Influence of frictional characteristics of core and sheath in relation with core-sheath ratio and spinning drums' speed on tensile characteristics of DREF-3 friction-spun yarns

Abstract

The influence of frictional characteristics of core and sheath, core-sheath ratio, and spinning, drums’ speed on the tensile characteristics of DREF-3 friction-spun yarns has been studied. The increase in fibre-to-fibre friction due to the increase in the level of add-on finish on core fibres/sheath fibres/both the fibres increases the yarn tenacity, initial modulus and energy-to-break. The tenacity increases by 18% for ~9-14% increase in fibre -to-fibre frictional force due to the increase in PEG-600 finish from 0% to 0.4%. For the same level of AVF-5/32 finish, the fibre-to-fibre frictional force increases by~14-19% which results in 20% increase in tenacity. The increase in fibre friction does not affect the yarn breaking extension but significantly increases the initial modulus. The core-sheath ratio of 70:30 results in maximum yarn tenacity, initial modulus and energy- to-break. The increase in spinning drums’ speed from 3500 rpm to 5000 rpm increases the tenacity; the improvement in yarn tenacity is however maximum at lower level of fibre friction and vice versa. The maximum tenacity is achieved at 5000 rpm spinning drums’ speed and higher level of friction.