Load-extension curves of a folded cotton yarn, which had been scoured or mercerised, then tendered to various degrees by oxidation, acid or heat, have been determined at relative humidities ranging from 9% to 100% (wet state).The strength and breaking extension of the grey yarn increase steadily with relative humidity, but the scoured and mercerised yarns give maximum values at about 85% r.h., and this maximum moves to lower relative humidities as the tendering increases. For the most highly tendered materials, the strength decreases with increase in relative humidity and, for the highly tendered mercerised yarn, the rate of decrease in strength is almost identical with that for a regenerated cellulose staple fibre yarn. The results are compared with data obtained by Turner for weathered cotton fabrics.Breaking load tests on fibres taken from the chemically modified yarns show that the strength-humidity relationship for the fibres is determined by the average length of the molecules, and that most of the effect of humidity on the strength of the yarn can be attributed to change of fibre strength with humidity.The rates of change of strength and breaking extension with humidity for the grey yarn agree with corresponding figures for singles yarn, tyre cord and fabric and lead to the conclusion that, in the range 45 to 85% r.h., the strength of grey cotton materials increases by 3 to 4%, and the breaking extension by 6 to 7%, for each 10% increase in relative humidity.
No takes yet. Share an insight, caveat, or question.
R. Meredith (1956) studied this question.