USE OF OXAZOLINE FUNCTIONALIZED POLYOLEFINS AND ELASTOMERS AS COMPATIBILIZERS FOR THERMOPLASTIC BLENDS

Oxazoline functionalized polypropylene, polyethylene, ethylene propyle ne copolymer (E/P), and styrene ethylene/butylene styrene copolymer (S EBS) were studied as compatibilizers in blends of polyolefins with pol yesters and polyamides. The blends investigated were polypropylene/pol yamide 6, polypropylene/polybutylene terephtalate, and polyethylene/po lyamide 6, with engineering thermoplastic contents of 30 wt %. The ble nds were prepared in a twin-screw midiextruder, and injection molded w ith a mini-injection molding machine. The effect of compatibilizing on the morphology and mechanical properties of the blends was of interes t. Compatibilization substantially improved the toughness of all teste d blends. Their strength and stiffness remained at the level of the bi nary blends when polypropylene or polyethylene based compatibilizers w ere used, but slightly decreased with other compatibilizers. Morpholog ical studies showed that the particle size was reduced, and the adhesi on of the dispersed phase to the matrix improved by compatibilization. The effect of unfunctionalized polyethylene, polypropylene, E/P, and SEES was also studied to compare the compatibilizers with them. (C) 19 98 John Wiley & Sons, Inc.