Crosslinking of cotton cellulose by lignin-isocyanate copolymer

Ethoxyl capped hydroxypropyl lignin (IIP-EL) was used as a finishing agent for cotton fabric to impart the property of crease recovery to the fabric. The synthesis of the finish involved two steps:

Synthesis of phenyl N( 3 - cyanato 4 methyl phenyl) carbamate by reacting phenol and Tolylene diisocyanate (TDI) in a 1:1 mole ratio.

Reaction of the above prepolymer with the modified lignin (HP- EL) using a mole ratio of 1:20 to form a lignin carbamate.

The lignin carbamate finish was crosslinked to cotton cellulose fabric through carbamoyl linkages when the fabric was cured. There is emperical evidence for the chemical crosslinking of cellulose with lignin. The effects of the finish on the fabric physical properties like durable press rating, dimensional stability, tensile strength, abrasion resistance, warp and weft recovery angle were investigated. Analysis of the results showed improvement in the durable press rating and excellent retention of tensile strength and abrasion resistance. The results of warp and weft recovery angle tests which relate to durable press properties, suggest the need to further investigate the possibility of using a different chain-extended lignin to achieve improved results.