The ring-opening isomerization polymerization behavior of 2,5,6,7-tetrahydro-3H-imidazo [2,1-b][1,3]oxazine(TII) has been studied under various conditions. The present study aimed at improving the low polymerizability of the above monomer(six-membered ring) up to a level comparable to that of 2,5,6-tetrahydroimidazo[2,1-b][1,3]oxazole(TIO) (five-membered ring). The optimum result could be observed when methyl trifluoromethanesulfonate (MeOTf) and nitrobenzene were used as an initiator and a solvent in the polymerization at 60 ℃ for 24 h. Polymers were confirmed by 1H NMR, 13C NMR and IR measurements. The molecular weight obtained by gel permeation chromatography(GPC) corresponded to the molecular weight theoretically calculated from the feed ratio. The melting temperature(Tm) of TII was conspicuously different from that of TIO, because of the difference in the alkyl group.

5원환의 2,3,5,6-tetrahydroimidazo[2,1-b][1,3]oxazole(TIO)와 비교하여 6원환인 2,5,6,7-tetrahydro- 3H-imidazo[2,1-b][1,3]oxazine(TII)가 중합반응성이 낮은 결점을 개선하고자 각종의 조건하에서 중합을 실시한 결과, 최적의 중합조건으로 methyl trifluoromethanesulfonate(MeOTf)을 개시제로 사용한, 극성이 높은 니트로 벤젠 용매의 60 ℃에서 24시간 반응시킴에 의해 고수율의 중합체를 얻었다. 생성된 중합체를 1H NMR과 13C NMR, IR 스펙트럼으로 분석하였으며, GPC로부터 구한 분자량과 이론분자량이 거의 일치함도 확인하였으며, 융점(Tm)은 알킬 그룹의 길이에 따라 큰 차이를 나타내었다.

Keywords: isomerization polymerization; six-membered ring; polyurea; ring-opening polymerization; melting temperature.