Preparation of Poly （L-lactic acid ）/Vermiculites Composites by in situ Copolymerization of Lactic Acid and Hydroxylic Vermiculites

L-lactic acid （L-LA） based copolymer/hydroxylation vermiculites composites （PLLA-co-bis A/HVMTs ） were prepared by in situ reaction among L-LA, adipic acid, and hydroxylation lamellar vermiculites （HVMTs） using bisphenoI-A epoxy resin as chain extending agent. HVMTs were obtained by sulfuric acid. leaching of lamellar vermiculites （VMTs）. The effects of sulfuric acid leaching on the VMTs structure were characterized by X-ray diffraction （XRD）, 29Si magic-angle spinning nuclear magnetic resonance （29Si NMR ）, Fourier transform infrared spectroscopy （FTIR）, field emission scanning electron microscopy （FE-SEM）, and thermogravimetric analysis （TGA）. FTIR, FE-SEM, and TGA were used to characterize the reaction activity of HVMTs. The results indicated that VMTs with increased hydroxyl groups had been successfully obtained and could react with--COOH of the reaction system. The amount of L-LA based copolymcr grafted on the surface of HVMTs was more than 22%. The onset decomposition temperature of L-LA based copolymer grafted on the surface of HVMTs was 30℃ higher than that of free L-LA based copolymer.