Evaluation of the permeability and in vitro cytotoxicity of functionalized titanate nanotubes on Caco-2 cell line

Titanate nanotubes (TNTs) are promising vectors for drug delivery due to their unique physicochemical properties such as biocompatibility, mechanical strength, and chemical resistivity. However, considering their strong hydrophilicity, pristine TNTs exert very limited permeability through the intestinal cell layer. The aim of this study was to turn the surface characteristics and thus enhance the permeability of TNTs by functionalization. TNTs were functionalized with trichloro(octyl)silane (TCOS) and magnesium stearate (MgSt). Carbon content and surface free energy of the functionalized TNTs were detected to evaluate the effectiveness of functionalization, by using CHNS analytical and optical contact angle (OCA) measurements, respectively. Caco-2 cell line was applied to test the permeability and the cytotoxicity of the samples. Cytotoxicity was evaluated by using MTT assay. The results revealed that the surface characteristics of TNTs may be adjusted in a wider range with TCOS-TNT than with St, but the samples show higher toxicity. Silane functionalized TNTs may be safe up to 1 mg/ml, while St functionalized TNTs up to 2 mg/ml concentration. The preparation method of MgSt-TNT was also superior from the aspect of environmental safety. The permeability was suitable for samples with moderate hydrophobicity (aqueous contact angle 60-90°).

Influence of Biochar Particulate on the Sorption Behaviour of Sansevieria Cylindrica Reinforced Vinyl Ester Composite

Purpose of this research is to evaluate the influence of biochar from corn cob and wood waste residues on the water resistivity of the Sansevieria cylindrica reinforced vinyl ester composite (SCVEC) to be utilized in structural and marine applications. Biochar filled SCVEC was allowed to immerse in different sources of waters like seawater, ground water and distilled water to study the water absorption of the material. Kinetics of water molecule transferring into the composite during immersion was studied by determining the diffusion coefficient, permeability coefficient and sorption coefficient. Fabricated composites were analysed for its Fickian behaviour under 720 Hrs of immersion in different water medium. Chemical resistivity for the fabricated composite were also studied to make the composite more accessible to marine environment. Results reveals that increase in biochar loading up to certain wt. % increases the water resistivity of the composite. Reinforcement of Biochar derived from corn cob was found to have potential water resistivity property compared to the biochar derived from wood wastes.

Local atomic order of the amorphous TaOx thin films in relation to their chemical resistivity

The experimental and theoretical studies of the local atomic order and chemical binding in tantalum oxide amorphous films are presented.

Testing Methods of Assessment for the Chemical Resistance of Insulating Materials Against the Effect of Selected Acids

The Czech Armed Forces' soldiers of all specializations and mainly the chemical corps'specialist are prepared for task fulfillment in military and non-military operations within those a real threat of weapons of mass destruction employment and, occasionally, the real danger of toxic industrial materials leakage is present. They can solve problems caused by acids leakage in contaminated areas mainly during task fulfillment in non-military operations on the Czech Republic territory in cooperation with Fire Rescue Brigades' chemical specialists. Individual protective equipment which is established in the Czech Armed Forces were neither design for this purpose and, moreover, nor tested and thus there is no real data concerning their chemical resistivity. In recent time, some methods have been introduced into the Czech Armed Forces environment. They are useful for determination of chemical resistivity of barrier materials against toxic compounds detectable with acid-basic (colorimetric) methods and conductometric ones. The paper deals with the possibility of using the presented methods and compares the suitability of their application in relation to the protective garments designated for the Czech Armed Forces members' body surface.

Effects of nano- and micro-sized inorganic filers on the performance of epoxy hybrid nanocoatings

Epoxy-based composite coatings were prepared using nanosilica (silicon dioxide (SiO2)) and zinc oxide (ZnO). Different concentrations (5.0, 10.0 and 15.0 wt%) of micro-sized ZnO particles were used along with a fixed amount (20.0 wt%) of nanosilica particles. The functional groups of the composite coatings were confirmed by the Fourier transform infrared spectroscopy. This result indicated that SiO2–ZnO particles were cross-linked with the epoxy. The scanning electron microscopy images of the samples revealed a good dispersion of ZnO particles. In addition, the samples showed an improved adhesive and chemical resistance properties as measured by the cross-cut tape test and chemical resistivity testing. At higher loading of ZnO, the composite coating showed poor properties. Besides that, thermogravimetric analysis, differential scanning calorimetry and ultraviolet–visible spectrophotometer were used to characterize the composite coatings. The properties were enhanced at higher loading of ZnO particles. The oxygen transmission rate was also impressive compare with the neat epoxy.

