Morphology assisted exchange reaction of poly(p-oxybenzoyl-co-p- mercaptobenzoyl)

Poly(p-oxyberizoyi-co-p-mercaptobenzoyl) (POB-co-PMB) needle-like crystals containing 7 mol%; p-oxybenzoyl (OB) unit were converted to poly(p-oxybenzoyl) crystals by heat treatment with S-acety W-marcaptobenzoic acid in an aromatic solvent via ester-thioester exchange reaction with reorganizing the super-structure. The morphology changed from needle to fish-bone while p-mercaptobenzoyl moiety was excluded from the crystals. When POB-co-PMB needle-like crystals containing 64 mol% OB unit was heat-treated withp-acetoxybenzoic acid, the content of OB unit increased to 89 mol% with maintaining the needle-like morphology. p-Mercaptobenzoyl unit in the crystals prepared in the middle copolymerization ratio was replaced by OB unit via exchange reactions between solid and liquid phases under the guidance of super-structure.