In this paper,the effects of two types of hydrogen bond modulating additives and melt processing shear on the crystallization behavior of nylon 12(PA12)were investigated by using urea and low molecular weight polyamide(PA)as hydrogen bond bridging additives and benzoyl hydrazine and octadecyl amine as hydrogen bonding inhibitors for PA12,respectively.The results showed that undergoing melt processing,addition of 1.0 wt％urea and 2.0 wt％low molecular weight PA both shifted the peak crystallization temperature of PA12 towards higher temperatures 8～9 ℃ and reduced the crystallization peak width at half height(FWHM)by 235％～239％;hydrogen bonding additives increased the enthalpy of crystallization by about 11.0 J/g,whereas the melt processing increased the enthalpy of crystallization by 3.4 J/g.This suggests that both processing shear and the hydrogen bonding additives significantly promoted PA12 crystallization.In contrast,either 0.5～1.5 phr benzoylhydrazine or octadecylamine shifted the peak crystallization temperature slightly to lower temperatures,with a decrease in the enthalpy of crystallization of about 2 J/g and a broadening of the FWHM of 9.7％～13.4％.It was shown that benzoylhydrazine and octadecylamine inhibited PA12 crystallization.Favorable melt rheology significantly promotes the effect of hydrogen bonding aids,whereas the role of hydrogen bonding inhibitors has little relationship with melt rheology.
万方数据
维普
