最新刊期
卷 24 ， 期 12 ， 2011
- 摘要：In this paper, we focus on the development and research of alga fiber materials. The materials have many excellent advantages: being resource-rich, renew able, biodegradable and biocompatible, et al. They are extensively used as drug release materials, scaffolds for tissue engineering and medical dressing. However, the application and preparation of functional fibers from alga fiber materials are still in its underdevelopment stage. Combining with the achievements of alga materials, we focus on the research and development of the alginate fibers and carrageenan fibers. The structure and rheological property of alginate and the carrageenan are studied. Moreover, the spin-forming of wet spinning and elect rostatic spinning are discussed.关键词：Alginate;Carrageenan;Wet spinning;Electrostatic spinning
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发布时间：2022-09-18 - 摘要：This paper reviewed research achievements of initiator and comonomer in the preparation of polyoxymethylene, and then summarized their research progress in structure and performance. It was pointed out that we must synthesize high performance polyoxymethylene such as introducing comonomers with sidegroups in order to improve toughness and thermal stability of polyoxymethylene. By optimizing molecular structure of comonomer, adjusting the amount of comonomer, we could gain high performance polyoxymethylene resin to adapt to the high speed, high temperature and high pressure working environment.关键词：Polyoxymethylene;High performance;Cationic Ring-opening Polymerization;Thermal stability;Toughness
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发布时间：2022-09-18 - 摘要：Development over the past decade in the field of Reversible Addition-Fragmentation Chain Transfer (RAFT) polymerization on surface modification is summarized. This is followed by four parts: (1) Physisorption of polymers synthesized by RAFT process; (2) "Grafting from" by grafting polymerization in the existence of surface radicals and free RAFT chain transfer agents (CTAs); (3) "Grafting to" by covalently tethering polymers synthesized by RAFT process through reaction of functional ends with a surface functional groups; (4) Grafting polymerization by grafting RAFT CTAs on the surface first, and then grafting polymerization can be achieved. The effect of RAFT polymerization on research and application in the field of surface modification is also prospected.关键词：Reversible addition-fragmentation chain transfer;Surface modification;RAFT agent;grafting polymerization
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发布时间：2022-09-18 - 摘要：Thermodynamic activation-deactivation cycles of the so-called nitroxide-mediated controlled radical polymerizations had been built up to control molecular weight distributions of architected polymer. The nitroxide-mediated radical polymerization (NMP), including fundamental controlled theory, initiator/mediator system, experiment methods and reaction conditions, it would be further developed by appearance of SG1from reaction kinetics to polymerization systems. In this paper, we review the recent achievements of NMP at the presence of SG1and its derivates in these systems such as bulk, solution, emulsion, miniemulsion and dispersion polymerization, as well as the development of reaction kinetics of SG1 as a mediator applied in controlled radical polymerization (CRP) in order to prepare functional polymer or block copolymer materials.关键词：Nitroxide-mediated radical polymerization ( NMP );DEPN (SG1);MONAMS;SG1-MAMA
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发布时间：2022-09-18 - 摘要：Since the traditional antimicrobial drugs are prone to trigger the drug resistance of bacteria and turn the bacteria into so called super-bacteria, novel antimicrobial drugs with different antimicrobial mechanism are desired. Polymeric antimicrobial agents mimicking the natural antimicrobial peptides with high antibacterial capability and good bio-selectivity, plus their simple synthesis, easy control of chemical structure and applicability of large scale industrial production, have been regarded as the next generation of antimicrobial drugs to replace the antibiotics. In this review, the concept of mimicking natural antimicrobial peptides and the development of polymeric antimicrobial drugs are introduced, and the structures, properties, and the factors determining the antimicrobial and bio-selective properties of polymeric antimicrobial drugs are discussed.关键词：Natural antimicrobial peptide;Antimicrobial activity;Bio-selectivity;Polymeric antimicrobial drug
