WORKING PARTY ON STRUCTURE AND PROPERTIES OF
COMMERCIAL POLYMERS
Number: 421/34/95
Title: Property Improvement via
Interfacial Chemical Reaction - Reactive Extrusion of EVOH/SMA and
Polyamide/MAH-EPR
Coordinator(s): J.E.
Curry, J.G. Bonner,
and P.S. Hope
Completion Date: 2001
Objective:
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.
Progress:
Experimental work on Nylon 12/MAH-g-EPR
ongoing. Second paper for PAC planned concerned with the mechanical
properties. A collaborative study of the structure and rheological
properties of EVOH/SMA blends produced by reaction extrusion by
P.S.Hope, J.G. Bonner and J.E. Curry, Pure Appl.Chem. 68,
1665-1685 (1996)
Last update: 10 September 1999
