Addition Of Silane Research Articles

Adsorption of natural dye phycocyanin by means of Laponite®: Synthesis and characterization of the hybrid obtained

This work addresses the use of Laponite® clay in various applications, focusing on its adsorption capacity and improvement of properties in water-based products. It describes the synthesis of Laponite® hybrids with the pigmented cyanobacterium phycocyanin (PC) to evaluate the adsorption capacity of the dye. This research addresses the importance of Laponite® clay in improving rheological properties of water-based products due to its ability to interact with components in aqueous solutions. Laponite® can be effectively dispersed in water, enhancing the dispersion of other elements in solution and preventing aggregation of solids. The structure and properties of synthetic Laponite® are described, highlighting its use in the textile industry as an additive for pigments and the formation of gels. Experimentally, Laponite® is used to adsorb phycocyanin, a cyanobacterial pigment, with the aim of achieving maximum adsorption. A design of experiments with different experimental conditions, including pH, addition of silane and surfactant, is used. A detailed analysis of the characterization of the resulting hybrids is presented, including colour, total solar reflectance (TSR), thermal analysis (TGA), EDS, FTIR and X-ray diffraction (XRD) measurements. The results show successful adsorption of the pigment in all experiments, with adsorption percentages above 97%. The colour of the hybrids is evaluated and the total solar reflectance is analyzed, highlighting their importance in applications such as coatings and printed textiles. Infrared spectroscopy and X-ray diffraction are used to study the structural properties of the hybrids. For future work, it is intended to be able to apply the hybrids obtained on an industrial scale in the colouring of textiles and plastic polymers.

Predicted Corrosion Performance of Organofunctional Silane Coated Steel Reinforcement for Concrete Structures: An Overview

This article provides a comprehensive overview of the potential use of organofunctional silane coatings in the corrosion protection of concrete reinforcement in close relation to other commercially used coating technologies—i.e., epoxy coatings and bath hot-dip galvanizing coatings. The application technology of the steel surface is described in detail, and the corrosion performance and bond strength in concrete are compared. The paper also points out the possibility of improving the durability of epoxy coatings by the addition of silanes and, in the case of application to the surface of hot-dip galvanized steel, they can prevent corrosion of the coating by hydrogen evolution. The application potential of organofunctional silanes is also presented in the form of hydrophobic coatings on concrete surfaces or as corrosion inhibitors in simulated concrete pore solutions. The use of a suitable type of modified silane coating on the surface of carbon steel reinforcement can increase the corrosion performance and can also increase the bond strength in concrete. However, these facts need to be experimentally verified.

Features of polymerization kinetics and heat realize of epoxy resin modified with silicone, silane and siloxane additives

Features of polymerization kinetics and heat realize of epoxy resin modified with silicone, silane and siloxane additives

The Influence of Environmental Factors on the Degradation of PLA/Diatomaceous Earth Composites.

In the present study, tests were carried out on composite samples on a polylactide matrix containing 25% by weight of mineral filler in the form of diatomaceous earth, base, and silanized with GPTMOS (3-glycidoxypropyltrimethoxysilane), OTES (n-octyltriethoxysilane), and MTMOS (methyltrimethoxysilane) silanes. The addition of two types of waxes, synthetic polyamide wax and natural beeswax, were used as a factor to increase the rheological properties of the composites. The obtained samples were characterized in terms of the effect of filler silanization on the degradation rate of the composites. The tests were conducted under different conditioning conditions, i.e., after exposure to strong UV radiation for 250 and 500 h, and under natural sunlight for 21 days. The conditioning carried out under natural conditions showed that the modified samples exhibit up to twice the degradation rate of pure polylactide. The addition of synthetic wax to the composites increases the tendency to agglomerate diatomaceous earth, while natural wax has a positive effect on filler dispersion. For composites modified with GPTMOS and OTES silanes, it was noted that the addition of natural wax inhibited the degree of surface degradation, compared to the addition of synthetic wax, while the addition of MTMOS silane caused the opposite effect and samples with natural wax degraded more strongly. It was shown that, despite the high degree of surface degradation, the process does not occur significantly deep into the composite and stops at a certain depth.

