Physical Properties of Chemically Modified Cottons

Abstract

Yarns manufactured from samples of the same six cotton varieties discussed in the previous paper were partially acetylated to an acetyl content of approximately 24% while held under tension. Certain physical properties of the component fibers, fiber bundles, and yarns were then measured. The changes in most properties were found to be associated with differences in the cottons and the acetyl contents. The averages for breaking loads and tenacities of the fibers were decreased while their linear densities and secant moduli were increased. Breaking loads, linear densities, and secant moduli of the yarns were increased. Elongation of the yarns at break was decreased, while tenacity remained essentially unchanged. The changes were greater for some cottons than for others; whether the changes were advantageous or disadvantageous would depend somewhat upon the use to which acetylated cotton is to be put.

Physical Properties of Fibers and Yarns of Partially Acety lated Cottons

“…The percentage breaking load retained hv the yarns was slightly greater than that of the fibers. This is in agreement with observations by Biclk~nalcl et al (16) on fibers from yarns which were acetylated while held at their original length.…”

“…Figure 3 also indicates that moisture increases the elongation of acetylated less than it does the unacetylated yarns. An increase of elongation was expected for yarns which were treated while relaxed, since the fibers are more highly swollen during such treatment than when held at constant length [ 16 ] . Increases in elongation of yarns are experi-, enced also when, in the process of scouring, fibers are swollen by much milder swelling'agents, such as water.…”

“…These changes were shown to be related both to inherent characteristics of the cotton and to the extent of Chemical substitution [ 4,14,16,17, 23,24).…”

“…THE partial acetylation of cotton has been found to produce a modified cellulose with improved resistance to chemical and heat degradation [4,14] _ and to microbiological deterioration [ 6, 8, 25 ~ . Whik the general appearances of the fiber and its products are essentially unchanged from that of scoured cotton, significant changes are found in the physical properties of the fibers [2,4,13,14,16]. These changes were shown to be related both to inherent characteristics of the cotton and to the extent of Chemical substitution [ 4,14,16,17,23,24).…”

“…Fiber lengths and moisture regain measurements were made according to ASTM recommended procedures [ 10,16 ) .…”