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增塑剂对聚乳酸性能影响的研究 总被引:7,自引:0,他引:7
采用熔融共混法,以丙三醇、乙酰柠檬酸三正丁酯(ATBC)以及邻苯二甲酸二辛酯(DOP)作为增塑剂,对聚乳酸(PLA)进行增塑改性,讨论了不同的增塑剂及含量对改性PLA性能的影响.结果表明,3种增塑剂均能提高PLA的韧性,其中利用ATBC增塑改性时效果最好,且当其含量为15~20 份时,改性PLA的力学性能较佳;随着ATBC的含量增加,PLA的熔体流动性进一步增强,熔点(Tm)、玻璃化转变温度(Tg)以及结晶温度均有所下降,PLA的结晶能力增强,维卡热变形温度呈先下降后上升的趋势,改性PLA的吸水率有所降低,降解率有所上升. 相似文献
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生物降解材料聚乳酸的合成 总被引:18,自引:0,他引:18
系统地介绍了包括丙交酯二步法、乳酸溶液聚合法和乳酸熔融聚合法在内的各种聚乳酸合成方法;并从安全和经济的观点出发,对聚乳酸的合成研究方向进行了展望,指出使用安全无毒的催化剂进行乳酸直接熔融聚合生产聚乳酸尤其值得大力开发。 相似文献
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系统论述了生物降解聚乳酸(PLA)合金复合材料的最新研究进展,着重介绍了聚乳酸合金中有巨大商用潜力的完全生物基降解高分子合金体系:PLA/淀粉合金、PLA/纤维素合金、PLA/聚ε-己内酯合金、PLA/聚酰胺合金、PLA/聚羟基脂肪酸酯合金、PLA/壳聚糖合金及PLA/稀土多元复合材料等。并提出利用稀土离子独特的4f电子亚层能级的空轨道与聚乳酸生物基复合材料中的羰基、羟基等含氧官能团配位来改善聚乳酸合金复合材料的综合性能,这为设计开发新型稀土-聚乳酸复合材料提供了新的思路,为聚乳酸产业化进程提供新的契机。 相似文献
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综述了聚乳酸共聚增韧改性的研究进展,详细介绍了直接缩聚法、开环聚合法、扩链剂法等聚乳酸的共聚改性方法,其中直接缩聚法得到的聚合物的相对分子质量较低,开环聚合法得到的聚合物的相对分子质量较高,扩链剂可以与其他2种方法配合使用。最后,综述了聚乳酸共聚物在医学领域及包装领域的应用研究进展。 相似文献
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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。 相似文献
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聚乳酸(PLA)的合成及应用进展 总被引:4,自引:0,他引:4
聚乳酸是近年来广泛应用,生物相容性和生物可降解性能良好的生物材料。综述了聚乳酸的合成,聚合机理以及应用等方面研究的最新进展,对未来的工作进行了展望。 相似文献
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催化剂对L-乳酸和乙醇酸共聚物结构性能的影响 总被引:1,自引:0,他引:1
以L-乳酸(LA)和乙醇酸(GA)(LA:GA摩尔比为20:80)为原料,在170℃、压力小于70 Pa下反应10 h,直接熔融聚合合成乳酸-乙醇酸共聚物(PLGA),研究了催化剂种类、催化剂用量以及复配催化剂比例对PLGA特性粘数的影响。结果表明,使用复合催化剂氯化亚锡(SnC l2)与对甲基苯磺酸(TSA),摩尔比为1:1,其中SnC l2相对LA与GA的总质量的质量分数为0.4%时,所得PLGA产物的特性粘数较高,为0.352 dL/g。红外光谱和核磁共振氢谱表明,PLGA为LA与GA共聚物,共聚产物中GA比例大于投料值,由差示扫描量热分析和X射线衍射分析表明,PLGA为非结晶高聚物。 相似文献
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The thermal and mechanical properties of the biodegradable blends of poly(L ‐lactic acid) (PLLA) and lignin prepared by manual mixing have been investigated. Both the results of DSC and FTIR spectral analyses indicated the existence of intermolecular interaction between PLLA and lignin. Furthermore, FTIR elucidated the existence of an intermolecular hydrogen‐bonding interaction. Study of the mechanical properties of the blends indicated that the maximum strength and the elongation of the material decreased and the Young's modulus remained almost constant when the lignin content reached 20%. Thermogravimetry indicated that lignin would accelerate the thermal degradation of PLLA when the content of lignin was more than 20%. Compared with some other biodegradable polymers, the blend of PLLA and lignin is thought to be a promising material, because the material properties, as well as the price, are at an acceptable level when the content of lignin is less than about 20%. Copyright © 2003 Society of Chemical Industry 相似文献
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Wei Zhong Jinjie Ge Zhenyu Gu Wenjun Li Xin Chen Yi Zang Yuliang Yang 《应用聚合物科学杂志》1999,74(10):2546-2551
Methylenediphenyl diisocyanate (MDI) was used as the chain extender for low molecular weight poly(lactic acid) (PLA) to produce high molecular weight biodegradable polymer material with a better heat resistance. PLA prepolymer with a number‐average molecular weight (Mn) of 5800 and a weight‐average molecular weight (Mw) of 9800 was produced by direct polycondensation using stannous octoate as the catalyst. After 40 min of chain extension at 175°C, the resulting polymer had a Mn of 15,000 and a Mw of 57,000. The glass transition temperature (Tg) of the low molecular weight PLA prepolymer was 48.6°C. After chain extension, the Tg of the resulting polymer was raised to 67.9°C, as determined by DSC. DMA results also indicate that the heat resistance was improved by the chain extension. The DSC spectrum and X‐ray diffraction pattern of annealed samples showed that both the crystallinity and rate of crystallization of PLA were lowered by chain‐extension reaction due to the formation of branched molecular structure. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2546–2551, 1999 相似文献
