Project Details:

Property Improvement via Interfacial Chemical Reaction - Reactive Extrusion of EVOH/SMA and Polyamide/MAH-EPR

Blends of ethylene vinyl alcohol copolymer (EVOH) and styrene maleic anhydride copolymer (SMA) are prepared by reaction extrusion in a twin screw extruder and characterized in terms of their rheology, phase morphology and degree of covalent bonding interaction (ester linkages) between phases. Strongly synergistic effects show up in the melt viscosity and elasticity of the blend with maximal effect at 50-60% EVOH despite poor stoichiometric balance. During a preceding feasibility study the degree of bonding interaction could be quantified by means of FTIR. This reactive system forms crosslinked gel when maximally reacted. The investigation will be extended to a second blend system having more commercial relevance. Here, blends of polyamide 12 and maleic anhydride (MAH) modified EP-rubber will be prepared by reactive extrusion by Werner & Pfleiderer and analysed in terms of rheology, phase morphology and degree of bonding. Synergy of properties is expected specially in a region of stoichiometric balance but a network structure should not develop. A side study investigating the process effects of residence time, vacuum level and RPM/rate variation upon reaction extend and morphology is also intended.

Experimental work on Nylon 12/MAH-g-EPRongoing. Second paper for PAC planned concerned with the mechanicalproperties. A collaborative study of the structure and rheologicalproperties of EVOH/SMA blends produced by reaction extrusion byP.S.Hope, J.G. Bonner and J.E. Curry, Pure Appl. Chem. 68, 1665-1685 (1996)