Flame retardancy and thermal properties of poly(butylene succinate)/ nano‐boehmite composites prepared via in situ polymerization

Abstract

AbstractPoly(butylene succinate) (PBS) and its nanocomposites with nanoboehmite (nBhm) were synthesized via direct esterification between succinic acid and butylene glycol (BG). Boehmite (Bhm) nanoparticles, up to 2%, were added in the polycondensation step. Repeatability of runs was observed by the amount of the gathered water. Temperature trajectory was considered as an indication of the polycondensation start. Mixing torque was measured and its rapid increase, up to 0.6 Nm, was deliberated as the end of the process. Polycondensation time decreases with an increase in amount of nBhm due to the catalytic role of aluminum in Bhm. The chemical structure of PBS was proved through Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopies. XRD spectrum and scanning electron microscope images show a good distribution of nanoparticles in the polymer matrix. Differential scanning calorimetric results determine that Tg increases with the nanoparticle content. Improved Avrami equation was fitted to study the kinetics of the crystallization of samples. As a result, spherulite crystal growth was determined based on the Avrami index. Thermal gravimetric analysis trends are the same, however, nanocomposites show more residual ash. Atomic force microscopy images show that nanocomposites have a rough surface. It was observed that the flame advancement decreases up to 60% and limiting oxygen index increases up to 8%.