Sandra Bischof

Prof. Dr. Sandra Bischof

1. University of Zagreb Faculty of Textile Technology, Department of Textile Chemistry & Ecology, Prilaz baruna Filipovica 28a, 10000 Zagreb, Croatia
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orcid

Research Focus & Metrics

Academic Career Length

19Years (2008-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 September 2015 in Composites Part B: Engineering
Verified
Journal Article
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ZKZorana Kovacevic
Zorana Kovacevic
Sandra BischofSandra Bischof
Sandra Bischof
Mizi FanMizi Fan
Mizi Fan

2 December 2020 in Materials
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Journal Article
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EMEva Magovac
Eva Magovac
IJIgor Jordanov
Igor Jordanov
Jaime GrunlanJaime Grunlan
Jaime Grunlan
Sandra BischofSandra Bischof
Sandra Bischof
Chemically bleached cotton fabric was treated with phytic acid (PA), chitosan (CH) and urea by means of layer-by-layer (LbL) deposition to impart flame retardant (FR) behavior using only benign and renewable molecules. Samples were treated with 8, 10, 12 and 15 bilayers (BL) of anionic PA and cationic CH, with urea mixed into the aqueous CH solution. Flammability was evaluated by measuring limiting oxygen index (LOI) and through vertical flame testing. LOI values are comparable to those obtained with commercial flame-retardant finishes, and applying 10 or more bilayers renders cotton self-extinguishing and able to pass the vertical flame test. Microscale combustion calorimeter (MCC) measurements show the average reduction of peak heat release rate (pHRR) of all treated fabrics of ~61% and the reduction of total heat release (THR) of ~74%, in comparison to untreated cotton. Decomposition temperatures peaks (T1max) measured by thermogravimetric analyzer (TG) decreased by approximately 62 °C, while an average residue at 650 °C is ~21% for 10 and more bilayers. Images of post-burn char indicate that PA/CH-urea treatment is intumescent. The ability to deposit such a safe and effective FR treatment, with relatively few layers, makes LbL an alternative to current commercial treatments.

4 November 2011 in Cellulose
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ABAna Budimir
Ana Budimir
Sandra BischofSandra Bischof
Sandra Bischof
SFSandra Grgac Flincec
Sandra Grgac Flincec

1 February 2011 in Croatian Medical Journal
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Journal Article
Open access
Sandra BischofSandra Bischof
Sandra Bischof
SGSandra Flinčec Grgac
Sandra Flinčec Grgac
ABAna Budimir
Ana Budimir
SKSmilja Kalenić
Smilja Kalenić
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. 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). 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. 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.

2 June 2024 in Sustainability
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ZKZorana Kovacevic
Zorana Kovacevic
Sandra BischofSandra Bischof
Sandra Bischof
NBNikola Bilandzija
Nikola Bilandzija
TKTajana Kricka
Tajana Kricka
Straw, the primary agricultural waste, constitutes approximately 20% of the total biomass in the EU. Only a small fraction of the material is applied in various products, e.g., animal bedding, mulch, building, and composite materials, while a significantly larger portion is often burned in the field. This practice, while prohibited for several reasons, including the increased risk of fire and the release of carbon dioxide contributing to global warming, is still prevalent. Given the increasingly evident effects of climate change, EU legislation aims to reduce greenhouse gas emissions as much as possible. One of the strategies includes applying the cascade principle in the circular economy. This principle aims to use the entire raw material, in this case, cereal crops, such that the products with the highest added value, like cellulose fibers from cereal straw, are extracted first. The vast potential for utilizing lignocellulosic agro-waste sustainably arises from its status as the most abundant organic compound on Earth. Its significant presence, renewability, and biodegradability make it a desirable source for producing materials in numerous industries. This study examines the potential of wheat fibers, isolated from the straw of two distinct cultivars (Srpanjka represents an old variety, and Kraljica represents the new variety) primarily for application in technical textiles. The following testing methods were applied: determination of wheat fibers and residues yield, fibers tensile properties, length, moisture content/regain, density, morphology, and Fourier transform infrared (FTIR) spectroscopy. The yield of isolated fibers relies on the wheat variety and the climatic conditions affecting plant growth, resulting in fiber yields from 10.91% to 15.34%. Fourier transform infrared (FTIR) analysis indicates reduced peak intensity, which is related to hemicellulose and lignin content, suggesting their improved deposition following the process of chemical maceration. Wheat fiber quality was found to be comparable to cotton fibers regarding its density. However, they showed a significant difference in higher moisture regain (9.72–11.40%). The vast majority of the scientific papers related to wheat fibers did not indicate the length of the individual fibers obtained by chemical maceration nor their strength. Therefore, this paper indicated that both varieties demonstrated sufficient fiber tenacity (greater than 10 cN/tex) and fiber length (2–3 cm), stressing the spinning potential of these fibers into yarns and extending their use to the apparel industry. Moreover, our research underscores the feasibility of adhering to the zero-waste principle. A high percentage of solid waste remaining after fiber extraction (25.3–39.5%) was successfully used for biofuel production, thus closing the loop in the circular economy.

1 April 2008 in Textile Research Journal
Verified
Journal Article
Closed access
DKDrago Katovic
Drago Katovic
Sandra BischofSandra Bischof
Sandra Bischof
SGSandra Flincec Grgac
Sandra Flincec Grgac
SKStana Kovačević
Stana Kovačević
Ivana SchwarzIvana Schwarz
Ivana Schwarz
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.