Properties of Poly(ether-b-amide)/MMT Composites Prepared with in-situ Polymerized PA12/MMT Nanocomposites

Abstract

Polyamide12(PA12) 올리고머가 층간에 삽입된 PA12/montmorillonite(MMT) 나노복합체(M-PA)를 4,4"-methylene bis(cyclohexyl amine)과 12-aminododecanoic acid를 이용하여 in-situ 중합으로 합성하였다. 이를 poly(tetramethylene glycol) (PTMG)의 양 말단에 hexamethylene diisocyanate(HDI)로 isocyanate 작용기를 가지도록 합성한 prepolymer와 반응시켜 M-PA 부분과 PTMG 부분이 각각 결정성의 hard segment와 soft segment를 형성하는 poly(ether-bamide)s (PEBA)/MMT 복합체(C-PEBA)를 제조하였다. 결과로서 MMT의 함량이 증가함에 따라 hard segment의 결정용융 엔탈피가 5 wt%까지 증가하다 이후 감소하였고, MMT가 단순 혼합된 같은 구조의 PEBA(B-PEBA)보다 최대신율과 강도가 증가하였으며 3 wt%일 때 최대값를 나타냈다. 영구 변형률은 MMT의 함량이 증가함에 따라 감소하였으며 특히 5 wt% 이상에서는 상업화된 PEBA인 Pebax®나 열가소성 폴리우레탄(TPU)보다 낮거나 비슷한 우수한 탄성성질을 가졌다. PA12/montmorillonite (MMT) nanocomposites (M-PA), polyamide12 (PA12) oligomers intercalated into the crystalline layers of MMT, were synthesized by in-situ polymerization with 4,4"-methylene bis(cyclohexyl amine), 12-aminododecanoic acid, and MMT. Poly(ether-b-amide) (PEBA)/MMT nanocomposites (C-PEBA) consisting of crystalline hard segment and amorphous soft segment from M-PA block and PTMG block repectively were prepared with M-PA and isocyanate terminated poly(tetramethylene glycol) prepolymer by hexamethylene diisocyanate (HDI). As a result, the crystalline melting enthalpy increased up to 5 wt% and then decreased with increasing the MMT content. The maximum strain and strength of the C-PEBA were shown at 3 wt% of MMT content and the values were larger than those of the control PEBA (B-PEBA), simply MMT blended one. However, the permanent setting of C-PEBA decreased with increasing the MMT content, especially at more than 5 wt%, similar to or less than those of Pebax® commercialized PEBA and a typical polyurethane thermoplastic elastomer (TPU).