Synthesis and Characterization of Structurally Modified Polyurethanes Based on Castor Oil and Phosphorus-Containing Polyol for Flame-Retardant Coatings

Abstract

Structural modification of castor oil has been done with tris (m-hydroxy phenyl) phosphate (THPP) using the ester exchange process. The resultant compound was a phosphorus-based polyol that was reacted with different diisocyanates like TDI, IPDI, HMDI, and MDI to form a series of flame-retardant polyurethanes. These polyurethanes have been characterized by various chemical and instrumental analysis techniques. Thermal and flame-retardant properties of these polyurethanes were determined in film form. Coating formulations were prepared and applied on mild steel panels. Various mechanical properties, hardness, and chemical resistance properties were determined. These data were compared with the coatings prepared by mechanical blends of polyurethanes based on THPP and castor oil. The overall properties of polyurethanes obtained using ester-exchanged product are better than those of the blends.