Polymeric Compounds Research Articles

Analysis of polymeric compounds using a matrix of epoxy resin reinforced with sisal fibers for application as reinforcement of pieces of wood

Studies show that there is still a small number of researches related to the rehabilitation and recovery of wooden structures, because knowledge about rehabilitation techniques and reinforcement in wooden structural elements is still not widespread. The same does not happen when it comes to designing wooden structures, since designers rely on Technical Standards, deeper scientific research and vast literature. Therefore, the importance of more in-depth scientific research on the technique of reinforcing wooden structures through the application of polymeric composites reinforced with natural fibers is evident. Since, economically and environmentally, it is preferable to rehabilitate a structure than proceed with its demolition and reconstruction. Such an attitude would provide a reduction in the consumption of natural resources and less waste generation. The objective of this work is to experimentally analyze the mechanical performance of wooden parts reinforced by epoxy matrix polymeric composites and fabrics made with sisal fibers. In addition, the mechanical behavior of the types of proposed reinforcements are verified.

Failure Analysis of AISI H13 Shafts Used in Twin Screw Extruders during Fluoropolymer Compounding

AISI H13 material finds wide use as screw shafts and screw elements in Twin Screw Extruders for Polymer Compounding applications owing to its high strength, excellent thermal shock resistance, high wear resistance and good fatigue strength. However, two AISI H13 shafts used in the Twin Screw Extruder supplied for fluoropolymer application experienced breakage after two years of service. Visual examination of broken shafts revealed deposits of processing material, rust marks and grooves at multiple locations on the shaft spline at the element to element butting zone. The location of breakage of the shaft was noted at Barrel No.5, which happens to be the vent zone of the extruder. The fracture surface was observed to be almost perpendicular to the rotating axis of the shaft. Macro-examination of the shafts showed abnormal wear at the groove areas and significant reduction in the diameter of the screw shafts with complete absence of spline in the zone adjacent to fracture. Hardness survey revealed values of 25-27 HRC that was 18-20 HRC lower than the hardness in supply condition. Microstructural examination on the failed shafts showed fine spheroidized carbides with ferrite in tempered martensitic matrix. SEM Analysis on samples from fracture surface revealed presence of multiple micro-voids and indicated coalescence of these voids. Based on the investigation & analyses it was inferred that the predominant mode of failure of the shafts had been “Corrosion Assisted Ductile Rupture” in elevated temperature operating conditions. Finally, recommendation to prevent occurrence of such failures has been proposed.

Self-growing organic materials.

The growth of living systems is ubiquitous. Living organisms could continually update their sizes, shapes, and properties to meet various environmental challenges. Such a capability is also demonstrated by emerging self-growing materials that can incorporate externally-provided compounds to grow as living organisms. In this minireview, we sum these materials from six aspects. First, we discuss their essential characteristics in the introduction section, then describe the strategies for enabling crosslinked organic materials to self-grow from nutrient solutions containing polymerizable compounds. The developed examples are concluded into five categories based on their molecular mechanisms in this section. In the third section, we explain the mechanism of mass transport within polymer networks during growth, which is critical to controlling the shape and morphology of the grown products. Afterward, simulation models built to explain the interesting phenomena observed in self-growing materials are discussed. The development of self-growing materials is accompanied by various fantastic applications, including tuning material's bulk properties, creating texture surfaces, growth-induced self-healing, 4D printing, self-growing implants, actuation, self-growing structural coloration, etc. These examples are summed up in the fifth section. Finally, we discuss the opportunities brought by self-growing materials and their facing challenges.

