Morphology development of immiscible polymer blends during melt blending: Effects of interfacial agents on the liquid-solid interfacial heat transfer

This article reports on a new phenomenon: The presence of a compatibilizer accelerates the melting/plastification of an immiscible polymer blend durin g melt blending. The increase in the rate of melting as a result of the add ition of a compatibilizer is believed to be one of the important factors re sponsible for the fact that the morphology of compatibilized blends develop s much faster than that of their uncompatibilized counterparts. To substant iate the above statement, blends based on polypropylene (PP) and polyamide 6 (PA6) were used as model systems. The compatibilizer was a graft copolyme r (PP-g-PA6) with PP as the backbone and PA6 as grafts. Its presence in a P P/PA6 blend accelerated the rate of melting of the PA6. This effect was obs erved only when the compatibilizer itself was molten and migrated to the in terfacial layer between the PA6 and PP phases. It is likely that the presen ce of the compatibilizer increased the chain entanglements at the PP and PA 6 interface and consequently reduced the thermal resistance of the interfac ial layer. Detailed mechanisms are discussed. (C) 1999 John Wiley & Sons, I nc.