Publication: Rheology and extrusion of medical-grade thermoplastic polyurethane
Program
KU-Authors
KU Authors
Co-Authors
Lu, Guangyu
Kalyon, Dilhan M.
Publication Date
Language
Type
Embargo Status
Journal Title
Journal ISSN
Volume Title
Alternative Title
Abstract
The selection of operating conditions and geometry for the processing of thermoplastic polyurethane, TPU, is a complicated task. This complication arises from the relatively high melting temperature of the crystalline hard blocks and the oxidative and thermal degradation and crosslinking that occur at temperatures that are relatively close to the melting temperature of the TPU. This article documents the rheology, extrusion, and structure development of a medical-grade TPU. The medical application requires that the additives commonly utilized in the development of polymeric resins, i.e., stabilizers, antioxidants, and lubricants, should be minimized; the TPU of this study contains no additives. At temperatures 10-20°C lower than the melting temperature of the TPU, the morphology of the hard blocks continues to evolve to generate a reversible increase in elasticity and shear viscosity of the TPU with increasing time. At temperatures greater than the melting temperature, the TPU undergoes degradation and crosslinking reactions, which give rise to a permanent increase in the elasticity and the shear viscosity of the TPU. The ramifications of the degradation and crosslinking at temperatures greater than 200°C and morphology modification upon the continuing evolution of the hard blocks at temperatures less than 200°C on the rheology and processing were investigated.
Source
Publisher
Wiley
Subject
Chemistry
Citation
Has Part
Source
Polymer Engineering and Science
Book Series Title
Edition
DOI
10.1002/pen.10158