Preparation Of Carbon Nanotubes/Chitosan Composite And Study On Their Mechanical Properties

Carbon nanotubes/chitosan (CNTs/CHI) composite foams were prepared by ice-templating. The produced CNTs/CHI composites possess unidirectionally oriented lamellar structure with uniform layer thickness and channels in submicron and micron scale respectively.We used wide-angle X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and thermogravimetric analysis to characterize the structure and thermal stability of the composite foams, and the elastic behaviors were investigated by cyclic compression tests. It is discovered that CNTs/CHI composite foams possess better recoverability and elastic properties than the pure chitosan foams. It is also discovered that the elasticity and mechanical strength of CNTs/CHI composite foams are influenced by freezing rate, fraction of CNTs and density. Owing to more ice dendrites and thinner lamellas being formed under fast freezing rate, the CNTs/CHI composite foams made under fast freezing rate (-10 cm/min) have worse mechanical properties than those made under low freezing rate (-6 mm/min). When the fractions of CNTs increase, the recovery ability of CNTs/CHI composite increases and achieves the maximum (87% of original length) at a fraction of 0.48 vol%, and then owing to the inadequate chitosan matrix and aggregation of CNTs, its recovery ability decreases significantly. Comparing the CNTs/CHI composite foams with low density (0.01 g/cm3), the CNTs/CHI composite foams which have high density (0.02 g/cm3) have better elasticity and mechanical strength.