This study aimed to characterize cellulose nanowhiskers extracted from discarded cotton fibers. The nanocellulose was characterized by dynamic light scattering, zeta potential, Scanning Transmission Electron Microscopy (STEM), Atomic force microscopy (AFM) and X-ray powder diffraction (XRD). The nanocrystals are characterized by a rod-like morphology with sizes between 100 nm and 300 nm. The acidic hydrolyses applied to the extract nanocrystals increased the crystallinity index from 72 to 86%. The average length and diameter obtained were 98.1±4.7 and 8.0±3.4 nm, respectively. The aspect ratio of the fibers, around 12.3, was lower than the values usually reported in the literature. The dynamic light scattering results were in accordance with the nano crystal dimensions showing an average size of 235 nm. Cellulose nanowhiskers obtained from cotton rejected by textile industry due to their abundance, low cost, high crystallinity, strength, low weight and biodegradability, are the ideal candidates for the processing of polymer nanocomposites.

Molded sisal fibers dip-coated with titanium dioxide (TiO2) nanoparticles were physico-chemical characterized and tested for the photocatalytic treatment of textile wastewaters. The X-Ray powder diffraction (XRD), X-Ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and the scanning electron microscopy (SEM) analysis revealed uniform TiO2 nanoparticles deposition in the anatase phase with and average diameter of 32 nm. The sisal/TiO2 nanocomposite exhibits a remarkable photodegradation yield of methylene blue solution (92%) maintaining a good efficiency even after 5 washing cycles (70%). The nanocomposite also exhibits a remarkable fast photo-induced hydrophilicity decreasing the contact angle from 140º to 6º after 7 minutes of UV exposure. Sisal fibers revealed to be a promising substrate for TiO2 nanocomposites in wastewater treatment due to its low cost, low density, high specific strength and modulus, no health risk, easy availability and renewability.

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In this study, functionalized polymer nanolatexes based on P(MMA‐co‐BA‐co‐MAA) are synthesized by semicontinuous emulsion polymerization. An evaluation of the effect of reaction parameters such as monomer composition and initiators type on the latex properties is performed. Consideration of these effects allows the synthesis of low surfactant concentration‐high functionalized polymer nanoparticles as small as 29 nm. Then, a functionalized nanolatex is used as a binder in dyeing process of soybean protein fabric (SBF) using the cationic dye, Basic Red 46. Colorimetric tests show that the previous functionalization of soybean fibers with the nanolatex improves the efficiency of dyeing process by up to 13%. In addition, washing and rubbing fastness tests revealed that dyed functionalized fabrics had better performance than the one without nanolatex.

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