Effect of molecular weight on the non-isothermal crystallization kinetics of PA6
The non-isothermal crystallization kinetics of polyamide 6(PA6)with average molecular weights of 15 600,20 100,and 34 000 g/mol at different cooling rates(ϕ)were studied using a differential scanning calo-rimeter.The non-isothermal crystallization kinetics of PA6 were analyzed using the Avrami equation modified by the Jeziorny and Mo Zhishen methods,and the Kissinger equation was used to calculate the non-isothermal crystalliza-tion activation energy(ΔE)of PA6.The findings show that as ϕ increases,PA6's molecular weight rises,its crys-tallization range—which includes a range of molecular weights—moves towards lower temperatures,and its crystal-lization enthalpy(ΔHc),peak temperature(Tc),and starting temperature(To)all gradually decline.The crys-tal growth of PA6 is mainly two-dimensional,and as the molecular weight increases,the crystallization rate of PA6 first decreases and then increases.The Avrami equation modified by Mo Zhishen's method can well describe the crystallization process of PA6.At the same crystallinity,as the molecular weight increases,the cooling function value(F(T))of PA6 first increases and then decreases.As the molecular weight increases,the absolute value of ΔE of PA6 shows a trend of first increasing and then decreasing.
polyamide 6molecular weightnon-isothermal crystallization kineticscrystallization ratecrys-tal activation energy
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