Aging studies of Kevlar 49 fibers

Conference · Tue Nov 01 04:00:00 EST 1983

OSTI ID:5277276

Morgan, R J; Pruneda, C O; Kong, F M

The aging mechanisms in service environment of Kevlar 49 fibers, E.I. duPont, (poly(p-phenylene)terephthalamide) are reviewed. The principal aging mechanisms considered are (i) u.v.-, (ii) hydrolytic- and (iii) stress-induced macromolecular chain scission and microvoid growth. U.V.-induced strength degradation can be significant as a result of photo-oxidative and photodegradative radical formation but in Kevlar 49-epoxy composites only the exterior yarn layer is deteriorated. Hydrolytic chain scission of the amide linkage and corresponding fiber strength deterioration is considered in terms of R.H., time, temperature and stress level. The rates of hydrolytic degradation at 100% R.H. in the 100 to 200/sup 0/C range are reported. The estimated rates of fiber degradation in various service environment conditions are also reported and shown not to be serious. The stress-induced aging of Kevlar 49 fibers is considered in terms of the growth and coalescence of inherent microvoids along the fiber axis together with the generation of new microvoids. (These growth processes involve no detectable macromolecular chain scission or deterioration in fiber strength.) At a critical microvoid volume fraction catastrophic failure occurs by interconnection of such voids.

• Research Organization: Lawrence Livermore National Lab., CA (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5277276
• Report Number(s): UCRL-89971; CONF-840415-6; ON: DE84003001
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360405* -- Materials-- Polymers & Plastics-- Degradation & Erosion-- (-1987)
AGING
ARAMIDS
CHEMICAL REACTIONS
DECOMPOSITION
ELECTROMAGNETIC RADIATION
FIBERS
HYDROLYSIS
LYSIS
MATERIALS
PETROCHEMICALS
PETROLEUM PRODUCTS
PLASTICS
RADIATIONS
SOLVOLYSIS
STRESSES
SYNTHETIC MATERIALS
ULTRAVIOLET RADIATION