EQUILIBRIUM MELTING TEMPERATURE OF POLY ε-CAPROLACTAM FRACTIONS

Equilibrium melting temperature T°m of poly ε-caprolactam (Nylon 6) fractions having the numberaverage molecular weight _??_n from 1.93×104 to 4.15×104 was evaluated according to the so-called annealing method proposed by Kamide (Kobunshi Kagaku, 25, 532 (1968)). For this purpose, apparent melting temperature Tm and the heat of fusion ΔH were determined by differential scanning calorimetry for the samples annealed at temperatures just below Tm of the untreated sample for various length of time. T°m=235.9°C, 236.4°C and 236.6°C were obtained for _??_n=1.93×104, 3.56×104 and 4.15×104, respectively.