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Although deterioration of silicone maxillofacial prostheses is severely accentuated in smoking patients, the phenomenon has not been systematically studied. To address a gap in the literature concerning the stability of maxillofacial prostheses during service, in this contribution, the effect of cigarette smoke on the aspect and physical properties of M511 silicone elastomer was evaluated. The aspect, surface, and overall properties of the silicone material, pigmented or not, were followed by AFM, color measurements, FTIR, water contact angle measurements, TGA‐DTG and DSC, hardness and compression stress–strain measurements. The types of the contaminants adsorbed were assessed by XRF, ESI‐MS, MALDI‐MS, and NMR spectral analyses. Important modifications in color, contact angle, surface roughness, local mechanical properties, and thermal properties were found in the silicone material for maxillofacial prostheses after exposure to cigarettes smoke. The presence of lead, nicotine, and several other organic compounds adsorbed into the silicone material was emphasized. Slight decrease in hardness and increase in Young's modulus was found. The combined data show important impact of cigarette smoke on the silicone physical properties and could indicate chemical transformations by secondary cross‐linking. To our knowledge, this is the first study making use of complementary physical methods to assess the effect of cigarette smoke on the aspect and integrity of silicone materials for maxillofacial prostheses. [ABSTRACT FROM AUTHOR]

Polymers play a crucial role in multiple industries; however, surface modification is necessary for certain applications. Exposure to non-thermal plasma provides a viable and environmentally beneficial option. Fused deposition molding utilizes biodegradable polylactic acid, although it encounters constraints in biomedical applications as a result of inadequate mechanical characteristics. This study investigates the effects of atmospheric pressure plasma generated by a dielectric barrier discharge system using helium and/or argon on the modification of polylactic acid surfaces, changes in their wettability properties, and alterations in their chemical composition. The plasma source was ignited in either He or Ar and was tailored to fit the best operational conditions for polymer exposure. The results demonstrated the enhanced wettability of the polymer surface following plasma treatment (up to 40% in He and 20% in Ar), with a marginal variation observed among treatments utilizing different gases. The plasma treatments also caused changes in the surface topography, morphology, roughness, and hydrophilicity. Plasma exposure also resulted in observable modifications in the dielectric characteristics, phase transition, and structure. The experimental findings endorse the utilization of plasma technologies at normal air pressure for environmentally friendly processing of polymer materials, specifically for applications that necessitate enhanced adhesion and have carefully selected prerequisites. [ABSTRACT FROM AUTHOR]

In this study, the effects of three diamine curing agents (aromatic, cycloaliphatic, aliphatic) on the photochemical behavior of bisphenol A diglycidyl ether networks were comparatively examined. In order to monitor structural changes and study the curing agents' action mode, the cured epoxy resins were characterized before and after photoirradiation by means of Fourier-transform infrared spectroscopy, contact angle, differential scanning calorimetry, scanning electron microscopy, and energy-dispersive X-ray analysis, mass loss, and color modification measurements. Water absorption tests were also conducted. The cured epoxy resins are to be used in different multicomponent polymer materials for outdoor protection. The presence of the cycloaliphatic hardener led to reduced water absorption, and after UV irradiation, an increase in the glass transition temperature and lowest mass loss of the corresponding cured epoxy resin compared to the ones cured with aromatic and aliphatic hardener. [ABSTRACT FROM AUTHOR]

Textile dyes have been reported of causing various stages of contact dermatitis. Reactive dyes are widely applied in dyeing cellulose fiber based textiles (100% cotton), skin fibers (hemp, flax), regenerated cellulose (cellulose acetate, viscose), protein fibers (natural silk, wool). The human body comes in contact daily with such compounds. This aspect is important for elucidating their biological effects on the human body, in correlation with physico-chemical properties. Dyes are chemical compounds containing chromophore and auxochrome groups. Authors herein report results concerning the influence of UV irradiation with λ > 300 nm on the structure and properties of different colored textiles. Subjects to study were textiles painted with four azo-triazine based dyes which were exposed to 100 h UV irradiation time and irradiation dose values up to 3500 J cm-2. The five azo dyes were: reactive orange 13, reactive red 183, reactive yellow 143, reactive blue 204 and reactive red 2. Structural modifications as a result of irradiation were undertaken by UV-Vis spectroscopy. It was observed that during UV exposure there occurred partial dyes detachment from the textiles, accompanied by glucosidic units and dye photodecomposition by C–N bond scission and degradation of aromatic entities and azo based chromophores. Color modifications were also investigated. Color differences significantly increased with the irradiation dose for all the studied samples.

In today's move to "sustainable production" the leather industry, as well as many other industries is recognized as a polluting one. Traditional chemical operations are polluting because of the levels of inorganic chemical waste. Process chemicals which are not consumed within the reactions necessary to convert collagen to leather are currently discharged to waste. These are usually applied during bulk production, such as inorganic agents from beam house and tanning processes, e.g. lime, sulphide, ammonium salts, sulphuric acid and sodium chloride, mineral tanning agents – mainly Cr(III) and the less common Al(III), Zr(III), Ti(III), Fe(III) salts -, whereas depending on the tanning process and the leather article produced organic chemical waste discharged comprises aldehydic and polyphenolic tanning products, bating enzymes, organic carboxylic acids and excess electrolyte stable synthetic fat liquors. It is rare for chemicals and water to be recovered for re-use from several of these process steps. Moreover, tanners worldwide are required to operate within strict legislative boundaries. Serious drawbacks continuously arise concerning the chrome–tanning process in leather industry and the environmental hazardous consequences of chromium containing effluents. In order to overcome this impediment, a great deal of research has been focused on developing chrome–free tanning methods in the past years, such as titanium tanning. In the present study, Ti–Al tanned bovine leather was characterized by means of SEM microscopy, EDAX elemental analysis, ATR–FTIR spectroscopy, thermogravimetry TGA, and differential scanning calorimetry DSC techniques.