Bis-amino Functionalized Iron N-heterocyclic Carbene as Epoxy Resins Hardener and Flame Behaviour Modifier.

The synthesis of a bis-amino-functionalized iron cyclopentadienone N-heterocyclic carbene complex (1) has been fine tuned to develop an hardener for the production of a novel hybrid epoxy resin (EP) with the aim of also reducing fire hazard. The synthesized organometallic complex well performs as curing agent both with DGEBA, preliminary employed, and the commercial pre-polymer Elan-tron® EC 157 in different formulations (loading range 5, 7.5, 10%wt). Thermogravimetric analyses revealed that curing temperature shows a significant intumescent char residual (yield 25%), possibly to due iron presence. DSC indicated that reaction rate and glass transition increase with complex 1 content, and under isothermal conditions the best performances have been identified at 170 °C and 7.5%wt of 1. The latter conditions has been finally employed for tests in cone calorimeter displaying a charring action of the complex included in the resins, together with an early ignition that has to be addressed playing on the formulation and chemical structure of the hardener. [ABSTRACT FROM AUTHOR]