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Masterbatches from a linear poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS) and halloysite nanotubes (HNT-QM) were obtained in different conditions of temperature and shear using two co-rotating twin-screw extruders. The influence of screw configuration and melt processing conditions on the morpho-structural, thermal and mechanical properties of masterbatches at macro and nanoscale was studied. A good dispersion of halloysite nanotubes and better thermal stability and tensile and nanomechanical properties were obtained at a lower temperature profile and higher screw speed. The effect of masterbatches, the best and worst alternatives, on the properties of a polypropylene (PP)–glass fiber (GF) composite was also evaluated. Double hardness, tensile strength and modulus and four times higher impact strength were obtained for PP/GF composites containing masterbatches compared to pristine PP. However, the masterbatch with the best properties led further to enhanced mechanical properties of the PP/GF composite. A clear difference between the effects of the two masterbatches was obtained by nanoindentation and nanoscratch tests. These analyses proved to be useful for the design of polymer composites for automotive parts, such as bumpers or door panels. This study demonstrated that setting-up the correct processing conditions is very important to obtain the desired properties for automotive applications.

Poly(3-hydroxybutyrate) (PHB) is a promising substitute to petroleum-based polymers in packaging and biomedical applications provided that its melt processability and degradability are improved. A new method to control the properties of PHB by using cheap calcium stearate (CS) as a lubricant and decomposition catalyst in melt-mixed PHB-CS compounds was first used. CS is composed of a metallic cation, which promotes PHB degradation, and a hydrophobic anion that improves the compatibility with PHB and processability. An environmentally friendly melt mixing technique was employed to obtain the PHB-CS compounds. Incorporation of 0.5 or 5 wt% CS reduced the melt viscosity and molecular weight of PHB, decreased the melting temperature with up to 5 °C, the crystallization temperature with more than 25 °C, and the degradation temperature with 15 and 40 °C, respectively. In small amounts (0.05 wt%), CS improved the processability and mechanical properties of PHB. In higher amount (0.5 wt%), CS slightly improved the Young's modulus, reduced the tensile strength and enhanced degradation. A better control of thermal and mechanical properties of PHB is, thus, possible by using different CS amount and processing conditions. These results are relevant for PHB application in the context of the global transition to biodegradable packaging.

Preventing and controlling the spread of multidrug-resistant (MDR) bacteria implicated in healthcare-associated infections is the greatest challenge of the health systems. In recent decades, research has shown the need for passive antibacterial protection of surfaces in order to reduce the microbial load and microbial biofilm development, frequently associated with transmission of infections. The aim of the present study is to analyze the efficiency of photocatalytic antimicrobial protection methods of surfaces using the new photocatalytic paint activated by light in the visible spectrum. The new composition is characterized by a wide range of analytical methods, such as UV-VIS spectroscopy, electron microscopy (SEM), X-ray powder diffraction (PXRD) or X-ray photoelectron spectroscopy (XPS). The photocatalytic activity in the UV-A was compared with the one in the visible light spectrum using an internal method developed on the basis of DIN 52980: 2008-10 standard and ISO 10678—2010 standard. Migration of metal ions in the composition was tested based on SR EN1186-3: 2003 standard. The new photocatalytic antimicrobial method uses a type of photocatalytic paint that is active in the visible spectral range and generates reactive oxygen species with inhibitory effect against all tested microbial strains.

The composition of electrical wires and cables is of critical importance in controlling fire risks. In this respect, polyvinylchloride (PVC) composites are extensively used. Yet, PVC composites are multiple systems in which the final properties depend on the nature and size of the reinforcement or flame-retardant agent and the type of lubricant used for their preparation. Thereby, in this study two series of PVC composites, with stearic acid and calcium stearate as lubricants were prepared in parallel, and additivated with various commercial minerals as reinforcement/flame retardant agents, such as calcium carbonate, alumina trihydrate (ATH) and HMH (a mineral of hydromagnesite and huntite). Following the structure (by FT-infrared), thermal behavior (thermal analyses and differential scanning calorimetry) and mechanical properties (dynamic mechanical analyses, tensile strength and elongation at break) of PVC composites, the flame-retardant effect of the selected minerals was investigated by measuring the limiting oxygen index (LOI). Only ATH and HMH-based composites presented higher flame-resistance, relative to the control samples, making them suitable for the proposed application. The contact angle was evaluated for determining the hydrophobicity of composites when using ATH or HMH, to get an opinion about the stability of the materials in moist environments. Finally, SEM was used to determine the homogeneity of PVC samples.

