The performance of ultraviolet (UV) protection, antimicrobial activity, and self-cleaning characteristics of nano titanium dioxide (TiO2) with acrylic binder were assessed on the cotton fabric using pad-dry-cure method. Titanium iso-propoxide was used as precursor with two different mediums of water and ethanol to synthesize nano-sol by sol-gel technique. The synthesized nano-sol-gel was then characterized by using Fourier transform infrared (FTIR) spectroscopy, particle size analyzer (PSA), X-ray powder diffractometry (XRD), and scanning electron microscopy (SEM). The nano TiO2 finished cotton fabrics were tested for ultraviolet protection factor (UPF), antimicrobial activity, self-cleaning action, and physical properties. The wash fastness of TiO2 nano finished cotton fabrics for 5th, 10th, 15th, and 20th washes was assessed and also their ultra protection factor values and the percentage reduction in bacteria in each stage were reported. The self-cleaning activity was assessed for 12 hours, 24 hours, and 48 hours duration by exposing coffee stain on the specimen fabrics to sunlight. The TiO2 nanoparticles had 12 nm when ethanol medium was used and 7 nm for water. The smaller nanoparticles had showed better results regards antimicrobial activity and self-cleaning. In case of UV-protection function it was found that the fabrics treated with 12 nm nanoparticles exhibit higher UPF values than the fabric treated with 7 nm nanoparticles. The durability of the imparted function was in the range of 32–36 washes for antimicrobial activity and UV-protection property.
OF THE DISSERTATIONOur overall objective is to understand how molecular mobility modulates diffusion rates and thus chemical reactivity in films made from amorphous β-lactoglobulin. The phosphorescence emission spectra and lifetimes of the triplet probe erythrosin B embedded in the β-Lg films provide measures of the modes, rates, and distribution of molecular mobility in the film, providing the molecular detail necessary to connect food quality and stability to molecular structure and mobility. The mobility contours generated from this research provided us with information about the onset temperature and level of molecular mobility required to support permeability of atmospheric oxygen. In β-Lgbased binary matrices, sugars (sucrose, trehalose, maltose), plasticizers (glycerol, sorbitol, maltitol and PEG-400), fatty acids (palmitic acid, caprylic acid) and protein (BSA) were selected to investigate how variations in composition influence the molecular mobility and oxygen permeability in amorphous β-Lg matrix. Further more complicated β-Lg -based ternary matrices (maltose and maltitol) and (PEG and sucrose) were generated inorder to gain a deeper understanding of edible films.iii In pure β-Lg films there was linear correlation between molecular mobility and oxygen permeability. Various additives showed different results with respect to mobility and permeability. The addition of sucrose, maltose, maltitol and trehalose greatly reduced the mobility and the permeability of the β-Lg matrix. Glycerol exhibited an antiplasticization effect and showed decreased mobility at a molar ratio of 1:1 glycerol/ β-Lg.PEG greatly enhanced the permeability of β-Lg matrix. Fatty acids palmitic acid and caprylic acid had a rigidification effect on the matrix with no change in permeability. We were able to detect dynamic synergies in β-Lg maltose and maltitol mixtures, whereby these sugar-polyol mixtures at equal ratios anti-plasticized the β-Lg matrix and at unequal ratios plasticized the matrix. The tertiary matrix comprising of β-Lg, PEG 400and sucrose brought about a substantial reduction in the permeability. A better understanding of the mobility in these complex matrices will help improve the effectiveness of β-Lg in barrier applications in real food systems.
The performance of ultraviolet protection, antimicrobial activity, soil release action and self-cleaning characteristics of nano zinc oxide (ZnO) with acrylic binder were assessed on the cotton fabric using pad-dry-cure method. Different precursors such as zinc chloride and zinc nitrate were used to synthesize nanoparticles by wet chemical technique. The synthesized nanoparticles were then characterized using Fourier transform infrared spectroscopy, particle size analyser, powder X-ray diffractometry and scanning electron microscopy. The nano ZnO finished cotton fabrics were tested for ultraviolet protection factor, antimicrobial activity, soil release action and self-cleaning action. The wash fastness of nano zinc oxide (ZnO) finished cotton fabrics after 5th, 10th, 15th and 20th washes were assessed. Also the ultraviolet protection factor values, percentage reduction in bacteria and soil release percentage in each washing stage are reported. The self-cleaning activity was assessed for 12, 24and 48 h duration by exposing 6% of coffee stain on the specimen fabrics to sunlight. The zinc oxide nanoparticle size of 24 nm was obtained from synthesis of zinc chloride as a precursor, and another nanoparticle size of 38 nm were obtained from synthesis of zinc nitrate as a precursor. The smaller nanoparticles (24 nm) show better results in terms of antimicrobial activity, soil release and self-cleaning action. In case of ultraviolet protection function, it was found that the fabrics treated with 38 nm nanoparticles exhibit higher ultraviolet protection factor values than the fabric treated with 24 nm nanoparticles. The durability of
The properties of amorphous solid proteins influence the texture and stability of low-moisture foods, the shelf-life of pharmaceuticals, and the viability of seeds and spores. We have investigated the relationship between molecular mobility and oxygen permeability in dry food protein films-bovine α-lactalbumin (α-La), bovine β-lactoblobulin (β-Lg), bovine serum albumin (BSA), soy 11S globulin, and porcine gelatin-using phosphorescence from the triplet probe erythrosin B. Measurements of the phosphorescence decay in the absence (nitrogen) and presence (air) of oxygen versus temperature provide estimates of the non-radiative decay rate for matrixinduced quenching (k TS0 ) and oxygen quenching (k Q [O 2 ]) of the triplet state. Since the oxygen quenching constant is the product of the oxygen solubility ([O 2 ]) and a term (k Q ) proportional to the oxygen diffusion coefficient, it is a measure of the oxygen permeability through the films. For all proteins except gelatin, Arrhenius plots of k TS0 reveal a gradual increase of apparent activation energy across a broad temperature range starting at ∼50°C; this suggests that there is a steady increase in the available modes of molecular motion with increasing temperature within the protein matrix. Arrhenius plots for k Q [O 2 ] were linear for all proteins with activation energies ranging from 24 to 29 kJ/mol. The magnitude of the oxygen quenching constants varied in the different proteins; the rates were approximately 10-fold higher in α-La, β-Lg, and BSA than in 11S glycinin and gelatin. Although the rate of oxygen permeability was not directly affected by the increased mobility of the protein matrix, plots of k Q [O 2 ] versus k TS0 were linear over nearly three orders of magnitude in the protein films, suggesting that the matrix mobility plays a specific role in modulating oxygen permeability. This effect may reflect differences in matrix-free volume that directly influence both mobility and oxygen solubility.
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