Interactions of Nonaqueous Solvents with Textile Fibers

Abstract

Measurements of longitudinal shrinkage and volume swelling of polyester (PET) fibers in a wide variety of solvents were made at room temperature for time periods sufficient to establish quasiequilibrium conditions. Evaluated in terms of the solubility parameters ( & d e l t a ; ) concept, these results, together with iodine displacement studies, indicate that: (1) PET may be treated as an ( AB ) x alternating copolymer, where A is a semirigid aromatic residue &mdash;CO-C 6 H 4 &mdash; with a &delta;-value of 9.8, and B is a flexible aliphatic ester residue &mdash;O-CH 2 -CH 2 -O-CO&mdash; with a &delta;-value of 12.1 ; and (2) the preferential interaction of a solvent with either of the two PET residues provides the necessary chemical energy to disrupt intermolecular cohesive forces between the polymer chains, permitting relaxation of internal orientation forces and shrinkage of the fiber. It is shown by successively treating PET in solvents of increasing plasticizing strength that solvent-induced crystallization, a secondary process involving chain folding of the newly relaxed chains, does not inhibit shrinkage at lower temperatures. Therefore, room temperature chemical annealing is viewed as being similar to low-temperature (<175&deg;C) thermal annealing, where small crystallites are formed which confer negligible dimensional stability on the fiber undergoing shrinkage.. ' ABSTRACT Five samples of fabric treated with a silicone resin to prevent felting were examined for the presence of fiber bonds, using optical microscopy, micromanipulation, and measurement of the force required to withdraw a single fiber from the fabric. In all cases fiber bonds were found to be present and to be responsible for the resistance to felting. A sample of similarly treated tops, which acquired very little resistance to felting as a result of the treatment, was also examined. The fibers in this sample were coated with the resin but showed no fiber bonding, and their frictional properties were similar to those of normal, untreated fibers. Stress is laid on the difficulty which may sometimes be encountered in demonstrating the presence of interfiber bonds, and on the need for examination by micromanipulation before the conclusion is reached that they are not present.

The Influence of Polymer Morphology on the Dyeing Properties of Synthetic Fibres

“…Similar claims had been made by other authors [53,54]. Further work with 1 :1 mixtures of benzyl alcohol and ethyl alcohol yielded similar results, with the advantage of reduced shrinkage of the nylon 6 fabric in the presence of the aliphatic co-solvent [55].…”

Kinetics studies of solvent‐induced crystallization of drawn poly(ethylene terephthalate) by the in situ density measurement

“…In order to calculate the density of the swollen region, p,, the values of p(co)* evaluated by thermal volume expansion coefficient of PET were substituted for P(W) and the f, values shown in Table I11 were used in Eq. (7). The density difference (p, -p,) is proportional to the extent of SINC excluding the surface-cavitated region and shown in Table IV.…”

The molecular factors affecting the solubility parameter

“…AEsp = -ac*(N2/Vl)r*3 (12) In the general case, the cohesive energy density is defined in terms of A E which lead directly to the appropriate expression needed to describe a2:…”