Polypropylene (PP) is a versatile polymer, with a wide range of applications, from household appliances to packaging and automotive components. Unfortunately, most of the PP products have a short life, which leads to a large amount of plastic waste. Recycling PP is an efficient way to offset the environmental pressure, and several technical solutions have been already proposed for PP recycling. However, dramatically reduced thermal and mechanical properties are generally obtained in the case of PP waste materials. In this work, the influence of PP waste on thermal and mechanical properties of PP waste/virgin PP blends was studied. A PP waste material (PPRR) was melted and compounded with high flow virgin PP homopolymer. The blends were characterized by dynamic mechanical analysis, differential scanning calorimetry, thermogravimetric analysis, mechanical tests and Fourier transform infrared spectroscopy. An increase by 20% of the tensile strength and modulus and 2.5 times increase in the melt flow index were observed in the case of the blend with 50% virgin PP as compare to PPRR, also an important increase in crystallinity. All the blends showed a better thermal stability than the virgin PP. The results recommend the blends with 30–50% virgin PP for the recycling of PP waste from raffia in high-performance applications.

In this study, a new solution for the development of an antiradar camouflage by overlaying several mono-pigment polymeric structures in a composite structure is provided. In this respect, powder materials with antiradar properties (carbon nanotubes, graphite, active charcoal, aluminum trioxide) were embedded in polymeric matrices. The performances of the developed products were tested using an experimental device for the measurement of electromagnetic efficiency within the frequency range from 1 to 18 GHz.

The photochemical degradation of polyolefin-TiO2 composite films was investigated and described in relationship with the concentration of photocatalyst and after different exposure times. UV-Vis-NIR and IR spectra reveal the presence of various degradation products, which are in direct connection with the photodecomposition mechanism. Various ratios between the absorbance of some typical IR characteristic bands can lead to the evaluation of photocomposition of polyethylene and polypropylene composite films containing TiO2 nanoparticles.The results show that the photocatalytic degradation of composites is significantly faster than the simple photolytic decomposition of pure polypropylene and polyethylene and could be used as a solution for the destruction of this type of wastes.

Conservation of wooden artifacts represents a common goal for researchers involved in cultural heritage studies all over the world. Unlike some other types of artifacts, such as natural or man-made stone, the wooden ones are much more exposed to degradation. The present work establishes the potential application for the treatment of wooden artifacts of some commercially consolidants, as well as of a traditional method. By evaluating the effects of the treatment on wooden artifacts models (using optical microscopy, Fourier transform infrared spectroscopy, thermal analyses and dynamic mechanical analysis) as well as their resistance towards staining materials and the overall aesthetic alteration, the best method can be proposed for the treatment of historical wood. The wooden models used for the experiments consisted of wood spatulas with standard dimensions (150x18x1.6 mm), on which six potential treatments were applied by immersion. By corroborating the results obtained and the evaluation of the recorded aesthetic changes, a proper treatment can be proposed.

