Strain hardening in regenerated cellulose fibres

Viscose and lyocell are two types of regenerated cellulose fibre which show different structure and mechanical properties due to their different production process. In order to study changes in the elastic modulus of fibres after plastic deformation, viscose and lyocell fibres were repeatedly strained and unloaded in cyclic tensile tests. The elastic modulus of both types of regenerated cellulose fibre increased with increasing plastic strain. With an increase in the elastic modulus of 47%, the strain hardening effect was more pronounced in lyocell, which shows higher crystallinity and higher orientation of cellulose chains than viscose, where an increase by 24% was observed.