Rheological behaviour of PP/PET and modified PP/PET blends. I. Steady state flow properties

Abstract

Both polypropylene (PP) and polyethylene terephthalate (PET) constitute a significant portion of post-consumer waste. To improve the recycling of immiscible PP/PET blends, a compatibilization should be utilized. In this study, steady state flow properties of unmodified and modified (by maleic anhydride) PP/PET systems were investigated. Three types of PPs with different flow properties were used to ascertain the influence of the matrix on the blend's rheology. According to the morphological observations and from the increased values of both viscous and elastic characteristics, an improvement in compatibility can be concluded (especially for blend whose components do not differ in viscosities largely) thus suggesting enhanced interphase interactions. Completely different behaviour was observed under the two temperature conditions used: at 265°C, rheological functions decrease with PET content in the blend, while at 245°C they increase, thus recalling the behaviour of particle-filled systems.