最新刊期
卷 34 ， 期 11 ， 2021
- 摘要：Thin-walled injection molded polypropylene was a new product of high added value polypropylene. In recent years, various domestic manufacturers have realized the development of new thin-wall injection molded polypropylene products by both the gas-phase polymerization process and the bulk gas-phase polymerization process. In this paper, the characteristics of thin-walled injection molding resin and the importance of developing the resin special materials by using the existing technology were both described. The research, development and production of special resin for thin-wall injection molding in China in recent five years were discussed from the perspective of polymerization technology. The characteristics of several polymerization processes were compared, and the catalysts, process parameters and product characteristics used in research and production were summarized.关键词：Thin-walled injection molding;Polypropylene;Polymerization process
- 15
- |
- 15
- |
- 1
发布时间：2022-08-30 - 摘要：Organic hybrid damping material is a kind of composite material with high damping performance developed in recent years. The high damping property mainly comes from the hydrogen bonding between the hindered phenol molecules and the polar matrix, in addition of high damping performance, the material also has excellent engineering properties such as high strength and high environment resistance. In this paper, the research status of organic hybrid damping material is discussed from the aspects of performance influencing factors, preparation process, research methods, etc., and the research examples of this kind of damping material system in recent years are introduced, the existing problems of organic hybrid damping material are analyzed, and makes a certain outlook on the development direction of this material.关键词：Organic hybrid damping;Composite materials;Research progress
- 13
- |
- 14
- |
- 0
发布时间：2022-08-30 - 摘要：Cellulose, as a renewable resource in nature, has a wide range of sources. In energy-shortage situation, cellulose based materials have attracted more and more attention. Nano cellulose from plant resources has the characteristics of light weight, high strength and good gas barrier, which makes it widely used in food packaging materials. In this paper, the application of cellulose nanofibers, microcrystalline cellulose and cellulose nanocrystals and their barrier properties, mechanical properties, antibacterial properties and degradability in food packaging materials were reviewed. The effects of nano cellulose on the properties of food packaging materials were summarized. The combination of nano composite materials and multi-layer design has great potential in the field of food packaging materials.关键词：Cellulose nanofibers;Microcrystalline cellulose;Cellulose nanocrystals;Barrier property
- 13
- |
- 13
- |
- 2
发布时间：2022-08-30 - 摘要：The ring opening (co-)polymerization of ε-caprolactone or/and lactides produces the biodegradable polymers. Targeting the cost reduction and non-toxicity of its catalysts to meet the demanding for food packaging polymer, the ferric chloride with its initiator of 1-tetradecanol are currently explored in the ring opening (co-) polymerization of ε-caprolactone or/and L-lactide. Results approve the good efficiency of FeCl3 in ring opening polymerizing of ε-caprolactone, and the polymerization parameters (such as molar ratio of monomer to iron, temperature and time) are useful in controlling the polymerization efficiency and resulting in polymers with different molecular weights. Extensively the catalytic system is also well active for the polymerization of L-lactide as well as copolymerization of ε-caprolactone and L-lactide; the feeding order of monomers (ε-caprolactone and L-lactide) and polymerization greatly influenced the microstructures of resultant polymers. The blocked copolymer, PCL-b-PLA can be only prepared with adding the first ε-CL and then LA. In addition, the stoichiometric amount of compounds acting as N,N-bidentate ligands is added in FeCl3 catalytic system in situ to influence the polymerization and adjust the molecular weight of polymers, in turn to realize the controllable polymerization.关键词：Ring-opening polymerization;Iron trichloride;PCL;Copolymerization;Biodegradable polyester
- 9
- |
- 11
- |
- 0
发布时间：2022-08-30 - 摘要：As time goes on, safety and environmental protection awareness of people was increased, how to prepare efficient halogen-free flame retardant PC/ABS materials has been loved by researchers. The flame retardant effects of coreshell tougheners, TPP and sesquisiloxane flame retardants on PC/ABS were studied, the results showed that:The toughening agent of core-shell structure has good toughening effect on PC/ABS alloy,and the toughening agent which core containing organosilicone is beneficial to the flame retardancy of the material; Sesquisiloxane flame retardant Si-9501 has good flame retardant effect on pure PC, butto PC/ABS alloy is not obvious; Phosphorous flame retardants TPP and Sesquisiloxane flame retardants Si-9501 have synergistic flame retardants in PC/ABS alloys, the flame retardant rating of PC/ABS was 1.6mmV0 and the oxygen index was 31.6% when 0.6% SI-9501 and 6% TPP were added.关键词：PC/ABS alloy;Core-shell structure;Sesquisiloxane flame retardant;Organosilicone flame retardants;Synergistic effect
- 14
- |
- 19
- |
- 0
