稻草的PEG接枝共聚可塑性化研究

发布时间：2018-03-13 14:39

  本文选题：稻草　切入点：PEG　出处：《江南大学》2015年硕士论文　论文类型：学位论文

【摘要】：稻草—废弃的资源,是我国最重要的一种可再生生物质资源之一。它可以直接燃烧用作燃料,但是这样不但造成浪费,而且还会严重造成大气污染,现在已经可以通过生物质能转换技术来生产各种清洁燃料。同时它还可以作为可再生天然高分子的载体,也是比较理想的材料来源,由其制成的改性复合材料可以成为传统有机材料的替代品。本课题设想以聚乙二醇(PEG)为改性试剂将纤维素改性方法应用于稻草改性中,利用高活性的4,4-二苯甲烷二异氰酸酯(MDI)作为一个桥接化合物,采用超声-微波共辐射技术,通过化学偶联反应在稻草纤维上引入一定数量的聚氧乙烯基柔性链段。这可以削弱稻草纤维大分子间的相互作用,改变稻草的物理、化学结构,从而得到具有热塑性的稻草改性材料。研究了微波功率、超声功率、时间、温度、以及PEG加入量对接枝程度的影响。因此获得了稻草MDI改性的优化反应条件,也确定了超声波-微波协同作用下稻草的PEG接枝共聚改性的最佳条件。Straw-MDI接枝过程：稻草与PEG质量比1：2；微波功率300 W,超声波功率270 W,反应温度60℃,反应时间60min; Straw-MDI与PEG的接枝过程：微波功率300 W,超声功率360 W,温度60℃,时间70 min。利用红外(FT-IR)、核磁(1H-NMR、13C-NMR)、XRD表征了接枝改性前后稻草纤维的物理、化学结构的变化。热分析(TGA和DSC)表征结果表明改性稻草的热稳定性均有所改善,并获得了预期的热塑性。此外在改性稻草的DSC曲线120℃-180℃左右出现一个宽广的熔融峰,在180℃以上,接枝稻草共聚物可以在不添加其他增塑剂的情况下热压成板。将改性的稻草粉与弹性聚氨酯(TPU)混合,在一定温度和压力下可制成高强度和高弹性模量的稻草/TPU复合材料。
[Abstract]:Straw-waste resource is one of the most important renewable biomass resources in our country. It can be burned directly as fuel, but it not only causes waste, but also causes serious air pollution. It is now possible to produce all kinds of clean fuels through biomass energy conversion technology. At the same time, it can also be used as a carrier of renewable natural polymers and an ideal source of materials. The modified composite can be used as a substitute for traditional organic materials. In this paper, the modified method of cellulose is supposed to be used in the modification of rice straw with polyethylene glycol (PEG) as the modification reagent. The highly active 4-diphenylmethane diisocyanate (MDI) was used as a bridging compound. A certain number of polyoxyethylene flexible segments were introduced into the straw fiber by chemical coupling reaction, which can weaken the interaction between the macromolecules of straw fiber and change the physical and chemical structure of rice straw. The effects of microwave power, ultrasonic power, time, temperature and the amount of PEG on the grafting degree of rice straw were studied. Therefore, the optimum reaction conditions for the modification of straw MDI were obtained. The optimum conditions of PEG graft copolymerization modification of rice straw under the synergistic action of ultrasonic and microwave were also determined. Straw-MDI grafting process was as follows: the mass ratio of straw to PEG was 1: 2, microwave power was 300W, ultrasonic power was 270W, reaction temperature was 60 鈩，

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