Self‐Growing Organic Materials

AbstractThe growth of living systems is ubiquitous. Living organisms can continually update their sizes, shapes, and properties to meet various environmental challenges. Such a capability is also demonstrated by emerging self‐growing materials that can incorporate externally provided compounds to grow as living organisms. In this Minireview, we summarize these materials in terms of six aspects. First, we discuss their essential characteristics, then describe the strategies for enabling crosslinked organic materials to self‐grow from nutrient solutions containing polymerizable compounds. The developed examples are grouped into five categories based on their molecular mechanisms. We then explain the mechanism of mass transport within polymer networks during growth, which is critical for controlling the shape and morphology of the grown products. Afterwards, simulation models built to explain the interesting phenomena observed in self‐growing materials are discussed. The development of self‐growing materials is accompanied by various applications, including tuning bulk properties, creating textured surfaces, growth‐induced self‐healing, 4D printing, self‐growing implants, actuation, self‐growing structural coloration, and others. These examples are then summed up. Finally, we discuss the opportunities brought by self‐growing materials and their facing challenges.

Effect of trisilanol isobutyl polyhedral oligomeric silsesquioxane (TPOSS) in recycled PET (rPET) and polypropylene based compound: Investigation on mechanical properties

Recycled polyethylene terephthalate is successfully prepared. This project is involved for “Circular economy” policy. It is successfully prepared into powder form by nano-grinder technique. 10 phr of PP-g-MA and 1 phr to 5 phr of TPOSS are added for compatibilizer and mechanical properties enhancement, respectively. PP-g-MA can form the chemical linkage of the anhydride groups with the polyamide end groups. 20 wt% of recycled polyethylene terephthalate powder and polypropylene based compound is successfully fabricated by melt mixing. Then, it is fabricated by melting spinning technique. Fourier transform infrared presents Si-O-Si linkage in binary blend compound. X-ray diffraction pattern reports that single phase is obtained. Adding TPOSS can be induced to crystallinity enhancement. No significant change of thermal properties was observed from room temperature to 300℃. Scanning electron microscope reports that with the PP-g-MA provides smoothness of surface. Recycled polyethylene terephthalate is uniformly distributed. Melting and crystallization temperatures are reported to be 162℃ to 167℃ and 115℃ to 120℃, respectively. All of throughput rate is reported to be 1.8 g⸳min-1 to 2.3 g⸳min-1. With the existence of TPOSS, the mechanical properties of compound are slightly increased. TPOSS are added for mechanical properties enhancement. The polymer compound presents the excellent properties. It is remarkable to note that recycled polyethylene terephthalate is considered as an excellent candidate for use as raw material for polymer compound production.

Unraveling the Adsorption Mechanism and Anti-Corrosion Functionality of Dextrin and Inulin as Eco-Friendly Biopolymers for the Corrosion of Reinforced Steel in 1.0 M HCl: A Thermodynamic and Kinetic Approach.

Reinforcing steel (RS) is mainly used in building construction and many industries, but it suffers from corrosion problems, especially in acidic environments. Biopolymers are characterized by their unique chemical composition, as they contain a variety of functional groups that are capable of binding strongly to the metal surface and forming a protective layer on it. Herewith, two biopolymers, viz. dextrin (Dex) and inulin (Inu), were tested as eco-friendly inhibitors for the corrosion of RS in 1.0 M HCl medium at different temperatures. Various experimental tools were utilized in this research. The inhibition efficiencies (% IEs) of the tested polymeric compounds were improved by increasing their doses while reducing with rising temperature. The % IEs of Dex and Inu at a dose of 500 mg/L reached 85% and 93%, respectively. The examined biopolymers displayed cathodic/anodic behavior (mixed type) with a foremost anodic one. The acquired higher % IEs were demonstrated by intense adsorption of Dex and Inu on the RS surface fitting the Langmuir isotherm. The influence of rising temperature in the range of 288-318 K on the corrosion behavior was examined, and the evaluated thermodynamic and kinetic parameters sustained the mechanism of physical adsorption of the polymeric inhibitors. Additionally, the kinetics of corrosion, as well as its inhibition by Dex and Inu, were also investigated. The SEM micrographs of the RS surfaces were accorded with all utilized experimental tools. The results gained from all used tools were discovered to be in good agreement with each other.

