Abstract
Equilibrium melting temperature θ°m of nylon 66 (polyiminoadipoyliminohexamethylene) fractions having the viscosity-average molecular weight Mv from 2.08×104 to 4.19×104 is determined according to the so-called annealing method proposed by Kamide (Kobunshi Kagaku 25, 532 (1968)). The apparent melting temperature θm and the heat of fusion ΔHf are evaluated by differential scanning calorimetry for samples annealed at temperatures just below θm of the untreated sample for various length of time ta. θ°m is determined by use of the relation: θ°m=lim ta→∞ΔHf→0 θm (ta, ΔHf) and is found to be 275.8°C for Mv=2.08×104, 275.5°C for Mv=3.68×104 and 275.7°C for Mv=4.19×104, respectively.
