Effect of functionalized organic saponite on performance, crystallization and rheology of poly (lactic acid)

In the work, organic saponite (OSAP) was modified with dioctadecyl dimethyl ammonium chloride and saponite by intercalation reaction. Moreover, functionalized OSAP (FOSAP) was prepared with OSAP, BASF chain extender Joncryl (R) ADR 4468 and p-phenylenediamine. The optimum reaction conditions of FOSAP were optimized by orthogonal experiment. X-ray diffraction and Fourier transform infrared spectroscopy (FTIR) results demonstrated that saponite had been successfully modified. Moreover, FOSAP/poly (lactic acid) (PLA) nanocomposites were prepared by melting intercalation with PLA and FOSAP. The mechanical properties, rheological behavior and crystallization properties of FOSAP/PLA nanocomposites were investigated. Mechanical properties showed that the impact strength and elongation at break of FOSAP/PLA nanocomposites reached 13.21 KJ/m(2) and 71.47%, respectively, when the amount of FOSAP in PLA was 0.3 wt%. In addition, the ColeCole curve showed that FOSAP had strong interfacial compatibility with PLA. Furthermore, the crystallization behaviors of PLA before and after modification during isothermal crystallization at 150 degrees C were investigated by Rheonaut technology for simultaneous rheology and FTIR, which demonstrated that FOSAP effectively promoted the crystallization of PLA and increased the storage modulus. Avrami equation showed that FOSAP changed the nucleation growing mode and significantly accelerated the crystallization rate of PLA, therefore the comprehensive performance of PLA was improved.