Microwave in-Situ Polymerization of Poly Lactic Acid and Carbon Nanotubes and Study of its Electrical Conductivity

Abstract

Poly lactic acid (PLA) is linear aliphatic thermoplastic polyester produced from renewable resources. Its degradable nature makes it very useful. High molecular weight PLA is produced by condensation method ring opening polymerization of Lactide. Carbon nanotubes are allotropes of carbon with a cylindrical nanostructure. It has extraordinary thermal conductivity, mechanical and electrical properties. Carbon nanotubes find applications as additives to various structural materials. Nanocomposite is a multiphase solid material where one of the phases has one or more than dimensions of less than 100 nanometers (nm). It is a solid combination of a bulk matrix and nano-dimensional phases differing in properties due to dissimilarities in structure. These materials show improvements in mechanical, thermal, electrical and barrier properties. In this study properties of nanocomposite of PLA and carbon nanotubes are studied, in which lactide is the monomer and carbon nanotube as the nanofillers.The in-situ polymerization was done in a Monomode microwave reactor. Microwave heating has been used for the synthesis of composite. Microwave heating is a faster method of heating as compared to the other methods. Fourier transform infrared microscopy confirmed the formation of nanocomposites. SEM and TEM images showed that the CNT is dispersed over the polymer matrix. CNT has very high electrical conductivity and thus synthesized nanocomposite expectedly shows high electrical conductivity. The electrical conductivity of nanocomposite spectacularly increases with the increase in concentration of nanofiller up to a certain value.