最新刊期
卷 26 ， 期 4 ， 2013
- 摘要：Naturally occurring macromolecules like proteins and DNA form helical structures. Synthetic helical polymers as mimics of biomacromolecules have been attracting ever-growing attention. On the basis of our recent achievements in optically active helical substituted polyacetylenes, this review article briefly introduces novel chiral materials derived from helical polyacetylenes and their applications. Special attention is devoted to chiral nanoparticles, chiral core/shell particles, chiral microspheres, and chiral (hydro)gels consisting of helical polyacetylenes. The applications of such helical polymeric materials in chiral recognition, chiral resolution, enantioselective crystallization, chiral catalysis, and enantioselective- controlled release are briefly summarized.关键词：Chirality;Helical polymers;Substituted polyacetylenes
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发布时间：2022-09-18 - 摘要：The wider practical application of biodegradable polymers has been restricted because of their disadvantages,such as high cost,slow crystallization, slow degradation rate, poor mechanical properties,and thermal instability. The fabrication of biodegradable polymer nanocomposites is one of the most effective methods to modify biodegradable polymers. Based on the recent studies on the modification of biodegradable polymers in our lab,this review summarizes the recent progress of poly(L-lactic acid) (PLLA) and poly (ε-caprolactone) (PCL) based nanocomposites by incorporating polyhedral oligomeric silsesquioxanes (POSS) with different functional groups as nanofillers. It has been found that POSS can enhance the crystallization and hydrolytic degradation processes and improve the mechanical properties of both PLLA and PCL effectively.关键词：Biodegradable polymers;Polyhedral oligomeric silsesquioxanes;Nanocomposites;Crystallization behavior;Properties
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发布时间：2022-09-18 - 摘要：Natural extracellular matrixs are net-like being composed of fibrin and fibers in nanoscale (50 〜500nm). From the biomimetic viewpoint,electrospinning technique would be a proper method to produce fibrous network mimicking the natural extracellular matrixes. Diameters of electrospun fibers range from tens of nanometers to micrometers, porous structures resulted from the loosely deposited fibers are of high porosity and high surface area, which are good choice for tissue engineering by providing proper environment for cells proliferation and differentiation. In this paper, an introduction to the preparation and biomedical application of several functional nanofibers is summarized basing on recent literature reports and the research works in our lab,focusing on developing novel regeneration materials for dental and hard tissue restoration.关键词：Electrospinning;Bone regeneration;Composite nanofibers;Bioactive carbon nanofbiers;Ceramic nanofibers
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发布时间：2022-09-18 - 摘要：With the development of the economy, enduring attention has been paid to effective utilization of renewable resources in both scientific and industrial community, due to the increasing consumption of petroleum. In the past decades, some progress has been made in the field of the synthesis and modification of biomass materials, which is based on renewable resources. In this article, we introduce the structure of several typical renewable biomass, such as saccharides, vegetable oil, terpenoids, and furan. The properties, modification and application of these novel biomass materials will also be involved.关键词：Polysaccharose;Vegetable oil;Terpenoids;Furan
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发布时间：2022-09-18 - 摘要：China needs more and more rubber resources to support its rapid development of economy since it became the world's second largest economy in 2010. Rubber materials could be obtained from two sources : one is natural rubber which comes from Hevea brasiliensis , but it is shortage in China; the other is synthetic rubber which is unsustainable because of its dependence on fossil resources. Therefore, using solar energy to develop biorubber is the future of sustainable development of China rubber industry. Biorubber can be divided into two categories : one is the bio-based engineering elastomer(BEE) which was synthesized from new bio-based monomers such as itaconic acid fermented from annually renewable agricultural and biomass feedstock, or synthesized from traditional bio-based monomers ( for example, isobutylene etc.) transformed from fermentative monomers (for example,isobutyl alcohol etc.) ; the other one is natural rubber including para rubber and the second natural rubber(SNR),such as TKS rubber, guayule and Eu-gum. The review shows research progress in BEE and SNR,but the para rubber is not reviewed here any more because of its long research history and lots of literatures.关键词：Biorubber;Bio-based monomers;Bio-based engineering elastomer;Second natural rubber
