Investigation of non-adhesive behaviour of waterborne polyurethane dispersions

Abstract

The current work probe the thermo-mechanical defects responsible for the non-adhesive behaviour of waterborne polyurethane dispersions (PUDs). A sequence of composition of PUDs has been developed by using blended macrodiols of hydroxyl terminated polybutadiene (HTPB) and polypropylene glycol (PPG). The urethane linkages have been developed by the use of 1,6 hexane diisocyanate (HDI). The polymer contents synthesized by prepolymer method have been dispersed in deionized water to develop ecofriendly dispersions. The dispersions were subjected to probe tack analysis to determine the extent of adhesiveness. The adhesive properties evaluated from probe tack curve show tack adhesion energy from 10.5 to 42. 5 J-m-2. The DMA analysis revealed high storage modulus up to 1.42 MPa for PUD films. The adhesive properties evaluated by the consideration, of the ratio of loss tangent, to the storage modulus (tanδ / E′) for comparison resulted in the values from 0.15 -0.71 MPa-1. The Tg ranges from 65 °C to 57 °C. The composition of blended macrodiols of high molecular weight HTPB results in tack less rigid films of PUDs.