Advanced Materials Research Vol. 1117

Abstract: The aim of the current research was to study regularities of chemical bath deposition (CBD) of tin sulphide thin films as function of tin and sulphur concentrations in the solutions. SnS thin films were deposited onto Mo-, ITO-and TO-coated glass and onto borosilicate glass substrates at room temperature for 24 hours. The concentrations of sulphur and tin (ratio 1:1) in the deposition solution were varied from 0.01 M to 0.09 M. Films were characterized by SEM and Raman spectroscopy. The structuraly best tin mono-sulphide films with good adhesion to the substrate were deposited at concentration of consituents in solution 0.03M. The films deposited at concentration of 0.01M had non-uniform and incomplete coverage of the surface on all used substrates whereas at tin and sulphur concentrations of 0.05M and higher films were peeling off of the substrate.

Abstract: Graphene oxide (GO) reduction is a promising way for graphene large scale synthesis. Pre-exfoliated graphite was oxidized and reduced. The material was compared to commercial graphene oxide and its reduced sample. The reduction process of graphene oxide is accomplished using sodium borohydride (NaBH₄) with variable-valence metal ion – cobalt – assistance. The reduced graphene oxide (RGO) was characterized by Raman spectroscopy. The particle size and suspension stability were determined. Electrical conductivity measurements of GO and RGO samples have been done in temperature range from-150°C to 85°C. Pre-exfoliation effect was determined.

Abstract: Transient or metastable phases offer an intermediate phase with additional flexibility for creating the end product. The processing pathway remains unknown when the final product is viewed. Biological processes frequently employ the amorphous phase as the transition phase. This is shown in mineralized tissues: invertebrates, pathological calcified deposits and murine fetal teeth. After a fast transition from an amorphous calcium phosphate to crystalline material, smaller changes occur over time. For an appreciation of the transition state, crystallinity is defined and measurement methods outlined. Biotechnology using transition material states offers fast, low temperature access to nanosized high temperature phases. Alfa tricalcium phosphate and apatite is made by a phase transition, but peroxyapatite requires long-range diffusion within the same structure. Tetracalcium phosphate is also possible, but this requires multiple transition states and phase decomposition. The pathway via the amorphous state offers an alternative route to biologically important materials.

Abstract: Nano-sized pure α-tricalcium phosphate (α-TCP) fabricated by a novel synthesis approach shows great potential for a faster transformation into calcium-deficient hydroxyapatite (CDHA) than conventionally prepared α-TCP. In this work, amorphous tricalcium phosphate precursors were precipitated and treated with a solvent (water or ethanol), and dried (freeze-dried and oven-dried) before heating at 775 °C. Nanosized α-TCP powders were investigated for their phase composition and crystallinity, particle shape and size, reactivity and cellular biocompatibility. Reaction with water showed faster CDHA formation for freeze-dried powder, at 6 hours, compared to ethanol treated powders, whereas a higher biocompatibility was found for pure α-TCP.

Abstract: F-doped hydroxyapatite (FHAp, Ca₁₀(PO₄)₆OH_2-xF_2x) was synthesized by two step technology – wet-chemical precipitation and pH-cycling. Obtained powders were dried and calcined for further characterization. FHAp were analyzed by Fourier transform infrared spectrometry (FT-IR), scanning electron microscopy (SEM) and UV-VIS spectrophotometry. FT-IR analysis approved fluoride incorporation into HAp structure, confirmed by OH...F bonding at 3546 and 745 cm^-1. SEM microphotographs showed, that as-synthesized FHAp precipitates consist of needle-like crystallites. UV-VIS spectroscopy results were used for the determination of actual F^- substitution level. After evaluation of results it was concluded, that fluoride substitution level in FHAp structure reached only x≤0.6. To perform higher substitution level, the technological parameters of the process need to be optimized.

Abstract: The current research focuses on peroxide ion incorporation in the structure of strontium hydroxyapatite (SrHAp) by exposure to H₂O₂ in a closed hydrothermal vessel under mild conditions at 130 to 170 °C. Peroxide enriched strontium apatite (SrPerAp) was characterized for structure by X-Ray diffraction, for peroxide content- by permanganometric titration and then viewed by SEM. This study continued from previous work that used 30%H₂O₂ and showed a higher included peroxide content after processing with 50% H₂O₂ at 130 °C 70% of the theoretical peroxide content in apatitic channels of strontium apatite. This is the highest peroxide content incorporated to date and employs a lower temperature than heating at 1300 °C.

Abstract: Comparison of the antimicrobial properties of textiles with amorphous coatings containing Zn and Si obtained by the sol-gel technology against microorganisms Pseudomonas fluorescens, Saccharomyces cerevisae, Trichoderma viride that can cause cotton textile destruction was made. Modified textile were evaluated using scanning electron microscopy, energy dispersive x-ray spectroscopy. Investigation of antimicrobial properties of the cotton fabric samples treated with different zinc acetate dihydrate concentration sols and various thermal post-treatments was made. Strong inhibition of microbial growth was detected for all cotton textile samples treated via sol-gel method according all tests microorganisms.

Abstract: In this research an effect of a flame-retardant coating with antimony trioxide (Sb₂O₃), commercial printing pastes Printperfec EX-TS, Tubvinyl 235MC and a pigment Bezaprint ROT KF onto a raw linen fabric and a bleached linen fabric has investigated. After the coating 5 washing cycles were applied to half of the fabrics. The burning test of the raw and the bleached linen fabrics and those coated with commercial printing pastes and antimony trioxide, as well as the washed fabrics was accomplished. The results of the test show, that the raw and the bleached linen fabric burns completely. The flame extinction was observed for coated fabrics and coated washed fabrics.

Abstract: Present paper relates to the field of “smart textiles” and demonstrates the results of research carried out on the development of a new type of knitted sensing elements (knitted resistive fabric (KRP)) which can be integrated in the garment applied for health monitoring. KRP produced from conductive resistive, nonconductive isolating and nonconductive elastomeric yarns. Elastomeric yarn is used as the base yarn and is knitted in the whole fabric, but isolating and resistive yarns (functional yarns) are used as face yarns and knitted in specific sequence. Proposed knitted resistive fabric has high sensitivity to strain deformation and can be used as sensing element to control deformation of the human body parts, joint motion, respiration etc.

Abstract: Hemp fibre nonwovens are developed in the research work with a goal to the materials surface modification applying metal and metal oxide nanoparticles. It is planned to investigate the electrical properties of nonwovens to determine their ability to serve as radiation insulation. Fibres cut into 5 cm long, some of them passed through Laroche Cadette equipment twice that opens the fibres and part manually combed before making nonwovens. Carded webs formed from prepared fibres by parallel-laid carding method. The fibres opened by using Laroche Cadette equipment formed web only by mixing hemp fibres with 15% Tencel fibres. Clean hemp fibres webs created from manually combed fibres. Hemp fibres nonwovens created by using hydroentanglement method.