Shrinkproofing of Wool with Polyglycine from the Polymerization of Anhydrocarboxyglycine

Abstract

Shrinkproofing of wool with anhydrocarboxyglycine is not possible from aqueous solution but can be achieved using 2% anhydrocarboxyglycine on the weight of the wool at 50° for 1 hr. in water-washed white spirit or trichloroethylene. Treatments at room temperature require a minimum time of 7 hr. The polymerization, initiated by water present in the wool, produces polyglycine with a degree of polymerization (DP_n) about 30. Descaling of treated fibers shows that all the polyglycine is located in the outside 10% by weight of the fiber; a surface layer can be seen by Sellotape microscopy and electron microscopy. It is this surface layer which is responsible for the large increase in the frictional coefficients μ₁ and μ₂ and decrease in ( μ ₁-μ ₂) which in turn effects shrinkproofing. At levels of treatment ⋞ 0.39% polyglycine, partial shrink proofing is produced by small spots of polyglycine distributed at random over the fiber with no appreciable amount of masking of the scale edges.