Influence of Calcium Silicate and Hydrophobic Agent Coatings on Thermal, Water Barrier, Mechanical and Biodegradation Properties of Cellulose

Thin films of cellulose and cellulose–CaSiO3 composites were prepared using 1-ethyl-3-methylimidazolium acetate (EMIMAc) as the dissolution medium and the composites were regenerated from an anti-solvent. The surface hydrophilicity of the resultant cellulose composites was lowered by coating them with three different hydrophobizing agents, specifically, trichloro(octadecyl)silane (TOS), ethyl 2-cyanoacrylate (E2CA) and octadecylphosphonic acid (ODPA), using a simple dip-coating technique. The prepared materials were subjected to flame retardancy, water barrier, thermal, mechanical and biodegradation properties analyses. The addition of CaSiO3 into the cellulose increased the degradation temperature and flame retardant properties of the cellulose. The water barrier property of cellulose–CaSiO3 composites under long term water exposure completely depends on the nature of the hydrophobic agents used for the surface modification process. All of the cellulose composites behaved mechanically as a pure elastic material with a glassy state from room temperature to 250 °C, and from 20% to 70% relative humidity (RH). The presence of the CaSiO3 filler had no effect on the elastic modulus, but it seemed to increase after the TOS surface treatment. Biodegradability of the cellulose was evaluated by enzyme treatments and the influence of CaSiO3 and hydrophobic agents was also derived.

Effect of silylating agents on the superhydrophobic and self-cleaning properties of siloxane/polydimethylsiloxane nanocomposite coatings on cellulosic fabric filters for oil–water separation

Two silylating agents, hexamethyldisilazane and trimethoxy(octadecyl)silane enhance the superhydrophobicity and self-cleaning properties of siloxane/PDMS nanocomposite coatings on cotton filters for oil–water separation.

Self-cleaning properties of polyester fabrics coated with flower-like TiO2 particles and trimethoxy (octadecyl)silane

The presented work reported the growth of 3D-shaped TiO2 flower particles on the surface of polyester fabrics using two step approaches of sol–gel technology and hydrothermal method. The scanning electron microscopy, EDS analysis, Raman spectroscopy, and X-ray diffraction techniques were employed to study the effect of titanium isopropoxide (TTIP) concentration on the growth of flower-like TiO2 microstructures. Later, a layer of trimethoxy(octadecyl)silane was applied on TiO2-coated polyester fabrics to fabricate the self-cleaning textiles. The physical self-cleaning properties were examined based on superhydrophobicity and contact angle measurements, where maximum static contact angle of 160.1o and minimum roll off angle of 3° was found for 2 mL TTIP concentration. The degradation of methyl orange dyes under UV light irradiation was observed to confirm the photocatalytic chemical self-cleaning behavior, where the samples coated with 2 mL TTIP decolorized the dye solution in 150 min, whereas the samples coated with 1 mL and 1.5 mL TTIP took almost 300 and 210 min, respectively.