Polymers containing the 2,5‐diphenylthiazolo[5,4‐d]thiazole moiety

Polyearbonates, alternating copolycarbonates, and polyesters were prepared from bisphenols containing the 2,5‐diphenylthiazolo [5,4‐d]thiazole moiety. The bisphenols used were 2,5‐bis(4‐hydroxyphenyl)thiazolo [5,4‐d] thiazole, 2,5‐bis‐(3‐hydroxyphenyl)‐thiazolo [5,4‐d] thiazole, and 2,5‐bis(4‐hydroxy‐3‐methoxyphenyl) thiazolo [5,4‐d] thiazole. The relative degrees of crystallinity for these polymers were determined and are discussed in relation to some of the physical properties. The degree of crystallinity observed for the polycarbonates varied from low to high, depending on the position of substitution in the phenyl rings. The alternating copolycarbonates with neopentyl glycol were all of a low degree of crystallinity and increased solubility. The polyadipates and polysebacates prepared were of a relatively high degree of crystallinity in spite of the flexibility permitted by the aliphatic diacid linkage. The solubilities of these polyesters were appreciable, even though the crystallinity was high.