ISSN:
0032-3888
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
The minimum surface strain required to induce crazing in polymethylmethacrylate and polystyrene in the presence of alcohols and n-heptane has been determined at various temperatures by bending strips of the polymers around formers of varying curvature and immersing them in the liquid reagents. For each polymer/liquid system the long-term crazing strain was independent of test temperature except within a single 30°C interval in which it decreased as the test temperature was raised. It was found that this temperature region corresponded to the glass-rubber transition of the given polymer when, after extended periods of immersion it had achieved equilibrium liquid sorption. This suggested that, in the crazing tests, a condition approximating to equilibrium sorption was being established at the craze tip and that crazing occurred on applying small strains in the presence of the liquids because of their plasticising effect.It was found that not only the plasticizing effect of the liquid environment but also the liquid molecule size influenced the crazing strain; the larger-molecule liquids caused lower long-term crazing strains than did the smaller-molecule liquids.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/pen.760130511
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