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分别以甘氨酸(Gly)和L-天冬氨酸(Asp)与L-乳酸(L-LA)直接熔融共聚制备改性聚乳酸(PLA),所得两种共聚物聚(乳酸-甘氨酸)[P(LA-co-Gly)]和聚(乳酸-天冬氨酸)[P(LA-co-Asp)]进行了表征。对P(LA-co-Gly),不同投料比时共聚物重均分子量(Mw)和分散度(Mw/Mn)随Gly投料量的增加而变小。与双官能团Gly直接改性的PLA相比,多官能团Asp直接改性的PLA具有一定的支链结构,分散度(Mw/Mn)二者接近或P(LA-co-Asp)的更高,但两种共聚物的Tg均比PLA的要大,亲水性有所提高。同时,所得共聚物均呈无定形态,且Mw都在2400到5600之间,能满足药物缓释对聚乳酸类高分子材料分子量的要求。 相似文献
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完全降解聚乳酸共混复合材料的研究进展 总被引:1,自引:0,他引:1
聚乳酸(PLA)是可完全生物降解的材料,广泛应用于包装、纺织、生物医用等领域。但其具有性脆,价格较高,疏水性大等缺点,限制了应用发展。近年来对聚乳酸共混改性已成为研究热点。根据共混组分的生物降解性,聚乳酸共混体系分为完全生物降解体系和部分生物降解体系。文中综述了近年来完全生物降解聚乳酸共混体系的研究,主要阐述了PLA/淀粉、PLA/天然纤维复合材料,并简要介绍了PLA/甲壳素、PLA/蛋白等PLA/天然高分子复合材料,以及PLA/PCL、PLA/PPC、PLA/PEO等PLA/合成高分子复合材料。 相似文献
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聚乳酸(PLA)基塑料相比于聚羟基脂肪酸酯、聚氨基酸等生物基塑料具有更佳的抗拉强度、延展性、光泽度和透明度[1],而相比于传统石油基塑料又具有可完全降解且无毒无害的优点。作为传统石油基塑料的首选替代品,纯PLA塑料也面临着玻璃化转变温度较低、断裂伸长率较差等缺陷,难以完全替代传统石油基材料。因此,自诞生以来,PLA基塑料的改性工作一直是国内外学者的研究热点,其方法主要包括共聚、共混和添加改性剂等。本文主要阐述近些年来PLA共混改性方法的进展,着重分析其方法、特点及应用。最后,对PLA基塑料的发展前景进行了展望。 相似文献
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聚乳酸(PLA)是一种新型可生物降解的高分子材料,具有良好的生物降解性、机械性和成型加工性,成为应用较为广泛的生物降解高分子材料之一[1-2]。但是PLA热稳定性较差,脆性严重且价格昂贵,通常需要进一步改性才能应用到实际生活中[3]。乳酸的检测方法主要有离子色谱法[4-5]、气相色谱法[6]等,但是离子色谱法只适用于乳酸单体残留量的测定,而PLA水解液中阴离子种类较为复杂,离子色谱法很难将其分离和测定;此外乳酸在气相色谱仪气化室中易发生分解,在用气相色谱法测定时,一般需要先将乳酸转化为酯类衍生物[7-8],操作较为复杂。 相似文献
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研究了环氧呋喃树脂反应增容改性聚乳酸/淀粉复合材料,对索氏提取法得到的淀粉进行1H-NMR、FTIR、XPS和静态接触角测试表征.结果表明在熔融共混过程中环氧呋喃树脂(FER)与淀粉及聚乳酸(PLA)发生化学反应,从而起到反应性增容的作用.另外,利用SEM、万能材料试验机和DSC分别对复合材料的界面相容性、机械性能以及热性能进行了表征,结果表明FER能够显著改善PLA和淀粉之间的界面相容性,在保持PLA高强度高模量的基础上,显著提高了PLA/starch复合材料的综合机械性能和结晶性能. 相似文献
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A one-pot two-step method based on direct melt polymerization (DMP) for the synthesis of polylactic acid (PLA) macromonomer and its further functionalized application has been developed. The first stage of the reaction is a copolycondensation of lactic acid (LA) and maleic anhydride (MAH) to obtain the macromolecule poly(lactic acid-co-maleic anhydride) (PLAM) with reactive double bonds, and the second stage is a radical copolymerization of different acrylates with PLAM to afford the modified PLA functional materials. The influences of the acrylates have been investigated. The results show that the species with substituted methyl groups in acrylate can polymerize relatively stable. On the other hand, the more carbon atoms in the ester segment of acrylate, the higher intrinsic viscosity [η] and terminal decomposition temperature for the acrylate-modified PLAMs. Among six kinds of acrylates used as the third monomer, such as acrylic acid (AA), methyl acrylate (MA), butyl acrylate (BA), methacrylic acid (MAA), methyl methacrylate (MMA), and butyl methacrylate (BMA), the BMA-modified PLAM has the biggest [η] (0.7566 dL/g) and the terminal decomposition temperature (418 °C) for there are more carbon atoms in BMA. Due to excellent reactivity of the intermediate PLAM, the final modified product can have the anticipated properties for the PLA material by the controllable regulating as different purposes. Thus, this strategy as a green and simple method provides well application prospect for PLA materials in industrial plastics, biomedicine etc. 相似文献
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聚丙交酯及其共聚物的研究进展 总被引:3,自引:0,他引:3
聚丙交酯(PLA)是一种非常重要的生物医用材料,由于它在体内可降解、无毒、安全,在临床上得到了广泛的应用.为了适应更多、更广的医学应用,要求对聚丙交酯的降解速度、力学性能等进行调节控制,或者要求改善PLA的亲水性、生物相容性、细胞亲和性等等,为此合成了一系列PLA的共聚物,并对其性能进行了研究.本文对上述领域的研究进展进行了综述,结合了作者常年来在PLA共聚物的合成与性能方面的研究,分成四大类进行阐述:(1)丙交酯与其它内酯类的共聚;(2)丙交酯与聚乙二醇类大分子的共聚;(3)丙交酯与带有功能基团单体的共聚;(4)丙交酯与其它天然材料的共聚,并简要地叙述其在医学领域应用的前景. 相似文献
