聚乳酸纳米复合材料的阻隔性能研究进展

聚乳酸作为一种可降解的高分子材料,广泛应用于生物医疗、合成纤维、食品包装等领域,但是其较差的阻隔性能,尤其是对水蒸气阻隔性能,限制了其在包装及医学等领域的应用。通过与纳米材料共混改性可明显地提高聚乳酸的阻隔性能。本文分析了聚合物纳米复合材料的阻隔机理,论述了近年来聚乳酸/蒙脱土复合材料阻隔性能方面的研究,并对今后的研究方向进行了展望。     

聚乳酸基生物医用复合材料研究进展

主要介绍了纳米羟基磷灰石、镁合金以及壳聚糖和聚乳酸复合的生物医用材料的性能以及研究现状,分析了复合材料性能提高的原因,说明了复合材料存在的优势,并对聚乳酸医用复合材料的发展及应用进行了展望。     

可生物降解聚合物基纳米复合材料降解性能研究进展

可生物降解聚合物中的层状硅酸盐纳米复合材料,可极大提高其力学性能,但同时会影响到材料的降解速率。研究纳米填料对可生物降解聚合物降解速率的影响及降解机理的变化,可拓宽其应用领域。综述聚乳酸(PLA)、淀粉、聚己内酯(PCL)、纤维素、聚羟基烷脂肪酸酯(PHA)、聚琥珀酸丁二醇酯(PBS)等可生物降解聚合物基层状硅酸盐纳米复合材料制备及降解性能研究现状及进展。     

聚乳酸/有机蒙脱土纳米复合材料的制备及降解性能研究

以聚乳酸和有机蒙脱土为原料,通过溶液插层法制备了聚乳酸/有机蒙脱土复合材料,分别用傅立叶变换红外光谱、X.射线衍射、热重分析等对聚乳酸/有机蒙脱土纳米复合材料的结构及热稳定性进行了表征,研究了材料的降解性能.结果表明,在聚乳酸/有机蒙脱土纳米复合材料中蒙脱土层间距为2.21 nm.层间距明显增大,表明聚乳酸分子插入到蒙脱土片层间,形成了插层型纳米复合材料.复合材料的热分解温度提高,热稳定性比纯PLA有明显的提高.在NaOH介质中降解结果表明,材料在碱性介质中降解性能和吸水性能良好.     

聚乳酸生物可降解材料填料复合改性研究进展

综述了聚乳酸类生物可降解材料中加入填料的复合改性研究进展,详细阐述了纤维、有机粒子、无机粒子、纳米粒子等填料分别对聚乳酸类生物可降解材料复合改性后材料性能的影响,并针对不同填料对材料性能的影响程度进行了对比分析,以及对未来生物可降解填料对聚乳酸类材料复合改性的发展与应用趋势进行了展望,为新型绿色生物可降解复合材料的发展奠定了基础。     

可降解聚乳酸复合材料研究进展

对聚乳酸（PLA）复合材料的生物降解性能进行综述,总结PLA与有机物（如木质素、纤维素等）、无机物（如碳酸钙、纳米银颗粒等）复合后力学性能、热性能、生物相容性、抗菌性的变化及在不同环境条件下生物降解速率的变化,梳理了PLA复合材料结构、组成与降解性能的相互关系,对降解性能可控的PLA复合材料应用前景进行了展望。     

碳纤维增强聚乳酸复合材料的研究进展

介绍了以碳纤维为增强纤维、聚乳酸为基体,采取相应的加工工艺制备出碳纤维增强聚乳酸复合材料的种类与制备工艺,研究了该复合材料的相关性能,发现该材料与聚乳酸材料相比力学性能、抗冲击性能得到了明显改善,有一定的降解性,并且生物相容性良好,适合于开发骨折内固定材料、骨修复材料等.概述了碳纤维增强聚乳酸复合材料在工业化生产及应用中存在的主要问题,并对今后的应用研究进行了展望.     

