【作者】 程国君；

【导师】 钱家盛；

【作者基本信息】 安徽大学 ， 高分子化学与物理， 2013， 博士

【摘要】 利用界面改性剂对纳米粒子进行表面修饰以提高其在聚合物基体中的分散性是制备聚合物纳米复合材料的关键技术。大分子表面改性剂的分子结构包括与纳米颗粒表面能形成化学键合的锚固基团和与聚合物基体有较好的相容性的柔性长链两部分,可以有效地控制纳米粒子与聚合物基体间的界面结构,从而改善纳米粒子的分散性,提高聚合物纳米复合材料的宏观性能。本论文利用自由基共聚合技术设计、合成了与MAPTMS、SBR和PS具有相关结构的St/AN/MAPTMS大分子界面改性剂,对比研究大分子界面改性剂与小分子界面改性剂修饰纳米粒子在聚合物基体中分散性的影响规律及其对界面性能的影响。1、通过自由基共聚合方法成功合成了大分子界面改性剂St/AN/KH-570共聚物,分子量可控在Mn=10000-20000；通过’H-NMR、FT-IR、GPC等确认了聚合物结构；通过DSC和TGA表征了大分子界面改性剂St/AN/MAPTMS的热性质,数据显示,大分子界面改性剂St/AN/MAPTMS具有良好的热稳定性和较宽的使用温度。2、用大分子St/AN/MAPTMS和MAPTMS为界面改性剂、以乙酸乙酯为溶剂对纳米TiN进行改性；用FT-IR和XPS研究了纳米TiN改性前后表面结构的变化,发现界面改性剂的硅醇烷(-SiOCH3)基团能够与纳米TiN表面羟基(-OH)通过脱水反应而接枝在纳米TiN表面；通过XRD、接触角分析、沉降实验,TGA、高分辨TEM等对改性纳米TiN性质进行分析并对比界面改性剂的改性效果。结果表明,界面改性剂的加入没有改变TiN的立方晶体结构；对比发现,大分子界面改性剂能够有效提高纳米TiN在有机溶剂中的分散稳定性、降低粒子团聚,其应用效率远大于小分子的MAPTMS。3、采用密炼-开炼两段混合工艺制备了不同界面改性剂修饰纳米TiN填充SBR复合材料,并利用TEM、SEM、橡胶加工分析仪和热分析技术研究了界面改性剂对SBR/TiN纳米复合体系界面性能的影响。研究结果表明：大分子界面改性剂St/AN/MAPTMS引入到SBR/TiN纳米复合材料体系,能够更有效提高纳米TiN在SBR基体中分散性和相容性;改善SBR/TiN混炼胶的硫化性能；在最佳填充量5phr下,混炼胶的拉伸强度提高近80%,同时大分子界面改性剂进一步改善SBR体系的动态加工性；并促进胶体的Tg提高近10℃。4、采用熔融共混的方法制备了不同界面改性剂修饰纳米TiN填充PS塑料体系复合材料,并利用TEM、热分析、和旋转流变仪等表征技术研究了界面改性剂对和PS/TiN纳米复合材料界面性能的影响。结果表明,大分子界面改性剂St/AN/MAPTMS比小分子改性剂MAPTMS更能有效提高纳米TiN粒子在PS基体中的分散性,增强界面粘结;大分子界面改性剂扮演了PS/TiN复合体系界面连接的重要角色,在2phr纳米粒子填充量下,大分子界面改性剂的加入,PS体系复合粘度、储能模量和损耗模量等提高近1个数量级,并进一步提高纳米复合材料的玻璃化转变温度和热稳定性。更多还原

【Abstract】 Surface modification on nano-particles by interfacial modifier is a key technology to improve the dispersion of nano-particles in polymer matrix. Since the movement units of macromolecular chain are more than those of small molecules, we may more effecitively control the interfacial structure between nano-particles and polymer matrix using the macromolecules as interfacial modifier. In this thesis, macromolecular interfacial modifier (St/AN/MAPTMS copolymer) is designed and synthesized using free radical copolymerization technique. The influences of molecular interfacial modifier and macromolecular interfacial modifier on dispersion of nano-particles and interfacial properties were studied and compared. The interfacial structure and property of nano-particle/polymer matrix are considered in detail by various examination techniques and property tests.1. Macromolecular interfacial modifier (St/AN/MAPTMS copolymer) was synthesized by free radical copolymerization with molecular weight Mn=10000-20000. The structures of St/AN/MAPTMS copolymer were confirmed by methods of1H-NMR and FT-IR. The thermal properties of macromolecular interfacial modifier were characterized by DSC and TGA technology. Macromolecular interfacial modifier (St/AN/MAPTMS) possess good thermal stability and wide using temperature.2. Nano-TiN particles were modified by St/AN/MAPTMS copolymer and MAPTMS respectively. The structures of native and modified nano-TiN were studied by FT-IR and XPS. The effect of interfacial modifier on nano-TiN was analyzed and compared by XRD, contact angle analysis, sedimentation experiment, TGA and high resolution TEM. The results show both surface modification show no effect on cubic crystal structure of TiN. The dispersion stability of nano-TiN in organic solvent is obviously improved by macromolecular interfacial modifier. it’s the application efficiency of macromolecular interfacial modifier was59.45%, which is far more than that of small molecular MAPTMS.3. Modified nano-TiN was filled into SBR using a hybrid technology of mixer-mixing. The influence of interfacial modifiers on properties of SBR/TiN nanocomposites was researched using TEM, SEM, rubber processing analyzer (RPA) and thermal analysis technology. Researching results show that macromolecule interfacial modifier (St/AN/MAPTMS) more effectively improve the dispersion and compatibility of nano-TiN in SBR matrix that MAPTMS alone does. Under the optimum condition, the tensile strength of the mixing rubber was increased about80%, and rubber’s Tg was increased almost10℃when SBR rubber filled with nano-TiN modified by macromolecular interfacial modifier.4. PS/nano-TiN composites was prepared using melting blending method. Nano-TiN was modified by MAPTMS and St/AN/MAPTMS respectively. The influence of interfacial modifier on properties of PS/TiN nanocomposites was studied using TEM, thermal analysis and rotational rheometer devices. Results show that the dispersion of nano-TiN in PS matrix can be effectively improved by macromolecule interfacial modifier (St/AN/MAPTMS copolymer) than small molecular interfacial modifier (MAPTMS). Macromolecular coupling agent played an important role on interfacial connection of PS/TiN composite system. The dynamic modulus of nano-TiN/polymer composites were significantly improved, and the glass transition temperature and thermal stability of nanocomposites were further improved.更多还原