聚乳酸类材料在生物医学领域的应用

本文概述了聚乳酸的主要合成方法及聚乳酸类材料在生物医学领域的应用,并对聚乳酸类材料的研究发展趋势进行了展望。     

聚乳酸基复合材料的研究进展

综述了近年国内外聚乳酸基复合材料的研究进展,主要包括聚乳酸与天然高分子材料复合、聚乳酸与合成高分子材料复合以及聚乳酸与其它分子材料复合等。同时对聚乳酸基复合材料在制备和应用过程中遇到的难题进行了分析和总结。开发综合性能优异的聚乳酸基复合材料的低成本制备关键技术将是今后该领域发展的主要方向。     

聚乳酸基复合材料的研究进展

综述了近年国内外聚乳酸基复合材料的研究进展,主要包括聚乳酸与天然高分子材料复合、聚乳酸与合成高分子材料复合以及聚乳酸与其它分子材料复合等。同时对聚乳酸基复合材料在制备和应用过程中遇到的难题进行了分析和总结。开发综合性能优异的聚乳酸基复合材料的低成本制备关键技术将是今后该领域发展的主要方向。     

聚乳酸类材料的应用研究进展

对聚乳酸类材料在塑料、纤维和医学等领域的应用作了广泛而深入的总结和评述,预示了聚乳酸类材料的演技开发前景。     

聚乳酸降解性能研究进展

聚乳酸是典型的"绿色塑料",因其良好的生物相容性、完全可降解性及生物可吸收性,是生物降解医用材料领域中最受重视的材料之一。本文介绍了聚乳酸的降解机理,着重对近年来有关聚乳酸降解性能的研究进行了综述。     

聚乳酸阻燃改性研究进展

聚乳酸是目前最具前景的生物基可降解材料之一,具有诸多优点而被广泛应用于生物医疗与家纺服饰等领域。然而,聚乳酸材料仍存在着易燃烧的不足,限制了其在阻燃要求较高领域的应用与发展,因此聚乳酸阻燃改性迫在眉睫。为更好地掌握聚乳酸阻燃改性现状与发展趋势,本文首先简要介绍了聚乳酸的燃烧过程与阻燃机理,为聚乳酸阻燃改性提供了理论指导。其次,全面综述了聚乳酸阻燃改性的最新进展,包括物理共混、化学共聚与表面修饰等方法,重点阐述了聚乳酸物理共混阻燃改性现状,同时分析总结了不同添加型阻燃剂的优缺点。最后,结合聚乳酸结构特点与阻燃材料发展态势,提出绿色环保、多功能性、高效稳定等阻燃聚乳酸材料将成为未来发展趋势。     

聚乳酸的改性及应用

详述了采用共聚、交联、共混、复合等方法对聚乳酸进行改性以改善其亲水性、生物相容性及其物理机械性能;介绍了聚乳酸在生物医学工程领域的应用,如药物缓释材料、骨固定材料、手术缝合线、眼科材料等,对其在生物医学领域的研究前景作了展望。     

以纺织品为目标的聚乳酸纤维研究进展

介绍了聚乳酸纤维的合成、性能,阐述了近年来面向纺织品领域的聚乳酸纤维共混改性和复合材料开发研究进展。通过改性和开发,增强了聚乳酸纤维在纺织品领域的性能和适用性,改善了材料的合成方法,推动了聚乳酸纤维进一步朝市场化发展。     

聚乳酸的合成及其在生物医药领域的应用进展

综述了近几年聚乳酸的合成,讨论了聚合过程中聚合时间、聚合温度、催化剂、体系真空度等对聚合反应的影响;介绍了聚乳酸在药物控制释放、组织工程材料、骨科材料、医用缝合线、眼科植入材料等生物医药领域的应用.     

