多糖类天然高分子/PVA可生物降解共混膜的研究进展

目的综述天然高分子(淀粉、羧甲基纤维素、壳聚糖、海藻酸钠和木质素)与聚乙烯醇(PVA)复合制备可生物降解共混膜的方法及性能的研究进展。方法分类讨论淀粉、羧甲基纤维素、壳聚糖、海藻酸钠、木质素分别与PVA进行共混制备共混膜的方法及应用。结果总结了多糖类天然高分子/PVA共混膜的研究与应用进展,并指出了该类共混膜今后发展的方向。结论多糖类天然高分子/PVA可生物降解共混膜的研究是目前科研的热点之一,该共混膜对降低环境污染和节约能源具有重要的意义,具有广阔的应用前景。     

生物降解高分子材料及其生物降解能力评价方法研究进展

介绍了生物降解高分子材料的降解机理、分类和评价生物降解能力的3种方法,重点对天然高分子材料、微生物合成高分子材料、化学合成高分子材料及掺混型高分子材料进行了综述,并简要介绍了当前限制生物降解高分子材料进一步发展的三大问题。     

纤维素基可生物降解共混高分子材料的制备和性能

综述了近年来以纤维素为共混组分制备可生物降解高分子材料的研究进展,重点介绍了纤维素或纤维素衍生物与其它天然高分子(壳聚糖、蛋白质、淀粉等)以及可降解合成高分子(聚乙二醇、聚己内酯、聚乳酸等)共混材料的制备和性能,揭示了纤维素基可生物降解材料在某些应用领域替代石油基材料的潜力.     

纳米SiO2改性可生物降解材料研究进展

纳米SiO2无毒,无味,无污染,具有优异的纳米特性,与高分子聚合物具有良好的相容性,被广泛应用于改善可生物降解材料性能等领域。综述了纳米SiO2的分散稳定性能,以及纳米SiO2改性聚乳酸、聚乙烯醇等合成型生物降解材料与淀粉、纤维素、壳聚糖、蛋白质、木质素等天然高分子材料的研究进展,并从降低价格及增强性能方面,对其改性可生物降解材料替代某些通用塑料的应用前景进行了展望。     

聚乙烯醇热塑加工的研究

聚乙烯醇(PVA)是综合性能优异的可由非石油路线大规模生产的一种高分子材料,但其熔点与分解温度接近,难以热塑加工,应用主要基于溶液法,仅能制备纤维、薄膜等低维制品或用作助、辅材料,限制了其应用和发展。文中介绍了我们近年来在PVA热塑加工方面的一些研究工作:通过分子复合和增塑,获得PVA热塑加工窗口,实现PVA热塑加工,建立了PVA熔融纺丝、吹塑成膜、挤出注塑、中空吹塑及热塑发泡等新技术,通过热塑加工制备性能优良的PVA/无机填料复合材料和PVA/生物质复合材料,为开拓PVA应用新领域、解决PVA工业发展瓶颈问题提供新理论、新技术。     

炔基化改性聚乙烯醇吸氢材料的制备及吸氢性能表征

以聚乙烯醇(PVA)高分子材料为基体,通过氨基甲酸酯化反应在PVA高分子链上引入炔基形成炔基功能化的高分子,利用核磁共振法对炔基化高分子的分子结构及接枝度进行表征。通过化学还原法制备出炔基化高分子负载纳米钯的复合材料,采用激光粒度仪确定纳米钯粒径分布。同时将不同接枝度炔基功能化的PVA和Pd/C催化剂,按照一定的比例采用研磨法制备出吸氢材料。利用PVT法对上述所有的吸氢材料的吸氢性能进行了研究。结果表明,氨基甲酸酯化改性PVA接枝度高的炔基化高分子与Pd/C混合研磨后的吸氢材料的吸氢效果最好,吸氢容量为0.8893 mol/kg。     

环境降解高分子材料

综述了环境降解高分子的研究现状、种类,介绍了光降解、生物降解、光/生物降解塑料,指出完全生物降解塑料在此领域中占有重要的地位,是目前研究的重点.并简单介绍了复合材料技术、纳米技术在生物降解高分子材料中的应用.     

