Sandra Flinčec Grgac

Cotton textiles modified with citric acid as efficient anti-bacterial agent for prevention of nosocomial infections

Aim To study the antimicrobial activity of citric acid (CA) and sodium hypophosphite monohydrate (SHP) against gram-positive and gram-negative bacteria, and to determine the influence of conventional and microwave thermal treatments on the effectiveness of antimicrobial treatment of cotton textiles. Method Textile material was impregnated with CA and SHP solution and thermally treated by either conventional or microwave drying/curing treatment. Antibacterial effectiveness was tested according to the ISO 20743:2009 standard, using absorption method. The surfaces were morphologically observed by scanning electron microscopy, while physical characteristics were determined by wrinkle recovery angles method (DIN 53 891), tensile strength (DIN 53 837), and whiteness degree method (AATCC 110-2000). Results Cotton fabric treated with CA and SHP showed significant antibacterial activity against MRSA (6.38 log10 treated by conventional drying and 6.46 log10 treated by microwave drying before washing, and 6.90 log10 and 7.86 log10, respectively, after 1 cycle of home domestic laundering washing [HDLW]). Antibacterial activity was also remarkable against S. aureus (4.25 log10 by conventional drying, 4.58 log10 by microwave drying) and against P. aeruginosa (1.93 log10 by conventional and 4.66 log10 by microwave drying). Antibacterial activity against P. aeruginosa was higher in samples subjected to microwave drying/curing than in those subjected to conventional drying/curing. As expected, antibacterial activity was reduced after 10 HDLW cycles but the compound was still effective. The surface of the untreated cotton polymer was smooth, while minor erosion stripes appeared on the surfaces treated with antimicrobial agent, and long and deep stripes were found on the surface of the washed sample. Conclusion CA can be used both for the disposable (non-durable) materials (gowns, masks, and cuffs for blood pressure measurement) and the materials that require durability to laundering. The current protocols and initiatives in infection control could be improved by the use of antimicrobial agents applied on cotton carbohydrate polymer.

The Effect of Microwave Drying on Warp Sizing

The paper describes our research of microwave usage in drying the size pick-up. An analysis of three different drying processes in relation to physical-mechanical properties of sized yarn has been carried out. Under the same sizing conditions, but different drying methods, the following parameters were determined: breaking force, elongation at break, abrasion resistance and yarn hairiness. The application of microwave drying method for warp sizing showed to be equally good, or even better in some cases, compared to the conduct and convection drying methods.

SEM Characterisation of the Cellulose Material Treated with Polycarboxylic Acid and Zeolite Nanoparticles

Coating of zeolite nanoparticles, previously dispersed in Polycarboxylic acid (PCA) solution, on cellulose textile surface has several advanced technological applications. One of the possible usages is for the Durable Press finishing enabling simultaneous enhanced antimicrobial or flame retardant properties. In this study, one of the polycarboxylic acid crosslinking agents, Citric acid (CA) is used to coat cotton fabric in the presence of synthesized zeolite applied as a catalyst. Cotton fabric samples were padded with a suspension containing zeolite powder in aqueous solution of CA crosslinking agent. Drying and curing of coated samples was performed at different curing conditions, either in a microwave oven or in conventional dryer. Scanning electron microscope (SEM) is used to characterize the surface morphology and confirm bonding of zeolite particles to cellulose fibers. Further characterization of coated surface is performed by attenuated total reflectance (ATR) Fourier transform infrared (FT-IR) spectroscopy while the effects of microwave irradiation on zeolite nanoparticles bonding is estimated by thermogravimetric analysis.

Analytical Assessment of the Thermal Decomposition of Cotton-Modacryl Knitted Fabrics

Fabric flammability is affected by various factors such as the fibre composition, fabric construction, FR (flame retardant) finish, oxygen concentration and environmental conditions (moisture content, heat). Inherently FR fabrics are synthetics which have been changed at the molecular level to make the fabrics thermally stable and able to pass FR tests. The thermal properties of knitted fabrics produced from cotton, modacryl and their blends were investigated in this paper. The design of FR knitted fabrics and an optimal blend ratio were evaluated by different thermoanalytical methods: the flame behaviour and thermal stability with the limited oxygen index (LOI), thermal gravimetric analysis (TGA), coupled thermal gravimetry – Fourier transform infrared technique (TG-FTIR) and microscale combustion calorimetry (MCC). Surface characterisation of the knitted fabrics designed was evaluated by the streaming potential method. Knitted fabric in the blend ratio C50:M50 proved to possess the most favourable FR characteristics, additionally confirmed by optimal hydrophilic properties evaluated through zeta potential measurement.

Physicochemical characterization of the multiuse medical textiles in surgery and as packaging material in medical sterilization

Abstract This work investigates changes in the physicochemical properties of dry multiuse medical textiles used in surgery and as packaging material in sterilization after 0, 1, 10, 20, 30, and 50 washing and sterilization cycles in real hospital conditions of the Clinical-Hospital Centre in Zagreb. Scanning electronic microscope (SEM) was used to perform morphological characterization. Physicochemical characterization and the resulting changes in the medical textiles were monitored using Fourier transform infrared (FT-IR) spectrometer. The change in the mass of the medical textiles as a results of temperature was determined by thermogravimetric (TG) analysis. Furthermore, structural characteristics based on the changes that resulted during the washing and sterilization processes are provided. The conclusion of the conducted research on the changes in the properties of multiuse medical textiles (Cotton/PES, Tencel®, and three-layer PES/PU/PES textile laminate) in real hospital conditions is that the medical textiles do manage to preserve properties after continuous use and it is safe to use them up to 50 washing and sterilization cycles.

Thermal analysis of N-carbamoyl benzotriazole derivatives.

Abstract Thermal properties of N-carbamoyl benzotriazole derivatives and N,N’,N’’-tribenzyloxyisocyanuric acid were investigated using thermogravimetric analysis and differential scanning calorimetry. The results revealed a difference between structural analogs of N-carbamoyl benzotriazole derivatives. They seem to be in agreement with the previously proposed formation of N,N’,N’’-tribenzyloxyisocyanuric acid from 1-(N-benzyloxycarbamoyl) benzotriazole, via an intermediary N-benzyloxyisocyanate acid, during heating. Substantially different thermal properties were observed for structural analogues, 1-(N-methoxycarbamoyl) benzotriazole and 1-(N-ethoxycarbamoyl) benzotriazole. In contrast to N-benzyloxyisocyanate, no corresponding reactions were observed for their decomposition products, i.e., methoxyisocyanate and ethoxyisocyanate.