天然纤维增强聚乳酸基可降解复合材料的研究进展

聚乳酸(PLA)以其优异的生物降解性在可降解材料领域备受关注,然而其脆性、热稳定性以及相对较高的价格限制了其应用领域。采用天然纤维增强PLA复合材料是改善PLA力学及热稳定性能的有效途径之一。本文综述了国内外对天然纤维增强聚乳酸基可降解复合材料的研究现状及新进展,讨论了动物纤维、植物纤维改性聚乳酸复合材料的性能、技术方法及潜在应用领域。此外,论文综述了PLA/植物纤维复合材料降解的研究进展,展望了PLA/天然纤维复合材料在降低PLA复合材料成本、提高力学性能并保持生物降解性能等方面的发展前景。     

生物医用材料聚乳酸的合成及其改性研究进展

聚乳酸是一种具有良好生物相容性的可降解生物材料,被广泛应用于医药、医疗和食品包装等领域。随着科学技术的进步,对聚乳酸材料的性能提出了新的要求和用途,研究者在合成方法和改性研究方面也取得了新的成果。本文阐述了聚乳酸的化学结构和基本特性,常用合成方法,包括阳离子聚合、阴离子聚合和配位聚合的基本概念和应用实例,介绍了近年来发展的酶催化聚合、超临界二氧化碳中聚合等绿色合成方法,着重介绍了聚乳酸亲水改性、pH响应改性和分支结构改性等几种用于医用方面的改性方法,最后对聚乳酸材料研究发展方向进行了展望,提出在聚乳酸基体中添加极低含量的无机纳米粒子填充物,可显著改善复合材料的性能,指出生物纳米复合包装材料的技术开发是未来几年着重研究的方向。     

纳米纤维素/聚乳酸/聚乙二醇三元复合材料的研究

将纳米纤维素(NCC)与聚乙二醇(PEG)、聚乳酸(PLA)共混制备出可生物降解的纳米纤维素/聚乳酸复合材料。考察了复合材料的力学性能、降解性和热稳定性能,结果表明:加入2%的纳米纤维素对复合材料有明显的增塑和增强效果;对复合材料进行TGA检测表明,复合材料的热稳定性较纯聚乳酸有所下降;由SEM检测看出,复合材料的柔韧性得到提高,从降解性能分析中看出,复合材料的降解速率随着纳米纤维素质量分数的增加而增加。     

可完全生物降解的聚乳酸共混体系研究进展

综述了国内外以聚乳酸（PLA）为基础的完全生物降解共混体系的研究进展,主要包括不同光学活性的PLA共混、PLA与脂肪族聚脂共混、PLA与天然高分子共混、PLA与聚己内酯共混、PLA与聚乙二醇共混、PLA与聚乙烯醇共混以及PLA与聚乙烯基吡咯烷酮共混等。目前的研究表明,将PLA与另一种完全生物降解组分共混,通过不同组分分子间的相互作用,使PLA材料在保持环境友好性的同时提高了力学性能、增加了韧性、并降低了生产成本等,从而扩展了PLA在工程塑料领域和包装等领域的应用。     

Polyesters with small structural variations improve the mechanical properties of polylactide

Improving the properties of biodegradable polymeric materials is needed to obtain materials competitive with current bulk plastics. Low‐molecular weight polyesters with small differences in their backbone were synthesized using a straight‐forward method and were subsequently blended with polylactide (PLA). The materials showed an improved ductility of up to 100% points and otherwise retained material properties. The changes in mechanical properties were shown to match the miscibility range of the materials and can be predicted by the solubility parameters of the materials up to a polyester content of roughly 10% w/w. The thermal stability of all the low‐molecular weight polyesters was higher than that of PLA, and most 25% w/w blends showed a thermal degradation behavior similar to that of neat PLA. Low‐molecular weight polyesters were demonstrated as being potential enhancers of the properties of PLA, while the materials degradability was maintained. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Facile Preparation of Cellulose/Polylactide Composite Materials with Tunable Mechanical Properties

