In-reactor polypropylene alloys in oriented film applications morphology and properties

The properties of Biaxially Oriented Polypropylene film prepared from PP blends with in-reactor PP-g-PS or PP-g-PMMA are studied. Cast sheets obtained from these compounds show sub-micron particle size distribution of the amorphous domains which were turned into discrete platelet-like form after simultaneous orientation on the TM Long stretcher. Enhancements in mechanical, barrier properties were measured for the all films. Tried on a tenter frame line as the outer layer of a co-extruded BOPP structure those compounds imparted high stiffness films and after air corona treatment provide high film surface energy. An apparent increase in the surface tension was observed on aging. The products deriving from the reactor granule technology broaden the property envelope of PP and can act as adhesion promoters or as compatibilizers of PP with other polar substrates.