The effect of draw ratio on the properties of pp/PET blends compatibilised by pp-&ITg&IT-(DAP-&ITco&IT-GMA)

Polypropylene/poly (ethylene terephthalate) (PP/PET) blends, compatibilised by glycidyl methacrylate (GMA) and diallyl phthalate (DAP) grafted PP [PP-g-(DAP-co-GMA)], were prepared under the different draw ratio (DR). The effect of DR on the properties of resultant blends was investigated by scanning electron microscopy, differential scanning calorimetry, rheological analysis, tensile and heat resistance tests. The results showed that the compatibility of PP/PET blends could be improved by PP-g-(DAP-co-GMA); as the increase of DR, the morphology of PET dispersed phase evolved as follows: spherical -> particle ellipsoidal particle -> stubby fibre -> lathy fibre -> bitty fibre, compared with the PET spherical particle, the PET microfibre possessed stronger heterogeneous nucleation effect on the crystallisation of PP, which was in favour of the improvement of crystallinity of PP. As a result, the mechanical properties and heat resistance were also enhanced obviously. The rheological analysis revealed that the complex viscosity (eta*), storage modulus (G') and loss modulus (G') were dependent on the morphology of PET. The viscoelasticity of the blends is improved when the PET was in the form of microfibre.