A solvent-free route was developed to fabricate 100% biobased, renewable, and degradable polylactide (PLA) composites reinforced with ball-milled celluloses. The results show that the original pulp cellulose fibers were modified to partial amorphization through 30-min ball milling. Filling the ball milled celluloses into PLA increased the tensile modulus for the resultant cellulose/PLA composite materials, while decreased their tensile strength and impact resistance. This method can be used to access the cost-efficient PLA-based composite materials with tunable mechanical properties. The variation analysis shows that filling content contributed more to the variations of their mechanical properties than that particle size did.     

Thermal properties and characterization of surface-treated RSF-reinforced polylactide composites

The thermal, mechanical, and biodegradation properties of composite materials made from polylactide (PLA) and rice straw fibre (RSF) were evaluated. To improve the properties of PLA/RSF composites, glycidyl methacrylate (GMA)-grafted polylactide (PLA-g-GMA) and treated (crosslinked) rice straw fibre (TRSF) were used to prepare the composites. The result showed that PLA-g-GMA/TRSF had noticeably superior mechanical properties compared with PLA/RSF because of greater compatibility between the polymer and TRSF. The dispersion of TRSF in the PLA-g-GMA matrix was more homogeneous, because branched and crosslinked macromolecules formed via condensation of the glycidyl methacrylate groups of PLA-g-GMA and the hydroxyl groups in TRSF. In addition, the PLA-g-GMA/TRSF composites were more easily processed because of their lower melt viscosities. The water resistance of PLA-g-GMA/TRSF was higher than that of PLA/RSF, although the weight loss of composites buried in soil compost indicated that both were biodegradable, especially at high levels of RSF substitution. The PLA/RSF and PLA-g-GMA/TRSF composites were more biodegradable than was pure PLA.     

New polylactide-layered silicate nanocomposites. 2. Concurrent improvements of material properties, biodegradability and melt rheology

Our continuing research on the preparation, characterization, materials properties, and biodegradability of polylactide (PLA)-layered silicate nanocomposites has yielded results for PLA-montmorillonite nanocomposites. Montmorillonite modified with trimethyl octadecylammonium cation was used as an organically modified layered silicate for the nanocomposites preparation. The internal structure of the nanocomposites in the nanometer range has been established by using wide-angle X-ray diffraction and transmission electron microscope analyses. All the nanocomposites exhibited superior improvement of practical materials properties such as storage modulus, flexural modulus, flexural strength, heat distortion temperature, and gas barrier property as compared to that of neat PLA. The biodegradability of neat PLA and a representative nanocomposite was also studied under compost, and the rate of biodegradation of neat PLA significantly increased after nanocomposites preparation. The melt rheology of neat PLA and various PLACNs was also studied.     

An overview of the recent advances in polylactide-based sustainable nanocomposites

The article reports recent advances in reference to the existing literature and presents a knowledge gap and potential solution ideas for polylactide (PLA) nanocomposites as sustainable materials. Various types of nanoparticles have been used for the development of PLA nanocomposites; however, this work focuses on PLA nanocomposites of nanoclay, nanocelluloses, carbon nanotube, and graphene. By providing a wholistic overview of the fundamental knowledge pertaining to PLA, and covering all critical aspects related to processing, characterization, and applications of PLA nanocomposites, this review provides a direction for future developments in the field of PLA nanocomposites suitable for various advanced applications, which is still scarce in the literature, including review articles. Moreover, the effects of dispersion/distribution of various types of nanoparticles on the degradation characteristics and special properties, such as cytocompatibility, electrical conductivity, and antimicrobial properties, of PLA nanocomposites are critically reviewed with regard to the nature of nanoparticles used for nanocomposite formation. In summary, this review provides new insight into the design and formulation of advanced PLA nanocomposites for a wide range of applications as sustainable materials.     