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发布时间：2022-09-18 - 摘要：The progress in the synthesis of graft copolymers via controlled/living cationic polymerization and by three different synthetic strategies of grafting from, grafting onto and macromonomer, is reviewed. The influence of the chemical structures of macroinitiator, branched chain, macromonomer, distribution of initiating sites and functional groups along macromolecular chains, the length of branches and Lewis acids on grafting polymerization is summerized. The characteristics of the above three synthetic strategies of grafting from, grafting onto and macromonomer is proposed. The microstructure, morphologies and surrounding response property in the specific environment of the graft copolymers are further elaborated. The potential application of the graft copolymers are also discussed.关键词：Graft copolymer;Cationic polymerization;Polyisobutylene;Polytetrahydrofuran;Poly(2-oxazoline)
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发布时间：2022-09-18 - 摘要：The special helical structure of cholesteric liquid crystal ( Ch-LC) make them characteristic optical properties of selective reflection and circular dichroism , the reflection intensity is limited to 50% of natural light (non-polarized light). If Ch-LC/polymer composites have double helical structure, the reflection intensity of the Ch-LC will be more than 50% maximum limitation of the non¬ polarized light, thus a high reflectivity flux of Ch-LC film will be prepared. This characteristic can extend practical applications of Ch-LCs used as reflector for reflective polarizer-free liquid crystal display and smart windows in buildings and vehicles, greenhouses and other applications in which light management is desired. This paper reviews the research progress of Ch-LC polymer composites reflecting double circular polarized light, and gives an outlook for the development of this field.关键词：Cholesteric liquid crystal;Selective reflection;Circular dichroism;Double helical structure;Total reflection
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发布时间：2022-09-18 - 摘要：Electrospinning nanofibers have attracted much attention because of their unique structure and superior performance, especially their potential advantages in energy and environmental technologies. Nowadays, the research and application of electrospinning nanofibers in membrane separation become research hotspot in the functionalization of new materials. In membrane separation, especially in water treatment, affinity membrane separation and air filtration, electrospinning nanofibers can increase separation efficiency, reduce energy cost, and expand the application of membrane separation technology. In this paper, we introduced the progress in the research of electrospinning nanofibers application in water treatment, affinity membrane separation and air filtration. In the end, we briefly pointed out the remaining problems, and looked forward to the future of electrospinning nanofibers.关键词：Electrospinning;Nanofiber;Membrane separation;Affinity membrane;Air filtration
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发布时间：2022-09-18 - 摘要：Through chemical modification of polysaccharides, we developed bromoisobutyryl- terminated polysaccharide initiators for subsequent atom transfer radical polymerization. A series of new cationic polymers composed of biocompatible polysaccharide backbones and polycation side chains of different length were designed. Cell transfection, cell toxicity, and the other properties of the material were characterized. The results of the characterization indicated the cationic polymers can condense DNA very well and have good buffer capacity and biocompability. The high gene transfection efficiency and cell viability of polysaccharide-based polycations compared with PEI and commercial transfection reagent demonstrate it has great potentials as efficient vectors in future gene therapy.关键词：Polysaccharide;ATRP;Gene vector;Gene transfection;Gene therapy
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发布时间：2022-09-18 - 摘要：Benzoxazine is a new type of thermosetting resin, which has attracted much attention because of its good mechanical properties, thermal stability, processability, molecular designability and no small molecules released during curing etc. However, the brittleness and poor toughness of the curing resins are still called for improvement. This paper reviewed research achievements of benzoxazine resins in recent years,in which the ideas and methods for the development of polybenzoxazines/POSS hybrid materials were mainly introduced and illustrated with specific examples. Those results revealed that the comprehensive performance of materials were significantly improved via the introduction of hybrid structures, which has certain directive significance on the development and application of benzoxazines resin and its composite materials and the other thermosetting resin.关键词：Benzoxazine;Hybrid material;Polyhedral oligomeric silsesquioxane
