POLY(ARYL ETHER OXAZOLE)S WITH TRIFLUOROMETHYL GROUPS

Poly(aryl ether oxazole)s with trifluoromethyl groups bound to the oxazole moieties have been synthesized from a bisoxazole monomer containing two activated fluorine atoms by nucleophilic displacement with bisphenols. The poly(aryl ether oxazole)s are completely amorphous with one exception. Their glass transition temperatures are between 136 and 191-degrees-C, depending on the structure of the bisphenol monomer. Due to their amorphous nature they are soluble in a number of common organic solvents. They have been thoroughly characterized by IR and NMR spectroscopy, DSC, GPC, and thermogravimetry. The polymers exhibit an unexpected instability at high temperatures. While other oxazole-containing polymers are stable in air up to more than 450-degrees-C, the new poly(aryl ether oxazole)s already start to lose weight at temperatures of about 310-degrees-C. This is attributed to their special oxazole structure, and a strategy is proposed and studied to overcome this low thermal stability.