生物降解高分子材料研究应用进展

介绍了生物降解材料的特点及降解作用机理,重点讨论天然高分子材料和化学合成高分子材料的研究应用进展,并对生物降解材料的发展前景进行了展望和论述.     

聚乙烯醇生物降解的影响因素

研究了水溶性高分子聚乙烯醇(PVA)的生物降解性及其影响因素.结果表明,PVA的分子量、结晶度对其生物降解性具有决定作用.通过等离子体作用或氧化处理,可在PVA分子上引入＞C=O、-O=C-O、-COOH等基团,从而提高PVA的生物降解性和降解速率.     

热塑性淀粉基薄膜研究进展

淀粉是由α-葡萄糖分子聚合而成的天然高分子材料,来源广泛,主要分布在植物的根茎中,具有价格低廉、可再生及可生物降解等优点。利用淀粉制备天然可降解塑料薄膜,对解决和改善环境污染有着重大意义。与淀粉基材料相比,聚乙烯、聚丙烯、聚苯乙烯等合成高分子为原料制成的热塑性产品具有气味刺激性、不可生物降解和污染环境等缺点。基于淀粉的天然优势,以淀粉为原料制成的可生物降解热塑性材料成为国内外研究人员的研究热点。主要综述了淀粉的结构和性质,淀粉的增塑方法,淀粉膜的制备方法,热塑性淀粉基功能性膜材料研究进展,并对热塑性淀粉基功能材料的研究内容进行了总结与展望。     

Poly(vinyl alcohol) nanocomposites reinforced with cellulose fibrils isolated by high intensity ultrasonication

Cellulose fibrils in micro and nanoscales generated from biomass are relative new reinforcing materials for polymer composites, which have potential lightweight and high strength and are biodegradable. The objective of this study was to reinforce biodegradable polymers by cellulose fibrils generated from several cellulose sources by ultrasonic treatment in order to utilize biomass to fabricate high-value products. The geometrical characteristics of the fibrils were investigated by polarized light microscopy (PLM) and atomic force microscopy (AFM). The degree of fibrillation of the fibers evaluated by water retention value was significantly increased after treatment. The treated cellulose and separated fibrils were used to reinforce poly(vinyl alcohol) (PVA) to make biodegradable nanocomposites by film casting. The mechanical properties of PVA were significantly improved by most of the small fibrils. The morphological characteristics of the nanocomposites were investigated with PLM, scanning electron microscopy, and AFM.     

Investigation of a novel freeze-thaw process for the production of drug delivery hydrogels

Poly(vinyl alcohol) (PVA) is a water-soluble, biocompatible and biodegradable polymer, which has been widely applied in biomedical fields. In this paper, novel physically cross-linked hydrogels composed of PVA and comprising a blend of poly(vinyl alcohol) (PVA) with different concentrations of HCl, NaOH and NaCl are prepared by a freezing/thawing treatment of aqueous solutions. The structure and complexation of the electrolytes were studied by Fourier transform infrared (FTIR) spectroscopy. The mechanical properties were investigated using rheometery and the thermal transitions of the hydrogels were examined by modulated differential scanning calorimetry (MDSC). Freeze/thawed PVA gels containing NaOH showed overall enhanced swelling with increased mechanical strength over traditional gels prepared by chemical or irradiative crosslinking techniques. These novel physically cross-linked hydrogels show promise for a variety of biomedical and drug delivery applications.     

Release of lysozyme from electrospun PVA/lysozyme-gelatin scaffolds

This article describes an electrospinning process in fabricating ultra fine fibers with core-shell structure. A biodegradable polymer, poly(vinyl alcohol) (PVA), was used as the shell; lysozyme was a kind of antioxidant; and gelatin were used as the core.Morphology and microstructure of the ultra fine fibers were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) analysis. As a comparison, composite nanofiber PVA/lysozyme-gelatin blend was prepared by a normal electrospinning process. In vitro drug release behaviors of the nanofibrous membranes were determined in phosphatebuffered saline (PBS) solution. It was found that core-shell nanofibers PVA/lysozyme-gelatin obviously exhibit higher initial release rates compared to that of PVA/lysozymegelatin blend nanofibers. The current method may find wide application in controlled release of bioactive proteins and tissue engineering.     

