Cyclic tensile properties of the polylactide nanocomposite foams containing cellulose nanocrystals

Abstract

Cellulose nanocrystal (CNC) filled polylactide (PLA) nanocomposites are of interest because both the filler particles and matrix polymer are biodegradable. Foaming with high pressure inert gas is a promising way to open potential applications of this kind of green nanocomposites as lightweight materials. To establish the structure–property relations of this kind of foams is hence of great significance. In this work, PLA/CNC nanocomposites containing three types of CNC particles, including pristine CNC and acetylated ones with lower and moderate degrees of substitution, were foamed using CO2 as the blowing agent for the studies mentioned above. The results show that the presence of all three kinds of CNC particles has large influence on cellular structure and cell morphology, and as a result, affects final mechanical properties of foams. The tensile cycle tests were then performed as an efficient tool to further figure out clear information on the contributions of reinforcement of filler and altered cell structure to the plasticity and elasticity of foams. The obtained results provide useful information on the optimization of cell structure and mechanical properties of PLA foams using small amounts of CNC particles through controlling their surface properties.