Die Drool and Polymer Degradation
Loading...
Authors
Hoy, Geoffrey S.
Giacomin, A. Jeffrey
Gilbert, Peter H.
Date
2015-06-24
Type
technical report
Language
en
Keyword
Die drool , Slip heating , Cohesive slip , Polymer degradation , Scission
Alternative Title
Abstract
Die drool is an operational problem associated with polymer extrusion. Extrudate
collects outside of the die, necessitating periodic disruptions for cleaning. There
exists some debate as to the mechanism that produces die drool: stress induced
fractionation or thermal degradation. This paper examines the latter. In cohesive
failure, a slip discontinuity develops in the velocity profile, where heat is generated by friction. This slip heating can contribute to resin degradation, resulting in lower molecular weight fragments in the die drool. This paper examines the kinetics of this degradation, its influence on die drool rates, and on the resulting polymer concentration profiles in the drool layer and in the bulk.