Compatible blends of epoxy resins and epoxidized polydienes

A polymer blend having sufficient compatibility to form a homogeneous mixture comprising:

• (a) a curable aromatic epoxy resin,
• (b) up to 60% by weight of an epoxidized polydiene polymer, and
• (c) an anhydride or polycarboxylic acid curing agent;
• wherein the epoxidized polydiene has the formula
• (A--B--A.sub.p).sub.n --Y.sub.r --(A.sub.q --B).sub.m
• wherein Y is a coupling agent or coupling monomers or initiator, and A and B are polymer blocks which are homopolymer blocks of conjugated diolefin monomers, copolymer blocks of conjugated diolefin monomers, copolymer blocks of diolefin monomers and monoalkenyl aromatic hydrocarbon monomers or homopolymer blocks of monoalkenyl aromatic hydrocarbon monomers;
• and the A blocks have a peak molecular weight as measured by Gel Permeation Chromatography of from 100 to 3000 and the B blocks have a peak molecular weight as measured by Gel Permeation Chromatography of from 1000 to 15,000;
• and n is greater than 0, r is 0 or 1, m is greater than or equal to 0, the sum of n and m ranges from 1 to 100, and p and q may be 0 or 1.