The physical properties of poly(ethylene 2,6-naphthalate) (PEN) copolymers were studied. PEN copolymers were synthesized successfully from the mixtures of ethylene glycol(EG), 1,3-propanediol (PD) and 1,4-butanediol (BD) with 2,6-dimethyl naphthalene dicarboxylate. The results indicated that PEN copolymers showed an amorphous state when the content of BD(PD) in applied EG/BD(EG/PD) mixtures was less than 40% during the polycondensation. As a result, the lowering of thermal properties, orientation, and mechanical properties was found, however, the dimensional stability was improved. This is a promising result to apply the synthesized PEN copolymers as flexibles substrates.

폴리(에틸렌 나프탈레이트) 중합 시 2,6-dimethyl naphthalene dicarboxylate와 함께 사용되는 디올 화합물인 ethylene glycol(EG), 1,3-propanediol(PD) 그리고 1,4-butanediol(BD)의 사용에 따른 공중합체의 물성을 살펴 보았다. EG와 함께 PD 혹은 BD를 40% 이내 첨가하는 경우 합성된 폴리에스터가 무정형을 유지함을 알 수 있으며 이는 열적 특성과 배향 특성, 그리고 기계적 특성을 저하시키는 반면 치수안정성을 증가시킴을 확인할 수 있어 합성 폴리에스터가 유연기판 소재로의 적용 가능성을 확인하였다.

Keywords: poly(ethylene naphthalate)/poly(propylene naphthalate) copolymer; poly(ethylene naphthalate)/poly(butylene naphthalate) copolymer; flexible substrate; coefficient of thermal expansion.