Experimental Studies on Behavior of Keratin Based Human Hair Fiber - A New Reinforcing Material for Composites

Composite materials are formed by two or more constituents at macroscopic level. Type and form of fiber plays a vital role in imparting required properties to the composite. Many researchers contributed to the development of artificial fiber composites which are not environmental friendly in nature. Sizable research is also done in the area of natural fiber composites. Human hair is a non-biodegradable waste available in abundant quantity across the world, but is rarely explored for applications in engineering fields. In the present study, a review on behavior of human hair fibers was made to understand their suitability as a reinforcing material in composites. Morphology of the hair fibers is reviewed and the density of the hair fibers was determined using Archimedes principle. Tensile strength of the hair fibers is experimentally estimated. Chemical resistivity and burning tests were conducted. Tensile and flexural properties of hair fiber reinforced polyester composite were experimentally determined and compared.

Effect of reduced graphene oxide on the solvent transport characteristics and sorption kinetics of fluoroelastomer nanocomposites

Molecular transport characteristics of fluoroelastomer nanocomposites in aromatic hydrocarbons exhibited improved chemical resistivity by the incorporation of reduced graphene oxide, due to its better reinforcing efficiency and improved polymer-filler interactions.

Quest for electroconducting structural polymers: CNTs/Polybond nanocomposites with improved electrical and mechanical properties

Electroconducting structural polymer-based nanocomposites were prepared by incorporating carbon nanotubes (CNTs) into commercially available Polybond (PB) using the melt compounding technique. The structural, morphological, electrical, thermal, mechanical, and chemical properties of the nanocomposites were investigated via Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), differential scanning calorimetry, thermogravimetric analysis, high resistance meter, a Universal Testing Machine (UTM), and chemical resistivity measurements, respectively. FTIR spectra showed the successful grafting of CNT functional groups onto polymer chains. SEM analysis confirmed that the optimum state of dispersion was made for the nanocomposites. Electrical conductivity, melting transition temperatures, mechanical properties, and chemical resistance were improved by incorporating CNTs into PB.

PREPARATION OF SOYPROTEIN BASED NANOPARTICLE

Soy protein based Nanoparticles were prepared via direct graft copolymerisation of soyprotein isolate (SPI) with ethyl methacrylate at a temperature of 120◦c using benzoyl peroxide as a catalyst. The technique used here was emulsion polymerisation technique. The products obtained ie., the graft copolymer and the homopolymer Poly(ethyl methacrylate)(PEMA) were separated from the product mixture by dissolving the mixture using chloroform in a separating funnel.The separated graft copolymer in the emulsion form was then spreaded over a glass plate to make a nano plastic sheet and the sheet was allowed to dry for 24 hrs at room temperature to remove chloroform from it. FTIR study confirmed the grafting of SPI and PEMA. XRD studies confirmed the presence of nanoparticles. TG-DTA, Hydrolytic stability, chemical resistivity and water absorption of the sample were studied. Grafting efficiency and grafting percentage of the sample were calculated.

Upgrading Electrical, Mechanical, and Chemical Properties of CNTs/Polybond® Nanocomposites: Pursuit of Electroconductive Structural Polymer Nanocomplexes

Electroconductive structural polymer-based nanocomposites (NCs) were prepared by incorporating carbon nanotubes (CNTs) into Polybond (PB) matrix via melt compounding technique. Chemical structure of NCs, investigated via Fourier transform infrared (FTIR) spectroscopy, corroborated successful grafting of CNTs functional groups onto PB chains. The morphology of NCs, as examined by scanning electron microscopy (SEM), ensured their optimum state of dispersion. Electrical conductivity, melting transition temperatures, mechanical properties, and chemical resistance of NCs were improved by incorporating CNTs into PB as established by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), high resistance meter (HRM), Universal Testing Machine (UTM), and chemical resistivity measurements, respectively.