Effect of organo-phosphorus and nano-clay materials on the thermal and fire performance of epoxy resins

The results of flame retardance and thermal stability of a reactively modified organo-phosphorus diglycidylether of bisphenol-A and an organo-phosphorus tetraglycidyl diaminodipheny1methane are reported here. The organo-phosphorus epoxy resins were synthesized by the reaction of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and diglycidyl ether of bisphenol-A and tetraglycidyl diaminodiphenylmethane, respectively, and then cured with a mixture of 3,5-diethyltoluene-2,4-diamine and 3,5-diethyltoluene-2,6-diamine. In addition to this, between 5 and 7.5% of organically modified polymeric layered silicate nano-clay was also added to neat epoxy resin or to the phosphorus-modified epoxy resin to investigate any synergies, or otherwise, a combination of clay and phosphorus on the flame, degradation, and thermal properties are also reported. The reaction kinetics of phosphorus-modified and epoxy cure were studied by FTIR, H-1-NMR, and DSC. Thermal properties and morphology of the final product were analyzed by thermogravimetric analysis, dynamic mechanical thermal analysis, X-ray diffraction, and cone calorimetry. Improvement in flame retardance by cone calorimetry was demonstrated by the addition of only 3% phosphorus or 7.5% clay into the epoxy compared with unmodified epoxy resins, whereas no evidence of synergy for a phosphorus and clay combination was found. (C) 2003 Wiley Periodicals, Inc.