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Effect of poly (lactic acid)‐graft‐glycidyl methacrylate as a compatibilizer on properties of poly (lactic acid)/banana fiber biocomposites
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The main aim of this study was to synthesis of poly (lactic acid) (PLA)‐graft‐glycidyl methacrylate (GMA) as well as its influence on the properties of PLA/banana fiber biocomposites. PLA‐graft‐GMA graft copolymer (GC) was synthesized by melt blending PLA with GMA using benzoyl peroxide and dicumyl peroxide as initiators. Graft copolymerization was confirmed by FTIR and 1H‐NMR spectroscopic studies. PLA/silane treated banana fiber (SiB) biocomposites with various GC concentrations were prepared by melt blending followed by injection molding techniques. The influence of GC content on the mechanical, thermal and moisture resistance properties of the composite was investigated. The addition of 15 wt% GC content in the biocomposite provided optimum tensile and flexural strength, which is attributed to the greater compatibility between fiber and PLA matrix. The thermal properties of biocomposites have been evaluated using thermogravimetric analysis which provided evidence of improved interfacial adhesion between SiB and PLA by the addition of GC. Additionally, GC enhanced the moisture absorption resistance of biocomposites. These results indicated that GC is indeed a good candidate as a compatibilizing agent to improve the compatibility in PLA/fiber biocomposites. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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通过将双端羟基的聚己内酯(PCL)、聚乳酸(PLA)预聚物以及苯基次磷酸离子盐扩链得到一种含苯基次磷酸盐的离子共聚物,将其与聚磷酸铵(APP)复合用于协同改性聚乳酸,离聚物中苯基次磷酸盐结构与APP具有优异的协同阻燃PLA的作用,同时该离聚物中PLA与苯基次磷酸盐结构有效提升了APP在PLA中的分散能力,最后该离聚物中PCL柔性链段有效改善了PLA的韧性,最终得到更高效阻燃性能且韧性也较好改善的PLA/PCLA-PIU/APP复合材料.一方面,离聚物中苯基次磷酸盐结构与APP协同有效促进了PLA的成炭,形成更连续致密的炭层从而阻隔可燃气体的释放,达到更好的阻燃效果.锥形量热、残炭的扫描电子显微镜(SEM)、能谱分析(EDS)、拉曼光谱等测试证实了这一结果,与纯PLA以及仅使用APP的PLA/APP相比,PLA/PCLA-PIU/APP的热释放速率与总热释放均降低,同时残炭的石墨化程度更高,形成了更为致密的炭层.另一方面,力学性能测试结果表明,离聚物中PCL柔性链段的存在使得与APP复合改性后的PLA的韧性相比纯PLA和PLA/APP有较大的提升;SEM测试表明,离聚物中PLA与苯基次磷酸盐结构起到增容作用,提升了APP在PLA中的分散性. 相似文献
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Baogou Wu Pengwu Xu Weijun Yang Martin Hoch Weifu Dong Mingqing Chen Huiyu Bai Piming Ma 《Journal of polymer science. Part A, Polymer chemistry》2020,58(3):500-509
The interfacial grafting copolymerization and the compatibility between poly(lactic acid) (PLA) and ethylene-vinyl acetate-glycidyl methacrylate elastomer (EVM-GMA) are adjusted by varying the blending temperatures. High temperature is favored to the grafting reaction between epoxy groups of the EVM-GMA and terminal groups of the PLA, resulting in better compatibility between the two components. Taking PLA/EVM-GMA (80/20) blend as an example, an increase in blending temperature from 175 to 230 °C led to a 42.8% reduction in EVM-GMA particle size, and consequently 137.8% and 52.6% increases in elongation at break (Eb) and notched impact strength (NIS), respectively. In comparison, the Eb and NIS of PLA/EVM blends without any interfacial reaction deteriorated dramatically due to thermal degradation of the PLA at high(er) temperatures. Furthermore, the PLA/EVM-GMA blend prepared at 230 °C possesses both excellent toughness (Eb > 60%, NIS > 60 kJ m−2) and high heat deflection temperature (>90 °C) after annealing at 100 °C. This work provides a new approach in designing high-performance biobased materials which may broaden the application range of PLA in engineering areas. © 2020 Wiley Periodicals, Inc. J. Polym. Sci. 2020 , 58, 500–509 相似文献