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Liliana Rosu Dan Rosu Cristian-Catalin Gavat Cristian-Dragos Varganici 《Journal of Materials Science》2014,49(13):4469-4480
The influence of ultraviolet irradiation of different doses (λ > 300 nm) on the structural and color modifications of cotton fabrics painted with four different azo-triazine dyes (Reactive Yellow 143, Reactive Orange 13, Reactive Red 183, and Reactive Red 2) was studied. High irradiation doses up to 3500 J cm?2 led to changes in the dyes structures. Structural changes before and after the complete irradiation were compared by applying FTIR, UV–Vis, and near infrared chemical imaging techniques. Color modifications were also investigated. Color differences significantly increased with the irradiation dose for all the studied samples. 相似文献
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Viorica E. Podasca Tinca Buruiana Cristian D. Varganici Emil C. Buruiana 《Journal of Polymer Research》2017,24(7):103
A new diblock copolymer, 1-methylpyrene isobutyrate–poly(methyl methacrylate–block-N-acryloyl-S-trityl-cysteine)-Br (Py–PMMA–b-ATCys-Br), was synthesized by atom transfer radical polymerization (ATRP) of N-acryloyl-S-trityl-L-cysteine monomer (ATCys) with 1-methylpyrene isobutyrate–poly(methyl methacrylate)–Br as a macroinitiator. The diblock copolymer and its precursor were characterized by 1H and 13C NMR spectroscopy, fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), gel permeation chromatography (GPC), and glass transition temperatures (Tg) measurements. Fluorescence properties of the diblock copolymer were investigated using various quenching (Cu2+, Hg2+, Fe2+, Fe3+, Co2+, Ni2+ and Pb2+) in dimethylformamide solutions, the more efficient quenchers being the Cu2+, Hg2+, Fe2+, and Fe3+ ions. In addition, the effect of in situ photogenerated silver nanoparticles on the copolymer fluorescence was also investigated. 相似文献
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Influence of two structural phases of Fe3O4 and γ‐Fe2O3 on the properties of polyimide/iron oxide composites
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Simona‐Luminita Nica Valentin Nica Vasile Cristian Grigoras Cristian‐Dragos Varganici Dumitru Popovici Camelia Hulubei Silvia Ioan 《Polymer International》2015,64(9):1172-1181
Partially aliphatic polyimide/iron oxide composites based on the poly(amic acid) from 5‐(2,5‐dioxotetrahydro‐3‐furyl)‐3‐methyl‐3‐cyclohexene‐1,2‐dicarboxylic acid anhydride and 4,4′‐oxydianiline with iron oxide in different weight percentages were obtained. The structural phases of the transition of magnetite to maghemite occurring in these composites, at different temperatures, are discussed. The physical characteristics, including magnetic, thermal, structural and morphological properties, evaluated using X‐ray diffraction, scanning electron microscopy and thermal analysis, are influenced by the interplay of the filler content and the structural changes of the composite. The X‐ray diffraction patterns of all samples show a cubic structure indexed as magnetite (Fe3O4) or maghemite (γ‐Fe2O3). Quantification of these two phases was evidenced by the Rietveld method. The electrical properties analysed under different humidity conditions evidence the potential applicability of these polyimide/iron oxide materials as humidity sensors. © 2015 Society of Chemical Industry 相似文献
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George Stiubianu Alina Nicolescu Alexandra Nistor Maria Cazacu Cristian Varganici Bogdan C Simionescu 《Polymer International》2012,61(7):1115-1126
A new pathway to cellulose–siloxane hybrid materials was investigated. Allylated cellulose was prepared by chemical modification of cellulose acetate using three different procedures and was crosslinked afterwards by hydrosilylation in the presence of Karstedt's catalyst. Poly[dimethyl(methyl‐H)siloxane] with 25 mol% Si? H side groups and 1,1,3,3‐tetramethyldisiloxane were used as crosslinking agents in different ratios as regards the unsaturated component. The occurrence of the reaction was verified using Fourier transform infrared spectrometry following the reduction until disappearance of bands corresponding to Si? H and C?C bonds with the formation of new Si? C bonds that led to the crosslinking of the cellulose derivative. The reaction products were processed as films that were insoluble in common solvents. Surface (static contact angle, water vapour sorption capacity and swelling in various solvents), mechanical and thermal properties of the networks processed as films were investigated and the results were correlated with the reactant ratios. The crosslinking density was determined based on differential scanning calorimetry data. Copyright © 2012 Society of Chemical Industry 相似文献
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Cationic hybrids from poly(N,N‐dimethylaminoethyl methacrylate) covalently crosslinked with chloroalkyl silicone derivatives effective in binding anionic dyes
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Maria Marinela Lazar Cristian–Dragos Varganici Maria Cazacu Ecaterina Stela Dragan 《应用聚合物科学杂志》2016,133(37)
The synthesis and characterization of some novel ionic organic/inorganic hybrids containing quaternary ammonium salt groups in the side chain, built on the basis of poly(N,N‐dimethylaminoethyl methacrylate), as an organic component and cation provider, and chloroalkyl‐functionalized silicone derivatives as crosslinkers and anion generators, are reported in this work. The resulted structures were investigated using Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and energy dispersive X‐ray spectroscopy. The swelling behavior of the ionic hybrids in water as a function of pH as well as the water vapor sorption capacity in dynamic regime was also studied. The cationic hybrids have a higher swelling capacity at pH 2 compared with deionized water (pH 6) due to the presence of tertiary amine groups belonging to the organic compound. The ionic organic/inorganic hybrids were tested as potential sorbents for anionic species such as dyes [e.g., methyl orange (MO)]. The equilibrium sorption capacity increased with the increase of the organic component up to around 32 mg MO/g hybrid. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43942. 相似文献
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Magdalena Aflori Bogdana Simionescu Irina-Elena Bordianu Liviu Sacarescu Cristian-Dragos Varganici Florica Doroftei Alina Nicolescu Mihaela Olaru 《Materials Science and Engineering: B》2013,178(19):1339-1346
The present paper reports on the evaluation of two silsesquioxane-based hybrid nanocomposites with methacrylate units containing titania and/or silver nanoparticles aimed as antibacterial coatings for monumental stones. Sol–gel reaction of titanium isopropoxide and/or 3-(trimethoxysilyl)propyl methacrylate, in the presence of silver nitrate and a primary amine surfactant, yielded new types of hybrid nanocomposites with high antibacterial/antifungal efficacy. Different polymer behaviours regarding a frequently used monumental stone originating from Romania were evidenced through Fourier-transform infrared (FTIR) spectroscopy and powder X-ray diffraction (PXRD) technique. Conclusions regarding the stones acid-resistant character and lower influence of salt weathering on its durability, as well as a better protective coating containing titania units were revealed. 相似文献
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