Synthesis, Fractionation, and Molecular Weight Determination of Difunctional Carboxy-terminated Poly(2-cyano-1,4-phenylene terephthalamide)

말단이 카르복실기로 된 Poly(2-cyano-1,4-phenylene terephthalamide)의 합성, 분별 및 분자량 측정

Difunctional carboxy-terminated poly(2-cyano-1,4-phenylene terephthalamide)(CT-CyPPDT) was prepared by low temperature solution polymerization of 2-cyano-1,4-phenylenediamine(CyPPD) with calcualted excess amounts of terephthaloyl chloride(TPC) in N-methyl-2-pyrrolidone(NMP) and was identified by UV-Vis spectrophotometry. CT-CyPPDT was fractionated by isotropic/anisotropic phase separation using triangular cross-fractionation method ; 10 fractions were obtained. Mark-Houwink relation of unfractionated and fractionated CT-CyPPDT was found to be [η]=2.51${\times}$$10^{-4}M_{n}^{1.02}$ and [η]=1.10${\times}$$10^{-4}M_{n}^{1.05}$ respectively in 97% $H_{2}SO_{4}$ and dimethylacetamide(DMAc) containing 5 wt.% LiCl at 30 $^{\circ}C$. The Mark-Houwink relation for CyPPDT indicates that the conformation is an intermediate worm-like chain between a coil and a rod-like particle. This is confirmed by the formation of anisotropic polymer solution above critical concentrations in 97% $H_{2}SO_{4}$ and DMAc and/or NMP containing inorganic salts such as LiCl.