Influence of steam and dry heat pretreatment on fibre properties and cellulase degradation of cellulosic fibres

Cellulosic fabric samples of cotton, viscose, lyocell and modal were pretreated with steam and dry heat in the range of 100–190°C. The samples were then treated with a Trichoderma reesei cellulase preparation (total culture filtrate – TC), with mechanical agitation, at a high enzyme dosage of 75% by weight of fabric, for 8 hours. Generally, viscose proved to be easily degradable, followed by cotton and modal. The degree of hydrolysis was the least for Lyocell. Dry heat pretreatments exerted a lower influence on degradation rate than steam pretreatments which showed a distinct maximum at a steam temperature of 130°C. The hydrolysis rate varied strongly depending on treatment conditions and fibre type. Water retention values in treated substrates were changed by up to 20% of initial values.