Experimental Investigation of a New Type of Interfacial Instability in a Reactive Coextrusion Process
Résumé
This paper deals with the study of new interfacial instabilities,
called “grainy” defects, in coextrusion process of
reactive multilayer polymers. The main objective was to
better understand this phenomenon since no help can be
found in the literature. The fundamental approach from a
micro-scale to a macro-scale involves the study of relationships
between polymer structure, processing, and
interfacial properties. The influence of these parameters
on the generation of “grainy” defects during coextrusion
has been assessed in correlation with physicochemical
properties. Through this work, rheological properties and
the interfacial morphology between tie and barrier layers
have been investigated by shear stress relaxation experiments
and transmission electronic microscopy, respectively.
Depending on the reactive polymers, the interfacial
coupling was found to significantly alter the stress relaxation
behavior by extending the relaxation time and generating
an interfacial roughness. Hence, relations between
the copolymer architecture, the relaxation process, and
the interfacial morphology were established in correlation
with the generation of grainy defects in coextrusion process.