Study on waterproofness and moisture permeability of densely woven fabric based on pore size distribution

In order to study the influence of pore size distribution of densely woven fabrics on their waterproofness and moisture permeability,different shrinkage composite filaments with the boiling water shrinkage 21. 7% and 10. 2%,respectively,and the linear density ratio of 1 ∶ 1. 1 were employed.Through the fluffy effect caused by different shrinkage,the pore size among filaments in fabrics was decreased and the porosity in composite filaments was increased. Relation between the pore size distribution of the fabrics treated at four treatment temperatures and the waterproofness and moisturepenetrability was analyzed. The results showed that the pore size distribution of densely woven fabrics was in a left avertence and asymmetric form. The graphs can be divided in four areas from right to left,including a platform area,a slowly increasing area,a peak area and a slowly decreasing area. As the shrinkage of the composite filament increased,each area showed an incorporative tendency,and the largest pore size reduced and the main pore size moved leftwards. In the pore size distribution graph with the maximum shrinkage,the peak area in the porosity of the filament is characterized in that the pore size range is of 4- 6 μm,the percentage of small pores occupied 76. 8%,and the platform area among the filaments is characterized in that the percentage of 10- 31. 1 μm large pores occupied 8. 9%. The slowly increasing area and the peak area,i. e. the pore number,in the pore size distribution played a leading role in the moisture permeability and the platform area,etc. large pores,had sufficient influence on the waterproofness of fabrics.