最新刊期
卷 29 ， 期 7 ， 2016
- 摘要：Block copolymers based on isoprene have attracted lots of attentions due to its excellent properties in the field of self-assembled materials, nanometer-sized materials and so on. In this paper, the development history of polyisoprene (PI) block copolymers was reviewed systematically in view of perspective of preparation methods involved in anionic polymerization and the living free radical polymerization including nitroxide mediate radical polymerization (NMRP), reversible addition-fragmentation chain transfer polymerization (RAFT) and atom transfer radical polymerization (ATRP). It is stated that the comprehensive application in combination of various polymerization technology based on controlled polymerization will be the future for synthesis of PI block copolymers.关键词：Polyisoprene;Block copolymers;Anionic polymerization;Living free radical polymerization
- 6
- |
- 10
- |
- 0
发布时间：2022-09-12 - 摘要：Slow/Controlled release fertilizer can be the premise of ensuring food production. It can improve nutrient utilization and reduce negative impact of fertilizer nutrient loss to the environment. Coated slow/controlled release fertilizer has better controlled release rate of nutrients. It can match crop nutrients need and fertilizer release rate through the formation of coating materials design. This paper reviews the coated slow/controlled release fertilizer research status, the controlled release mechanism and release properties evaluation methods of fertilizer nutrients. The existing problems and future development trends of coated slow/controlled release fertilizer research and application are also elaborated.关键词：Slow/Controlled release fertilizer;Coated type;Nutrient release mechanism;Mathematical model;Property evaluation
- 7
- |
- 11
- |
- 13
发布时间：2022-09-12 - 摘要：Because of the one-dimensional hollow structure and functionality,polymer micro/nano tubes have demonstrated extensively application prospects in separations, electronic devices, catalyst carrier, drug delivery and so forth. In this article,the preparation technologies of polymer micro/nano tubes were described systematically on the basis of recent research advances. The features of hard template,soft template and non-template methods were mainly discussed.关键词：Polymer;Micro/nano tube;Template;Preparation
- 7
- |
- 9
- |
- 0
发布时间：2022-09-12 - 摘要：Effective hemostasis is the key to relieving pain and reducing the rate of mortality. Hemostatic materials should be characterized by good hemostasis effect, biocompatibility, biodegradability and nontoxicity. Chitosan and alginate, two natural marine polysaccharide polymer compounds, are wonderful biomaterials widely used in medical field. In addition, their good biocompatibility,excellent biodegradability, outstanding hemostatic effect and antimicrobial property make themselves excellent hemostatic materials for healing the wounds. This article reviews the recent research on the adoption of the two marine polymer compounds as hemostatic materials, and discusses the prospects of future study.关键词：Chitosan;Alginate;Antibacterial;Hemostasis
- 5
- |
- 10
- |
- 1
发布时间：2022-09-12 - 摘要：As the abundant natural renewable aromatic polymer, lignin can be used to produce high value-added phenolic compounds. The degradation of lignin has aroused increasingly broad interests,and there are many methods used in that field to obtain high yield of phenolic compounds under the degradation of lignin,among which the microwave-assisted degrading method has attracted much attention for its advantages which include environmentally-friendly, fast,efficient, energy saving, easy to control, safe and highly selective. In order to understand the current research situation of lignin-degrading microwave-assisted conversion to phenolic compounds, and to predict the future development direction of this field,based on reviewing its research progress, this paper reviews the features, advantages and the mechanism of efficient microwave-assisted degradation technology; and investigates the degradation effect of different catalysts used to lignin under microwave-assisted condition; also introduces the method and effects when adding some effective reagents under microwave-assisted condition. At the same time,this paper reviews the separation and detection methods,characteristics,advantages and application prospects of the products which are produced by the degradation of lignin. Finally,on the basis of all above, this paper looks to the development direction of the studies on how lignin degrades to green chemicals by microwave-assisted method.关键词：Lignin;Microwave;Degradation;Detection
