The effect of expandable graphite and montmorillonite (MMT) clay on the morphology, thermal stability, and flammability properties of the maize stalk/PBS bio-composite

The current study investigates a comparison of expandable graphite (EG) and montmorillonite clay (MMT) on the properties of polybutylene succinate (PBS)/maize stalk fiber (MSF) bio-composite. Maize stalk and fillers (EG and MMT) were incorporated into the PBS at 10 and 3 wt%, respectively. The scanning electron microscope (SEM) images showed a fibre pull-out from the PBS matrix, while the incorporation of 3 wt% of MMT improved the adhesion between the maize stalk and PBS matrix. In this study, the received MMT was already modified with octadecylamine and Aminopropyltriethoxysilane which improved the interaction between the fiber and PBS matrix. There seems to be a poor interaction between the MSF and EG, which influenced the properties between fiber and PBS negatively when compared with PBS/MSF/MMT hybrid composite. The flame resistance, and storage modulus of hybrid composites were improved due to better dispersion of MMT. The silane treated MMT based hybrid composite showed better flame retardancy (pHRR of 682.5 kW/m²) than the EG based hybrid composite system (pHRR of 697.6 kW/m²). The T_10% and T_50% of the PBS/MSF/MMT composite showed superior thermal stability than that of the PBS/MSF/EG composite. However, the T_10% and T_50% temperature values for PBS/MSF composite were revealed as 311.1°C and 363.9°C, respectively. Incorporation of MMT and EG to PBS/MSF enhanced the T_50% values of the composite to 372.2°C and 366.7°C, respectively.