Modification Of Inorganic Nanoparticles By N-Hexadecylphosphonic Acid And Preparation Of Polymer/Inorganic Nanocomposites

Polymer/inorganic nanocomposite is an important research branch inmaterials science and engineering.It can combine the excellent properties ofpolymer and inorganic nanoparticles.But the inorganic nanoparticles are easy toagglomerate and usually incompatible with the hydrophobic polymer matrix.Inorder to promote a homogeneous dispersion of inorganic nanoparticles inpolymer matrix,it is necessary to modify the surface of the inorganicnanoparticles.The modification effect is especially important to the properties ofthe nanocomposite.The research of surface modification of nanoparticles ismeaningful.The phosphonic acid can form strong bonding with many kinds of inorganicparticles.It has many advantages in comparison with general modifiers,such ascoupling agents and many surfactants.In this thesis,TiO₂and Ni nanoparticles were modified by usingn-Hexadecylphosphonic acid.The TiO₂/PP and Ni/PP composites have also beenprepared. After surface modification,the hydrophilic TiO₂and Ni nanoparticlesbecome lipophilic.The modified TiO₂and Ni nanoparticles are covered by alayer of n-Hexadecylphosphonic acid and nickle phosphonate respectively.Boththe modified TiO₂and Ni can distribute uniformly in PP matrix.By contrast,theunmodified TiO₂and Ni nanoparticles aggregate seriously in PPmatrix.Modified TiO₂/PP have better mechanical properties than unmodifiedTiO₂/PP.The dielectric constant and dielectric loss of modified Ni/PP can keepstable in a wide frequency range.At10MHz,when the volume fraction ofmodified Ni changes from5%to40%,the dielectric constant of Ni/PP changesfrom4.1to16and the dielectric loss changes from0.003to0.027.In this thesis,lipophilic Fe₃O₄and Ni nanoparticles were also synthesizedin n-Hexadecylphosphonic acid/cyclohexane/water/ethanol microemulsion.Theproperties of Fe₃O₄and Ni nanoparticles were investigated.