- 6
- |
- 9
- |
- 0
发布时间：2022-09-12 - 摘要：In recent years,with the development of regenerative medicine technique,there has been a heated attention and research about reconstruction of human organs by means of tissue engineering. One important factor of accelerate wound repair by designed dressing materials, which has significant impact on the structure and nature of regeneration tissue. Natural polymer chitosan (CS) has broad-spectrum antibacterial activity and powerful hemostatic function, non-harmful degradation products, has good biological compatibility, bioactivity and bio-degradability, which can effectively promote wound healing and tissue repair and regeneration in the field of biomedical dressing has broad application prospects. This article mainly reviewed in recent years, chitosan wound dressing design molding methods, and discuss the dressing performance and usage of different molding processes and antibacterial agents. It may contribute us to effectively design and develop new types of chitosan-based antimicrobial wound repair material.关键词：Chitosan;Antibacterial;Wound dressings;Nanofibers mat;Hydrogel;Sponge
- 7
- |
- 10
- |
- 4
发布时间：2022-09-12 - 摘要：Starch has been a major source for preparing biodegradable plastics because of its inherent biodegradability, ready availability and relatively low cost. The research and application of starch plastics have been developed rapidly in recent years. The research interest is focused on improving the performance (mechanical and water resistance etc). Nowadays, inorganic or mineral fillers are widely used in composite materials to improve its performance. In this paper, the progress of the effects of inorganic substances on mechanical properties of starch plastics is reviewed in recent years. According to their different categories, we mainly reviewed the effect of inorganic substances on the mechanical properties of starch plastics, including oxide, hydroxide carbonate, silicate and phosphate salt etc. At last,the latest research progress, problems, and the trend in the future are also proposed.关键词：Key words : Inorganic substances;Starch plastic;Enhancement;Progress
- 5
- |
- 9
- |
- 8
发布时间：2022-09-12 - 摘要：Siliceous earth is a non-metallic minerals mainly composed of low quartz and clay mineral such as Kaolin and muscovite, has a unique particles and layer superimposed structure. This work adopts silica and siliceous earth as hybrid filler on Natural Rubber (NR). The vulcanization characteristics and mechanical properties of NR composites were discussed. The results show that after modification,average particle size of siliceous earth decreases. When silica and siliceous earth work together, which is beneficial to enhance liquidity at the beginning stage of NR vulcanization,extend the scorch time and not significantly lower curing rate, can improve the processing performance of rubber. Tensile test results show that the hybrid filler compared with silica or siliceous earth used alone, can improve the tensile strength, modulus and crosslinking density of the NR composites,and in the meanwhile don't reduce elasticity of NR composites. Siliceous earth and silica has synergistic reinforcement effect on NR. Dynamic mechanical analysis results show that siliceous earth is more advantageous to reduce the heat and rolling resistance of NR vulcanizates.关键词：Siliceous earth;Silica;Natural rubber;Reinforcing properties
- 4
- |
- 10
- |
- 0
发布时间：2022-09-12 - 摘要：The kinetics of polymerization of p-methoxybenzeneoctyl dimethyl allyl ammonium chloride (ADMAAC) and acrylamide (AM) initiated by potassium persulfate-sodium bisulfate redox complex in aqueous solution was studied by egular sampling. The polymerization rate equation and apparent activation energy was measured. The content of residual ADMAAC was determined by interaction anion and cation, and the content of residual AM was determined by UV spectrophotometry, and the composition of copolymer at low conversion was obtained by the difference value of input content and residual content of monomer, and the reactivity ratios of monomers in polymerization were obtained by Kelen-Tudos method. The results show that when the polymerization temperature is 40℃,the polymerization rate equation is Rp = K [M]1.241[KPS]0.52[SHS]0.55. The apparent activation energy is 73. 