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Aging of polyamide 11. Part 1: Evaluating degradation by thermal, mechanical, and viscometric analysis

Aging of polyamide 11. Part 1: Evaluating degradation by thermal, mechanical, and viscometric analysis

Category
Journal publication
Abstract
Hydrolytic degradation at elevated temperatures is a key reason for failure in offshore flexible risers. In this article, the aging of polyamide 11 in deoxygenated water at 90°C and 120°C was studied. Tensile and dynamic mechanical thermal analysis tests were performed to measure changes in mechanical properties. Viscometry, gravimetric measurements, differential scanning calorimetry, and thermogravimetric analysis were used to link these properties with morphological changes. General trends are increased stiffness, tensile strength, and glass transition temperature as well as decreased glassy state damping efficiency with increased aging times. Changes can be initially ascribed to plasticizer depletion and then to interplay between molecular weight decrease and crystallinity increase. Viscosity at hydrolysis equilibrium indicates that brittle failure typically involves oxidation or UV exposure.
Client
  • Norges forskningsråd / 193167
Language
English
Author(s)
Affiliation
  • Norwegian University of Science and Technology
  • SINTEF Industry / Materials and Nanotechnology
Year
2015
Published in
Journal of Applied Polymer Science
ISSN
0021-8995
Volume
132
Issue
20