Effect of non-halogen flame retardant additives on the properties of vinyl ester resins and their composites

The paper describes the effect of combination of char forming additives and char forming catalysts on limiting oxygen index (LOI), smoke density and mechanical properties of neat as well as glass fibre reinforced Vinyl ester (VE) resins. Three different samples of VE resins were prepared by reacting diglycidyl ether of bisphenol-A and methacrylic acid in stoichiometric (1:2, sample A) and non-stoichiometric (1: 1.7, sample B and 1: 1, sample C) amounts. These resins were diluted with reactive diluents (50% w/w) styrene (S)/glycidyl methacrylate (GMA) or a combination of GMA with S for fabrication of neat sheets as well as composites, Incorporation of flame retardant additives (combination of ammonium polyphosphate, azobiscarbonamide, tris (2-hydroxyethyl) isocyanurate and hydrated alumina) in the laminates increased the LOI and decreased the smoke density values. The highest LOI was observed in laminates based on resin C containing flame retardant additives and a phosphorus containing amine as a hardener.