2021

Kokol, Vanja; Vivod, Vera; Peršin, Zdenka; Kamppuri, Taina; Dobnik-Dubrovski, Polona

Low moisture absorbency of hydrophobically coated flame-resistant (FR) fabrics do not correlate well with the thermophysiological comfort. In this frame, we were the first to study the effect of screen-printed microfibrillated cellulose (MFC) on fabric’s breathability and moisture build-up and transfer as user-friendly and wear-related comfortable coating. The amount of MFC applied and its patterning was varied using different printing parameters, the density and thickness of FR fabric, and studied by add-on measurement and microscopic imaging. The effect of MFC coating and its durability (attachment) after a post-printing of hydrophobic polyacrylate on the same (layer-by-layer) or other side of the fabrics was considered, thus to maintain one side of the fabric (facing towards the wearer) hydrophilic while keeping the other side (facing outward) hydrophobic. The results showed that MFC provides uniform and repeatable printing, which gave homogeneous patterning with good layering on the fabrics, although, resulting in the MFC concentration, squeegee’ pressure, and fabric’ structure dependent add-on, its imprinting and co-crosslinking within the polyacrylate. This slightly reduced the fabric air-permeability, but increased it surfaces wetting, moisture uptake kinetic and capacity (hydroscopicity), without affecting the water vapour transfer. Besides, the polyacrylate could fix the MFC pre-printed on the other side of the fabric, thus maintaining its hydrophilicity, being more pronounced in the case of less open and thicker fabric, while improving its tensile/tear strengths and abrasion resistance, without deterioration of the fabric`s flammability.