Preparation and Characterization of Nano-Sized Co(II), Cu(II), Mn(II) and Ni(II) Coordination PAA/Alginate Biopolymers and Study of Their Biological and Anticancer Performance

Four of the crosslinked sodium alginate and polyacrylic acid biopolymers based nanoscale metal natural polysaccharides, [M(AG-PAA)Cl(H2O)3], where M = Co(II), Cu(II), Mn(II) and Ni(II), AG = sodium alginate and PAA = polyacrylic acid, have been synthesized and structurally characterized. Because of their numerous biological and pharmacological activities of polysaccharides, including antimicrobial, immunomodulatory, antitumor, antidiabetic, antiviral, antioxidant, hypoglycemic and anticoagulant activities, polysaccharides are one of the near-promising candidates in the biomedical and pharmaceutical fields. The complexity of the polymeric compounds has been verified by carbon and nitrogen analysis, magnetic and conductance measurements, FT-IR spectra, electronic spectral analysis and thermal analysis (DTA, TG). All the synthesized complexes were non-electrolytes with magnetic moments ranging from 1.74 to 5.94 BM. The polymeric complexes were found to be of octahedral geometry. The developed coordination polymeric was found to be crystalline using X-ray powder diffraction examinations, which is confirmed by the SEM analysis. As a result, the crystallite size of all polymeric nanocrystals was in the range of 14 - 69 nm. The test of four compounds exhibits a broad spectrum of antimicrobial activity against both Gram-positive and Gram-negative bacteria and fungal Candida albicans. Using DPPH as a substrate, studies on radical scavenging tests are carried out. The findings demonstrated the antioxidant activities of each complex. In addition, results showed that the two chosen polymeric complexes had a good ability to kill cancer cells in a dose-dependent way. The copper(II) polymeric complex showed to its superior functionality as evidenced by microbial activity. After 72 h of interaction with the normal human breast epithelial cells (MCF10A), the synthesized polymeric compounds of Cu(II) and Co(II) showed exceptional cytocompatibility with the different applied doses. Compared to poly-AG/PAA/Co(II), poly-AG/PAA/Cu(II) exhibits a greater anticancer potential at various polymeric dosages.

An Insight into Synthesis of the Antifreeze Alkaline Hydrogel Electrolyte: Fine‐Tuning Chemistries for Efficient Ion Transport

AbstractHerein, the chemical compatibility of the hydrogel electrolyte in highly alkaline pH was evaluated. Through simple experiments, we demonstrated that the frequently used polymer compound, acrylamide, is not stable at a high pH. The addition of glycerol as a cryoprotectant in highly alkaline hydrogels was also problematic due to the possible base‐initiated decomposition of glycerol to polyglycerols. Hence, a quick and simple one‐pot synthesis of highly alkaline potassium poly(acrylate) hydrogel with 1 vol % glycerol was proposed. The ionic conductivities of the hydrogel are 46.48 mS/cm and 8.67 mS/cm at 22 and −23 °C, respectively. One important benefit from the addition of the cryoprotectant is that the hydrogel sustained its mechanical features at temperatures as low as −80 °C. We also reported here for the first time the diffusion coefficients (D at ∼10−8 cm2/s), ionic mobilities (μ at ∼10−7 cm2/Vs), and ion density (n at ∼10−7 cm−3) of the hydrogel electrolyte used in flexible alkaline batteries.

Enhanced compressive strength of preheated limonite pellets with biomass-derived binders

Sodium lignosulfonate (SL) is a powder-like by-product of the pulp and paper industry derived from lignocellulosic biomass. SL can potentially be a low-cost and highly efficient binder for the pelletization of iron ore powder in the ironmaking industry because it is a natural polymer compound containing multiple functional groups, such as hydroxyl, carboxyl, and sulfonic acid. In this paper, the strong organic binder, namely SL, was used to enhance the compressive strength of the limonite pellet, which is required to reduce VOC emission during the iron-making process. The limonite pellets' pellet size variation and compressive strength prepared with SL-based binders were studied at a temperature range from 900 °C −1100 °C. Experimental results showed that the compressive strength of the preheated pellets was the highest at a preheating temperature of 1100 °C, reaching 342.55 N/P which is qualified for the subsequent iron-making process. These experimental results provide essential references for optimizing the preparation of limonite pellets with SL-based binders. Furthermore, this study employed artificial neural networks to process experimental data and generate predicted values for corresponding experimental conditions. The predicted results closely matched the observed values, further assisting enterprises in accelerating their digitization and automation processes.

