Preparation and thermal characterisation of poly(lactic acid) nanocomposites prepared from organoclays based on an amphoteric surfactant

摘要

New polymer-clay nanocomposites composed of poly(lactic acid) and a novel organoclay based on cocamidopropylbetaine (CAB) and sodium montmorillonite (MMT) were prepared by solution casting and characterised by X-Ray Diffraction Analysis (XRDA), Transmission Electron Microscopy (TEM) and Thermogravimetric Analysis (TGA). A similar series of composites based on PLA and Cloisite 30B, a commercially available organoclay, were prepared for comparison. The thermal stability of the CAB-MMT organoclays decreased with increasing surfactant loading. Experimental organoclays with an organic content similar to that of the commercial organoclay were found to be of comparable thermal stability. XRDA analysis of the PLA-organoclay nanocomposites showed that PLA intercalated the gallery space of both types of organoclay to similar extents and the increased spacing was confirmed by TEM. The thermal stabilities of the PLA-organoclay composites based on CAB-MMT were higher than those based on the commercial organoclay.