Preparation And Properties Of Organic Polymer/Modified Vermiculite Nanocomposites

In recent years, with the development of the scientific technology, the requirements on the polymer properties is becoming more and more, higher and higher, and severer and severer. In some ways, the applications of single organic polymers often are limited because some properties can t meet the requirements, such as lower trength and hardness, weathering resistance and thermal stability etc. Nylon as one of the five engineering plastics in the industry has important applications, but nylon exists the faults of low temperature impact strength which makes its application limited; Polylactic acid (PLA) is a biodegradable, biocompatible, nontoxic aliphatic polyeaster derived from renewable resources, However, broad substitution of PLA for conventional plastics is thwarted by its some defects such as poor heat resistance, slow crystallization rate and brittle behavior under impact loads. While organic polymer/layered silicate nanocomposites can combine the advantages of organic polymer and layered silicates, and thus promote the properties of polymer. So organic polymer/layered silicate nanocomposites have become the hotspot of the research.Firstly, the nanometer-sized exfoliated vermiculite was modified with y-Aminopropyltriethoxysilane (KH-550) and inorganic acid. In the process of amino modified vermiculite the amount of silane coupling agent is researched. Finally the organic polymer /modified vermiculite nanocomposites materials were prepared in in-situ polymerization. This paper discussed the results of the exfoliated vermiculite functionalization. The results of in-situ polymerization were discussed by Fourier transform infrared spectroscopy (FTIR), viscosity test Field emission scanning electron microscope (FE-SEM) and Transmission electron microscopy (TEM). The effect of VMT on detailed crystallization and the mechanical properties of PA66/ modified VMT nanocomposites were also discussed.The results revealed that reactive group (amino or hydroxyl) was grafted onto the vermiculite lamellar and the fuctionalized vermiculite was successfully prepared by modification with silane coupling agent or inorganic acid. The organic polymer/modified VMT nanocomposities were successfully prepared by in-situ melt polycondensation, and the covalent bond was formed between the organic polymer and the fuctionalized vermiculite. After adding functional VMT, the morphology characterization of polymer changed greatly, the amino modified VMT in the PA66 matrix appeared self-assembly phenomenon. TGA analysis validated quantitatively the grafting of PLLA on the surface of hydroxyl modified VMT. The grafting ratio reached 28.3%. Meanwhile the amount of KH-550 could affect the degree of the VMT modification, and then had influence in crystallization behavior, mechanical properties and thermal stability of the nanocomposites.