ISSN:
0887-6266
Keywords:
Chemistry
;
Polymer and Materials Science
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
As-spun poly(p-phenylene terephthalamide) (PPTA) fibers have been annealed by three different methods: (1) the relaxation mode; (2) the constant temperature mode; and (3) the constant tension mode. Wide-angle x-ray diffraction (WAXD) was used with all three modes to characterize the changes in three crystal structure parameters: the degree of crystal orientation, the apparent crystal size, and the lattice strain along the c-axis of the crystal unit cell. It was found that internal stresses in the fibers, which are frozen-in during either the fiber spinning process or in later annealing, is the key factor causing these structure parameter changes. Our thermal shrinkage stress measurements may reasonably represent the fiber's internal stresses. The thermal shrinkage modulus and the tensile modulus of the PPTA fibers under these annealing modes have been determined. Based on a serial model, quantitative structure-property relationships can be established. The effects of annealing temperature and applied tension on both the microscopic crystal structures and the macroscopic properties are also discussed.
Additional Material:
15 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/polb.1990.090281308
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