Synthesis and Characterization of Difunctional Amino-terminated Poly(m-phenylene isophthalamide) and Poly(2-cyano-1,4-phenylene terephthalamide) Telechelics

말단이 아미노기로 된 Poly(m-phenylene isophthalamide) 및 Poly(2-cyano-1,4-phenylene terephthalamide) 텔레킬릭스의 합성 및 특성분석

Difunctional amino-terminated poly(m-phenylene isophthalamide)(AT-PMIA) and poly(2-cyano-1,4-phenylene terephthalamide)(AT-CyPPDT) telechelics were prepared by low temperature solution polymerization of isophthaloyl chloried (IPC) and terephthaloyl chloride(TPC) with calculated excess amounts of m-phenylenediamine(MPD) and 2-cyano-1,4-phenylenediamine(CyPPD) in dimethylacetamide(DMAc) and N-methyl-2-pyrrolidone(NMP), respectively. Purity of amino groups of the telechelics was determined by measuring the molar extinction coefficient(${\varepsilon}_{\lambda}{max}$) of a protonated bis-Schiff base which was formed from the reaction of 4-(dimethylamino) benzaldehyde(DMBA) with diamines in the presence of p-toluenesulfonic acid(TA) in dimethylacetamide(DMAc) containing 2%(wt.) LiCl; the number average moles of amino groups in the telechelics was calculated from their $M_{n}$ using the Mark-Houwink equations for carboxy-terminated PMIA(CT-PMIA) and CyPPDT(CT-CyPPET), i.e., [η]=7.96${\times}$$10^{-4}M_{n}^{0.71}$ and [η]=2.51${\times}$$10^{-4}M_{n}^{1.02}$, respectively. It decreased as reactant mole ratio (${\gamma}$) approached 1.0. It increased, however, as expected on reaction with further excess diamine after the polymerization reaction. Reactivity of amino groups of the telechelics was confirmed by change in intrinsic viscosity([η]) and numberaverage molecular weight($M_{n}$) with the coupling reaction of IPC and TPC.