原位聚合表面修饰纳米sio2尼龙6杂化材料的制备与性能研究.pdf

河南大学 硕士学位论文 原位聚合表面修饰纳米SiO2/尼龙6杂化材料的制备与性能研究 姓名：陈方飞 申请学位级别：硕士 专业：材料加工工程 指导教师：李小红 2011-06 V 摘 要 选用带有不同表面官能团的纳米 SiO2， 利用原位聚合的方法制备了几种性能优良的 纳米 SiO2/尼龙 6（PA6）杂化材料，分析了其机械性能、热性能和熔融结晶行为；考察 了纳米 SiO2表面修饰基团的种类和组成以及纳米 SiO2的加入方式对杂化材料性能的影 响，发现不同表面修饰纳米 SiO2与 PA6 基体间形成不同界面结构，从而造成杂化材料 性能出现明显差异主要研究内容和结果如下： 1、在聚合反应初期加入纳米 SiO2，表面含饱和有机碳链的纳米 SiO2（DNS-2 和 DNS-3）和表面含氨基官能团的纳米 SiO2（RNS-A）均能在 PA6 基体中良好分散，且 均能在纳米 SiO2较低添加量的情况下（≤1wt%）有效地改善 PA6 的综合性能TGA 和 FT-IR 等分析表明，DNS-2 和 DNS-3 与 PA6 基体之间以氢键和物理方式结合，而 RNS-A 与基体 PA6 之间以氢键和化学键方式结合， 并且 RNS-A 粒子和尼龙分子链在杂 化材料体系中形成局部三维网络结构。

2、DNS-2、DNS-3 和 RNS-A 都能够增强增韧 PA6，但三者的增强增韧效果有所不 同RNS-A 能显著提高 PA6 的缺口冲击强度和拉伸强度，这是由于其在杂化体系中形 成三维网络结构所致；当其含量为 0.5wt%时，杂化材料的缺口冲击强度和拉伸强度达 到最大，分别比纯 PA6 的提高 45.7%和 18.2%DNS-3 能够大幅度地提高 PA6 的拉伸 强度；当其含量分别为 0.2wt%和 1.0wt%时，杂化材料的缺口冲击强度和拉伸强度达到 最大，分别比纯 PA6 的提高 12.5%和 34.5%DNS-2 能在不影响 PA6 缺口冲击强度的 前提下适度提高其拉伸强度；当其含量为 0.4wt%时，杂化材料的缺口冲击强度和拉伸 强度达到最大，分别比纯 PA6 的提高 9.8%和 20.7% 3、DNS-2 和 DNS-3 型纳米 SiO2对 PA6 的热稳定性影响不大，而 RNS-A 由于能够 和 PA6 分子链在体系中形成三维网络结构，从而显著限制了 PA6 分子链的运动，并且 大量界面化学键的破坏需要消耗更多的能量，从而有利于材料热稳定性的提高RNS-A 含量为 1.5wt%的杂化材料的热分解温度比纯 PA6 的高 10 ℃。

4、DNS-2、DNS-3 和 RNS-A 的加入对杂化材料的熔融峰温影响不大，但都使杂化 材料的熔融曲线上出现低温熔融小肩峰；与此同时，DNS-2、DNS-3 和 RNS-A 的加入 均能起到异相成核剂的作用， 有利于提高PA6 的结晶速率、 结晶峰温和结晶度 但RNS-A VI 与 PA6 基体的强界面作用使得 PA6 分子链的运动受到明显限制，对应杂化材料的结晶 峰温和结晶度呈现先增后降的趋势 5、在聚合反应初期加入纳米 SiO2，通过调节纳米 SiO2表面饱和有机碳链与氨基官 能团的比例发现，随着纳米 SiO2表面氨基数量的减少，杂化材料中纳米粒子表面接枝 的尼龙量也逐渐减少其原因可能在于，随着纳米 SiO2表面氨基数量的减少，参与尼 龙聚合反应的氨基数量也相应减少另外，随着纳米 SiO2表面氨基数量的减少，对应 杂化材料的力学性能逐渐下降，杂化材料的熔融峰温、结晶峰温和结晶速率均呈现出下 降的趋势 6、在聚合反应不同时期加入 RNS-A，对比 RNS-A 与 PA6 基体的界面作用及其对 杂化材料的力学性能、熔融结晶行为的影响，发现 RNS-A 加入时间推迟后，纳米粒子 表面接枝的尼龙量增多。

