Fatigue behaviour of some temperature-resistant polymers

✍ Scribed by J. P. Trotignon; J. Verdu; Ch. Martin; E. Morel

• Publisher: Springer
• Year: 1993
• Tongue: English
• Weight: 583 KB
• Volume: 28
• Category: Article
• ISSN: 0022-2461
• DOI: 10.1007/bf00367585

✦ Synopsis

Static and flexural (5 Hz, 20 ~ fatigue properties of three linear polymers, polyetherimide (PEI), polysulphone (PSU), polyetheretherketone (PEEK) and one three-dimensional polymer, amine cross-linked epoxy (EPO), were compared. In all cases, the fatigue lifetime was governed by crack initiation and a brittle rupture occurred. The order of stress endurance limit is: PEEK (65 MPa)>EPO (28 MPa)>PEI (24 MPa)>PSU (18 MPa). For PEI and essentially PSU, this value increased with orientation. It thus appears that there is no relation between the fatigue durability and the ductility or toughness as established from static tests. The results suggest that crack initiation involves large-scale configurational changes such as crazing. These changes would be inhibited or reduced by chemical (EPO) or physical (semi-crystalline polymers such as PEEK), cross-linking.