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发布时间：2022-09-18 - 摘要：Hyaluronic acid is widely used for medical field, tissue engineering and clinical medicine due to its excellent moisture retention, viscoelasticity, lubricity, biocompatibility and biodegradability. The unstability and sensitivity of natural HA to strong acid, base, heat and hyaluronidase limit its clinical application, so the research on modificated HA has been paid more attention. This review concentrates on the recent research achievement on the preparation of HA derivatives by corss-linking, esterification, composition and copolymerization, as well as their clinical application especially in ophthalmic surgery, phonosurgery, osteoarthritis treatment and drug delivery system.关键词：Hyaluronic acid ( HA);Modification;Biocompatibility;Biodegradability;Clinical application
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发布时间：2022-09-18 - 摘要：poly (vinylidene fluoride) (PVDF) and vinylidene fluoride ( VDF ) / trifluoroethylene ( TrFE) copolymers are of considerable current interest for their great ferroelectric and piezoelectric properties. Recently, modified by physical or chemical process, PVDF based fluoro polymer exhibits excellent dielectric and energy storage properties, which is highly expected to be applied in the field of high energy density discharge capacitors. The fluoro polymer with optimized composition treated by the extrusion and subsequent stretching methods possess high dielectric constant ( 12 ~ 60) and very high breakdown electric field. The highest energy storage density is more than 25J/cm3 ( 600 ~ 700MV/m) at room temperature, which is significantly improved of energy density over traditional capacitor dielectric film materials. The recent development of these high performance polymers as dielectric and energy storage materials is summarized in this article.关键词：Fluoropolymers;PVDF;Dielect ric;Energy storage
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发布时间：2022-09-18 - 摘要：Based on the "lock-and-key" inclusion complexation between cyclodextrins and various guest molecules, which is strictly intermolekular non-covalent interaction, novel macromolecular networks can be formed. The novel networks have attracted much attention and have been the focus of macromolecular self-assembly in recent years due to the advantages of selectivity, regulating capability of cyclodextrins. In this paper, the recent progresses of macromolecular networks assembled by inclusive associations is reviewed, which mainly include: (1) supramolecular polymers, nanoparticles, association thickening fluid or supramolecular hydrogels induced by the complexation between cyclodextrin dimers, cyclodextrin crosslinked polymers, pendent cyclodextrin polymers, multi-arms star or hyperbranched polymers and the amphiphilic polymers; (2) hybrid organic-inorganic hydrogels prepared from CD-grafted new functional inorganic species and amphiphilic polymers; (3) the design and preparation of the supramolecular hydrogels with stimuli-responsive properties including pH, temperature, light, etc and their potential applications as drug / gene delivery carriers and tissue engineering scaffolds.关键词：Cyclodextrin;Inclusive association;Mmacromolecular network;Supramolecular hydrogel
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发布时间：2022-09-18 - 摘要：With the advance of nano science and technology, the researches on particulate emulsifiers expanded from emulsion filed to nano material preparation. The kind of particulate emulsifiers also developed from inorganic particles to inorganic/organic composites, polymeric particulate emulsifiers, and natural macromolecule particulate emulsifiers; therefore the fast developments of them are received more attentions on the industry and academic in recent years. This paper reviewed recent progress on the macromolecular particulate emulsifiers. The basic concepts and the mechanism of the emulsification of Pickering emulsions were introduced, and the studies on the synthetic methods, the environmental responses and the applications of the macromolecular particulate emulsifiers were discussed. In addition, the new trends in this field were described and the future of macromolecular particulate emulsifiers was prospected.关键词：Polymer;Natural macromolecule;Particulate emulsifier;Environmental response;Pickering emulsion
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发布时间：2022-09-18 - 摘要：The infection and tissue damage around the biomaterials are mainly caused by the bacterial adherence to the surface of the material. A new kind of antibacterial ciprofloxacin-polyurethane ( CFPU) was synthesized in order to prevent the infection. The degradation of CFPU in the phosphate-buffer saline ( PBS) ( pH =7.4, 37 ℃) was studied. The antibacterial ability and the cytotoxicity of the degradation so lutions were assayed. The results showed that ciprofloxacin( CF) was kept effectively in CFPU while the drug loss was below 2% under the mimetic humoral condition. In the presence of cholesteral esterase( CE), CF release was obviously larger than in the PBS only. Hence, the increase of the concentration of CE accelerated the release of CF, which indicated the control release ability of the material. The enzymatic degradation showed an ability to kill bacteria and the minimum inhibitory concentration ( MIC ) was measured as 0.376μg/mL. The degradation solutions were hypotoxicity according to the MTT assay.关键词：Antibacterial;Cont rol release;Polyurethane;Ciprofloxacin;Degradation;Cholesterol esterase
