32—THE DEGREE OF POLYMERIZATION AND ITS DISTRIBUTION IN CELLULOSE RAYONS. PART IX.—THE INFLUENCE OF DISTRIBUTION OF DEGREE OF POLYMERIZATION ON THE MECHANICAL PROPERTIES OF MONOFILAMENTS

Abstract

Blends of secondary cellulose-acetate fractions (DP 40—1200) were spun by a wet-spinning technique into monofilaments; these filaments were stretched to produce different degrees of orientation, and then saponified to cellulose filaments. The birefringence of the filaments was measured and used as an index of orientation; the tenacities and breaking extensions were determined with a Cambridge extensometer. Some measurements were also made on cellulose acetate filaments. Similar measurements were obtained with monofilaments made from cellulose rayons for which the distributions of degree of polymerization (DP) were known. The rayons were first fully acetylated and then spun into monofilaments by a technique different from that used for secondary acetates. These filaments were saponified before tests were made on them. It was found that the tenacity of a filament can be computed from its DP distribution and relations between tenacity and DP for filaments made from fractions. Neither the number-average nor t...