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Mihir Sheth R. Ananda Kumar Vipul Dav Richard A. Gross Stephen P. McCarthy 《应用聚合物科学杂志》1997,66(8):1495-1505
Poly(lactic acid) (PLA) and poly(ethylene glycol) (PEG) were melt-blended and extruded into films in the PLA/PEG ratios of 100/0, 90/10, 70/30, 50/50, and 30/70. It was concluded from the differential scanning calorimetry and dynamic mechanical analysis results that PLA/PEG blends range from miscible to partially miscible, depending on the concentration. Below 50% PEG content the PEG plasticized the PLA, yielding higher elongations and lower modulus values. Above 50% PEG content the blend morphology was driven by the increasing crystallinity of PEG, resulting in an increase in modulus and a corresponding decrease in elongation at break. The tensile strength was found to decrease in a linear fashion with increasing PEG content. Results obtained from enzymatic degradation show that the weight loss for all of the blends was significantly greater than that for the pure PLA. When the PEG content was 30% or lower, weight loss was found to be primarily due to enzymatic degradation of the PLA. Above 30% PEG content, the weight loss was found to be mainly due to the dissolution of PEG. During hydrolytic degradation, for PLA/PEG blends up to 30% PEG, weight loss occurs as a combination of degradation of PLA and dissolution of PEG. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 1495–1505, 1997 相似文献
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Biodegradable poly(lactic acid) (PLA) composites were prepared using an innovative combination of wood fiber (WF) and 1,3,2,4‐bis(3,4‐dimethylobenzylideno)sorbitol (DMDBS). DMDBS acted as an effective nucleating agent, which improved the mechanical properties and slowed down the degradation of the WF/PLA composites. The enzymatic degradation of the composites was examined by immersing in proteinase K or cellulase buffer. The presence of DMDBS resulted in a 26.7% increase of the crystallinity compared to the WF/PLA composites. The increase in crystallinity enhanced the thermal stability and tensile strength of the WF/DMDBS/PLA composites by 8.5%. The durability of the WF/DMDBS/PLA composites after nucleated modification was enhanced after enzymolysis. After nucleated modification, the surface of the WF/PLA composites showed clear cracks due to degradation, while these appeared about 2 weeks later in the case of the WF/DMDBS/PLA composites. The results revealed that the introduction of cellulase degraded WF in the composites, which increased hydrolysis or enzymolysis sites. The combination of nucleated modification and enzyme buffer gave an expanded downstream application of WF/PLA composites in packaging and agricultural materials. © 2019 Society of Chemical Industry 相似文献
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以左旋乳酸(L?LA)和乙醇酸(GA)为原料,利用一步法熔融共聚合成聚(乳酸?乙醇酸)(PLLGA)共聚物,通过差示扫描量热仪(DSC)对共聚物薄膜的结晶性能进行了表征,并利用Avrami方程对其进行了等温结晶动力学研究,通过万能拉伸试验机和压差法气体透过仪对共聚物薄膜的力学性能和气体阻隔性能进行测试。结果表明,PLLGA共聚物薄膜中GA的引入对材料结晶性能有较大影响,在GA含量为4 %(摩尔分数,下同)的PLLGA中,GA表现为成核剂作用,共聚物结晶比纯聚左旋乳酸(PLLA)薄膜快,半结晶时间减少;而在GA含量为8 %的PLLGA中,GA则表现出限制分子链运动的作用,破坏共聚物分子间的规整度,导致材料结晶性能大幅度降低,处于非晶态;随着GA含量的增加,PLLGA薄膜的拉伸强度和弹性模量逐步下降,而断裂伸长率大幅度增加,GA含量为8 %的PLLGA的断裂伸长率达到了130.1 %,是纯PLLA薄膜的21.3倍;同时,PLLGA薄膜的气体阻隔性显著增加,5 ℃时,相比于纯PLLA薄膜,GA含量为8 %的PLLGA薄膜的O2、CO2、N2透过量分别降低了47 %、41 %和39 %。 相似文献