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发布时间：2022-09-18 - 摘要：A new cellulose ether ester carboxymethyl cellulose acetate butyrate ( CMCAB) was synthesized by alkalization, etherification of big liquor ratio and partial homogeneo us esterification reaction. The structure and thermal properties of CMCAB was analyzed by 1H-NMR, FTIR, XRD, TG and DSC, and surface tension of CMCAB solution and rheology of CMCAB water dispersions were also studied. The hydrophilic carboxy group in CMCAB molecular chain was well distributed. CMCABs had low crystallinity and good thermal stability, and Tg were about 110 ℃.As quantity of acetyl increased and quantity of butyryl decreased, Tg of CMCAB deceased, while crystal form and thermal stability changed little. Structure of CMCAB had little influence on surface tension of solution. CMCAB water dispersions exhibited good thixotropic property.关键词：Cellulose ether ester;Water dispersions;Chemical structure;Properties
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发布时间：2022-09-18 - 摘要：In this article, luminescent ZnS/PPV nanofibers are fabricated by the electrospinning technique. Apparatuses including scanning electron microscopy, fluorescence microscopy, fluorescence spectrophotometer and X-ray diffractometer have been used in the process of studying characteristics. The diameteres and morphology of the fibers are different by varying the concetantion of zinc acetate. The diameteres of the fibers are about 400 nm. By fluorescence spectrophotometer and fluorescence microscopy, nanofibers with luminescence are indicated. The emission peaks of pure PPV are different from the peak of ZnS/PPV fibers. Fibers have potential applications in luminescent area.关键词：Poly(phenylene vinylene)(PPV);Zinc Sulfide(ZnS);Nanofibers;Luminescence
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发布时间：2022-09-18 - 摘要：Amphiphilic linear polymers were prepared by palmitic acid mobified and quaternization of linear polyethylenimine (LPEI). Through the ionic bond or hydrogen bond interactions between the amino and citric acid anion, amphiphilic linear polymers has been successfully employed to transfer the 18nm citrate-protected gold nanoparticles (AuNP) from water into chloroform without aid of other compounds such as thiols, TOAB and so on. The chloroform solutions of AuNPs were characterized by UV-vis spectrometry and dynamic light scattering. It was found that the sizes and shapes of the gold nanoparticles were preserved during the phase-transfer process,the product of palmitic acid modified LPEI afterquaternization (LPEI15k-C160.73 N+) exhibited higher efficiency in transferring the large AuNPs. furthermore the amphiphilic linear polymers could form relatively homogeneous and densely packed shell around the gold core revealed by transmission electron microscopy. Moreover, the AuNPs capped with the amphiphilic linear polymers could be also stored in dryness for at least 35 days at room temperature.关键词：Linear polyethyleneimine;Gold nanoparticles;Amphiphilic;Phase transfer
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发布时间：2022-09-18 - 摘要：Modified inorganic powder materials ( one-dimensional Mg SO4 whisker, two-dimensional Mica and three-dimensional SiO2 ) was added into polypropylene with 5 % content. The microcellular foam PP composite was made under the condition of twice-open mold. According to the principle of interfacial adhesion, Liquid-solid interface PP composite system was calculated adhesion work by measurements of the contact angle. Taking heterogeneous nucleation theory and reinforcement effect, mechanical behavior of microcellular foam PP composite was analyzed by inorganic powder material, The results showed that PP/Mica composite system showed the maximum impact strength, which is improved by 79.17 %.It is not only to reduce cost and but also to effects enhance. So Micapowder is the best two dimension filler on enhancement in foamed PP composites.关键词：PP;Impact strength;Adhesion work;Microcellular foam;Tensile strength
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发布时间：2022-09-18 - 摘要：Modified nanosilica was prepared by esterifying nanosilica with hydoxyethyl acrylate in the presence of p-toluenesulfionic acid. Characterization of the pro ducts by Fourier transform infrared spectrometer ( FT-IR) and thermogravimetric analyzer ( TGA) showed that 70.5 % of Si-OH groups on nanosilica could esterify with hydoxyethyl acrylate. Applied in UV curable coatings, unmodified and modified nanosilica could improve the pencil hardness and abrasion resistance of the cured films, the best properties of the films was obtained when addition of nanosilica was from 4wt % to 6wt %, however, the curing rates of coatings decreased and the viscosities of coatings increased. Compared to the coatings with unmodified nanosilica, the coatings with modified nanosilica had lower viscosities, more even dispersion, faster UV curing rate and their cured films had better pencil hardness and abrasion resistance.关键词：Nanosilica;Hydoxyethyl acrylate;Modification by esterification;Hybrid coating
