Crystallization behavior of PA6/SiO2 organic–inorganic hybrid material

Poly 2-hydroxy propylmethacrylate-methyl methacrylate/SiO{sub 2} (PHPMA-MMA/SiO{sub 2}), an active composite was used to synthesize polyamide-6/SiO{sub 2} (PA6/SiO{sub 2}) organic-inorganic hybrid materials via blending method. X-ray diffraction analysis (XRD) results showed that the addition of PHPMA-MMA/SiO{sub 2} composite induced PA6 to transit from {alpha} to {gamma} crystal form. The nonisothermal crystallization kinetics of PA6 and PA6/SiO{sub 2} hybrid materials was investigated by differential scanning calorimetry (DSC). Jeziorny method derived from Avrami analysis and a method developed by Liu were employed to describe the nonisothermal crystallization process of PA6 and PA6/SiO{sub 2} hybrid materials. Based on our experimental data, if the relative degree of crystallinity was approximately 60% or more, the Jeziorny method was not valid to describe the nonisothermal crystallization process, while Liu method was successful to describe the whole nonisothermal crystallization process. When X(t) was below about 60%, the crystallization rates of PA6 and PA6/SiO{sub 2} hybrid materials were very approximate, but when X(t) was approximately 60% or more, the crystallization rate of PA6 was quicker than that of PA6/SiO{sub 2} hybrid materials. Moreover, the addition of PHPMA-MMA/SiO{sub 2} composite decreased the crystallization activation energy {delta}E calculated by Kissinger equation because of the {gamma} transition.