Examination of the extract from lichen (<i>Cetraria islandica</i>) after an ultrasonic impact

An integral part of human healthy nutrition is intake of biologically active substances. Extraction is an important stage of isolation of different bioactive substances from plants and effectiveness of their extraction increases with the use of ultrasonic treatment. The aim of this research was to study an effect of different types of aqueous media and treatment methods on Cetraria islandica, including the use of principles of ultrasonic treatment and maceration methods (infusion). The experimental studies consisted in detecting an effect of the active acidity of the aqueous medium (solvent) and method of impact upon extraction on several physicochemical and rheological indicators. The experimental samples of extracts were examined by the following indicators: active acidity and redox potential detected by the ionometric technique; dynamic viscosity and the depth of output of polymeric forms of phenolic substances determined by measuring the optical density and transmission coefficient. Mathematical processing of data using the regression analysis was carried out. The results are presented as graphs, tables and regression equations. It has been established that transfer of substances from Cetraria islandica to its extracts had high results at pH = 7.0 and рН = 9.0 of the solvent. When obtaining extracts by the infusion method, the quantity of polymeric compounds in the transition process was 1.3 times higher than the quantity of monomeric forms of phenolic compounds. The highest value of the dynamic viscosity was revealed in the extract sample obtained by the infusion method in the alkaline medium. The extracts obtained can be used in food system modeling.

Addition of aceh bentonite in an effort to improve the heat resistance properties of polyurethane-based paint coatings

Polyurethane is a polymer compound whose main chain constituent is urethane group (-NHCOO-). Polyurethanes can be mixed with other polymers or other fillers in an effort to enhance and improve the properties of the single polymer. Metal coating materials are needed for metal materials that have properties resistant to heat thermal condition and corrosion that can damage the structure,. The priority and novelty of this research is to utilize the natural bentonite which is very potential in the local area to fill polyurethane-based coating paint in order to improve its properties. This research looked at the effect of mixing Polyurethane with Bentonite filler obtained from Nisam, North Aceh which has been modified with CTAB and AgNO3 surfactants. The sample formulation used is polyurethane and polyurethane with North Aceh Bentonite variations of 1.5, 2.5, and 3.5%. Characterization with the addition of Bentonite produces polymers that have good thermal stability capabilities. The addition of Bentonite filler into polyurethane polymer can affect the mechanical properties of the material. The Polyurethane/Bentonite composite sample has better thermal resistance, where in pure Polyurethane, the initial weight reduction of the pure Polyurethane sample is 50-150 ℃, the decomposition of pure Polyurethane is at 385 ℃. For Polyurethane/Bentonite 98.5:1.5% w/w nanocomposite, the initial weight reduction is 150-300 ℃, decomposition at 416 ℃. For Polyurethane/Bentonite 97.5:2.5 w/w, the initial weight reduction is 150-250 ℃ and decomposition at 430 ℃. Polyurethane/Bentonite 96.5:3.5 w/w initial weight reduction is also at 200-300 ℃ and decomposition at 458 ℃.

