Effects of nanoclay cloisite 20A and alkali treatments on structure-property relationships of bagasse/recycled polypropylene nanocomposites

Abstract

This study was aimed at evaluating the individual and combined effects of organically modified nanoclay cloisite 20A and alkali treatments on the valorization of totally waste-based bagasse fiber/recycled polypropylene nanocomposites. FTIR spectra indicated the reduction of bagasse fibers’ hydroxyl moieties due to hemicellulose removal resulting from alkali treatment. There were also trace diminutions in C-O peak intensities due to the degradation of little amounts of lignin. X-ray Scattering revealed the intercalation of nanoclay in the polymer matrix. The improved interaction of fiber-polymer interfaces brought about by alkali treatment was also confirmed by scanning electron microscopy. The physical properties of the nanocomposites were improved due to the barrier properties of nanoclay against water ingress. The flexural strength and modulus of elasticity increased by both individual and combined treatments; however, the impact strength decreased by the individual treatments. Thermogravimetric analysis demonstrated that the temperatures of first and second stages of composites’ thermal degradation increased due to the treatments via the formation of a carbonized char layer thermally insulating the deeper composite layers. Differential scanning calorimetry showed some slight increases in the melting temperature, melting enthalpy, crystallisation temperature, crystallisation enthalpy, and crystallinity index of the treated composite formulations due to the nucleating effect of nanofillers. The overall results confirmed that the combination of nanoclay cloisite 20A and NaOH treatments could significantly improve the overall properties of the studied composites. This was due to some interesting synergistic effects of the given treatments on the nanocomposites converting the bagasse/recycled PP composites to high performance materials of choice.