Crystallization and thermal behavior for a series poly(ethylene terephthalate-co-isophthalate) (PETI)s with various concentration of dimethly isophthalate (IP) was studied. The spherulite morphology, observed by polarized optical microscopy and light scattering apparatus, showed that incorporation of IP increased degree of imperfection in the supermolecular structure. From the DSC thermogram, it was found that the melting temperature and the endotherm peak area decreased with the increased IP content. The cold-crystallization temperature decreased as IP was inceased up to 7 mol%; however, above this concentration it increased with the increased IP tent. The DMA peak width of PETI was equivalent to that of poly(ethylene terephthalate) (PET), indicating that there was no significant difference of micro-homogeneity at the molecular level of PETI and PET.

공중합 비율이 각기 다른 Poly(ethylene terephthalate-co-isophthalate)(PETI)의 결정화 거동과 열적특성을 살펴보았다. 편광현미경과 광 산란 장치로 구정의 몰폴로지를 관측한 결과 PETI의 dimethyl isophthalate (IP)의 함량이 증가할수록 라멜라 결정의 고차구조에서 결함에 의한 불규칙성이 증가함을 알 수 있었다. PETI의 IP 함량 증가에 따라 용융 온도와 흡열 용융 피크 면적은 감소하였다. 한편 IP 함량이 7 mol% 까지는 IP함량 증가에 따라 cold-crystallization 피크 온도가 감소하였으나, 그 이후에는 다시 증가하였다. PETI의 유리전이온도(Tg)는 Poly(ethylene terephthalate)(PET)에 비하여 낮아지지만 분자수준에서의 미시적 균일성은 PET와 거의 같았다.