Polyurethanes, synthesized by polyester polyols and aliphatic or aromatic diisocyanates for a crease resist finishing agent, were prepared by two-step reactions, that is, prepolymer synthesis and chain extension. The structures of synthesized polyurethanes were confirmed by the measurement of FT-IR and 1H-NMR spectrometer. The number average molecular weight (Mn) and the weight average molecular weight (Mw) of the polyurethane with aromatic diisocyanate(MDI) were higher than those of the synthesized polyurethanes with aliphatic diisocyanate( HDI, H12MDI). The glass transition temperature (Tg) of soft segments in polyurethanes with MDI, HDI, H12MDI were -25, -42 and -50 ℃, respectively. In the polyurethanes obtained by two-step reaction, thermal stability and tensile strength increased with increasing hard segment contents, whereas elongation at break decreased with increasing hard segment contents.

본 연구에서는 섬유의 구김을 방지하기 위해 첨가제인 폴리우레탄을 2단계 중합반응을 통하여 합성하였으며, 단계 반응 중합체의 구조와 합성된 폴리우레탄의 구조를 FT-IR과 1H-NMR 스펙트럼으로 확인하였다. 방향족 이소시아네이트인 4,4-diphenylmethane diisocyanate(MDI)로 합성한 폴리우레탄의 평균 분자량이 지방족 이소시아네이트인 hexamethylene diisocyanate(HDI), 4,4-dicyclohexylmethane diisocyanate(H12MDI)로 합성한 폴리우레탄의 분자량보다 크게 증가하였다. 또한 MDI, HDI, H12MDI로 합성한 폴리우레탄의 유리전이온도(Tg)는 각각 -25, -42, -50 ℃로 나타났다. 합성 폴리우레탄의 경질부분 함량이 증가함에 따라 열 안정성과 인장강도는 증가하였고, 파괴점에서의 연신율은 감소하였다.

Keywords: aromatic and aliphatic diisocyanates; hard segment content