聚乳酸材料在3D打印技术中的应用

分别对聚乳酸材料的特性、改良方法、加工工艺、应用领域进行论述。3D打印聚乳酸类塑料产品的应用范围较广,涉及医疗卫生、产品包装、工业制造等领域。随着材料科学研究的持续深入,聚乳酸材料的性能不断优化,必将加快3D打印技术的推广与应用。     

聚乳酸合成技术研究进展

聚乳酸因可生物降解、性能优异、应用广泛而深受青睐。本文介绍了2种主要化学合成聚乳酸的方法：丙交酯开环聚合法和乳酸直接缩聚法。分析了这2种方法的优势和缺陷：丙交酯开环聚合法设备简单,可得到大分子量的聚乳酸,缺点是成本较高,整个工艺复杂,路线长;乳酸直接缩聚法原料乳酸来源充足,价格便宜,单体转化率较高,工艺简单,不需要经过中间体的纯化,因而成本较低,缺陷是较难得到高分子量的聚合物。文中指出积极开展聚乳酸的合成工艺研发、进一步降低生产成本是当前聚乳酸研究的重要课题,重点在于简单易行的高分子量聚乳酸合成工艺的突破。     

静电纺丝技术在聚乳酸改性及应用中的作用

聚乳酸及其复合材料作为绿色生物材料,其良好的生物相容性和可降解性在组织工程支架、药物控释体系等领域得到了广泛的应用。静电纺丝技术制备的聚乳酸膜具有孔隙率高、比表面积大等特点。对聚乳酸的共聚物或与其他生物材料的共混物进行静电纺丝,可改善聚乳酸亲水性差、降解酸性和降解周期不易控制的缺点,进一步扩大聚乳酸在药物缓释体系中的应用。介绍了静电纺丝技术的原理和发展,描述了聚乳酸及其复合材料的静电纺丝及其在药物缓释体系中的应用。     

Overview of Poly(lactic acid) (PLA) fibre

Poly(lactic acid) (PLA) is an aliphatic polyester which can be derived from 100% renewable resources. PLA fibres can be dyed with disperse dyes, just like PET fires, although a modifid wet processing processes are employed. A variety of wet processing applications (pretreatment, dyeing, clearing, and subsequent finishing treatments) that imparts the greatest chemical and physical effect on the PLA fires necessitate major attention. Part II of this review reviews the wet processing (pretreatment, dyeing, clearing, subsequent finishing treatments, washing etc.) of PLA fibre and its effects on the fibre. This was accomplished through a broad literature survey including recent research and development in the area.     

Toughening of polylactide with epoxy-functionalized methyl methacrylate–butyl acrylate copolymer

Glycidyl methacrylate-functionalized methyl methacrylate–butyl acrylate (GACR) core–shell structure copolymers were synthesized to toughen polylactide (PLA). With an increase in GACR content, the PLA/GACR blends showed decreased tensile strength and modulus; however, the elongation at break and the impact strength were significantly increased compared with that of PLA. The brittle fracture of neat PLA was gradually transformed into ductile fracture by the addiction of GACR. From dynamic mechanical analysis, the rigidity of the PLA/GACR blends was decreased with the increase of GACR content. The addition of GACR decreased the degree of crystallinity of PLA. The GACR was found to aggregate to form clusters with size increasing with increasing GACR content by transmission electron microscope analysis. The clusters dispersed in PLA matrix uniformly. It was found that PLA demonstrated large area, plastic deformation (shear yielding) and cavities in the blend upon being subjected the tensile and impact tests, which was an important energy-dissipation process and led to a toughened and transparent blend.     

Investigation of structure and mechanical properties of toughened poly(l‐lactide)/thermoplastic poly(ester urethane) blends

In this study, poly(l ‐lactide) (PLA) is melt‐blended with thermoplastic polyurethane (TPU) to modify the brittleness of PLA. An aliphatic ester‐based TPU was selected in order to have an ester sensitivity for degradation and an inherent biocompatibility. Using this compatible TPU, there was no need to apply problematic compatibilizers, so the main positive properties of PLA such as biocompatibility and degradability were not challenged. The detected microstructure of PLA/TPU blends showed that when the TPU content was lower than 25 wt %, the structure appeared as sea‐islands, but when the TPU content was increased, the morphology was converted to a cocontinuous microstructure. A higher interfacial surface area in the blend with 25 wt % TPU (PLA25) resulted in a higher toughness and abrasion resistance. The various analyses confirmed interactions and successful coupling of two phases and confirmed that melt‐blending of PLA with the aliphatic ester‐based TPU is a convenient, cost‐effective, and efficient method to conquer the brittleness of PLA. The prepared blends are general‐purpose plastics, but PLA25 showed an optimum mechanical strength, toughness, and biocompatibility suitable for a wide range of applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43104.     

