Thermal Characterization of Biodegradable Poly (Lactic Acid)/Clay Nanocomposites
Aliphatic polyesters such as polylactides have various applications due to their biodegradable and/or biocompatible character. Poly (L-lactide) is produced from L-lactic acid, which is derived itself from the fermentation of corn or sugar beet. PLA with a glass transition temperature around 55 °C is a relatively stiff and brittle polymer with low deformation at break. Polymer nanocomposites have been a subject of a large number of research studies in the last decade. However, to commercialize polymer nanocomposites (especially bio-degradable polymer nanocomposite) there are still a number of technical barriers. Polymer nanocomposites based on initially biodegradable Poly (lactic acid) (PLA) and organically modified layered silicates were prepared by melt processing using a Brabender twin screw mixer. Several organically modified montmorillonite (Nanoclay) were incorporated at 1% loading level into the PLA. However, a completely exfoliated morphology has been evidenced by X-ray diffraction analysis for the combination of PLA and the natural montmorillonite modified with a quaternary ammonium salt, Cloisite® 30B, this is the most hydrophilic among the organically modified montmorillonite. Further studies were done on the same combination with loading levels of 1%, 2%, 3%, 4% and 5%. Thermal stability of the Nanocomposites was studied using TGA. An increase in thermal stability with the clay content is observed by TGA with a maximum obtained for a loading of 3 wt% of 30B nanoclay. Glass transition and melting point data were collected and analyzed using DSC. The onset of Tg has been increased by the addition of the 30B nanoclay.
KeywordsPoly Lactic Acid Biodegradable Polymer Polymer Nanocomposites Biodegradable Poly High Loading Level
- Burton, R.H., Folkes, M.J. 1986. In: Clegg, D.W., Collyer, A.A. (ed.), Mechanical properties of reinforced thermoplastics. London: Elsevier.Google Scholar
- Cowie, J.M.G. 1991 Polymers: chemistry & physics of modern materials, Chapman & Hall, New York.Google Scholar
- Gilnian, J.W., Kashiavagi, T.C.L., Giannelis, E.P., Manias, E., Lomakin, S., Lichtenhan J.D. et al., 1998. In: Le Bras, M., Caniino, G., Bourbigot, S., Delobel, R. (eds.), Fire retardancy of polymers, The Royal Society of Chemistry, Cambridge.Google Scholar