Non-Isothermal Crystallization Kinetics of PEG Plasticized PLA/G-POSS Nanocomposites

In this study, the non-isothermal crystallization kinetics of epoxy functionalized poly(hedral oligomeric silsesquioxane) (G-POSS) reinforced plasticized or unplasticized poly(lactic acid) (PLA) was investigated. Poly(ethylene glycol) (PEG) was used as plasticizer at a constant content of 10% by weight. A micro-compounder was used to prepare PLA/G-POSS, PLA/PEG, and PLA/PEG/G-POSS nanocomposites. G-POSS content was varied as 1, 3, 7, and 10 wt%. Avrami, Ozawa, and combined AvramiOzawa kinetic models were implemented to understand the non-isothermal crystallization behavior of aforementioned nanocomposites. Moreover, the nucleation activity of G-POSS particles was investigated in terms of Dobreva and Gutzow models. The data for kinetic analysis were obtained through differential scanning calorimeter. It was found that the crystallization rate of both plasticized and unplasticized PLA nanocomposites increased with the addition of G-POSS. It was highlighted that G-POSS is an effective nucleating agent for plasticized and unplasticized PLA nanocomposites. In parallel, these findings were in good agreement with activation energies obtained from Friedman model. In addition, all kinetic results were supported by polarized optical microscopy. (C) 2015 Society of Plastics Engineers