Halloysite nanotubes immobilized by chitosan/tannic acid complex as a green flame retardant for bamboo fiber/poly(lactic acid) composites
Xiaobei Jin, Elin Xiang, Rong Zhang, Daochun Qin, Mingliang Jiang, Zehui Jiang
Abstract
Abstract In order to develop an environmentally benign flame retardant for bamboo/PLA composites (BPC), chitosan (CS) and tannic acid (TA) were used as cationic and anionic polyelectrolyte respectively to stabilize halloysite nanotubes (HNT) on the surface of bamboo fiber (BF) and poly(lactic acid) (PLA). Mechanical performance tests showed that the flexural properties of BPC were moderately enhanced with the addition of HNT, while the incorporation of CS/TA complex (FR) exhibited a slight increase. The results of thermogravimetric analysis demonstrated that CS/TA complex and HNT improved the thermal stability of the BPC synergistically, which increased the char residue. Limiting oxygen index and cone calorimetry tests were used to study the flammability of BPC and the results showed that the addition of CS/TA complex and HNT had a synergistic effect on the flame retardant performance of BPC materials. The macroscopic and microscopic morphological studies confirmed the formation of HNT layer in the matrix of BPC/5FR@5HNT samples, which facilitated more stabile char residue with the best flame retardant performance.