【作者】 杨俊；

【导师】 林志勇；

【作者基本信息】 华侨大学 ， 材料学， 2004， 硕士

【摘要】 采用阴离子原位聚合法制备MC尼龙6／TiO₂纳米复合材料，利用TEM研究了纳米TiO₂在MC尼龙6中的分散性，DSC、XRD、力学性能测试等方法研究了纳米复合材料的结晶与熔融及其结构与性能关系，得出了如下的结论： （1）TEM研究纳米复合材料的分散性结果表明：纳米含量小于1％时，具有良好分散性；纳米含量大于1％时，纳米粒子开始出现团聚现象。XRD分析表明：纳米TiO₂不影响尼龙6的结晶形态。 （2）DSC法研究了纳米复合材料的等温结晶行为，采用Avrami方程研究其结晶动力学。复合材料等温DSC曲线表明，纳米TiO₂改变了尼龙6的等温结晶行为。Avrami法研究结晶动力学结果表明纳米TiO₂对尼龙6起到成核剂的作用，提高了其结晶速率，减小了半结晶时间。Hoffman结晶成核理论计算结果说明纳米TiO₂阻碍了尼龙6分子链的运动，使尼龙6由晶核生长占主导地位逐渐向成核机制占主导地位的转变。 （3）DSC研究了纳米复合材料非等温结晶行为，采用三种不同的处理方法研究复合材料的非等温结晶动力学。研究结果表明：Ozawa法不适用，Jeziomy法基本适用，Mo法是最佳处理方法；其结果表明纳米粒子对尼龙6有成核作用，改变了尼龙6成核机理，纳米粒子的引入提高了复合材料的结晶活化能，说明纳米粒子对尼龙6分子链具有阻碍作用。 （4）DSC法研究了纳米TiO₂对复合材料等温和非等温熔融行为的影响。研究结果表明：尼龙6及其纳米复合材料等温熔融为三重峰，非等温 摘要熔融为二重峰。纳米TIO:提高了复合材料等温熔融的低温峰峰温，并随纳米含量增加而增加，高温峰峰温基本不变。纳米Tio:加入提高了复合材料非等温熔融低温峰峰温，而高温峰峰温基本不变。纳米Tio:粒子对复合材料等温和非等温熔融行为的影响说明了纳米粒子对尼龙6的成核作用提高了基体的晶粒完善性，同时提高了其平衡熔点。 （5）纳米TIO:提高了复合材料的热稳定性，提高了复合材料的拉伸强度、弯曲强度、冲击强度，减小其断裂伸长率，起到了增强增韧的作用。紫外辐照结果表明:辐照时间7一14天时，尼龙6和复合材料力学性能随辐照时间延长而下降，辐照时间为21天时，辐照导致交联又提高了尼龙6及纳米复合材料的力学性能。纳米含量为1%的复合材料抗辐照性能较好.更多还原

【Abstract】 MC nylon 6/TiO2 nanocomposites have been prepared by means of anion in-situ polymerization. The dispersity of nano-TiO2 in nylon 6 was studied by TEM, and the crystallization and melting behavior, structure and mechanical properties of nanocomposites was studied by DSC, XRD and mechanical properties methods. The conclusions as follows:(1). When the nano-TiO2 content <1%, it has a good dispersity. When the nano-TiO2 content >1%, it begin to cluster. Nano-TiO2 doesn’t influence on the crystal style of MC nylon 6.(2). The results of isothermal DSC of nylon6 and nanocomposites show that nano-TiO2 influenced the behavior of isothermal crystallization of nylon 6. The results of Avrami equation show that nano-TiO2 were nucleation reagent of nylon 6, which raised the crystallization rate and decreased the half time of isothermal crystallization. The values of Kg of nanocomposites througing Hoffman equation increased with the increase of nano-TiO2 content.(3). The results of non-isothermal DSC of nylon6 and nanocomposites show that nano-TiO2 influenced the behavior of non-isothermal crystallization of nylon 6. The non-isothermal crystallization of nylon 6 and nanocompsoites was analyzed by the methods of Ozawa, Jeziomy and Mo, the results show that the method of Mo is optimal method for nylon 6 and nanocompsoites. The results of the non-isothermal crystallization kinetics show that nano-TiO2 were nucleation reagent of nylon 6, which changed the nucleate mechanism of nylon 6 and increased the crystallization activation energy, indicating the nano-TiO2 baffled the movement of molecular segments of nylon 6.(4). The isothermal and non-isothermal melting behaviors of nylon 6 and nanocomposites have been studied by means of DSC. The results show that the isothermal melting curves have three peaks and non-isothermal melting curves have two peaks. The values of temperature of the low temperature peaks increased and the high temperature peaks invariable, indicating that nano-TiO2 enhanced the perfection of crystal of nylon 6.(5). Nano-TiO2 increased thermal stability of composites and mechanical properties, but decreased elongation at break, which indicate nano-TiO2 has strengthening and toughening ability. The results of UV-irradiation show that the mechanical properties of nylon 6 and nanocomposites decreased with the increase of UV-irradiation time at the beginning, but when the UV-irradiation time is 21 day which leaded to crosslink and made the mechanical properties of nylon 6 and nanocomposites increased. The nanocomposite with 1% TiO2 is the optimal composite to resist UV-irradiation.更多还原