This research aimed to create novel multifunctional cellulose fibres with water- and oil-repellent, self-cleaning, and flame retardant properties. A sol mixture of fluoroalkyl-functional siloxane (FAS), organophosphonate (OP) and methylol melamine resin (MR) was applied to cotton fabric by the pad-dry-cure method. Successful coating was verified by scanning electron microscopy and Fourier transform infrared spectroscopy. The functional properties of the finished fibres were investigated using the static contact angles of water and n-hexadecane, the water sliding angles, the vertical test of flammability, the limiting oxygen index, and simultaneous thermal analysis. The results revealed that a homogeneous composite inorganic-organic polymer film formed on the cotton fabric surface exhibited the following properties: static contact angle of water of 150° and of n-hexadecane of 128°, water sliding angle of 10°, limiting oxygen index of 34 %, and high thermal stability. These results demonstrate the synergistic activity of the compounds in the coating, which resulted in the creation of a ”lotus effect” on the fabric surface as well as excellent flame retardancy and thermal stability.
COBISS.SI-ID: 2936432
Weakly ionised gaseous plasma created in a moist tetrafluoromethane gas at a low pressure with an electrodeless radiofrequency discharge was applied to modify the surface properties of cellulose fibres. The plasma was used to increase the adsorption of zinc oxide (ZnO) nanoparticles such that cellulose fibres with good ultraviolet (UV) protective properties could be created. The UV protection factor (UPF) values of the ZnO-functionalised fibres were determined as a function of the plasma treatment time. The chemical and physical surface properties of the plasma-treated fibres were examined using scanning electron microscopy, X-ray photoelectron spectroscopy, and wettability tests. The quantity of zinc on the fibres was determined using inductively coupled plasma mass spectroscopy. The results indicated that 30 s of plasma treatment resulted in ZnO-functionalised samples with lower UPF values than samples without plasma treatment due to the creation of fluorine-rich functional groups on cellulose fibres and the agglomeration of ZnO nanoparticles. The highest UPF values (50+) were obtained when samples were treated with plasma for 10 s. These high UPF values were a result of the increased adsorption of uniformly distributed ZnO nanoparticles caused by fibres surface functionalization and roughening upon plasma treatment. Furthermore, the mechanical properties of textiles treated with moist CF4 plasma for 10 s were slightly improved.
COBISS.SI-ID: 3006576
In this research, a new two-step procedure of the surface modification was developed with the aim of creating the ”lotus effect” on the cotton fabric surface. In the first step, the fibres were treated with the low-pressure water vapour plasma, followed by the application of a pad-dry-cure sol-gel coating with the water- and oil-repellent organic-inorganic hybrid precursor fluoroalkyl-functional siloxane (FAS). The tailored ”lotus effect” was confirmed by measurements of the static contact angle of water (154°) and n-hexadecane (140°), as well as by measurements of the water sliding angle (7°), which were used to identify the superhydrophobic, oleophobic and self-cleaning properties of the modified fibres. The results show that the plasma pre-treatment simultaneously increased the surface polarity, roughness, and surface area of the fabric. The application of the FAS coating after plasma pre-treatment caused a slight increase in the surface roughness, accompanied by a decrease in the surface area, indicating that the architecture of the surface was significantly changed. This result suggests that the surface pattern affected the ”lotus effect” more than the average surface roughness. The plasma pre-treatment increased the effective concentration of the FAS network on the fabric, which resulted in enhanced repellency before and after repetitive washing, compared with that of the FAS-coated fabric sample without the plasma pre-treatment.
COBISS.SI-ID: 2799984
In this research, we succeeded to introduce a novel two-step procedure for chemical modification of cellulose fibres with antimicrobial activity, which included the pad-dry-cure method to apply a reactive inorganic-organic hybrid sol-gel precursor (RB) followed by the in situ synthesis of AgCl particles on the RB-treated fibres. This process enabled the preparation of fibres with highly effective and durable antimicrobial properties at a sufficient concentration of AgNO3 in the solution. The results showed that this application process yields the following important benefits: (i) the in situ synthesis enabled a simple and environmentally friendly preparation of AgCl particles from AgNO3 and their embedment into the fibres; (ii) the presence of the RB silica matrix increased the fibres’ capacity for adsorbing AgCl particles compared with the same fibres without RB; (iii) the AgCl particles were bound to the RB silica matrix by physical forces, which allowed for their controlled release from the fibres; (iv) the modified cellulose fibres provide a 100% bacterial reduction even after 10 repeated washing cycles; and (v) chemical modification did not significantly change the fibres whiteness, wettability or softness.
COBISS.SI-ID: 36032773
The feasibility of a complete enzymatic one-bath pre-treatment of the cotton fabric at low temperature was investigated in this study. The cotton fabric was enzymatically desized, scoured and bleached with an enzyme mixture of starch degrading enzymes, pectinases and glucose oxidases, respectively. Starch-degrading enzymes hydrolyzed the sizing agent into glucose. Enzymes glucose oxidases catalyzed the oxidation of β-D-glucose to D-glucono-δ-lactone and simultaneously generated hydrogen peroxide. The desizing and hydrogen peroxide generation took place for one hour at temperature of 50 °C in a slightly acid pH range. For bleaching, hydrogen peroxide was converted into peracetic acid by incorporating the bleach activator tetra acetyl ethylene diamine (TAED). Bleaching took place at 50 °C and neutral pH, where peracetic acid is most effective. Enzymes pectinases were added into the pre-treatment bath to remove pectins from fibres and improve their wettability. Whiteness values, water absorbency, polymerization degree and tenacity at maximum load were measured on pre-treated samples. The total organic carbon, pH and biodegradability were measured on residual pre-treatment baths. It was established that hydrogen peroxide can be efficiently enzymatically produced from the sizing agent and converted with TAED to form peracetic acid to bleach the cotton fabric. Cotton fabrics with a medium degree of whiteness, WI=51, and good water absorbency can be obtained at low water and energy consumption.
COBISS.SI-ID: 2776432