【作者】 牛盾；

【导师】 孙挺； 王林山；

【作者基本信息】 东北大学 ， 材料物理与化学， 2005， 博士

【摘要】 随着塑料污染的日益严重，可降解塑料的研究已经成为世界各国竞相开发的热点之一。本课题利用醚化改性反应对稻草进行化学改性，使其转化为具有一定热塑性的材料，并对其微观结构及物化性能进行测定。 在研究中，将纤维素改性方法应用于稻草改性，以环氧氯丙烷和氯化苄作为醚化剂，NaOH作为预处理剂、溶胀剂，以季铵盐作为相转移催化剂(PTC)，得到有一定增重率的改性稻草粉，讨论并分析了预处理前后稻草的性能及化学结构的变化，得出了稻草改性的优化反应条件，并分析了改性的可行性及其原理，从而确定了最佳改性条件：在预处理阶段，用10％的NaOH先浸泡粉碎后的稻草12h，再蒸煮1h；在苄基化改性阶段，每克稻草采用氯化苄8.00mL，水6.00mL，浓度为6.0mol／L的NaOH8.00mL，十六烷基三甲基溴化铵0.010g，在100℃下，反应4h，得到增重率为68.78％的苄基化稻草。红外光谱分析、X—ray衍射分析和差示扫描量热分析表明苄基化稻草的微观结构发生了改变，出现了147.53℃的玻璃化转化温度，在此温度以上材料就可以产生部分流动，说明稻草部分被改性成为热塑性物质。 通过对未处理稻草和苄基化改性稻草分别以不同质量分数与聚乙烯(PE)共混，测其力学性质可知，对于稻草粉末和苄基化改性稻草，随着其加入质量分数的增加，拉伸强度，弯曲强度，冲击强度都相应下降。虽然两者的力学性能均有降低，但降低幅度很小，通过比较可知苄基化改性稻草能更有效地替代聚乙烯(PE)，随加入质量分数的增大，对拉伸强度，弯曲强度，冲击强度的变化比未改性稻草的下降趋势平缓。同时，苄基化稻草与塑料共混的相应力学性能的值大于未处理稻草粉末的共混物。改性稻草与未处理稻草粉末相比更适合作为聚乙烯(PE)的填料或替代品。 用毛细管流变仪对改性后的稻草样品与聚乙烯塑料的混合物进行了流变性测定，探讨了混合物中改性稻草的含量、共混物的剪切应力、剪切速率、温度对表观粘度的影响。结果表明，改性后稻草样品与聚乙烯的混合物具有一定的流动性，属于非牛顿流体；表观粘度随着混合物中改性稻草含量的增加逐渐增加；随着温度的升高而逐渐降低；而对非牛顿指数的影响却正好相反，即混合物中改性稻草更多还原

【Abstract】 With the development of plastic industry, the pollution of plastics is seriously increasing. The research for degradable plastics has become one of hotspot in the world. In this thesis, etherification reaction was applied to rice straw to modify it into a thermoplastic material. The microstructure and physics and chemical property of modified rice straw were studied.In the present work, Cellulose modification technique was employed and modification rice straw was carried out with NaOH being used as pretreatment agent and swelling agent, epichlorohydrin and benzyl chloride as etherifying agent, deionized water as solvent, and quaternary ammonium salt as phase transfer catalyst The optimum conditions for modification reaction were determined. In the preprocessing time, firstly, soak the rice straw with 10% NaOH for 12 hours, and then boil it for 1 hour. Under the conditions of temperature for 100℃, Modified each gram rice straw with 8.00mL benzyl chloride、 6.00mL de-ionized water、 8.00mL NaOH with the concentration is 6.0mol/L and 0.010g hexadecyl trim ethyl ammonium bromide respond 4 hours and weighting percentage of benzylated straw is 68.78%.. Compared with raw rice straw, modified rice straw changed much in microstructure and decreased in polarity. DSC showed modified rice straw appears the vitrification point is 147.53 ℃, becoming a kind of thermoplastic material.Nature straw and benzylated straw was respectively mixed with polythene (PE) . With the increase of nature straw and benzylated straw content, breaking strength, bending strength and impact strength are all reduced, but the reduction extent of mechanical behaviors for them are little. From the comparison, we can conclude that benzylated straw can be more effective on replacing PE to improve mechanical behaviors than nature straw. Modified straw is more fit to be padding for PE or it’s substitute than nature straw.Analyze the rheological property of the blend mixed with Modified rice straw and polythene with capillary rheometer. The effects of the content of straw sample in the blend, shear stress, shear rate and different temperatures on rheological behavior are discussed. The results show that the blend has definite rheology in experimental range and belongs to Non-Newtonian fluid; its viscosity descends with increasing of both shears更多还原