Effect of Copper Sulphate on Hydrogen Peroxide Bleaching with Hydrolysis on P/C Fabric Mechanical Properties

Abstract

Surface modification of polyester and Polyester / Cotton material is not a new concept to a processing man. Alkaline oxidation of P/C blends with copper sulphate, hydrogen peroxide and base hydrolysis has shown some interesting trends.The present work includes the investigation of effect of padding copper sulphate (3 levels) and bleaching with hydrogen peroxide followed by base hydrolysis (2% concentration) at 1:5 and 1:10 MLRs with treatment temperature selected at 110 and 120 degrees centigrade on fabric mechanical properties like tensile strength, bending length, crease recovery and compressibility. In general it is observed that following copper sulphate treatment the weight increases, and decreases after bleaching. Due to the action of caustic, substrate suffers from loss of weight due to removal of chains from surface by NaOH. With increase in bath ratio (w/v) and concentration of copper sulphate, an increase in weight after copper sulphate treatment is observed, followed by decrease in weight after bleaching and loss of weight following hydrolysis. The increase in weight with increase in copper sulphate concentration is mainly due to padding. The results clearly show a positive shift following alkaline oxidation and hydrolysis from gray level. Higher bath ratios with higher hydrolysis temperature have registered a positive shift by about 30%.Decrease in bending length following bleaching and base hydrolysis has indicated the softness of the substrate. At higher bath ratio and hydrolysis temperature, as copper sulphate concentration increases, nearly 20% positive shift is observed in stiffness values. Due to alkaline oxidation and base hydrolysis with higher copper sulphate concentration at higher bath ratio and temperature, nearly 20% negative shift increase recovery values have proved that fabric has become softer following finishing. An excellent compression behavior is observed in bleached, hydrolysed samples. With increase in copper sulphate concentration the compressibility has registered an increasing trend with hydrolysed samples.