Abstract: Resin systems containing a dicyclopentadiene-based epoxy resin and an ortho-alkylated aromatic diamine hardener exhibit low moisture absorption, high Tg and good retention of properties under hot and wet conditions. These properties make the resin systems especially useful in aerospace applications.

Abstract: A polymer composition especially suitable for producing fiber-reinforced structures having advantageous fracture toughness comprises a polyarylsulphone component and a thermoset resin component, each of which components is present at least partly as a phase continuous in at least one dimension. Preferred polyarylsulphones contain repeating units (PhSO.sub.2 Ph).sub.n and (Ph).sub.a linked through ether and/or thioether, where Ph is phenylene, n=1 to 2 and a=1 to 3; and such polyarylsulphones having amino end groups are provided as new compounds. The compositions can be made by spinodal decomposition of a mixture of the polyarylsulphone and a thermoset resin precursor.

Abstract: The present invention is directed to a composite resin system comprised of thermoplastic and thermoset resins wherein the phase morphology is cocontinuous. To this composite resin system are added particulate toughening agents which improve the toughness.

Abstract: A polymer composition especially suitable for producing fibre-reinforced structures having advantageous fracture toughness comprises a polyarylsulphone component and a thermoset resin component, each of which components is present at least partly as a phase continuous in at least one dimension. Preferred polyarylsulphones contain repeating units (PhSO.sub.2 Ph).sub.n and (Ph).sub.a linked through ether and/or thioether, where Ph is phenylene, n=1 to 2 and a=1 to 3; and such polyarylsulphones having amino end groups are provided as new compounds. The compositions can be made by spinodal decomposition of a mixture of the polyarylsulphone and a thermoset resin precursor.