59—An Investigation into Bending and Torsional Rigidities of Some Fibres

Bending rigidities by static and dynamic methods, and torsional rigidities by a simple dynamic method, have been measured for a series of fibres. Bending rigidities are discussed in relation to tensile measurements, and, for fibres with approximately round cross-sections, the tensile modulus usually falls between the dynamic and static bending moduli. The acrylic fibres have high bending and torsional rigidities and the regenerated proteins are characterised by low bending rigidities. Bending rigidity of viscose varies as the 1·96th power of the denier and torsional rigidity as the 1·9th power.