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 HNO3 and NaOH solution modifications were conducted. The HNO3 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 HNO3 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 KJm(-2) were obtained at the HNO3 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. (c) 2018 Society of Plastics Engineers