Abstract
The uses of trapping agents to trap nylon-6 radical and polyethyl-eneterephthalate (polyester) radicals produced by stress in highly oriented fibers was studied under various conditions; in the presence of solvent, in a temperature range from 0° to 50° and with various strain rates. The stability of the trapped radical is insensitive to solvent, temperature and time of the experiment. The maximum concentration of trapped radical in nylon-6 observed at specimen fracture is 1.4 x 10¹⁶ spins/cc at room temperature. The maximum concentration of trapped radicals in polyester fiber varies with the conditions of testing but is less than 1.75 x 10¹⁵ spins/cc. The concentration of trapped radicals in both nylon-6 and polyester is sensitive to temperature, strain rate and the presence of solvent. These results completely disagree with the kinetic theory of strength proposed by Zhurkov. The experimental results strongly suggest that the strength of polymer fiber depends upon the tie chains inside an amorphous phase. And it may also depends upon the amorphous phase content in the fiber. Various fracture models and their limitations are discussed in connection with the experimental results.
Sringam, Sutat (1976). Electron spin resonance of trapped radicals in nylon-6 and in polyethyleneterephthalate fibers. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -475513.