Bound water in Kevlar 49 fibers
From elemental analyses, thermogravimetric-mass spectroscopy studies and re-evaluation of previous water diffusion studies in Kevlar 49 fibers it is concluded that these fibers can contain two types of sorbed moisture. The fibers can absorb up to approx. 6 wt % loosely bound water with an activation energy for outgassing by desorption of 6 kcal/mole. This loosely bound water is a direct result of the presence of Na/sub 2/SO/sub 4/ impurities and the perturbations they induce on the packing of the rod-like poly (p-phenylene terephthalamide) macromolecules. Kevlar 49 fibers also inherently contain up to 30 wt % additional water which is tightly bound within the crystal lattice. This water exhibits an activation energy for outgassing by diffusion of approx. 40 kcal/mole and is only evolved from the fiber in significant quantities at t > 350/sup 0/C over a period of hours.
- Research Organization:
- Lawrence Livermore National Lab., CA (USA)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6208024
- Report Number(s):
- UCRL-85838; CONF-810813-5; TRN: 81-013191
- Resource Relation:
- Conference: National American Chemical Society summer meeting, New York, NY, USA, 23 Aug 1981
- Country of Publication:
- United States
- Language:
- English
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