混杂植物纤维增强聚乳酸可生物降解复合材料的制备及性能研究

发布时间：2018-06-07 03:43

本文选题：聚乳酸 + 植物纤维　；参考：《华南理工大学》2015年硕士论文

【摘要】：随着石油资源的日益短缺和环境污染的日趋严重,不依赖于石油资源的可降解高分子材料以及可再生的植物资源得到了快速的发展。剑麻纤维(SF)具有许多传统纤维所无法比拟的优势,利用其填充增强聚乳酸(PLA),不仅能够降低聚乳酸的成本,提升其性能并拓宽应用范围,同时还能够解决上述问题并实现可持续发展。本文基于单一剑麻纤维自身性能的缺陷,采用两种性能不同的植物纤维-竹原纤维(BF)和椰壳纤维(CF),分别与剑麻纤维进行混杂,研究混杂植物纤维增强聚乳酸复合材料的性能。采用碱液对三种植物纤维进行表面处理,制备了剑麻/竹原纤维混杂增强聚乳酸复合材料(PLA/ASF/ABF)和剑麻/椰壳纤维混杂增强聚乳酸复合材料(PLA/ASF/ACF),研究了混杂比对两种混杂复合材料力学性能、微观形貌、结晶性能和热性能的影响,同时对混杂复合材料的混杂效应进行了分析。研究结果表明:经过碱处理后,三种植物纤维表面的半纤维素、木质素等小分子物质均被不同程度的去除,纤维长径比增加,并且在氮气环境下的热稳定性得到提高。在三种单一纤维增强聚乳酸复合材料中,剑麻纤维增强聚乳酸(PLA/ASF)具有相对较好的力学性能,但冲击性能提升幅度较小,而单一竹原纤维和椰壳纤维增强聚乳酸的冲击性能均有较大幅度的提升。此外,三种植物纤维均能提高复合材料的结晶能力和结晶度,并且与未改性相比,碱处理均能提高复合材料的热稳定性。将剑麻纤维与竹原纤维进行混杂增强聚乳酸后,混杂复合材料表现出的力学性能变化并不规律,只有在混杂比为5:5时,混杂复合材料的力学性能相对较好。与纯聚乳酸以及相同纤维含量的单一纤维增强复合材料相比,混杂复合材料在混杂比为5:5时拉伸性能变化不大,而其它性能尤其是冲击性能得到较大幅度提高,达到了混杂增强效果。此外,混杂比对混杂复合材料的热性能影响幅度较小。将剑麻纤维与椰壳纤维进行混杂后,混杂复合材料的力学性能呈现出较明显的变化趋势,在混杂比为7:3时,混杂复合材料体现出较好的力学性能,与纯PLA以及相同纤维含量的PLA/ASF相比,混杂复合材料其拉伸强度略有降低,但高于PLA/ACF,而弯曲和冲击强度均有较大幅度的提高,且均高于纯PLA以及相同纤维含量的PLA/ASF和PLA/ACF;除了拉伸模量外,其它力学性能均表现为正混杂效应。此外,当混杂比为7:3时,混杂复合材料的结晶能力和结晶度最高,与力学性能相一致;而混杂比对混杂复合材料的热稳定性的影响幅度较小。
[Abstract]:With the increasing shortage of petroleum resources and environmental pollution, biodegradable polymer materials and renewable plant resources, which are independent of petroleum resources, have been developed rapidly. Sisal fiber (SFL) has many advantages that can not be compared with traditional fibers. Using it to fill and strengthen polylactic acid (PLA) can not only reduce the cost of polylactic acid (PLA), but also improve its performance and widen its application range. At the same time can also solve the above problems and achieve sustainable development. Based on the defect of single sisal fiber, two kinds of plant fiber, BF and CFC were mixed with sisal fiber to study the properties of hybrid plant fiber reinforced polylactic acid composite. The surface of three kinds of plant fibers was treated with lye solution. Sisal / bamboo fiber hybrid reinforced poly (lactic acid) composites (PLA / ASF / ABF) and sisal / coconut fiber hybrid reinforced poly (lactic acid) composites (PLA / ASF / ACFF) were prepared. The mechanical properties and micromorphology of the two hybrid composites were studied. The effects of crystallization and thermal properties on the hybrid composites were analyzed. The results showed that after alkali treatment, the hemicellulose and lignin on the surface of the three kinds of plant fibers were removed to varying degrees, the aspect ratio of fibers increased, and the thermal stability of the fibers was improved in nitrogen environment. Among the three single fiber reinforced polylactic acid composites, sisal fiber reinforced PLA / ASF has relatively good mechanical properties, but the impact property is relatively small. However, the impact properties of single bamboo fiber and coconut shell fiber reinforced polylactic acid were greatly improved. In addition, three kinds of plant fibers can improve the crystallinity and crystallinity of the composites, and the alkali treatment can improve the thermal stability of the composites compared with the unmodified ones. When sisal fiber and bamboo fiber were mixed to reinforce polylactic acid, the mechanical properties of hybrid composites were irregular. Only when the hybrid ratio was 5:5, the mechanical properties of hybrid composites were relatively good. Compared with pure poly (lactic acid) and single fiber reinforced composites with the same fiber content, the tensile properties of hybrid composites have little change at 5:5, while the other properties, especially the impact properties, are greatly improved. The hybrid enhancement effect is achieved. In addition, the influence of hybrid ratio on thermal properties of hybrid composites is small. When sisal fiber and coconut shell fiber were mixed, the mechanical properties of hybrid composites showed a more obvious change trend. When the hybrid ratio was 7:3, the hybrid composites showed better mechanical properties. Compared with pure PLA and PLA/ASF with the same fiber content, the tensile strength of hybrid composites decreased slightly, but the tensile strength of hybrid composites was higher than that of PLA / ACF, while the flexural and impact strength of the hybrid composites were improved greatly. All of them were higher than those of pure PLA and PLA/ASF / PA / ACF with the same fiber content, except tensile modulus, the mechanical properties showed positive hybrid effect. In addition, when the hybrid ratio is 7:3, the crystallinity and crystallinity of the hybrid composites are the highest, which are consistent with the mechanical properties, while the influence of the hybrid ratio on the thermal stability of the hybrid composites is relatively small.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB332

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