Bilateral Structure of Cotton Fibers as Revealed by Enzymatic Degradation

Abstract

The morphological appearance of cotton fibers scoured at 100 and 140°C then subjected to a treatment with cellulase, has been examined as a function of the enzymatic action time. The rate of enzymatic digestion varies according to the region of the secondary wall under consideration, and examina tion of the degraded fibers by optical and scanning electron microscopy clearly shows the bilateral structure of cotton. Four zones can be distinguished in the secondary wall, which differ in their accessibility to reagents. These differences can be attributed to local variations in the packing density of the fibrillar structure, caused by the mechanical forces which appear in the fibers during their drying. The effect of scouring at a higher temperature is to increase the rate of enzymatic degradation without affecting the relative and important differences in the resistance to biodegradation of the different regions of the secondary wall.