This work aims at developing polyamide 1010 (PA1010) composites with improved fire behavior using a halogen-free flame-retardant system based on melamine (Me) and gallic acid (GA) complexes (MA). The MA complexes were formed by hydrogen bonding, starting from 1:2, 1:1, 2:1 Me:GA molar ratios. PA1010 composites were obtained by melt mixing, followed by compression molding. MA provided a plasticizing effect on the PA1010 matrix by decreasing the glass transition temperature. The influence of MA on PA1010 chain packaging was highlighted in the X-ray diffraction patterns, mainly in the amorphous phase, but affected also the &alpha, and &gamma, planes. This was reflected in the dynamic mechanical properties by the reduction of the storage modulus. H-bonds occurrence in MA complexes, improved the efficiency in the gaseous form during fire exposure, facilitating the gas formation and finally reflected in thermal stability, thermo-oxidative stability, LOI results, and vertical burning behavior results. PA1010 containing a higher amount of GA in the complex (MA12) displayed a limiting oxygen index (LOI) value of 33.6%, much higher when compared to neat PA1010 (25.8%). Vertical burning tests showed that all the composites can achieve the V-0 rating in contrast with neat PA1010 that has V-2 classification.

Four metal substituted hydroxyapatites (HAPs) were prepared and characterized using energy-dispersive X-ray fluorescence, X-ray diffraction, thermal analysis, and transmission electron microscopy. ...

Seven curcumin derivatives were synthesized by an ecological method, in a microwave field. The compounds obtained were purified and characterized by means of elemental analysis, UV-VIS, fluorescence, IR, 1H-NMR and 13C-NMR spectroscopy. Structure-property relationship in the b-diketone derivatives are discussed with respect to the structure and nature of the substituents for possible applications in optical sensors and luminescent materials.

Iron (III) doped TiO2 nanopowders were synthesized by solgel method starting from the concentrated alcoholic solutions of tetraethyl (TET) and tetraisopropyl (TIP) orthotitanate precursors. TET precursor leads to gel formation while TIP precursor conducted to powder generation. The optimized thermal treatments, derived from TG/DTA analysis, allowed the transformation of precursor powders and gels into crystalline powders with anatase structure, as determined by X-ray diffraction (XRD). Corroboration of XRD, FT-IR and Raman investigations lead to the conclusion that Fe3+ was introduced substitutionally into TiO2 matrix. TEM analysis revealed similar morphology for all prepared samples, consisting of nanometric particles. UV–vis spectroscopy evidenced that Fe3+ dispersed into TiO2 matrix shifts the optical bandgap to the visible range. The photocatalytic mineralization of oxalic acid over Iron (III) doped TiO2 nanopowders under simulated solar irradiation was studied to assess the application potential of these materials in depollution field. CO2 production was identified as main product of photocatalytic reaction. The CO2 output was proportional to the surface area of the photocatalysts. In mean time, the lower was the optical band-gap of tested materials the higher was the photocatalytic activity for mineralization of oxalic acid. Introduction of Fe3+ into TiO2 lattice leads to creation of optically active redox sites, able to absorb the visible component of solar light. A reaction mechanism was advanced based on experimental facts. The role of substitutional Fe3+ in mechanism of oxalic acid photomineralization was examined in relationship with generation of e− and h+ charges and O2− and OH radicals. The optimized preparation method, requiring lower amounts of reagents and milder synthesis conditions, lead to homogeneous Fe3+/TiO2 materials with promising potential for depollution applications.

The seven curcumin derivatives were deposited on palygorskite in order to obtain hybrid materials. The fluorescence emission spectra of the obtained materials show a decrease in fluorescence intensity relative to the respective dyes, due to the environments around the dyestuff molecules created in the host matrices. Absorption studies show the best adsorption on the inorganic matrix, for the compounds with the hydroxyl groups. Correlating fluorescence spectra of hybrid materials with the results for absorption spectra of the dyes adsorbtion on the surface of the clay lead to the conclusion that a high percentage of the adsorbed dye had the effect of fluorescence quenching. Thus, it was confirmed that the fluorescent properties of hybrid materials depend on the interactions established between the fluorescent dyestuff and the inorganic network.

