Study On The Preparation Of Polymer/layered Silicate Nanocomposites By In-situ Intercalative Polymerization

In this research, we have studied the organic modification of the layered silicate and the preparation of some polymer/layered silicate nanocomposites by in-situ intercalative polymerization. The mechanism of forming the polymer/layered silicate nanocomposites by this method has been probed. The structures and properties of the nanocomposites have also been tested.To render the layered silicate more organophilic, protonated alkylammonium was used as intercalative. The increasing of the intersheet spacing was obtained as evidenced by XRD measurements. Together with the result of IR measurement, we considered that the alkylammonium cation were intercalate into the silicate layers.The nylon-6/layered silicate nanocomposites were obtained through in-situ intercalative polymerization, with different contents of the organ layered silicate mixing into the melt of e -caprolactam. Examined by the TEM, the silicate layers were either exfoliated or delaminated in the PA6 matrix. The properties of thermal properties, crystallization, sorption of water and Melt Index were tested and analyzed. The result showed that the properties of the nanocomposite were prior to nylon-6, and they were variable with the contents of the modified layered silicate . The crystal temperature of the nylon-6 increased clearly because the silicate layers took the role of nucleators. And it's sorption of water decreased remarkably. A new mechanism of forming nylon-6/layered silicate composites was presented in this paper and a model of forming the nylon-6/layered silicate nanocomposites was also assumed.By the same method, PET/layered silicate nanocomposites were prepared. Observation to the TEM of the PET/layered silicatenanocomposites showed that a small portion of the layered silicate were exfoliated and the others were resulted in multilayer morphology, in which the layer spacing increased clearly.PBT/layered silicate nanocomposites were synthesized for the first time. It's TEM photographs showed that a part of the silicate layers were exfoliated into about 10-20nm thickness. According to the Molau experiments, strong chemical linkage took place between the layered silicate and the PBT chains.The comparison of nylon-6/layered silicate to polyester/layered silicate nanocomposites led to a conclusion that the monomer's steric hindrance and polarity influence the forming of polymer/layered silicatenanocomposites.