Screening of commercial starches for textile coating application

Abstract

This work screens the use of commercial starches for coating applications, as a potential alternative to PVC plastisol. PVC plastisol solutions for coating applications are expected to show a high viscosity of 10-100 Pa.s at low shear rate of 0.1-1 s-1 and a low viscosity of 1-10 Pa.s at high shear rate (higher than 1000 s-1). Three types of commercial starch samples were studied with dynamic shear tests under small deformation and with a specially modified capillary rheometer developed to characterize low viscosity solutions. All the starch solutions had tendency to form weak gels except 10% Waxy Maize starch solution which is a viscoelastic fluid. Larger concentrations resulted in too viscous and shear thickening solutions with aging problems. The conclusion of this rheological screening is that 15% Waxy Maize is the most promising candidate for desired application.