바이오기반 비결정성 나일론 및 금 나노복합체 합성과 특성

Abstract

Polyamides (PA) containing N-substituted pyrrolidone ring on main chain were synthesized by melt polycondensation of salt type monomers composed of biomass monomer itaconic acid (IA) and long chain aliphatic diamines such as 1,8-octanediamine (C8DA), 1,10-decanediamine (C10DA) and 1,12-dodecanediamine (C12DA). Differential scanning calorimetry, dynamic mechanical analysis and tensile testing showed that these PAs are amorphous polymer with physically crosslinked structure and their Tg’s, modulus and strength decreased with increasing chain length of diamines. These PAs exhibit plastic deformation accompanied yielding, and the plastically deformed sample can be recovered to original shape upon heating them above their Tg’s. Such shape memory effects were also observed when the polyamides are immersed in water at room temperature due to lowering of Tg below room temperature by absorbed water molecules. PA/gold nanocomposites were prepared via thermal reduction of HAuCl4 in a matrix polymer derived from IA and C10DA. TEM analysis revealed that morphology of gold nanoparticles in the nanocomposites was affected by preparation method. Uniform dispersion of spherical gold nanoparticles in matrix PA were obtained when homogeneous solution of the PA and HAuCl4 are prepared first and then the mixture was thermally treated. On the contrary, various shaped gold nanoparticles including spherical, polygonal and rod-shapes were formed in matrix polymer when the polymer film was immersed in an aqueous HAuCl4 solution for a certain time and then thermally treated. The light responsive properties of the PA/gold nanocomposites were affected by the morphologies of the gold nanoparticles formed in the matrix polymer. A nanocomposite with uniform spherical morphology of gold nanoparticles exhibited photothermal effect and shape memory behavior when it is irradiated with 532 nm laser. In comparison, the nanocomposite containing various shaped gold nanoparticles showed the photo-responsive effects under both 532 nm laser and NIR light.