The fracture of the 10wt% BC/PLA composite with agglomeration of BC particles resulted in the increase of stress concentration zones and weakened the interfacial bonding strength of the sample [20,50] Thereafter, the generation, the growth and the propagation of flaws along the interfaces between PLA and BC particles clusters. contributed to the final coalescence of the larger cracks [51]. The agglomeration of the BC particles caused partially separation of micro-spaces between particle and particle, and particle and polymer and thus, obstructed stress propagation when tensile tress was loaded [52]