其原因可能在于，在聚合反应后期尼龙分子链充分增长，与 RNS-A 接枝的尼龙链长度增加 与此同时， 较长的尼龙分子链有利于扩大杂化体系中三 维网络结构的网格， 从而造成杂化材料性能的差异 当聚合反应进行4 h后再加入RNS-A 时，对 PA6 力学性能的改善效果最佳；纳米粒子添加量为 0.5wt%时杂化材料的缺口冲 击强度和拉伸强度同时达到最大，分别比纯 PA6 的提高 113.4%和 48.2%随着 RNS-A 加入时间的推后，杂化材料的熔融峰温变化不大，熔融小肩峰消失，结晶峰温降低，结 晶速率变小，但结晶度与纯 PA6 的相当或者较高 关键词：表面修饰纳米 SiO2，尼龙 6，杂化材料，原位聚合，制备，性能 VII ABSTRACT The different surface modified nanosilica/PA6 hybrid materials with excellent performance were synthesized by in-situ polymerization, and the mechanical properties, thermal properties and melt crystallization behaviors of hybrid materials were evaluated. The effects of different kinds and composition of modifier on the surface of nanosilica and the way of adding nanosilica on the properties of hybrid materials were analyzed, and found that the different interface structure between PA6 matrix and nanosilica resulted in distinctly different properties of hybrid materials. 1. When nanosilica was introduced into the reaction system at the early stages of polymerization, the results showed that both surface-modified nanosilicas containing saturated carbon chains (DNS-2 and DNS-3) and amino group (RNS-A) were well dispersed in PA6 matrix and were all able to effectively improve the comprehensive properties of PA6 even at a low dosage (≤1wt%). Thermogravimetric analysis (TGA) and Fourier transform infrared spectrometric (FT-IR) analysis etc. indicated that DNS-2 and DNS-3 were linked with PA6 matrix via hydrogen bond or physical adsorption, while RNS-A could act as a monomer to participate in the polymerization of PA6 and form local three-dimensional network structure via covalent bonding. 2. DNS-2, DNS-3 and RNS-A could all strengthen and toughen PA6 matrix, but they had different strengthening and toughening effects. Of all the three kinds of nanosilica, RNS-A was the best one to improve the notched impact strength and tensile strength of PA6, because it was able to form three-dimensional network structure in the hybrid system. As RNS-A was doped in PA6 matrix at a dosage of 0.5wt%, resultant hybrid material had the maximum impact strength and tensile strength which were higher than that of PA6 matrix by 45.7% and 18.2%, respectively. DNS-3 could greatly increase the tensile strength of PA6. The PA6 hybrid doped with 0.2wt% and 1.0wt% DNS-3 possessed the maximum impact strength and tensile strength which were higher than that of PA6 matrix by 12.5% and 34.5%, respectively. Besides, DNS-2 could moderately increase the tensile strength but had little effect on the notched impact strength of PA6. The PA6 hybrid material doped with 0.4wt% DNS-2 possessed the maximum impact strength and tensile strength which were higher than that of PA6 matrix by 9.8% and 20.7%, respectively. VIII 3. Both DNS-2 and DNS-3 had little effect on the thermal stability of PA6, while RNS-A significantly increased the thermal decomposition temperature of PA6. This is because RNS-A could participate in the polymerization of PA6 and form local three-dimensional network structure via covalent bonding, greatly limiting the movement of PA6 molecular chains. Besides, the destruction of a large number of interface chemical bonds require more energy. The thermal decomposition temperature of PA6 could be increased by 10℃ when it was doped with 1.5wt% RNS-A. 4. DNS-2, DNS-3 and RNS-A all had little effect on the melt temperature of PA6 but resulted in endothermic 。