Abstract
Numerous studies have been shown on the toughening of epoxy networks using reactive butadiene-acrylonitrile oligomer having both carboxyl (CTBN) and amine (ATBN) end groups. In some other system, acrylate elastomer or oxazolidinone modified epoxy networks have also been discussed. Furthermore, the modifications by functionary terminated siloxane oligomer were discussed.
Aim in using various elastomer was two-fold, first to improve the fracture toughness of the matrix, second to reduce the water sorption of the networks due to highly hydrophobic nature of the elastomers.
In the case of CTBN or ATBN modification, thermal and chemical resistance of the final systems have also been reduced due to the nature of the modifier. Recently another approach has been taken to modify the epoxy resins which seems to provide better improvement in the overall properties of the resulting networks without any significant loss in the modulus. In these example, reactive functionally terminated Bisphenol-A Polysulfone (PSF) oligomer were used as the modifier into the epoxy networks systems.
