Synthesis and characterization of branched polyether ester urethanes/organo-clay nanocomposites

Flame retardant branched polyether ester urethanes were prepared by reacting phosphorous based polyether ester polyol with three different types of diisocyanates like IPDI, HMDI, and TDI. Branched polyether ester polyol has been synthesized through ring-opening of pyromellitic dianhydride followed by esterification. This prepared branched polyol was used for the preparation of branched polyurethanes through condensation polymerization. Modification of Na-MMT clay is done to improve the interlayer distance between two silicates sheets for the preparation of BPEEU nanocomposite through the intercalation method. The interlayer distance of clay after modification was increased by 3.78 angstrom, which was measured using XRD. Morphological study shows an addition of 3% O-MMT clay gives excellent properties whereas the addition of 5% clay in polymer matrix increases aggregation and brittleness of branched polyurethanes which results in failure of coating and casting. The addition of clay increases thermal stability by 30-4p0%. The hardness and tensile strength of neat BPEEUs increased with the addition of 3% O-MMT clay in BPEEUs. Flame retardant property of branched polyurethanes nanocomposites shows that clay particle does not have any impact on the flammability of polymer. Branched polyurethanes show excellent chemical and solvent resistance properties due to the presence of the high number of polypropylene in the molecular structure.