Release of lysozyme from electrospun PVA/lysozyme-gelatin scaffolds

This article describes an electrospinning process in fabricating ultra fine fibers with core-shell structure. A biodegradable polymer, poly(vinyl alcohol) (PVA), was used as the shell; lysozyme was a kind of antioxidant; and gelatin were used as the core. Morphology and microstructure of the ultra fine fibers were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) analysis. As a comparison, composite nanofiber PVA/lysozyme-gelatin blend was prepared by a normal electrospinning process. In vitro drug release behaviors of the nanofibrous membranes were determined in phosphate-buffered saline (PBS) solution. It was found that core-shell nanofibers PVA/lysozyme-gelatin obviously exhibit higher initial release rates compared to that of PVA/lysozyme-gelatin blend nanofibers. The current method may find wide application in controlled release of bioactive proteins and tissue engineering.     

Alyssum lepidium mucilage as a new source for electrospinning: production and physicochemical characterisation

The electrospinning technique was used for the nanofiber production of Alyssum lepidium mucilage with acetic acid and polyvinyl alcohol (PVA) polymer. Some parameters such as voltage, polymer concentration, tip‐to‐collector distance, and feed rate were optimised and applied for the fabrication of the nanofiber membranes of the seeds mucilage. The scanning electron microscopy images were used to find the optimised conditions for the electrospinning process. It was found that the aqueous solution of Alyssum mucilage/PVA (80:20), voltage (18 kV), polymer concentration (50%), tip‐to‐collector distance (10 cm) and feed rate (0.125 ml/h) could be successfully used to obtain uniform nanofibers with diameters as low as 139.9 nm. X‐ray diffraction and Fourier transform infrared spectrometer analysis also proved the presence of the alyssum mucilage/PVA nanofiber. In this study, the used electrospun procedure was biodegradable, inexpensive, non‐toxic, and maintainable enough to optimise the mucilage nanofiber fabrication as a new source, thereby improving the potential application of the nanofiber biomembrane in filtration and medical systems with biocompatible and biodegradable properties.Inspec keywords: electrospinning, nanofibres, nanofabrication, polymer fibres, scanning electron microscopy, X‐ray diffraction, Fourier transform infrared spectraOther keywords: Alyssum lepidium mucilage, electrospinning, physicochemical characterisation, nanofiber production, acetic acid, polyvinyl alcohol, PVA polymer, polymer concentration, tip‐to‐collector distance, feed rate, scanning electron microscopy, X‐ray diffraction, Fourier transform infrared spectrometer analysis, voltage 18 kV, distance 10 cm     

生物可降解高分子材料

对生物可降解高分子材料的种类、研究现状进行了综述。对生物可降解塑料进行了较详细的论述。介绍了生物可降解高分子材料的应用。     

成膜助剂对CCMC/PVA复合膜力学特性及生物降解特性的影响

采用流延成膜工艺制备了CCMC/PVA生物降解复合膜,研究了PVA、乙二醛以及PPE 3种成膜助剂对复合膜的力学性能和生物降解性能的影响。结果表明:添加一定量的成膜助剂,可以增强复合膜的机械性能、调控复合膜的生物降解性能;当PVA添加量为30%(质量分数)、乙二醛添加量为2%(质量分数)、PPE添加量为0.6%(质量分数)时,复合膜的拉伸强度可达22.5 MPa,断裂伸长率可达258%,固体琼脂平板培养50 d,微生物生长达到4级,土埋100 d,复合膜失重率达到92%。     

可生物降解性聚合物-层状硅酸盐纳米复合材料的研究进展

可生物降解性聚合物一层状硅酸盐纳米复合材料比聚合物基体有更好的力学强度、热稳定性、热变形温度、气体阻隔特性和更快的降解速率，表现出剪切变稀、模量升高、似固体行为等流变特性。文中综述了可生物降解性聚合物纳米复合材料的制备方法、表征手段、性能测试及其应用等方面的研究进展。