天然聚合物基纳米复合膜的制备及其性能研究

发布时间：2018-05-26 21:20

本文选题：纳米二氧化钛 + 醋酸酯淀粉　；参考：《兰州交通大学》2017年硕士论文

【摘要】：石油基塑料因受到石化原料的限制及其对生态环境的破坏等诸多不良因素的影响,研究开发降解塑料以取代石油基塑料具有重要的战略意义。来源广泛的天然绿色资源淀粉有良好的环保和生物降解性能,以淀粉为基体的塑料成为降解塑料的理想选择。淀粉基塑料的推广和应用受到其机械及加工性能的制约。目前将无机纳米粒子复合于天然聚合物基体中的研究受到广泛关注,本实验将纳米TiO_2复合于醋酸酯淀粉(PMS)/聚乙烯醇(PVA)共混系统中,实现无机物在有机物中的掺杂,采用流延工艺制备了一系列纳米复合薄膜材料,研究了薄膜的性能及结构;并通过正交试验优化了复合薄膜制备的工艺条件,在完善工艺和控制成本方面提供了一定的参考。超声分散的纳米TiO_2与PMS/PVA的共混体系中,加入增塑剂山梨醇(SOR)、聚乙二醇400(PEG400)以及增强剂羧甲基纤维素(CMC)、海藻酸钠(SA)、尿素(UR)可有效地改善复合薄膜的力学性能和耐水性能。纳米TiO_2的含量对不同增塑剂体系中复合膜的力学性能和吸水性能有不同的影响。在SOR增塑剂体系中,当纳米TiO_2含量为0.003g(占总量0.03%)时,薄膜的力学性能以及耐水性较好,拉伸强度(TS)可提高71.1%,吸水率降低了4.14%,断裂伸长率(E)达到53.87%。在纳米TiO_2用量为0.003g(占总量0.03%)的共混系统中,SOR与UR的质量比为1:3时复合薄膜的TS可提高51.5%,E达到73.8%,吸水率降至72.12%。在增强剂CMC和SA质量比为1:1共混体系中,分别用SOR和PEG400作为增塑剂,复合薄膜的拉伸强度分别提高34.78%和31.27%,吸水率分别降低到71.74%和88.10%,透光率提高到60.21%,54.85%。正交试验显示在0.003g纳米TiO_2与3.5g PMS,山梨醇1.2g、尿素0.7g、CMC:SA=1:1工艺条件下,复合膜的拉伸强度达到32.10MPa,此时膜的力学性能较佳。红外光谱分析(FTIR)表明纳米TiO_2可与系统中组分之间形成氢键作用,尿素与聚合物分子链上的羟基有较强的作用;电子显微镜(SEM)显示适量的纳米TiO_2与共混系统具有很好的相容性,但过量后会使复合膜结构不均匀,性能变差。CMC和SA增强剂的加入与体系形成了稳固的结构,能与纳米TiO_2促进体系的相容和共混并形成了更牢固的空间网状结构,同时还可以使纳米TiO_2团聚现象得以改善,相容性变好。
[Abstract]:Due to the limitation of petrochemical raw materials and the damage to the ecological environment, it is of great strategic significance to study and develop degradable plastics instead of petroleum-based plastics. The natural green resource starch has good environmental protection and biodegradability, and the plastic based on starch is the ideal choice for degradable plastics. The popularization and application of starch-based plastics are restricted by their mechanical and processing properties. At present, the study of inorganic nanoparticles composite in natural polymer matrix has received extensive attention. In this experiment, nano-sized TiO_2 was mixed in the system of starch acetate / polyvinyl alcohol (PVA) to achieve the doping of inorganic compounds in organic compounds. A series of nanocrystalline composite thin film materials were prepared by casting process, the properties and structure of the films were studied, and the process conditions were optimized by orthogonal experiment, which provided some reference for improving the technology and controlling the cost. The mechanical properties and water resistance of the composite films can be improved effectively by adding sorbitol sorghum, polyethylene glycol 400 PEG400), carboxymethyl cellulose (CMC), sodium alginate (SA), urea urr (TiO_2) in the ultrasonic dispersive blend system of nanometer TiO_2 and PMS/PVA, and adding the plasticizer sorbitol, polyethylene glycol (PEG400) and the reinforcing agents (CMCC, sodium alginate, urea-urr) into the blend system. The content of nano TiO_2 has different effects on the mechanical properties and water absorbency of the composite films in different plasticizer systems. In the SOR plasticizer system, when the content of nanometer TiO_2 is 0.003 g (0.03g / total), the mechanical properties and water resistance of the films are better. The tensile strength of the films can be increased by 71.1%, the water absorption decreases by 4.14%, and the elongation at break reaches 53.87%. When the mass ratio of TiO_2 to UR is 1:3, the TS of the composite film can increase 51.5% and reach 73.8%, and the water absorption rate decreases to 72.12 in the blend system with 0.003 g (0.03%) of nanometer TiO_2. When SOR and PEG400 were used as plasticizers, the tensile strength of the composite films was increased by 34.78% and 31.27%, respectively, the water absorption was reduced to 71.74% and 88.10%, and the transmittance was increased to 60.21% and 54.85%, respectively. Orthogonal test showed that the tensile strength of the composite membrane was 32.10 MPA under the conditions of 0.003 g TiO_2 and 3.5 g TiO_2, 1.2 g sorbitol and 0.7 g urea CMC: SA1: 1. The mechanical properties of the composite membrane were better. FTIR analysis showed that nano TiO_2 could form hydrogen bond with components in the system, urea had strong effect on hydroxyl group in polymer chain, and electron microscope showed that proper amount of nano TiO_2 had good compatibility with blend system. However, the structure of the composite membrane will be uneven after excessive, and the properties of the composite membrane will become more uniform, and the addition of the performance of .CMC and SA reinforcements will form a solid structure, which can promote the compatibility and blending of the system with nanometer TiO_2 and form a more solid spatial network structure. At the same time, it can improve the aggregation of nano TiO_2 and improve the compatibility.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.2

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