Etude des propriétés du mélange polyéthylènetéréphtalate/modificateur de choc

Abstract

This study is part of the recovery and mechanical recycling of polyethylene terephthalate (PET) waste which is an abundant deposit due to its wide use in the packaging sector. The presence of the residual moisture during its processing in the molten state causes hydrolytic degradation leading to the decrease of its properties. In order to limit hydrolytic degradation, a crystallization (annealing) was carried out on recycled polyethylene terephthalate (PETr) to obtain crystallized recycled polyethylene terephthalate (PETrC). To improve the mechanical properties of the latter, it was mixed with a styrene-ethylene / butylene-styrene copolymer grafted with maleic anhydride (SEBS-g-MA) as an impact modifier and then compared it with PETr and virgin PET (PETv). Indeed, the study carried out on the Brabender plastograph showed that a 20% increase in the torque was observed after crystallization of the PETr. On the other hand, thermogravimetric analysis (ATG) has shown that the crystallization of PETr improves its thermal stability. Incorporation of 20% SEBS-g-MA revealed a significant increase in impact strength of 356%, 158% and 188% for PETrC, PETr and PETv, respectively. This can be explained by the enhancement of the interface resulting from the reaction between the functional groups of PETrC and those of SEBS-g-MA, which was subsequently confirmed by IFTR (Fourier Transform InfraRed) analysis. On the other hand, analysis of thermal properties by differential scanning calorimetry (DSC) has shown that the temperature of cold crystallization of the PETrC / SEBS-g-MA mixture decreases and that its degree of crystallinity varies slightly from that of PETrC. The thermomechanical characterizations by dynamic mechanical analysis (DMA) and the heat deflection temperature (HDT) have shown that the addition of SEBS-g-MA to PETrC leads to the decrease of the conservation modulus and the HDT