Thermal and morphological properties of nanocomposite materials based on graphene oxide and l-leucine containing poly(benzimidazole-amide) prepared by ultrasonic irradiation.

A new poly(benzimidazole-amide) (PBIA) was fabricated by polycondensation of 1,3-bis(5-amino-1H-benzimidazole-2-yl)benzene with chiral diacid under green media by using tetra-n-butylammonium bromide as a cheap commercially available molten ionic salt at 120°C. The affection of reaction time on the polymer yield and viscosity was tested and optimized for PBIA. Inherent viscosity value of the prepared PBIA under optimized conditions is 0.31dL/g. Then to acquire a uniformly dispersion of graphene oxide (GO) in the PBIA matrix, GO was prepared through strong oxidation procedure. After that, GO/PBIA nanocomposites (NCs) with different loading of GO were synthesized through solution mixing method under ultrasonic irradiation and the resulting NCs were characterized by different techniques. Through FE-SEM micrographs and TEM results of NC samples it can be found that the individual GO sheets were good dispersed in the polymer matrix. Also, the thermal properties of the obtained NCs were investigated and the obtained results illustrate high thermal stability with LOI values around 39-41%.