘要：The melting temperature and crystallization temperature under high pressure are of importance for studying the high-pressure crystallization and annealing of polymers. In this study, the melting temperature of polyoxymethylene (POM) and poly(ethylene oxide) (PEO) were measured by the differential thermal analysis method in the range of 50~ 300 MPa. It was found that the melting temperatures of POM and PEO increased with the increasing pressure. The fitted Tm (P) relationships were Tm (K)=441.2+0.1044P (MPa) and Tm (K)=345.1+0.1143P (MPa) for POM and PEO, respectively. The XRD analysis revealed that the recovered samples which crystallized under 100, 200 and 300 MPa had the same structure with that under ambient pressure, indicating that the structure of crystal phase is stable up to 300 MPa. The experimental results in this study provide reference data for the high-pressure crystallization and annealing of POM and PEO.关键词：Polyoxymethylene;Poly(ethylene oxide);High-pressure differential thermal analysis;Melting temperature;Crystallization temperature
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发布时间：2022-09-09 - 摘要：A kind of quaternary ammonium polysulfone (PSF-BA) containing an aldehyde group on the side chain was obtained by the reaction of CPSF and 4-(imidazole-1-yl) benzaldehyde based on the preparation of chloromethylated polysulfone (CPSF). Subsequently, cross-linked polysulfone/poly(vinyl alcohol) anion exchange membrane (PSF-VA) was fabricated by the reaction of PSF-BA with polyvinyl alcohol (PVA). The chemical structure of modified polymer was characterized by infrared spectroscopy (FT-IR), and water uptaking (WU), size stability and alkali resistance were explored. PSF-VA composite AEMs keep excellent dimensional stability, alkali resistance and mechanical properties under high water absorption. The water absorption of PSF-AC-3 AEM (IEC is 1.47 mmol/g) at 25 and 85 ℃ is 29.9% and 47.6%, the hydrogen ion conductivity is 0.041 and 0.090 S/cm, but the swelling ratio is only 13.7% and 36.8%. The properties are even better than those of Nafion115 membrane under the same conditions. The PSF-AC AEM keeps good dimensional stability and alkali resistance at high conductivity, and the retention of ion conductivity is up to 84.7% after being soaked in strong alkali for 30 days, overcoming the problems of poor dimensional stability and alkali resistance of AEM under high ionic conductivity.关键词：Polysulfone;Poly(vinyl alcohol);Quaternary ammonium;Crosslinked structure;Dimensional stability;Alkali resistance
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发布时间：2022-09-09 - 摘要：Sodium alginate (SA)/titanium dioxide (TiO2) composite nanofiber membrane was prepared by electrospinning technology and applied in the adsorption of heavy metal ion Cu2+ in water. The composite nanofiber membranes were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), contact angle and mechanical properties. The results show that the surface of the composite nanofiber film is smooth, and the fibers are randomly arranged in three dimensions. After adding TiO2, the average diameter of nanofibers decreased and the hydrophilicity was greatly improved. The tensile strength and elongation at break are 9.56 MPa and 15.46%, respectively. The adsorption results showed that the saturated adsorption of SA/TiO2 nanofiber membrane for a single component of Cu2+ could reach 76.99 mg/g. The adsorption process can be described by Langmuir and Freundlich adsorption models. From the correlation coefficient, the adsorption process of SA/TiO2 nanofibers for Cu2+ is more consistent with Freundlich model.关键词：Electrospinning;Sodium alginate;TiO2;Adsorption performance;Cu2+
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发布时间：2022-09-09 - 摘要：Diatomite and silica were mechanically blended with natural rubber (NR)/dissolved styrene butadiene rubber (SSBR) to prepare composite materials. The process, dynamic properties and mechanical properties of the composites were studied, and the fracture morphology of the composites was observed by SEM. The results showed that with the increase of diatomite content, the vulcanization time of the composites decreased, the Mooney viscosity and the Payne effect increased, the loss factor increased too, while the mechanical properties decreased; but the scorch time and the loss factor at 60 ℃ were changed little. When the dosage of diatomite was 20 phr, the agglomeration and gelation of silica were reduced, the Payne effect of the composite was weaker and the microstructure was uniform;When the dosage of diatomite was 10~20 phr, the tensile strength and modulus were higher. When the dosage of diatomite was 30 phr, the loss factor of the composite at 0 ℃ was larger.关键词：Diatomite;Silica;Natural rubber;Solubilized styrene butadiene rubber;Composite;Dynamic mechanical properties
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发布时间：2022-09-09 - 摘要：Polymer Chemistry is a comprehensive professional course following the four basic chemistry courses, and in the theoretical teaching of Polymer Chemistry, the polymerization of olefin monomer is one of the important knowledge points, and its polymerisate is also the most commonly used polymer material. Whether olefin monomer could be polymerized needs to be discussed from two aspects of chemical reaction thermodynamics and kinetics. The relevant criteria and thermodynamic parameters of chemical reaction thermodynamics could provide important information of reaction direction and polymerization limit for polymerization reaction. This paper mainly discusses the polymerization thermodynamics of olefin monomer.关键词：Polymer chemistry;Olefin monomer;Polymerization thermodynamics
