The Theory of Shrinkproofing of Wool; Part VI: Identification by Light Microscopy of Scale Masking and Spot Welding of Fibers by Polymer Deposits

Abstract

Light microscopy has been used to examine polyglycine and poly(hexamethylene sebacamide) deposited on the fiber by polymerization of the appropriate monomers and also polymethylmethacrylate deposited from solution in acetone. Two types of deposits occur: (i) a thin, discontinuous layer which covers most of the cuticle and is observed by mounting in “Sellotape” and (ii) irregularly placed, large pieces of polymer which cover only a very small fraction of the cuticle and are observed by mounting in water. The former is produced by polymerization of monomers in situ and effects shrinkproofing by scale masking, and the latter is produced by treatments with preformed polymer, in which case shrinkproofing is due to spot welding of fibers. It is thus possible to distinguish by simple microscopic examination of the treated fibers between the two different types of shrinkproofing produced by polymer deposition. It is concluded that deposition of preformed polymer by the usual techniques results in formation of irregularly placed, large pieces of polymer and that shrinkproofing is achieved by means of spot welding of fibers.