Die Drool and Polymer Degradation. (11th February 2016)

• Record Type: Journal Article
• Authors: Hoy, Geoffrey S.; Giacomin, A. Jeffrey; Gilbert, Peter H.
• Is Part Of: Polymer-plastics technology and engineering. Volume 55:Number 3(2016)
• Page Start: 242
• Page End: 258
• Publication Date: 2016-02-11
• Subjects: Cohesive slip -- die drool -- polymer degradation -- scission -- slip heating; Polymers -- Periodicals; Polymerization -- Periodicals; Polymers -- Periodicals; Engineering -- Periodicals; Plastics -- Periodicals; 668.9
• DOI: 10.1080/03602559.2015.1070871
• Languages: English
• ISSNs: 0360-2559

Abstract

ABSTRACT: Die drool is an operational problem associated with polymer extrusion. The extrudate collects outside of the die, necessitating periodic disruptions for cleaning. There is a debate over the mechanism that produces die drool: stress induced fractionation or thermal degradation. This article examines the latter. In cohesive failure, a slip discontinuity develops in the velocity profile, where frictional heating occurs. This slip heating can contribute to resin degradation, resulting in lower molecular weight fragments in the die drool. This article examines resin degradation kinetics and its influence on die drool rates and on the resulting drool layer and bulk polymer concentration profiles. GRAPHICAL ABSTRACT: