In today’s modern world, plastics are used for a variety of everyday applications from plastic shopping bags to medicinal applications, but most of these plastics are resistant to environmental influences such as humidity and microbial attack. The ecological problem we now face in our landfills is the large volume of non-biodegradable plastics, which has made the development of biodegradable plastics an urgent matter. Because of this situation, the Chemical Metrology Group of NMISA (National Metrology Institute of South Africa) has embarked on a collaborative effort with the Fibre and Polymer Technology Department of KTH (Royal Institute of Technology) in Sweden to develop methods for the analysis of biodegradable polymers. During the project, commercial and research samples are analysed with various techniques, such as Pyrolysis-GC-MS, GPC, FTIR, SEM, TGA, TGA-FTIR and DSC. The aim is primarily to evaluate what information can be obtained by Pyrolysis-GC-MC and FTIR-TGA with respect to thermal properties and degradation products. Currently polylactide (PLA) is the focus of many studies and it is one of the most promising degradable polymers. One trend is to improve the properties of PLA through addition of different nanofillers. In this work polylactide nanocomposites are made by blending polylactide (PLA) with zinc oxide, titanium dioxide, halloysite (aluminosilicate) or surface modified montmorillonite (phyllosilicate). The materials are characterized by scanning electron microscopy (SEM) and DSC. The thermal stability and resulting thermal degradation products are analysed by TGA and Py-GC-MS. The results especially show the influence of nanoparticle surface modification on the degradation product pattern.