Study on Epoxy/Thermoplastic Blends Based on the Addition of a Novel Aromatic Block Copolymer

In this article we present a study of the properties ofsome epoxy/thermoplastic blends based on the additionof a novel block copolymer of an ABA type. Theblock A was a commercial poly(2,6-dimethyl-1,4-phenyleneether or oxide) (PPE or PPO) while block B was arandom copolyethersulphone synthesized in our laboratory.The comparison with the epoxy blends modifiedonly with the homopolymers A or B is also reported. Thehomopolymers were also mixed via solution blendingand the resulting physical mixture was used as modifierfor comparison purposes. The blends have beenthoroughly characterized by parallel plate rheometry,dynamic mechanical thermal analysis (DMTA), and scanningelectron microscopy. Upon curing, the epoxyblends containing the physical mixture underwent phaseseparation showing a morphology which resembled thecombination of those found for the blends modified witheach of the homopolymers. On the contrary, the additionof the block copolymer resulted in a unique morphology.The viscoelastic properties of the blends both in theunreacted and cured state varied significantly when theblock copolymer was added rather than the homopolymersor their physical mixture.