FRACTOGRAPHY APPLIED TO POLYMERIC MATERIALS: PART 10: EFFECT OF SORBED WATER ON FRACTURE BEHAVIOUR OF PMMA

Authors
  1. Chan, P.
  2. Mitchell, A.B.
Corporate Authors
Defence Research Establishment Atlantic, Dartmouth NS (CAN);New Brunswick Research and Productivity Council, Fredericton NB (CAN)
Abstract
The purpose of the present work is to investigate the effect of sorbed water on the fracture behaviour of PMMA. Specimens were tested under constant loading in either dry or water saturated condition at ambient temperature. The applied stress varied from 46.3 to 53.0 MPa for dry tests, and from 32.4 to 46.3 MPa for wet tests. The results showed a nearly linear relationship between the applied stress and the log time-to-rupture for both dry and wet specimens. The fracture of specimens tested in dry condition initiated on the exterior of the specimens, while the fracture of specimens tested in wet condition initiated in the interior of the specimens. The surface crazes, observed on the lateral free surface close to the fracture face of the wet PMMA samples, appeared to be greater in density and more prominent than those found in dry samples. The present investigation also provided evidence that sorbed water by PMMA was detrimental to performance as the creep rupture strength was appreciably reduced. The sorbed water is believed to behave as a plasticizer, and as well, the water form clusters, resulting in earlier craze development, faster craze growth and more rapid craze breakdown of the polymer.
Report Number
DREA-CR-94-401 — Contractor Report
Date of publication
01 Dec 1993
Number of Pages
68
DSTKIM No
94-02402
CANDIS No
141144
Format(s):
Hardcopy;Originator's fiche received by DSIS

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