REACTIVE EXTRUSION OF PP NATURAL RUBBER BLENDS/

Reactive extrusion of polypropylene (PP)/natural rubber (NR) (90/10) b lends was conducted in the presence of a peroxide[1,3-bis(t-butylperox y)benzene] and coagent (trimethylolpropanetriacrylate, TMPTA). Effects of peroxide and coagent content were studied in terms of melt index ( MI), melt viscosity, morphology, thermal, and mechanical properties. A t a constant content of the coagent, melt viscosity increased at a low and decreased at a high content of the peroxide. On the other hand, m elt viscosity increased monotonically with the coagent concentration a t constant peroxide content. The increase and decrease of viscosity we re interpreted in terms of crosslinking and chain scission of PP, whic h governed the rubber domain size and mechanical properties of the rea ctive blends. (C) 1995 John Wiley and Sons, Inc.