The Effect of Antibacterial Particle Incorporation on the Mechanical Properties,Biodegradability, and Biocompatibility of PLA and PHBV Composites

The composites based on polylactide (PLA) and poly (3‐hydroxybutyrate‐co‐3‐hydroxyvalerate) (PHBV) with the addition of antibacterial particles: silver (Ag) and copper oxide (CuO) are characterized. Basic mechanical properties and biodegradation processes, as well as biocompatibility of materials with human cells are determined. The addition of Ag or CuO to the polymers do not significantly affect their mechanical properties, flammability, or biodegradation rate. However, several differences between the base materials are observed. PLA‐based composites have higher tensile and impact strength values, while PHBV‐based ones have a higher modulus of elasticity, as well as better mechanical properties at elevated temperatures. Concerning biocompatibility, each of the tested materials support the growth of fibroblasts over time, although large differences are observed in the initial cell attachment. The analysis of hydrolytic degradation effects on the structure of materials shows that PHBV degrades much faster than PLA. The results of this study confirm the good potential of the investigated biodegradable polymer composites with antibacterial particles for future biomedical applications.     

Preparation,characterization, and biodegradability of renewable resource‐based composites from recycled polylactide bioplastic and sisal fibers

The biodegradability, morphology, and mechanical thermal properties of composite materials composed of polylactide (PLA) and sisal fibers (SFs) were evaluated. Composites containing acrylic acid‐grafted PLA (PLA‐g‐AA/SF) exhibited noticeably superior mechanical properties because of greater compatibility between the two components. The dispersion of SF in the PLA‐g‐AA matrix was highly homogeneous as a result of ester formation and the consequent creation of branched and crosslinked macromolecules between the carboxyl groups of PLA‐g‐AA and hydroxyl groups in SF. Furthermore, with a lower melt temperature, the PLA‐g‐AA/SF composite is more readily processed than PLA/SF. Both composites were buried in soil to assess biodegradability. Both the PLA and the PLA‐g‐AA/SF composite films were eventually completely degraded, and severe disruption of film structure was observed after 6–10 weeks of incubation. Although the degree of weight loss after burial indicated that both materials were biodegradable even with high levels of SF, the higher water resistance of PLA‐g‐AA/SF films indicates that they were more biodegradable than those made of PLA. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

New polylactide/layered silicate nanocomposites. 5. Designing of materials with desired properties

Understanding the structure/property relationship in polymer/layered silicate nanocomposites is of great importance in designing materials with desired properties. In order to understand these relations, a series of polylactide (PLA)/organically modified layered silicate (OMLS) nanocomposites have been prepared using a simple melt extrusion technique. Four different types of OMLS have been used for the preparation of nanocomposites, three were modified with functionalized ammonium salts while fourth one was a phosphonium salt modified OMLS. The structure of the nanocomposites in the nanometer scale was characterized by using wide-angle X-ray diffraction and transmission electron microscopic observations. Using four different types of layered silicates modified with four different types of surfactants, the effect of OMLS in nanocomposites was investigated by focusing on four major aspects: structural analysis, thermal properties and spherulite morphology, materials properties, and biodegradability. Finally, we draw conclusions about the structure/property relationship in the case of PLA/OMLS nanocomposites.     

聚乙交酯、聚丙交酯及聚乙交酯丙交酯纤维的研究进展

聚乙交酯（PGA）、聚丙交酯（PLA）和聚乙交酯丙交酯（PGLA）纤维作为生物可降解材料,广泛应用于医疗等领域,其中PLA纤维还作为绿色环保纤维广泛应用于服装、家纺等传统纺织品领域。纤维的制备、降解及应用是这类纤维在近年来研究的重点。介绍了国内外此类纤维在制备、降解以及应用方面的研究进展。