Grafting on Wool Through Free Radical Formation on the Protein

Abstract

A new method was developed to improve grafting of polymers to wool. Polyacrylic acid and five other vinyl polymers were grafted, up to 130 weight percent, onto wool from aqueous media in 3 to 48 h at ambient to 80°. In order to assure free radical formation on the protein as a starting point for polymerization, two catalyst systems were used. One was acidic free radical catalysts which formed ammonium-type salts with wool. The other was a H2O 2/wool redox system. Fabric with 100 wt percent polyacrylic acid graft remained relatively soft and pliable. Polyacrylic acid grafted fabric with 60% uptake showed only 5% shrinkage in an Accelerotor test. However, neutralization of polyacrylic grafted wool by Na2CO2 showed no shrinkage in a similar wash test even at 24 wt percent uptake. While such neutralized grafted fabric exhibited lower strength, no such deterioration was observed when bivalent bases or carbonates had been used for neutralization.