Reologické chování PP/PET a modifikovaných PP/PET směsí. II. Dynamické viskoelastické vlastnosti.

Abstract

Článek se zabývá studiem dynamických viskoelastických vlastností směsí polypropylenu (PP) s polyetylentereftalátem (PET). Z faktorů ovlivňujících tokové chování byl studován efekt zvolené PP matrice, způsob kompatibilizace, vztah k fázové struktuře a porovnání reologických charakteristik stanovených při oscilačním a ustáleném smykovém režimu při měření na rotačním reometru.

The increasing amount of post-consumer waste leads to a search for effective recycling methods. Compatibilisation of immiscible blends of polypropylene (PP) and polyethylene terephthalate (PET) represents one such novel approach that allows recycling of significant scrap materials without any need for separation steps. The intention of this paper is to investigate dynamic viscoelastic properties of unmodified and modified PP/PET blends. To study the effect of matrix, three polypropylenes differing in flow properties were chosen. The compatibilisation was carried out by both one- or two-step reactive in situ techniques. In the former case, the addition of 1 wt.% of maleic anhydride (MA), and in the latter, polypropylene supplied as already modified by the producer were employed. The positive effect of compatibilisation can be concluded not only from the results of the morphological study (dispersed phase size reduction, strengthened interfacial adhesion), but also through increased values of viscous and elastic characteristics, which suggests enhanced interactions between the blend components. Comparing steady shear and dynamic viscoelastic properties, the various extent of deformation applied during both types of measurements leading to different material response should be considered.