发布时间：2022-08-30 - 摘要：To enhance the reactivity of the terminal hydroxyl groups of cholesterol or diosgenin, the cholesteryl or diosgenin derivatives were prepared by chain extension reaction, which was used as initiators to initiate the ring-opening polymerization of trimethylene carbonate (TMC). Two kinds of main-chain polycarbonate liquid crystals with different liquid crystal motifs were prepared. The structure and properties of the obtained liquid crystal polymers were tested and characterized by means of hydrogen-1 nuclear magnetic resonance (1H-NMR), differential scanning calorimetry (DSC) and polarizing microscope (POM). The results show that the introduction of cholesteric or diosgenin gives polytrimethylene carbonate a liquid crystal property, and the structure of the liquid crystal motifs has a significant influence on its liquid crystal properties.关键词：Trimethylene carbonate;Cholesterol;Diosgenin;Liquid crystal polymer
- 10
- |
- 11
- |
- 0
发布时间：2022-08-30 - 摘要：Using diphenylmethane diisocyanate (MDI) and trimethylol propane (TMP) as raw materials, polyurethane midbodys were synthesized under mild conditions. The surface end group —NCO and chelating agent containing —NH2, —SH active group were added to extend the chain reaction to prepare the chelating polyurethane adsorbent (PU-MEAM). The types and dosages of chelating agents were optimized with adsorption capacity and adsorption rateas the index,the structure was characterized by IR, XRD and SEM, the adsorption performance was investigated of the amino modified polyurethane adsorbent of Hg (Ⅱ) ions in water. The results showed that the adsorption capacity reached 48.34mg·g-1 of PU-MEAM was better when the chelating agent melamine was 1 mmol, at normal temperature, pH value 4, time was 60min and initial concentration was 100mg·L-1, Adsorption kinetics conforms to the quasi-second-order kinetics model and belongs to chemical adsorption, Adsorption thermodynamics conforms to the Langmuir model of monolayer adsorption, In Hg(Ⅱ) and Ca(Ⅱ), Mg(Ⅱ) in the mixed system of Hg (Ⅱ) with high selectivity, respectively, selectivity coefficients were 14.82 and 7.75.关键词：Polyurethane;Chelation;Adsorbent;Selectivity;Mercury ion
- 11
- |
- 13
- |
- 1
发布时间：2022-08-30 - 摘要：This paper uses electrolyte MIVM (eMIVM) and electrolyte NRTL model (eNRTL) to calculate the osmotic coefficient of the two-component ionic surfactant system containing sodium and chlorine respectively, and compares the calculation results of the two models. Through comparison, it is found that eMIVM has certain advantages over eNRTL in both the sodium and chlorine systems. The fitting deviations of eMIVM and eNRTL in the sodium-containing system were 0.0230 and 0.0420 respectively, and the relative errors of fitting were 2.88% and 4.98% respectively. In the chlorinecontaining system, the fitting deviations was 0.0594 and 0.0606, and the fitting relative errors was 13.19% and 13.95%, respectively. At the same time, the osmotic pressure of the solutions was correlated with the calculation of osmotic coefficient in this paper. It can be seen that in some sodium-based systems, the osmotic pressure calculated by eMIVM is closer to the experimental values, and the calculated deviations is smaller than that of eNRTL, which is more in line with the actual application situation. In addition, in some systems containing sodium, eNRTL shows an opposite fitting trend. This may be because eMIVM has a more reliable statistical thermodynamic basis compared with eNRTL, and can simultaneously describe the contribution of molecular interaction (enthalpy) and the number of microscopic states of molecular configuration (entropy) to excess Gibbs energy. This indicates that eMIVM can be applied to the ionic surfactant system, further expanding the applicability of this model.关键词：Ionic surfactants;Osmotic coefficient;Osmotic pressure;eMIVM;eNRTL
- 8
- |
- 12
- |
- 0
发布时间：2022-08-30 - 摘要：Use freezing/thawing treatment prepared a high toughness composite hydrogel from hydrophobic drug-loaded silicone oil dispersed in poly(vinyl alcohol) solution. The hydrogel owned a relatively stable structure through fluorescent microscopy, silicone oil was dispersed and permeated in the hydrogel matrix as microdroplets, no aggregation or migration were observed when the hydrogel sample was placed stationary after 5 weeks. The mechanical properties of hydrogel enhanced proportionally with increasing the silicone oil content, indicating silicone oil not only act as drug reservoirs dispersed within the hydrogel matrix, but also improved the mechanical properties for strong adsorption effect of PVA chains on hydrophobic surfaces.Ultrasound is used to control trigger the hydrophobic drug release from the hydrogel, the result showed the drug were instantly and rapidly released under ultrasound exposure. Mechanism of ultrasound controlled drug release is studied in this paper, and the results indicate the mechanical effect is the main reason.关键词：Ultrasound;Hydrogel;Controlled release;Hydrophobic drug;PVA
- 11
- |
- 12
- |
- 0