In the present work, a cobalt phthalocyanine-supported reduced graphene oxide material (rGO-CoPc) was used as a catalyst for the degradation of rhodamine B (RhB) and pentachorophenol (PCP) in the presence of peroxymonosulfate (PMS). Inductively coupled plasma (ICP-OES), Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) were employed to characterize the properties of the composite and Co loading in the material. The catalytic activity of the rGO1-CoPc1 catalyst (rGO:CoPc = 1:1) was evaluated by UV–vis absorption spectroscopy at varying PMS concentrations and catalyst dosages. The complete dye removal was achieved in 9 min by rGO1-CoPc1/PMS system with a high initiation rate constant of 1.019 min−1 using RhB (25 µM), PMS (0.1 mM) and rGO1-CoPc1 (0.5 mg/mL). The removal efficiency was found to be as high as 100% after 11 cycles, suggesting a long-lasting catalytic activity of the of rGO1-CoPc1/PMS system. Quenching experiments suggested that sulfate (SO4 −) radicals are the dominant species in the degradation process although hydroxyl (OH ) radicals are also involved in the reaction mechanism. Furthermore, the catalyst was successfully applied for the efficient degradation of pentachlorophenol (PCP). A full degradation of PCP (25 µM) was achieved within 20 min using rGO1-CoPc1 (0.5 mg/mL) and PMS (0.6 mM). This study demonstrated that the use of rGO-CoPc as a heterogeneous catalyst for PMS activation is useful for the advanced oxidation processes (AOP) for practical wastewater treatment.

The present paper studies the effect of polyaniline grafting on magnetite functionalized with aminopropyltrimethoxysilane. All the compounds were characterized by analytical techniques (X-ray fluorescence, X-ray diffraction, Fourier transform infrared spectroscopy, thermal analysis, Transmission electron microscopy), as well as by determining their magnetic properties. The electron microscopy analysis of the hybrids shows similar morphologies for all the samples. The presence of the iron atoms on the surface of the final product supports the idea of the existence of an inverted core-shell type structure, the more polar ferrite orienting itself towards water. The correlation between the maximum grafting probability and the maximum magnetization is evidenced, demonstrating the importance of the polymer grafting method on the magnetic properties.

Transparent hydrophobic or super-hydrophobic thin films prepared on plastic substrates haveattracted attention in recent years because they can be suited to optical applications such as lenses [...]

Worldwide agricultural production is permanently threatened by the numerous fungi and [...]

Cellulose is the most abundant renewable biopolymer in nature, being the main constituent of [...]

The camouflage effect aims to reproduce natural or artificial surroundings in terms of color, [...]

Analysis of cultural heritage artifacts represents a very important first step in any restoration/conservation attempt. Fourier-Transform Infrared Spectroscopy - Attenuated Total Reflectance (FTIR-ATR) technique can be successfully applied for the study of a wide range of historical artifacts (several papers describing the application of FTIR for the analysis of historical metals, paper, ceramic, fabrics, etc.). The present paper aims to present the application of FTIR-ATR for the characterization of historical fibers. The analyzed artifact represents a traditional pillowcase originating from Moldavia historical region, from the end of the XIXth century – beginning of the XXth century, belonging to a private collection. The technique offers some advantages because relatively small samples are directly analyzed after they are pressed against the surface of the diamond crystal without damaging the samples. Identification of fiber type enables sometimes to approximate the age of an artifact, the climate type or the trade routes and manufacturing process used. The artifact is formed of two major components: the support textile fiber and the colored fibers. The most encountered materials traditionally used for such objects are wool, flax and hemp. While wool is easily identified in the FTIR spectra due to its sharp and intense characteristic peaks, in the case of cellulosic fibers and especially for differentiation between flax and hemp fibers it was necessary to calculate the average values of the band intensity ratios I1595/I1105 and I1595/I2900.

The recent development of several methods for extracting curcumin from the root of the plant Curcuma longa has led to intensified research on the properties of curcumin and its fields of application. Following the studies and the accreditation of curcumin as a natural compound with antifungal, antiviral, and antibacterial properties, new fields of application have been developed in two main directions—food and medical, respectively. This review paper aims to synthesize the fields of application of curcumin as an additive for the prevention of spoilage, safety, and quality of food. Simultaneously, it aims to present curcumin as an additive in products for the prevention of bacterial infections and health care. In both cases, the types of curcumin formulations in the form of (nano)emulsions, (nano)particles, or (nano)composites are presented, depending on the field and conditions of exploitation or their properties to be used. The diversity of composite materials that can be designed, depending on the purpose of use, leaves open the field of research on the conditioning of curcumin. Various biomaterials active from the antibacterial and antibiofilm point of view can be intuited in which curcumin acts as an additive that potentiates the activities of other compounds or has a synergistic activity with them.

