Composite fibrous substrates having protein sheaths

A method of preparing a composite fibrous substrate, the method comprising the steps of:

• contacting a fibrous substrate comprising core fibers with an aqueous solution of water-soluble carbohydrate and a crosslinker and, optionally, a suitable crosslinker catalyst;
• heating the fibrous substrate to dryness;
• and
• curing at a temperature sufficient to cause reaction between the crosslinker and the carbohydrate;
• to give a composite fibrous substrate comprising a carbohydrate sheath attached around the individual core fibers of the substrate and wherein the carbohydrate sheath is adhered to itself by covalent bonds.

A method of dyeing a composite fibrous substrate, the method comprising:

• contacting a fibrous substrate comprising core fibers with an aqueous solution of water-soluble carbohydrate, a crosslinker, a colorant and, optionally, a suitable crosslinker catalyst;
• heating the fibrous substrate to dryness;
• and
• curing at a temperature sufficient to cause reaction between the crosslinker and the carbohydrate;
• to give a dyed composite fibrous substrate comprising a carbohydrate sheath attached around the individual core fibers of the substrate and wherein the carbohydrate sheath is adhered to itself by covalent bonds and wherein the colorant is within the carbohydrate sheath.