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A series of aromatic/aliphatic poly(propylene terephthalate-co-succinate) (PPTSu) random copolyesters of high molecular weight were synthesized. Enzymatic hydrolysis study showed that copolymers with terephthalate content up to 60 mol % could be hydrolyzed. Cocrystallization, thermal behavior, and spherulitic morphology were investigated. Melting points of the copolymers were depressed and followed a rather sigmoid curve, without exhibiting a eutectic behavior. Wide-angle X-ray diffraction patterns indicated that the copolymers crystallized in PPT crystal, but the interplanar spacings varied linearly. These are probable indications of isomorphic cocrystallization. A single T g was found for the copolyesters. Interestingly, after crystallization of the PPTSu copolymers with up to 60 mol % terephthalate content, the remaining amorphous phase showed increased mobility, as proved by a reduction of the T g compared to the amorphous samples. This indicates some kind of segregation of chain segments occurring during crystallization, with preferable incorporation of propylene tetrephthalate (PT) units into the crystals and enrichment of the amorphous phase in hydrolyzable propylene succinate (PSu) sequences. As for neat PPT, banded spherulites were observed for the copolyesters. Most mechanical properties decreased with increasing PSu content compared to neat PPT.