Polymer Decomposition
Biochemical and chemical reactions that break down the long chain glucose molecules in plant based fibres facilitate the modification of fabric hand and surface appearance. Through cellulose hydrolysis, the oxygen bridges between the repeating units of the polymer are severed by water molecules. This process is often catalyzed by enzymes or acids to increase the rate of reaction at lower temperatures.
Enzyme Interaction
Cellulase enzymes used in the finishing of denim garments target the protruding fibres on the surface of the yarn to create a smoother texture. During cellulose hydrolysis, these biological catalysts bind to the amorphous regions of the cotton fibre to weaken the surface hairiness. The action results in the removal of pills and a reduction in the fuzzy appearance of the finished cloth.
This enzymatic treatment replaces traditional mechanical sanding which can be more abrasive to the underlying structure.
Tensile Loss
Reductions in the structural integrity of the fabric occur when the reaction penetrates deep into the secondary wall of the cotton fibre. If cellulose hydrolysis is allowed to proceed unchecked, the loss of weight and strength becomes a liability for garment durability. Mills must balance the aesthetic benefits of a soft hand against the risk of the material tearing during consumer use.
Processing Limit
Controlling the duration and temperature of the bath prevents the total destruction of the textile substrate. After the desired degree of cellulose hydrolysis is reached, the bath is heated to a high temperature to denature the enzymes. This termination step ensures that the chemical activity stops and the fabric remains stable during subsequent laundering.
