Influence of Diisocyanate Structure on the Synthesis and Properties of Ionic Polyurethane Dispersions

Abstract

A number of aqueous polyurethane dispersions based on polytetramethylene glycol (PTMG), 1,4-butanediol (1,4-BDO), dimethylol propionic acid (DMPA) and diisocyanates of differing structures such as toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), and dicyclohexylmethane diisocyanate (H12MDI) were prepared. IR Spectroscopy was used to check the end of polymerization reaction and also the polymer characterization. The effects of diisocyanate structure on the particle size, contact angle, mechanical and thermal properties of the emulsion-cast films were studied. Average particle size of prepared polyurethane emulsions change by different diisocyanate based polyurethane. TDI based PU shows higher average particle size and contact angle than the others. Tensile strength, hardness, and elongation at break were higher in the case of MDI based polyurethane. Thermal property and thermal stability is also affected by variation of diisocyanate molecular structure.