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发布时间：2022-09-09 - 摘要：As a professional basic course, Polymer Chemistry plays an important role in the training of non-polymer talents in light industry. Light chemical engineering (dyeing and finishing) major is a light industry major, and the relevant theoretical courses of this major endow the students with the basic theoretical knowledge of polymer. The course of Polymer Chemistry is of great significance to realize the talent training goal of this major. On the basis of analyzing the importance of setting up the course of Polymer Chemistry in light chemical engineering (dyeing and finishing) major, this paper points out the problems existing in the teaching of Polymer Chemistry course in the major of light chemical engineering (dyeing and finishing), and puts forward the ideas of curriculum reform to improve the teaching effect of Polymer Chemistry, so as to promote the course to play a role in realizing the goal of talent training of this major.关键词：Polymer chemistry;Teaching reform;Teaching method
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发布时间：2022-09-09 - 摘要：This paper discusses the teaching practice of the comprehensive experiment project named "Study on the properties of halogen-free flame retardant polypropylene" in Polymer Physics Experiment. Under the background of halogen-free flame retardant materials, students studied different testing methods of material properties and deeply analyzed the relationship between structure and properties of halogen-free flame retardant modified polypropylene system. The form of teaching organization is optimized in order to arouse the undergraduates’ interest in learning and impel them to explore unknown scientific problems in limited time. They can imperceptibly improve their professional quality and innovative ability. The form of teaching organization is optimized by introducing teamwork and competition, carrying out the problemoriented experimental teaching, and establishing the open system of laboratory and precise instrument.关键词：Polymer physics experiment;Comprehensive experiment;Form of teaching organization;Halogen-free flame retardant polypropylene
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发布时间：2022-09-09 - 摘要：With the continuous economic development and scientific progress, our state attaches great attention on training innovative talents and improving the quality of practical teaching in colleges and universities, and regards college students' innovation and entrepreneurship as a powerful driving force to promote China's economic development. In regard to common problems in current college cultivating mode, combining with comprehensive analysis of cultivating students' innovation and entrepreneurship ability in recent years, we propose a growth-oriented talent training plan to explore a innovative talent training system "relying on project, leading by mentor, undergraduates synergy with postgraduates" based on the academic competition and college students' innovation and entrepreneurship projects. It provides a reference for colleges and universities to construct the innovative training mode of college students.关键词：Innovation practice ability training;Academic competition;Innovation and entrepreneurship project;Alldirrction education;All-process education
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发布时间：2022-09-09 - 摘要：Polymer chemistry is one of the core courses of polymer materials and engineering. The experimental course and the theoretical course of polymer chemistry are carried out in coordination and interactive integration. Students are required to implement the experiment safely according to the experiment scheme, collect experiment data, and further understand the polymerization theory from the experimental phenomena and results. In the student-centered teaching mode of polymer chemistry experiment, students are the main body, and teachers are the course designers and instructors, who design relevant assessment steps for the experimental course and provide effective learning materials and learning guidance. In this exploration, through preview links such as virtual simulation experiment practice and pre class assessment, the experimental operation is standardized, the efficiency of the experimental is improved, the curriculum objectives of the experimental are achieved, and the students' ability to construct knowledge, think and analyze problems in the experimental class is improved.关键词：Student centered;Combination of virtual and reality;Polymer chemistry;Experiment
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发布时间：2022-09-09 - 摘要：Under the background of "double first-class" construction and combined with the course characteristics of Polymer Physics, this paper explores the teaching objectives, teaching modes and evaluation methods based on OBE concept. In the teaching process, we should take the "learning outcomes" of students as the guidance, strengthen the combination of theoretical knowledge and ability training, enrich the teaching approach, optimize the evaluation system and stimulate learning interest and self-learning consciousness. It is beneficial to improve knowledge reserve, innovative thinking and practical ability of students in polymer materials, which could cultivate the talents with high-quality comprehensive ability to meet the social demand in polymer materials.关键词：Double first-class specialty construction;OBE concept;Polymer physics;Curriculum reform
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发布时间：2022-09-09
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