Influence of flame retardant and glass fiber on nonisothermal crystallization behavior of PA66

摘要

This paper studied the influence of melamine polyphosphate flame retardant(MPP-FR) and glass fiber on nonisothermal crystallization behaviors of PA66 by differential scanning calorimetry(DSC). The composites of glass fiber reinforced PA66(PA66/GF) and glass fiber reinforced flame retarded PA66(PA66/GF/FR) were prepared by a twin-screw extruder. The DSC experimental results demonstrate that the presence of MPP-FR resulted in the increase of crystallization rate and the decrease of supercooling degree required for crystallizing nucleation, and the presence of glass fiber resulted in the increase of crystallization rate and the increase of supercooling degree. The Avrami analysis shows that the nonisothermal crystallization process of PA66 and its composites follows the Avrami equation. The activation energy for the transport of the macromolecular segments to the growing surface was calculated by using the Kissinger method based upon DSC data, and the calculated and PA66/GF/FR, respectively. The activity of nucleation of GF and MPP-FR was 0.87 and 0.79 respectively, which were obtained by calculation of Dobreva's method. The results indicate that the MPP-FR presents more effective ability of the heterogeneous nucleation than GF does. The crystal morphology was observed by means of polarized optical microscope(POM).