In the preparation of polymer/clay nanocomposites, organoclay plays an important role in lipophilizing and dispersing the clay into less polar polymer matrixes. Organic modifiers of various chain lengths were examined in different types of clays, smectite, montmorillonite (MMT), and mica, to prepare their corresponding organoclays. The layered structure and gallery spacing of organoclays and polylactide (PLA) nanocomposites shows that, with a modifier of the same chain length, the gallery spacing of the organoclay was largest for mica and smallest for smectite because of the higher ion-exchange capacity of mica and physical jamming of the modifier due to a restricted conformation at the core part of the clay of larger size. The increment of the modulus in a smectite nanocomposite, compared to that of PLA, is higher than MMT or mica nanocomposite due to better dispersion in a smectite system for the same clay loading. Being a well-dispersed system, smectite nanocomposites have better gas barrier properties than the MMT or mica systems, which are larger in size but stacked in nature in their nanocomposites. A new idea for obtaining porous ceramic material from layered silicate/polymer nanocomposites by burning is unveiled using various clays and the mechanism of their formation is elucidated.

New polylactide (PLA)/layered silicate nanocomposites have been prepared successfully by simple melt extrusion of PLA and organically modified montmorillonite. The d spacings of both the organically modified montmorillonite and intercalated nanocomposites were investigated by wide-angle X-ray diffraction (WAXD) analysis, and the morphology of these nanocomposites was examined by transmission electron microscopy (TEM). Using oligo( -caprolactone) (o-PCL) as a compatibilizer, the effect of compatibilizer in nanocomposites was investigated by focusing on two major aspects: morphological analysis and mechanical property measurements. The intercalated nanocomposites exhibited remarkable improvement of materials properties in both solid and melt states as compared to that of PLA matrices without clay.

Our ongoing research on the preparation, characterization, materials properties, and biodegradability of polylactide (PLA)/organically modified layered silicate (OMLS) nanocomposites has yielded results for PLA/organically modified synthetic fluorine mica (OMSFM) nanocomposites. Synthetic fluorine mica (SFM), modified with N-(coco alkyl)-N,N-[bis(2hydroxyethyl)-N-methylammonium cation, was used as an OMLS for the nanocomposites preparation. The internal structure of the nanocomposites in the nanometer range was established using wide-angle X-ray diffraction (WAXD) analyses and transmission electron micrographic (TEM) observations. All nanocomposites exhibited remarkable improvement of various materials properties with simultaneous improvement in biodegradability than that of neat PLA. This is the first report that deals with the ultimate degradability of PLA and corresponding nanocomposites under compost.