Uniaxial Elongational Flow of the Melt of Ethylene-Propylen Copolymer/Styrene-Maleic Acid Copolymer Blends

Abstract

Uniaxial elongational viscosity-time curve (time<430 s (strain<1.3)) was measured at 175°C for the melt of an immiscible blend with and without a compatibilizer. The immiscible blend (PP-EPR/SMA) was composed of 70wt% ethylene-propylene copolymer (PP-EPR) and 30wt% styrene-maleic acid copolymer (SMA). Ethylene fraction of PP-EPR was about 14wt% and maleic acid fraction of SMA was about lOwt%, respectively. The compatibilizer used in the present experiment was 15wt% styrene-butadiene-styrene block copolymer (SBS; Styrene/Butadiene=3/7 by wt%). Both of PP-EPR/SMA and PP-EPR/SMA/SBS showed the binary-phase mor-phology of particles and polymer matrix. Dynamic moduli G'. G and viscosity under shear flow η were also measured at 175°C and at the angular frequency or shear rate ranging from 10-5 to 102 s-1. G'. G and η of PP-EPR/SMA/SBS were almost consistent with those of PP-EPR/SMA. It is noted that non-linear behavior of the uniaxial elongational viscosity was observed for PP-EPR/SMA whereas it was not for PP-EPR/SMA/SBS. Morphology observation of PP-EPR/SMA/SBS elongated samples by scanning electron microscope showed that interface between particles and polymer matrix was compatibilized well enough and the particles were elongated by the polymer matrix. On the other hand, particles in PP-EPR/SMA were observed to be pealed off from polymer matrix.