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发布时间：2022-09-18 - 摘要：Surface-silvered polyimide (PI) film, due to the combination of the excellent thermal and mechanical properties of the polyimide matrix and the unmatched optical reflectivity and electrical conductivity of the surface silver (Ag) layer as well as as its light weight and flexibility, has been found widely attractive in aerospace and microelectronic industry and therefore has been extensively studied in recent years. In this review, we described the currently-used main techniques that were developed for the preparation of surface-metallized polyimide films, including external deposition, supercritical fluid impregnation, in-situ single-stage self-metallization, surface-modification ion-exchange self- metallization and direct ion-exchange self-metallization methods, and compared their advantages and disadvantages for producing the metallized polymer films. Particularly, the progress in the preparation of highly reflective and conductive surface-silvered polyimide films via the surface-modification ion- exchange self-metallization technique and direct ion-exchange self-metallization technique, both of which were developed in our groups, was summarized. With these two methods, double-surface- silvered polyimide films with high surface reflectivity and conductivity were produced by employing simple silver compounds as the silver precursor, which possess the advantages of processing simplicity and considerably reduced cost. Moreover, the finally-obtained polyimide-silver composite films were prepared with surface reflectivity over 100% and surface conductivity comparable to native silver metal. Excellent interfacial adhesion between the surface silver layer and the polyimide substrate was realized and the surface-metallized hybrid films basically maintain the essential thermal and mechanical properties of the parent polyimide. Especially, it should be emphasized that, with the direct ion- exchange self-metallization procedure, double-surface-silvered polyimide films could be realized by employing an aqueous silver ammonia ( [Ag(NH3)2]NO3) solution with a concentration of only 0. 01M and an ion-exchange time of merely 5min, which were demonstrated to be the most efficient film preparation route with the most economical silver usage.关键词：Polyimide;Silver;Reflective;Conductive;Surface-metallization
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发布时间：2022-09-18 - 摘要：Polypropylene (PP) is a large branch in the plastic field and attracts more and more attention in auto industry and academic field for its excellent properties. Polypropylene has good mechanical property, processability,low cost, but less toughness,low elongation at break and low distortion temperature. Thus,to acquire PP material with optimized performance becomes a big issue. The modification of PP material is actually a regulation of the regularity of the polymer chain and control of the crystal spherulites size. Nucleating agent has been applied to modify PP products for decades for its easy processability when applied in PP. Many kinds of nucleating agents with identified characteristics have been exploited in the past decades. Here we introduce another new nucleating agent category-polymeric nucleating agent. We concluded the studies of polymeric nucleating agent in PP system, and we considered that the future of the application of polymeric nucleating agents in PP system is promising.关键词：Polypropylene;Nucleating agent;Polymeric nucleating agent
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发布时间：2022-09-18 - 摘要：Organic-inorganic hybrids, combining the advantages of organic materials and inorganic materials, are a new generation functional materials following the one-component material, composites and gradient materials. Based on Polyhedral oligomeric silsesquioxane nanoparticle (POSS) which can be designed and modified, a serious of high performance polymer /POSS hybrid materials were prepared through sol-gel,reactively blending, UV-curving, ATRP,self-assembly method, respectively.关键词：Polyhedral oligomeric silsesquioxane;Organic-inorganic hybrids;High performance
