Thermal behaviour of dendritic methacrylated polyesters

Abstract

A dendritic polyester based on pentaerythritol and 1,2,4—benzenetricarboxylic acid anhydride followed by modification with glycidyl methacrylate was synthesised by using a divergent approach. The dendrimer (D-2) thus obtained had approximately eight double bonds. Several blends of D-2 with varying proportions of bismethacryloxy derivative of diglycidyl ether of bisphenol-A having styrene as a reactive diluent (VE resin) were prepared. The Brookfield viscosity of VE resin increased with an increase in D-2 content in the blends.Curing behaviour of these resins in the presence of AIBN was investigated by DSC. No significant change in curing exotherm was observed by addition of D-2 to the VE resin. Isothermal curing of resin samples in the presence of AIBN was done at 60 °C for 5 h and then at 150 °C for 90 mins. A significant improvement in char yield at 600 °C in nitrogen atmosphere was observed in samples containing D-2.Mechanical properties of glass fiber reinforced laminates with 31 ± 3% of resin content (w/w) were also determined. Smoke density of laminates increased with decrease in D-2 content in the resin, whereas only a marginal effect on limiting oxygen index was observed.