High-toughness PLA/Bamboo cellulose nanowhiskers bionanocomposite strengthened with silylated ultrafine bamboo-char

We prepared poly(lactic acid) (PLA)/bamboo cellulose nanowhiskers (BCNW) bionanocomposite with a high toughness but a low modulus in the previous work. In this paper, a new reinforcement, silane surface-modified ultrafine bamboo-char (UFBC), was employed to strengthen the binary PLA/BCNW bionanocomposite. The ternary bionanocomposite films were fabricated by a solution casting with different contents of surface-treated UFBC in the range of 0.25 wt% to 4.0 wt%. The functionalization of UFBC with (3-mercaptopropyl)trimethoxysilane (A-189) favored its dispersion in the PLA matrix; sea-island and nuclear-shell characteristics were observed by the scanning electron microscopy (SEM) and transmission electron microscopy (TEM). When the UFBC content was 0.25 wt%, the tensile strength and elongation at break increased by 99.26% and 104.93%, respectively, comparing to the neat PLA. Differential scanning calorimetry (DSC) results showed that glass transition temperature , crystallization temperature , crystallization enthalpy and crystallinity increased with the increase of UFBC contents. Thermogravimetric analysis demonstrated that the thermal degradation stability decreased with the UFBC addition. BCNW and UFBC produced a synergistic effect on composites’ toughening and strengthening. These results provided a basic understanding of PLA enhancement mechanism and a simple approach for PLA composite manufacture with sound mechanical properties .