Rheological Behaviors of Polypropylene/Poly(1-butene) Blends

The rheological behaviors of polypropylene (PP)/poly(1-butene) (PB) blends with homo-polypropylene (PP1) or impact polypropylene (PP2), a poly(propylene-co-ethylene) as the PP component were studied. With increasing of PB resin content for both PP/PB blends, the blends showed higher G'(), G''() and *() at low frequencies but lower values at high frequencies which implied that the processability was improved. A two-phase morphology was observed through the various rheological responses, including G'()- terminal region curves, Cole-Cole plots and the weighted relaxation spectra with the PB contents up to 40wt%. With the same PB content, the rheological parameters of the PP2/PB blends were quite different from those of the PP1/PB, which can be attributed to the stronger interaction between PB chains and the ethylene-co-propylene copolymer in PP2. The impact strength of the PP2/PB blends was improved dramatically over that of the PP1/PB. The more significant toughening effect for the PP2/PB blends can be attributed to the special responses of its rheological behaviors.