Mechanisms of degradation of cotton and effects of mercerization‐stretching upon the course of these mechanisms, III. Heat treatments

Abstract

AbstractChanges in the physical as well as chemical structure of scoured and slack mercerized restretched (90–103% of original length) cotton yarns brought about by heat treatments and the effects of these on the strength properties of the cotton yarn were investigated. No striking changes in copper number, carboxyl content, iodine sorption, degree of polymerization (P) and strength properties were observed when the scoured and the mercerized yarns were heated at 160, 180, 200, and 210°C for up to 10 min. On the contrary, with the exception of carboxyl content, marked changes in these properties were determined when heat treatment was carried out for up to 96 h and 5 h at 160°C and 210°C, respectively. However, the mercerized yarns retained higher strengths in spite of higher degradation as compared to scoured yarn. The interrelationship between strength and P as well as strength and percentage of bonds broken together with measurements of frequency of successive regions of high lateral order indicated that mercerized cotton exhibited a more uniform structure which improved the distribution of stress along the fibre.