Surface modification of bamboo‐char and its reinforcement in PLA biocomposites

High‐temperature bamboo‐char is a potential polymer reinforcement due to its porous structure, high strength and modulus. To improve the surface structure and properties of bamboo‐char, different concentrations of HNO 3 and NaOH solution modifications were conducted. The HNO 3 treatment grafted amino groups on bamboo‐char and NaOH treatment modified carbonyl and carboxyl groups. The specific surface area and the total pore volume of bamboo‐char reduced with HNO 3 treatment, whereas the two values firstly increased and then decreased in the case of NaOH treatment; the maximum values of 30.422 m 2 ·g −1 and 0.066 cm 3 ·g −1 were reached at 10 wt% NaOH concentration. The maximum tensile strength and modulus of PLA/bamboo‐char composites were achieved up to 65.36 and 1012.0 MPa at 15 wt% NaOH concentration. The maximum elongation at break was reached at 15.36% and impact strength of 25.69 KJ·m −2 were obtained at the HNO 3 concentration of 39 and 54 wt%, respectively. These results will help to extend the application of bamboo‐char in polymer composites. POLYM. COMPOS., 39:E633–E639, 2018. © 2018 Society of Plastics Engineers