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发布时间：2022-09-18 - 摘要：Three kinds of curing agents, aromatic diamine (SAA), anhydride (THPA) and tertiary amine (DMAP), were employed to cure the azo-type dimeric liquid crystalline epoxy resins. The phase behavior of liquid crystalline thermosets (LCTs) from different hardeners was studied by polarized optical micrograph and X-Ray Diffraction. DMAP, catalyzing the homopolymerization of epoxy groups,is helpful to the ordered arrangement of mesogens, resulting in LCTs with a smetic phase. For SAA, the smetic LCT can be obtained by cured at a low temperature, but only nematic LCTs can be prepared at high curing temperature. All the LCTs from THPA have the nematic phase. Thermal properties of the LCTs were studied by DSC and TGA.Glass transition temperatures from the three hardeners show the order of SAA>DMAP>T HPA,and the onset temperatures of decomposition have the order of DMAP >SAA>T HPA.关键词：Curing agent;Azo;Thermal properties;Phase behavior;Liquid crystalline epoxy resins
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发布时间：2022-09-18 - 摘要：Polymers would undergo aging when exposed to weathering conditions. The evaluation of life duration of organic polymers is essential in order to ensure serviceability and reliability over their lifetime. In this paper, lifetime prediction methods for organic polymers in recent decades are summarized. Meanwhile, the development of novel prediction methods owing to the rise of new condition monitoring techniques are introduced and commented. The common used standards are listed. Finally, research trends in this field are forecasted.关键词：Organic polymers;Lifetime prediction;Aging
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发布时间：2022-09-18 - 摘要：With the rapid development of electronic industry, the quantity of abandoned printed circuit board also increases year by year. This great amount of waste printed circuit boards may cause serious pollution to the environment. Waste printed circuit boards are of high recycling value. If appropriate methods of its recovery are adopted, it’s of great significance not only to solve our country’s increasingly shortage of mineral resources, but also to the environment protection. This paper expounds the economic and environmental significance of recycling waste printed circuit boards, and introduces in details three chemical recovery methods as hydrometallurgy method, pyrolysis method and supercritical fluid method.关键词：Printed circuit boards (PCB);Resource recycling;Hydrometallurgy;Pyrolysis;Supercritical fluid.
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发布时间：2022-09-18 - 摘要：How to use function of PowerPoint document to lecture some knowledge point via design Animation effect in "polymer physics" course teaching were introduced in this paper. Some making arts in creating presentation aiming at ensuring clear sights for students who sit at the rearward in the classroom, such as the arrange in pairs or groups of colors, the choice of fonts types and sizes, the choice of background, are introduced. The eyesights of students can get benefit from well lighting in classroom when proper color pairs and font sizes be adopted and get rid of drawing the curtains in class. A skill of drawing curves by using "autoform" in command menu is introduced. The beautiful and vivid animations designed with the PowerPoint are helpful to enrich the teaching contents and prompt the teaching effect.关键词：PPT;Arrange in pairs or groups of color;Choice of font type;curve drawing
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发布时间：2022-09-18 - 摘要：The Lowest Energy Principle is one of the most common rules in nature, which can be used to explaine many phenomena of polymer chemisty. In this paper, some concrete embodiment of the Lowest Energy Principle in polymer chemisty has been expatiated from polymerization direction, stability of free radials and rearrangement reaction of polymerization etc., and the application of the lowest energy principle in explaining laws and phenomena of polymer chemisty reaction has been preliminary explorated. Practice has proved that explaining some concepts and reactions in polymer chemistry teaching by using the lowest energy principle can make things more easy.关键词：Lowest Energy Principle;Polymer chemistry;Teaching;Application
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发布时间：2022-09-18
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