Estimation of pore size and porosity of modified polyester/PVA blended spun yarn

The performance of a textile material depends on the arrangement of its constituent fibres. For good mechanical behaviour strong inter fibre cohesion is necessary. In order to impart comfort characteristics, a permeable structure is desired. Staple fibre, by virtue of its limited length and other constraints, cannot produce fully compacted structure. For an optimum performance, a balance between the permeable and cohesive characteristics is necessary. An estimation of the openness of the structure may help in designing product for specific requirement. The degree of openness, however, may be varied through necessary modifications during and post manufacturing stage. In the present study empirical relations have been developed to calculate the equivalent pore diameter and porosity for three different modes of packing in yarns. Theoretical calculation was done for all three possible modes of packing while the experimental evaluations were made using the cross sectional images. The change in pore size and porosity were also estimated for a polyester/PVA blended yarn on removal of PVA component. A comparison of experimentally measured porosity was made with the results obtained theoretically. Hexagonal close packing resulted lowest porosity and experimentally measured values were in close association with the theoretically measured porosity.