Polyphenyltriazoles on Kombucha‐Derived Bacterial Cellulose: Synthesis, Structural Evaluation and Hydrophobicity

AbstractBacterial cellulose‐based materials have diverse applications as leather‐like materials, wound‐healing materials, and optoelectronic materials etc. Particularly, functionalization by polymer or organic compounds can help improve specific properties to diversify application areas. In this work, we reported a facile approach to functionalize Kombucha‐derived bacterial cellulose (BC) by AB‐type “Graft Through” click polymerization reaction. Since by this technique, the polymer was anchored on the surfaces as well as was produced in solution, and it provided the flexibility of detailed characterization on the surface as well as in a solution. Apart from standard spectroscopic characterization techniques, multinuclear solid‐state 13C, 29Si, and 15N NMR spectroscopic studies were undertaken extensively for finding the detailed structural information unambiguously. Thermal analysis, X‐Ray Diffraction analysis, and Small Angle Scattering (SAXS) was undertaken to understand the crystallinity and fibrous properties of the bacterial cellulose materials, while various microscopic analyses were undertaken for morphological studies. Those are particularly helpful in understanding the hydrophobicity of the materials an essential parameter for diversifying the application areas of the materials.

Anion-templated Self-assembly for the Preparation of Silver-t-butylthiolate Clusters

Silver thiolate polymers are intercepted to form different structural fragments when reacting with variant solubilizing reagents, which usually serve as the starting point for the preparation of clusters. However, such a process is still far from clear. Herein, we report the controlled synthesis of silver-t-butylthiolate clusters from reactions of polymeric [AgtBuS]n and suitable templates in the presence of solubilizing reagents to offer a detailed look at the mechanism of cluster's formation. As the provided solubilizing reagents have weak coordination ability, such as O- or N-donating ligands, the obtained polymeric compound retains the linear structure pattern that S and Ag atoms are arranged alternately. When extra templates NO3− and CO32- are applied, the disk-like clusters Ag19 and Ag20 are constructed with the same [AgtBuS]5 circles that may directly cyclize from the linear [AgtBuS]n fragments. In contrast, (EtO)2PS2− and (iPrO)2PS2− anions have large size and strong coordination ability rendering the structure of the polymer completely fragmented. Thus extremely short [AgtBuS]n pieces with silver ions and solubilizing ligands assemble around the templates V2O74- and W2O94-, leading to the formation of clusters Ag22 and Ag24.

Playing with [{Mo6Bri6Sei2}(CN)a6]4− Cluster Building Blocks and Mn(salen)+ Nodes for the Crystal Engineering of Inorganic Coordination Polymers

AbstractWe present here the syntheses and structural characterizations of inorganic polymeric cluster compounds, Cs[Mn(salen)]3[{Mo6Br6Se2}(CN)6] (1) and (H3O)(TBA)[Mn(salen)]2[{Mo6Br6Se2}(CN)6] (2) (TBA=tetrabutylammonium ((n‐C4H9)4N+)), built‐up from [{Mo6Br6Se2}(CN)6]4− molecular building blocks and Mn(salen)+ complexes (salen = salen = N,N′‐bis(salicylidene)ethylenediamine). The nature of additional counter cations (i. e. Cs+ or TBA+) enables to control the interactions between the [{Mo6Br6Se2}(CN)6]4− building blocks and the Mn(salen)+ groups. Thus, 1 was obtained by slow diffusion of a methanol solution of K2Cs2[{Mo6Br6Se2}(CN)6] cluster compound into a methanol solution of Mn(salen)ClO4. 2 was obtained in a similar way but after the addition of tetrabutylammonium bromide into the solution of Mn(salen)ClO4. 1 is a bimetallic 3D coordination compound ( ) and 2 is a bimetallic 2D compound ( ). Structural correlations between 1 and 2 are discussed and compared with relevant examples found in the literature.