Strategies for interfacial localization of graphene/polyethylene-based cocontinuous blends for electrical percolation

We have investigated melt blending approaches to interfacial localization of few-layer graphene in cocontinuous polymer blends with polyethylene as one of the components. When linear low-density polyethylene (LLDPE)/polypropylene (PP) or high-density polyethylene (HDPE)/polylactic acid (PLA) and graphene were mixed all together, graphene preferred polyethylene over PP or PLA. When PP and graphene were premixed and blended with polyethylene, some graphene was trapped at the blend interface but not enough to cover the large interfacial area. In contrast, an ultralow electrical percolation was achieved (< 0.1 vol%) in HDPE/PLA blend due to smaller interfacial area. In another approach, polystyrene was added as a tertiary minor component to HDPE/PLA blends. This continuous interfacial layer containing graphene led to a low electrical percolation threshold (< 0.2 vol%). From these investigations, we suggest general ways to reduce a percolation threshold by kinetic control of the morphology of cocontinuous polymer blends.     

Overview of Poly(lactic acid) (PLA) Fibre

Poly(lactic acid) (PLA), the first melt-processable synthetic fibre produced from annually renewable resources, combines ecological advantages with excellent performance in textiles. PLA successfully bridges the gap between synthetic and natural fibres and finds a wide range of uses, from medical and pharmaceutical applications to environmentally benign film and fibres for packaging, houseware, and clothing. Ease of melt processing, unique property spectrum, renewable source origin, and ease of composting and recycling at the end of its useful life has led to PLA fibres finding growing interest and acceptance over a range of commercial textile sectors. Our review of poly(lactic acid) (PLA) fibre is divided into two parts. Part I of this review gives information about production, properties, performance, environmental impact, and enduse applications of PLA fibres. The aim of Part II is to review the wet processing (pretreatment, dyeing, clearing, subsequent finishing treatments, washing, etc.) of PLA fibre and its effects on the fibre. These were accomplished through a broad literature survey, including recent research and development in the area.     

紫外线吸收剂在PLA/PBAT生物降解薄膜中的应用

通过挤出共混造粒、吹塑成型工艺制备出了聚乳酸(PLA)/聚对苯二甲酸-己二酸丁二醇酯(PBAT)完全生物降解薄膜。研究了一种二苯甲酮类紫外线吸收剂对PLA/PBAT薄膜抗紫外老化的作用。采用万能拉力试验机、紫外-可见吸光光谱仪、差示扫描量热法(DSC)对PLA/PBAT薄膜在紫外老化过程中的性能进行了测试和表征。结果表明,选择的紫外线吸收剂能有效减缓PLA/PBAT薄膜在老化过程中力学性能的下降。紫外老化更易发生在薄膜的无定型区,该紫外线吸收剂能明显降低薄膜在老化过程中结晶度的变化。同时,添加该紫外线吸收剂能大幅度降低薄膜在紫外老化过程中产生的凝胶含量。     

改性碳酸钙对聚乳酸的增韧研究

通过偶联剂对碳酸钙(CaCO3)进行表面改性的方法,使CaCO3与聚乳酸(PLA)之间的作用力增强,提高复合材料的性能。研究了可使PLA/CaCO3复合材料的冲击强度、断裂伸长率显著提高的方法,实验结果表明:通过对CaCO3粒子的改性,使CaCO3比表面积加大,因而与基体接触面积增大,受到应力时会产生更多的银纹和塑性变形区,吸收大量的能量,从而达到增韧、增强的目的。