Structural investigation of cellulose nanocrystals extracted from chili leftover and their reinforcement in cariflex-IR rubber latex

Abstract

The morphology and chemical composition of chili fibres were investigated. Unusual low lignin content was found when compared to other annual plants. High aspect ratio cellulose nanocrystals (CNCs) were prepared from these fibres by an acid hydrolysis treatment. CNCs extracted from chili leftover were characterized using FT-IR, AFM, TGA and XRD to access their functional, structural, thermal and crystallinity properties, respectively. The length and diameter of the chili leftover CNC were 90-180 nm and 4-6 nm, respectively, resulting in an average aspect ratio of 26. This high aspect ratio ensures percolation at low filler content which in turn results in high thermal and mechanical properties of the nanocomposites. These CNCs were used to prepare nanocomposite films using the highly marketing commercial latex called Cariflex-Isoprene (IR) by casting/evaporation in order to investigate their reinforcing effect. The mechanical properties of nanocomposite films were investigated in both the linear and nonlinear range by DMA and tensile test, respectively, and their morphology was studied using scanning electron microscopy.

Keywords: Aspect ratio; Cellulose nanocrystals; Chili leftover; Dynamic mechanical analysis; Scanning electron microscopy; Tensile tests.