发布时间：2022-08-30 - 摘要：In the process of examining the innovation ability of college students, if the influence of cooperation innovation between innovation subjects (colleges and enterprises) cannot be comprehensively considered under the current trend of cooperation between industry, university and research institutes, the true innovation ability of college students cannot be truly reflected by the obtained evaluation results. Based on the research of existing capability evaluation index system, the influence of industry-university-research collaboration is taken into account in the process of determining the evaluation index of innovation ability, a new evaluation index system of college students' innovation ability is construct. And the subjective and objective combination weighting method further are adopted to determine innovation ability. The index weight of the ability is finally obtained by the fuzzy Topsis method. The operability and scientificity of the evaluation index system and evaluation method are verified by the form of examples.关键词：Industry-university-research cooperation;Innovation ability;Quantitative analysis;Subjective and objective combination weighting method;Fuzzy topsis method
- 11
- |
- 11
- |
- 0
发布时间：2022-08-30 - 摘要：Under the background of new technology, "Research Methods of Polymer Materials" , as an important professional course of polymer materials and engineering major, needs to be upgraded and reformed to keep abreast of the development of new technology. Based on the characteristics of polymer materials and engineering major and the teaching experience of "Polymer Materials Research Methods" , the teaching content, methods, practical teaching and evaluation methods were reformed according to the problems existing in the current curriculum. In this way, we look forward to improving the interest in learning, enhancing the innovation ability of the students, and promoting teaching quality of "Research Methods of Polymer Materials" course.关键词：New technology;Teaching reform;Research methods of polymer materials
- 14
- |
- 14
- |
- 0
发布时间：2022-08-30 - 摘要：The curve of polymer temperature-deformation is an important method to study the mechanical state of polymer materials. However, this part of the content is relatively simple in textbook, which resulted more difficult to understand this part for most students. In order to achieve better teaching effect, we summarized the temperaturedeformation curves of polymers with different condensed states, and analyzed the effect factors in detail, such as molecular weight, crystallinity and cross-linking degree etc. It suggested that most students can learning this content better. The teaching effect is effective.关键词：Polymer Physics;Temperature-deformation curve;Polymer structure
- 15
- |
- 14
- |
- 0
发布时间：2022-08-30 - 摘要：At an anticipated post-epidemic timing, the "curriculum ideology and politics" introduces the combination of online and offline polymer chemistry courses through the online learning website "ulearning" . The value building, ability cultivation, and knowledge transmission as the trio value for the course learning in the "curriculum ideology and politics" . Also, the initiation into industry production experience and classroom through the mixed teaching design process before, during, and after class structures a diversified evaluation method with students' learning attitude, learning process, and learning ability as the core and continuous improvement as the purpose. The results show that, while cultivating students' professional ability, it also actively helps students acquire a more progressive outlook on life and values, improving their ideological and political literacy.关键词：Polymer chemistry;On-line and off-line teaching;Curriculum ideology and politics;Combination
- 21
- |
- 17
- |
- 0
发布时间：2022-08-30 - 摘要：Focusing on the perspective of engineering education professional certification, starting from the requirements of certification, the current situation and existing problems of the "polymer science experiment" teaching in Anhui University of Science and Technology were analyzed. Through reasonable adjustment and improvement of course content and teaching progress, coherent teaching model was proposed, and two experimental examples were used for research and elaborate, the experimental content were connected in series and interlocking, which improved the experimental effect. After three years of continuous improvement and teaching practice, it has been proved that the coherent experimental teaching model not only improves students' interest in experimental courses and their ability to solve practical problems, but also cultivates students' innovative ability and rigorous scientific attitude. It has important reference significance for experimental teaching under professional certification standards.关键词：Engineering education professional certification;Coherent teaching;Polymer science experiment
- 13
- |
- 15
- |
- 1
发布时间：2022-08-30 - 摘要：Various engineering examples are important teaching materials in the teaching of plastic materials and formula design courses. We have summarized a large number of examples into a number of topics to systematically teach students. Case-based teaching can guide students to start with basic theories, conduct reasonable analysis and multi-level decomposition of the structure and performance of plastic products, establish a structure-processing-performance logical relationship chain, and help students correctly choose plastic resins, additives, and rationally design simple formulas. The teaching practice of plastic materials and formula design based on engineering cases can fully mobilize students' learning enthusiasm and interest in learning, and at the same time reflect the subjectivity of students to participate in teaching, effectively enhance students' ability to analyze and solve problems, and truly realize "learning for application" teaching objectives.关键词：Application cases;Plastic materials and formula design;Teaching reform
- 11
- |
- 14
- |
- 0
发布时间：2022-08-30
- 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