BIOPHARMACEUTICAL INVESTIGATION OF ANTIOXIDANT GEL

Introduction: With the recognized association between oxidative stress and skin diseases, incorporating antioxidants into treatment strategies has gained importance. However, dermatological dosage forms containing antioxidants are underrepresented on the pharmaceutical market. The search for delivery systems that ensure antioxidant stability and enhance antioxidant effects on the skin remains is quite relevant. Among the various dosage forms, gels have gained significant interest in recent times.
 The purpose of this study work is to conduct a comparative biopharmaceutical investigation of gels containing the synthetic antioxidant ethylmethylhydroxypyridine succinate (EMHPS) at different concentrations of the active ingredient.
 Materials and methods: The study utilized gel compositions containing EMHPS at concentrations ranging from 2.5% to 7.5%. Synthetic polymer compounds were employed as gelling agents, and the gels were prepared under laboratory conditions according to the technological scheme developed by the author. The obtained samples were assessed for thermal, colloidal, and mechanical stability. The release rate of EMHPS from the gels was determined by the dialysis method using a semipermeable membrane according to Kruchinsky. Dialysate samples were collected over a 5-hour period and analyzed spectrophotometrically at 297 nm. The data obtained were checked for normal distribution and statistically processed using Excel tables.
 Results: The studied gels exhibited thermal and colloidal stability, no delamination occurred under elevated temperature and centrifugation conditions. The gels and their bases demonstrated mechanical stability, with respective values ranging from 1 to 2. Analysis of the dialysis results revealed that the release of the active substance from all three gel samples commenced after 15 minutes, exhibited intensive increase within the first 60 minutes, and continued to gradually increase from 1 to 4 hours. Although the fraction of released active substance remained consistent across the three gels at each time interval, the absolute EMHPS amount in the dialysate depended on the drug concentration
 In conclusion, synthetic-based gels containing EMHPS can be successfully formulated, meeting the criteria of thermal, colloidal, and mechanical stability. These gels demonstrated the ability to release 47-49% of the active substance within the first 30 minutes, proportional to its concentration

PH Responsiveness of Microwave Polymer-Type Modified Magnetic Nanoparticles for Synergistic Emulsion-Breaking Effect on Thick Oil

Summary In this study, a polymeric magnetic emulsion-breaking compound of ferric tetroxide and cationic polyacrylamide (Fe3O4@CPAM) was designed and synthesized, and its functional groups, chemical bonding, magnetic properties, and thermal stability were characterized. Finally, the pH-responsive behavior of the microwave-modified magnetic nanoparticles (MNPs) in terms of their demulsification effect on thick oil-in-water emulsions was investigated using the morphology and distribution of oil droplets, zeta potential, and contact angle of the MNPs. The results showed that with increasing pH, the water separation of the emulsion initially decreased and then increased, and the best emulsion-breaking effect was achieved at pH 3. The highest water partition of the emulsion was 64.39% at a concentration of 175 mg/L for Fe3O4 MNPs alone before modification. Under the same conditions, the water separation rate of the emulsion for Fe3O4@CPAM was 78.95%, indicating that, compared with the conventional demulsification method, microwaves can promote oil-water separation. The highest water separation rate of MNPs before microwave modification was 85% at pH 3, whereas the water separation rate of MNPs after microwave modification reached 94.70% under the same conditions. This proves that microwaves and modified MNPs have a synergistic emulsion-breaking effect, mainly because the combination of microwaves and polymer modification enhances the hydrophobicity and neutralizes the charge of the MNPs, thus improving the emulsion-breaking efficiency.

Graded-Index Active Layer for Efficiency Enhancement in Polymer Solar Cell

In this paper, narrow-bandgap polymer acceptors combining a benzotriazole (BTz)-core fused-ring segment, named the PZT series, were used with a high-absorption-efficiency polymer (PBDB) compound with branched 2-butyl octyl, linear n-octyl, and methyl to be utilized as a graded-index (GI) active layer of the polymer solar cells (PSCs) to increase the photocurrent and enhance solar efficiency compared to the existing PBDB-T:PZT and PBDB-T:PZT-γ. In addition, a two-dimensional photonic crystal (2D-PhC) structure was utilized as a light-trapping anti-reflection coating (ARC) thin film based on indium tin oxide (ITO) to reduce incident light reflection and enhance its absorption. The dimensions of the cell layers were optimized to achieve the maximum power-conversion efficiency (PCE). Furthermore, the design and simulations were conducted from a 300 nm to 1200 nm wavelength range using a finite difference time-domain (FDTD) analysis. One of the most important results expected from the study was the design of a nano solar cell at (64 µm)2 with a PCE of 25.1%, a short-circuit current density (JSC) of 27.74 mA/cm2, and an open-circuit voltage (VOC) of 0.986 V.

