Diffusion of organic volatile molecules in LDPE/Halloysite nanocomposites

Abstract

Diffusion behavior of d‐limonene and menthol propylene glycol carbonate were determined in halloysite/Low density polyethylene (LDPE), nanocomposites by a desorption method under nonisothermal conditions. Nanocomposites were prepared by melt mixing and diffusion coefficients of the organic molecules were determined in LDPE without halloysite, in the presence of halloysite, and with halloysite previously impregnated with each molecule. In general, the diffusion coefficient decrease for the molecules studied through the polymeric matrix with the amount of nanoclay loaded. Physical barriers due to halloysite nanoclay dispersed in the matrix give rise to an increase in activation energy for diffusion lowering the diffusion coefficients and desorption rate of the organic molecule through the LDPE matrix. No significant changes in crystallinity that affect the diffusion coefficients were found in the LDPE matrix by the addition of halloysite. The minimum release rate or maximum resistance for molecules to diffusion toward the surface in the halloysite/LDPE nanocomposite was found when the organic molecules were previously impregnated in the halloysite. An indication that impregnation of halloysite with the organic molecule will help to slow, and properly used, to dose their release rate. POLYM. COMPOS. 37:1267–1273, 2016. © 2014 Society of Plastics Engineers