Fluorescent film-forming materials were obtained by embedding salicylaldazine (SAA) in silica hybrids generated by sol&ndash, gel processes from different silane precursors in acid catalysis. Tuned local environments for the fluorophore were generated in the hosting network by modifying silica sols with organic groups through the co-condensation of tetraethylortosilicate (TEOS) and different alkoxysilanes hydrolysis products. The photophysical properties of the luminescent hybrid films were studied in direct relationship with structural, textural, and surface properties and based on interactions between SAA species and the silica hosting network. Film-forming materials were studied in order to determine differences in absorption and fluorescence emission due to the environments around the fluorophore. The variations recorded in the fluorescence emission spectra of the hybrid films were related to interactions established between the fluorophore species and their sterically hindered surroundings of the host hybrid silica, where free molecular motions are restricted. The influence of the type and amount of network modifier and of the fluorophore loading on the transparency of the films and fluorescence intensity was also investigated. The study carried out led to the elucidation of the necessary conditions for obtaining luminescent film-forming materials with high luminescence intensity and transparency useful for the design of new light concentrators.

Several binary composites based on Crystal Violet Lactone (CVL) color former and Phenolphthalein (PPht) developing agent dissolved in 1-tetradecanol (TD) were studied in order to determine how different ratios between components influence the thermochromic behavior of the composites. The color dependence on temperature was investigated in direct relationship with structural changes and interactions between components. The stoichiometry of the colored complex was determined from diffuse reflectance data and confirmed by means of steady state fluorescence measurements and temperature modulated differential scanning calorimetry. The color former: developing agent molar ratio equal to 1:2.5 was determined to ensure the reversibility of the process in optimal conditions. The characteristics of the color path and the influence of thermal history during thermochromic transition were analyzed from the variations of CIELAB color parameters during successive heating/cooling cycles. Dynamic colorimetric properties of the thermochromic binary composite containing the components in optimum ratio are described by four characteristic temperatures in the hysteresis.

We used laser techniques to create hydrophobic thin films of layered double hydroxides (LDHs) and organo-modified LDHs. A LDH based on Zn-Al with Zn 2+ /Al 3+ ratio of 2.5 was used as host material, while dodecyl sulfate (DS), which is an organic surfactant, acted as guest material. Pulsed laser deposition (PLD) and matrix assisted pulsed laser evaporation (MAPLE) were employed for the growth of the films. The organic anions were intercalated in co-precipitation step. The powders were subsequently used either as materials for MAPLE, or they were pressed and used as targets for PLD. The surface topography of the thin films was investigated by atomic force microscopy (AFM), the crystallographic structure of the powders and films was checked by X-ray diffraction. FTIR spectroscopy was used to evidence DS interlayer intercalation, both for powders and the derived films. Contact angle measurements were performed in order to establish the wettability properties of the as-prepared thin films, in view of functionalization applications as hydrophobic surfaces, owing to the effect of DS intercalation.

Analytical characterization methods can be used to study historical documents, with the aim to give an exhaustive scenario regarding the used paper, methods of obtaining it in ancient times, offering in the same time information about economic aspects, commerce or culture. In the present study, four samples of paper from Transylvanian old books (late XVIIth–early XIXth centuries) were analysed using surface methods (Fourier transform infrared spectroscopy - FTIR, X-ray diffraction - XRD, X-ray fluorescence - XRF and colour evaluation), microscopical techniques (optical microscopy and atomic force microscopy - AFM) and thermal analysis. The results, accompanied by the historical study allowed the differentiation between the compositions of papers and the identification of the fillers and manufacturing techniques. The results suggest the possibility of developing a manufactured-paper composition data-base, useful in identification and authentication of old paper samples.