GC/MS and DART-MS as complementary methods for investigating the effects of weathering on chemical profiles of ignitable liquids: A case study for paint thinner

In this study, gas chromatography/mass spectrometry (GC/MS) and direct analysis in real time mass spectrometry (DART-MS) were used to analyze paint thinner samples weathered under different conditions. As GC/MS total ion chromatograms (TIC) of weathered paint thinner samples varied significantly due to the disparate evaporation rates of organic compounds in the mixture, DART-MS spectra have shown more consistent profiles among different samples. The distinctive ion clusters identified in the DART-MS spectra were attributed to the less volatile glycol ethers and polymeric compounds with alkyl chains in the paint thinner samples. Analysis of variance-principal component analysis (ANOVA-PCA) was applied to study the contributions of weathering degree and temperature factors to the total variance of GC/MS TIC and DART-MS spectral datasets and found that both factors played significant roles in the weathering process (p < 0.05), though weathering degree contributed to considerably more total variance to GC/MS TIC profiles (i.e., 93.4%). The paint thinner GC/MS and DART-MS profiles were compared with those from other common ignitable liquids, such as gasoline, torch fuel, lighter fluid, and Japan drier. The partial least squares discriminant analysis (PLS-DA) models were constructed to classify the ignitable liquids with the classification rates of 99.97 ± 0.02% and 99.80 ± 0.08% for models based on GC/MS and DART-MS data, respectively. Our study has shown that DART-MS can provide discriminative information for distinguishing ignitable liquid samples and complement the existing GC/MS method by the detection of less volatile compounds.

Ultraviolet Light Radiation Effects on Viscoelastic Property Variation in Polymers

Viscoelastic materials exhibit a variable mechanical behavior generally investigated through Dynamic Mechanical Analysis (DMA). Such kind of test is carried out on standardized specimens, which have to be specifically produced or extracted from the component to be characterized, causing its destruction. This work, taking advantage of an innovative non-invasive testing procedure, based on an instrumented evaluation of indentation, aims to experimentally study the viscoelastic properties changes in polymer compounds, caused by exposure to UV rays. The analysis has been executed on two different polymer compounds designed for tire tread. An extensive use of UV radiation is performed to generate changes in rubber compound properties, but as concerns tire compounds application, there are only a few studies in literature and the same can be stated regarding the monitoring of properties over time using non-destructive procedures. In order to evaluate the viscoelastic properties variation, a proper test bench has been developed employing an UV lamp coupled with an innovative testing device. A test campaign has been carried out on the different tire compound specimens, tested in different conditions in terms of exposure time, exposure face and after various time ranges from the exposition. The tested compound samples exhibit a different chemical composition in terms of polymer blend ratio. The overall results highlight: the ability of the proposed technique to measure the variation in the mechanical behavior of the materials induced by exposure to UV rays and significant variations in viscoelastic properties induced on the compounds as a function of the time of exposure to UV rays and of the chemical composition.

Synthesis and crystal structure of catena-poly[[[aqua-{2-[(E)-(1-cyano-2-imino-2-meth-oxy-ethyl-idene)hydrazin-yl]benzene-sulfonato}-sodium]-di-μ-aqua] dihydrate

In the polymeric title compound, {[Na(C10H9N4O4S)(H2O)3]·2H2O} n , sixfold coordinated Na+ cations are linked into a chain parallel to [010] by sharing common water mol-ecules. Next to the four bridging water mol-ecules, each Na+ cation of the chain is bonded to the O atom of a terminal water mol-ecule and an O atom of the SO3 - group of the sulfonate anion. Classical O-H⋯O, O-H⋯N and N-H⋯O hydrogen bonds and additional π-π inter-actions connect these chains into a three-dimensional network.