New aromatic polyamides and polyimides having an adamantane bulky group

Abstract

This paper reports the synthesis and characterization of a new rigid diamine monomer, having a spiro carbon moiety and an adamantane bulky group in its structure; namely spiro-(adamantane-2,9′(2',7'-diamino)-fluorene) (SADAF). After its synthesis, using a straightforward methodology, a novel family of aromatic polyimides (PIs) and polyamides (PAs) has been attained by reaction of SADAF with three aromatic dianhydrides and two diacid chlorides, respectively. Two of the polyimides were obtained through the formation of the corresponding polyamic acid and subsequent thermal cycloimidization, whereas the other one, the polyimide from SADAF and 2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA), could be synthesized by chemical imidization from the polyamic precursor. Regarding polyamides, two new ones, made from SADAF and isophthaloyl chloride (IPC) and the diacid chloride of 2,2-bis(4-carboxyphenyl) hexafluoropropane (6FC) could be obtained. All the polymers showed high Tg, above 350°C, and excellent thermal resistance, with onset degradation temperatures higher than 450°C. Polymers formed by the combination of SADAF with 6FDA and 6FC were prepared as dense films with good mechanical properties and their permselectivity properties were measured.