Liquid sorption behaviour of nonwovens

Abstract

In this paper, spunbond, meltblown and spunbond–meltblown–spunbond (SMS) nonwovens made from polypropylene are analysed for liquid transport behaviour. The thickness, grams per square metre (GSM), porosity, fibre diameter, fibre orientation distribution and water contact angles of these nonwovens are measured. Vertical wicking with decane using tensiometry and water absorbency and spreading using gravimetric absorbency tester are reported. The equivalent pore radii of the nonwovens are deduced from the vertical sorption experiments using tensiometry. The sorption rate under vertical wicking and water spreading rates are faster along machine direction compared with that in cross‐direction due to preferential fibre orientation. The thickness of the nonwoven, fibre diameter and porosity play a vital role in transporting liquid. Thin nonwovens have poor vertical wicking and spreading rate. SMS web has poor absorbency behaviour mainly due to the inability of its top S‐layer to pull the liquid from the middle M‐layer. The measured water spreading lengths with respect to time are compared to the theoretical ones using a model developed by earlier researchers. This model reasonably predicts the spreading behaviour of nonwovens.