Processing and characterizations: Effect of PPG molecular weight on properties of phosphate based polyurethanes

Abstract

The flame retardant polyurethanes coatings are used to develop advanced materials due to their ability to reduce the annihilating effect. The present work deals with the synthesis of PPEEUs reacting three different molecular weights phosphate-based poly (ether- ester) polyols with two diisocyanates (IPDI and HMDI) to produce six different phosphate-poly (ether- ester- urethanes). Physico-chemical properties of polyols and polyurethanes were measured. Functional groups present in the compounds were confirmed by Fourier transform infrared spectroscopy. Structural analysis was done using NMR spectroscopy. Surface free energy results show an increase in contact angle decreases surface free energy between liquid and solid surface. The TGA results showed that a decrease in 2–3 % char yield value with an increase in the molecular weight of PPG. Mechanical properties of coatings increase with an increase in PPG molecular weight. SEM-EDX shows PPEEU is rich in phosphorus. The morphological study of represents metal substrate has excellent bonding property with polyurethanes. Results reveal that the increase in the molecular weight has excellent physical and mechanical properties but has poor thermal and flame retardant properties.