A first aspect of the present invention is a composition of matter, comprising: one or more polyaryletherketone copolymers, each of the one or more polyaryletherketone copolymers comprising (a) a first monomer including an aryl ether ketone and (b) a second monomer including an aryl ether ketone and a first phenylethynyl moiety, each of the one or more polyaryletherketone copolymers having two ter