Background: The addition of nanoparticles to cellulose paper can improve its mechanical
strength, chemical stability, biocompatibility and hydrophobic properties. Silica nanoparticles are
known to be inert, hydrophobic, biocompatible, biodegradable and have a good distribution being deposited
on surfaces. The main characteristics of 20 nm SiO2 nanoparticles are good chemical and thermal
stability with a melting point of 1610-1728°C, a boiling point of 2230°C with a purity of 99.5%.
Objective: To carry out the hydrophobization of paper based on Kraft cellulose and on cellulose obtained
from soybean husk with 20-nm size SiO2 nanoparticles and to study hydrophobicity, morphology and topography
of the prepared composites. Few relevant patents to the topic have been reviewed and cited.
Methods: The ground and roasted soybean husk was treated with a NaOH, washed and dried. Hydrophobization
of paper was carried in aqueous medium by SiO2 addition in weight ratios “paper-SiO2 ”
of 0.01-0.05 wt.%, stirring, filtration and drying. The obtained cellulose sheet composites were characterized
by Scanning Electron Microscopy (SEM), Transmisión Electron Microscopy (TEM), FTIRspectroscopy,
Mullen proofs of hydrophobicity, and contact angle measurements.
Results: The mechanical properties of paper nanocomposites (tensile strength and compression) increased
considerably by varying the concentrations. The tensile strength increased by 41-46% and the
compressive strength increased by 55-56%. The existence of fiber nanofoils, good adhesion of 20-nm
SiO2 nanoparticles to the paper surface, and their homogeneous distribution were observed.
Conclusion: Cellulose was successfully obtained from soybean husk, applying the alkaline-based extraction
method. A good reinforcement of cellulose fibers is observed due to the outstanding characteristics
of the silicon dioxide nanoparticles.