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发布时间：2022-09-18 - 摘要：The chitosan solution and sodium hyaluronate solution was mixed to prepare the CS-SH polyelectrolyte composite (PECs) solution and characterized the size distribution and zeta potential of the colloidal particle formed in the solution. Then, removed the solvent with the technique freeze drying. The structure of PECs nanofibers mats was investigated by fourier transform infrared spectrometer (FT-IR). The morphology of PECs nanofiber mats was characterized by scanning electron microscope (SEM). Furthermore, the drug encapsulated and released properties of PECs nanofibrous membrane was studied by a hydrophobic drug paclitaxel (PTX). The results showed that the PECs nanofibers carrier demonstrated a slow released property for the PTX. As drug release carriers, it has played an important role in prolonging drug valid time, reducing the number of medicine, enhancing the treatment effect and reducing the toxicity.关键词：Polyelectrolyte composite;Freeze drying;Nanofibrous membrane;Paclitaxel (PTX)
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发布时间：2022-09-18 - 摘要：Tertiary amine functionalized polymer was prepared and employed as thermo-reversible crosslinker for acrylic rubber containing active chlorine (ACM) through reversible quaternization/de- quaternization between the tertiary amines and chlorine groups. Butyl acrylate/4-vinylpyridine copolymer crosslinker was synthesized through emulsion polymerization. The effect of the dosage of the crosslinker, thermo-compression temperature and time on the crosslinking degree and mechanical property of ACM was investigated. The reversibility of the crosslinked ACM was revealed by DSC, torque measurement during heating/cooling cycles and thermal re-processing of the crosslinked ACM. The tensile strength of BA-4-VP copolymer crosslinked ACM filled with carbon black could reach at 8. 5MPa. The crosslinked carbon black filled ACM rubber could be re-shaped through thermo- compression to obtain specimen with a larger tensile strength and a smaller elongation at break.关键词：Thermally reversible covalent crosslinking;ACM containing active chlorine;Quaternization
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发布时间：2022-09-18 - 摘要：This paper summarizes the recent research progress of intumescent fire retardant coating, the often used intumescent flame retardants,including carbon catalysts, charring agents and blowing agents have been summarized and classified. The base resin, synergistic agent sand other additives have also been discussed. The trends of the future development of the flame retardant coating have been proposed.关键词：Fireproof coating;Intumescent;Flame-retardant system
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发布时间：2022-09-18 - 摘要：Thermo-responsive branch copolymer was prepared via copolymerization with N- isopropylacrylamide (NIPAm) and the thermo-responsive macromonomer. The main chain and branch chain of thermo-responsive branch copolymer performed two different phase transition temperatures in aqueous solution. After dual-phase-transition, "grape cluster"morphology with large specific surface area could be observed by SEM. There were two break points in light scattering curves, which further explained the dual-phase-transition process in morphology. Two relatively independent endothermic peaks could be observed at 35℃ and 21℃ in DSC curves of the thermo-responsive branch copolymer sample, which described the dual-phase-transition process from the viewpoint of thermodynamics. The order of groups changing induced by temperature was investigated by 2D-IR spectroscopy. The result confirmed that the BA unit, which only existed in the branch chains, changed prior to the NIPAm units. The "grape cluster"morphology effectively increased the specific surface area of thermo- responsive polymer, which might be potentially applied in bioseparation.关键词：Thermo-responsive polymer;Branch copolymer;Phase transition;Two-dimensional infrared correlation spectroscopy
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发布时间：2022-09-18 - 摘要：This paper is an overview of the influence of the inorganic flame retardants on the fire performance and smoke release of polyvinyl chloride (PVC). The flame retardants and smoke suppressants used in PVC have been classified and summarized. The flame retardants,including metal hydroxide, antimonide,boride,stannide,red phosphorus and zinc compounds have been discussed in detail which includes the flame retardant mechanism, loading and technologies. The application of hydrotalcite, zeolite and montmorillonite in improving the flame retardancy of PVC has also been discussed. It is suggested that ultra-fining, special activated surface treatment and compounding of flame retardants and smoke suppressants would attract more attention in the future development of the flame retardant and smoke suppressant PVC.关键词：Polyvinyl chloride (PVC);Flame retardant;Smoke suppressant
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发布时间：2022-09-18
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