Preparation And Interfacial Control Of Polymer-TiN Nanocomposites

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.