Preparation Of PA6/Nano-Magnesium Hydroxide Composite By In Situ Polymerization

In this study, magnesium hydroxide (nano-MH and whisker-MH) were modified by Silane coupling agent (KH-550) firstly, then MH was mixed with caprolactam evenly. PA6/MH composites were prepared by Anionic in-situ polymerization with sodium methoxide as main catalyst. The structure and properties of modified MH, Anionic PA6 and PA6/MH composites were characterized by FTIR, scanning electron microscope (SEM), mechanical testing, thermogravimetric analysis(TGA), differential scanning calorimetry (DSC), dynamic thermomechanical analysis (DMA), melt flow rate(MFR).The results of FTIR, TGA and XRD showed that KH550 was grafted to the surface of MH modified by KH-550. The mechanical properties and crystal of PA6 with sodium methoxide as main catalyst didn't change.With increasing the content of MH, the mechanical properties of PA6/NMH composites varied from enhancement to weakening. When the content of nano-MH was 3% and the content of whisker-MH was 1%, the mechanical properties of composites showed significant improvement. With the content of MH increasing, MH reunited and spreaded unevenly among PA6, mechanical properties of composites became poor. Modified MH were more uniformly dispersed and diffcult to aggregate in composites. Modified MH could enhance the bonding of MH and PA6, so mechanical properties of PA6/MMH showed improvement over PA6/MH. The results of TGA indicated that thermal stability of composite materials became lower and higher compared to PA6, when MH content were 1% and 5% in low-temperature phase. Glass transition temperature and crystallization rate of PA6/MMH were higher and improved than PA6. Melt flow rate of PA6/MH and PA6/MMH composites showed lower than PA6. Compared to PA6/MH composites, the processability of PA6/MMH composites was improved...