Anionic waterborne polyurethane dispersions from maleated cotton seed oil polyol carrying ionisable groups

A novel class of bio-based, DMPA free, catalyst free, anionic waterborne polyurethane dispersions (PUD) have been successfully synthesized. Hydroxylated cottonseed oil has been maleated using maleic anhydride to introduce hydroxyl groups and ionisable carboxyl groups. This maleated polyol (MAHCSO) has been employed to develop water-based polyurethane dispersions through a prepolymer method and chain extension with dihydrazides at the dispersion stage. The -OH groups of the MAHCSO formed urethane bonds, and the carboxylate groups acted as an internal ionizer to stabilize the polymer dispersion in water. The significant effect of the ionic content in the polyol (MAHCSO) and chain length of dihydrazide on particle size, physico-chemical, thermal and mechanical properties of the resulting PUD films were investigated.