Stress cracking of nylon polymers in aqueous salt solutions
- 137 Downloads
- 13 Citations
Abstract
The susceptibility of nylon polymers to environmental stress cracking in aqueous salt solution was investigated. The time to fail (complete rupture) was recorded for razor-cut precracked samples which were totally immersed in water, sodium chloride, or calcium chloride at various initial stress intensity levels and temperatures. Ductile failures were observed in both water and aqueous sodium chloride at all temperatures. However, in saturated aqueous calcium chloride the nylon failure mode changed from ductile tearing, at room temperature, to crazing and crachng at elevated temperatures (50 to 100° C). Lithium and magnesium chlorides were also observed to be potent cracking agents at the elevated temperatures. The temperature interval over which cracking occurred corresponded to the onset of the Oass transition temperature,Tg of the nylon. Thus, nylon 6, having a lowerTg, was more susceptible to cracking than nylon 6,6 et any given temperature. [)n the other hand' nylon 11, having a lower ratio of amide tornathy!onegroups, wasnotuuuoaptib!eto salt-induced cracking, For the nylon 6 and nylon 6,6 the failure kinetics in salt solutions were similar, regardless of whether dry samples or previously moisturized samples were examined. Thus e simple tempmra1ure-moisture content equivalence does not apply forsalt-induced stress cracking in aqueous solutions.
Keywords
Lithium Sodium Chloride Elevated Temperature Nylon Stress IntensityPreview
Unable to display preview. Download preview PDF.
References
- 1.C. D. Weiske,Kuntstoffe 54 (1964) 626.Google Scholar
- 2.
- 3.Idem, ibid. 13 (1969) 1657.Google Scholar
- 4.Idem, ibid. 13 (1969) 1673.Google Scholar
- 5.Idem, ibid. 14 (1970) 1799.Google Scholar
- 6.M. G. Wyzgoski in “Macromolecular Solutions: Solvent Property Relationships in Polymers”, edited by R. B. Seymour and G. A. Stahl (Pergamon, New York, 1982) p. 41.Google Scholar
- 7.
- 8.
- 9.
- 10.
- 11.
- 12.M. I. Koran, “Nylon Plastics” (Wiley, New York, 1973) p. 329.Google Scholar
- 13.W. F. Brown Jr andJ. E. Srawley, “Plane Strain Crack Toughness Testing of High Strength Metallic Materials” (ASTM Special Technical Publication No. 410, 1966) p. 11.Google Scholar
- 14.