85kJ/mol, which Is higher than the activation energy Ea (70. 32 kj/mol) of AM aqueous solution homopolymerization,according to the experience formula of Arrhenius, and the values of reactivity ratios are rADMAAC = 0.197、rAM = 4. 503. The important kinetic parameters for controlling of ADMAAC-AM copolymerization reaction is determined. The product of reactivity ratio of two monomers is less than 1,the copolymerization behavior type of ADMAAC and AM is a non-ideal copolymerization behavior without azeotropic point, the copolymer composition curve below the diagonal.关键词：Acrylamide;Polymerization kinetics;Polymerization rate equation;Apparent activation energy;Reactivity ratios
- 5
- |
- 10
- |
- 3
发布时间：2022-09-12 - 摘要：The gestodene sustained-release implants were prepared by twin-screw extrusion process with poly (ε-caprolactone) as a carrier. The molecular weight was investigated by Gel permeation chromatography (GPC) and the structure of the implant was observed by Scanning electron microscopy(SEM) and the state of the drug dispersed in the poly (ε-caprolactone) was measured by Fourier transform infrared spectroscopy (FT-IR). The drug loading content and the accumulative release ratio were determined by Ultraviolet spectrophotometry(UV). The results showed that the molecular weight had no obvious change after extrusion. The drug loaded implants were fabricated successfully and the drug did not precipitate on the surface of the drug loaded implants. The drug loaded implant was a physical mixture of drug and carrier. The drug release profile was long-term sustained and fit the first order equation well in vitro(r2 =0. 9948).关键词：Gestodene;Poly(ε-caprolactone);Sustained-release implants;Drug release in vitro
- 5
- |
- 8
- |
- 0
发布时间：2022-09-12 - 摘要：With the ultra-high molecular weight polyethylene (UHMWPE) fibers as materials, the influence of processing pressure, temperature and time on the infiltration rate of trimethylolpropane trimethacrylate(TMPTMA) under the different supercritical carbon dioxide fluid state using Minitab software to design experiment were studied and the optimal set range of factors were determined ; The supercritical CO2 process was optimized through the signal factor experiment, in addition, the gel content and creep rate of UHMWPE fibers after electron beam irradiation were tested. The results showed that the processing temperature had the most significant effect on the infiltration rate of TMPTMA, followed by pressure, time had the minimal effect. The optimal conditions were processing pressure 25Mpa, temperature 80℃,time 30min; The higher the infiltration rate of TMPTMA was, the better effects of sensitizing irradiation crosslinking and anti-creep of UHMWPE fibers after electron beam irradiation were.关键词：Ultra-high molecular weight polyethylene fiber;Supercritical carbon dioxide;Electron-beam irradiation;Infiltration rate;Minitab
- 6
- |
- 8
- |
- 0
发布时间：2022-09-12 - 摘要：To play the main role of students in teaching, the author practiced task driven thematic teaching in some sections of polymer physics. The contents of molecular weight, molecular weight distribution, plasticizing agents,liquid-crystal polymers, rubber elasticity and introduction of polymer molding process were designed to be eight themes. The syllabus was designed as tasks which strengthen the connection between theory and corresponding applications. As an effective complement to traditional teaching, task driven thematic teaching strengthens the students' learning process before class and improves their initiative, innovation and cooperation spirit.关键词：Task driven;Thematic teaching;Polymer physics
- 5
- |
- 13
- |
- 0
发布时间：2022-09-12 - 摘要：This paper expound the three conservation equation principles about fluid flow and its physical meaning of their expressions, analyze their solving necessary of combining fluid rheological constitutive equation and simulate the digital results; The polymer rheological constitutive relation's principle are discussed on natural philosophy, so deepening the teaching contents, inspiring students' thinking, achieving better teaching effects.关键词：Fluid flow equation;Constitutive relation;Rheology;Teaching
- 5
- |
- 9
- |
- 0
发布时间：2022-09-12
- 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