Tailoring the Solubility and Thermal Characteristics of Poly(ether ether ketone)s

Abstract

The solubility and thermal properties of poly(ether ether ketone) (PEEK) have been modified by incorporating various ratios of a comonomers, 4,4’-difluorobenzophenone, 1, and its geometric isomer 3,5-difluorobenzophenone, 2. The resulting polymers have the same chemical composition, allowing for accurate structure-property relationships to be determined. The use of monomer 2 affords PEEK systems that carry pendant benzoyl groups, which provide a versatile site for the introduction of functional groups. The ratio of monomer (2:1) had a dramatic influence on the thermal properties and solubility characteristics of PEEK. At lower ratios, 50:50 and 75:25, the polymers were completely amorphous and soluble in N- methylpryrrolidinone, while at higher ratios, 80:20, 85:15, and 90:10, the materials became semi-crystalline and their solubility decreased. TGA analysis indicated excellent thermal stability as the materials 5 % weight loss temperatures (Td5%) in excess of 410°C.