Enhancement of the Surface and Mechanical Properties of Polyurethane Coating Through Changing the Additive Ratio of Silane

AbstractContinuous development in the formulation and processing techniques of polyurethane (PU) coatings improves an aesthetic appearance as well as protection against environmental factors. In this study, the formulation of PU coating with polyethylene glycol 600 (PEG600), isophorone diisocyanate (IPDI), and trimethoxysilylpropylcarbamoyloxyhexane (TMSCH) silane‐based additive is optimized to obtain high scratch‐resistant coating. An addition of 43.1 wt.% TMSCH in PU formulation resulted in a significant improvement in the scratch resistance and wettability properties compared with pure PU film. The homogenously prepared micron‐thick coatings are characterized using scanning electron microscopy analysis and Fourier transform infrared spectroscopy. The results confirm the presence of silane additives in the PU coating matrix. The mechanical properties improved due to the increased crosslinking networks via the formation of urethane bonds by increasing the TMSCH in PU formulation. Prepared PU coating showed combined features of transparency, hydrophobicity, scratch resistance, and mechanical strength that make it a promising candidate for household appliances.

Cobalt-catalyzed synthesis of amides from alkenes and amines promoted by light.

Catalytic methods to couple alkene and amine feedstocks are valuable in synthetic chemistry. The direct carbonylative coupling of alkenes and amines holds promise as a perfectly atom-economical approach to amide synthesis, but general methods remain underdeveloped. Herein, we report an alkene hydroaminocarbonylation catalyzed by unmodified, inexpensive cobalt carbonyl under mild conditions and low pressure promoted by light. Silane addition after the reaction enables sequential cobalt-catalyzed amide reduction, constituting a formal alkene hydroaminomethylation. These methods exhibit exceptional scope across both alkene and amine components with high chemo- and regioselectivity and proceed efficiently even in the absence of solvent. The formation of a hydridocobalt through photodissociation of a carbonyl ligand is proposed to enable catalytic activity under mild conditions, which addresses a long-standing challenge in catalysis.

Capacitance breakthroughs in free-standing electrodes through MXene functionalization

The discovery of the large group of 2D materials called MXenes has gathered much attention due to their potential applications in various fields as well as the evergrowing discoveries about their nature. One of the most interesting applications is energy storage devices. Herein, we demonstrated the impact of the functionalization with two different silanes on the electrochemical and structural properties of Ti3C2Tx MXene. Materials are prepared and characterized as free-standing films obtained by a simple vacuum filtration method. The structure of the modified MXene electrodes was confirmed via SEM, FTIR, and XPS analysis. At the same time, the electrochemical properties were determined by cyclic voltammetry and galvanostatic charge-discharge in a two-electrode setup in aqueous electrolyte. Capacitance values at lower scanning speeds revealed the benefits of PEG silane functionalization (25.38 F/g), showing higher values compared to pure MXene (23.95 F/g) and MEMO silane (23.37 F/g). Capacitance retention decreased with the addition of silanes, but there was a significant increase in capacitance in the first 100 cycles. This study clarifies the benefits of adding different silanes to the structural and electrochemical properties of MXene for energy storage applications.

SYNTHESIS AND CHARACTERIZATION OF NEW NILUTAMIDE NO2 GROUP MODIFIED 1,2,3-TRIAZOLES AS In vitro ANTICANCER AGENTS

Nilutamide (1) of the NO2 group can be converted to NH2 by addition of triethyl silane and Wilkinson’s catalyst to give amino compound (2) via reduction. It is further treated with t_BuONO by TMSN3 in RB flask containing CH3CN to give 3-(4-(4-azido-3-(trifluoromethyl) phenyl)-5-5-dimmethylimidazolidine-2,4-dione (3). Azide furthermore reacted with different terminal alkynes in the presence of Sharpless catalyst to form 5,5-dimethyl-3-(4-(4-phenyl-1H1,2,3-triazol-1-yl)-3-trifluoromethyl imidazolidine-2,4-diones(4a-4j) with favorable yields depicted (scheme-I) in this manuscript. All the compounds were screened for in vitro anti-cancer activity, among them compound 4h containing the 4-CN group showed highest anticancer activity PC3=-1.94±1.16µM and DU-145=1.54±0.32 and MCF7=1.43±0.92 µM. Compound 4d NO2 group resulting compound 4d exhibited PC3 3.38±2.07 and DU-145 =3.58±1.57 µM. Compound 4C containing Ome group PC3=2.10±1.38, DU-145=1.57±0.32 and MCF-7=2.08±1.64 µM as IC50 in µM, Etoposide is used as a reference.

Dual-functional trisiloxane as binder additive for high volume expansion Li-ion battery electrodes

Silicon-based anodes for lithium-ion batteries have the inherent advantage of higher capacity. However, the inherent expansion of Si within the anodes during cycling, causing low battery life, has limited its application. Various approaches are being investigated to mitigate the adverse effects, ranging from the patterned deposition of Si, blending silicon materials with graphite active materials, and using modified polymeric binders. Inspired by the super spreading capabilities of siloxane compounds and with an aim to optimize the graphite-SiO composite electrode, this work focuses on tweaking the binder formulation with a trisiloxane-based additive which enables uniform dispersion of active material within the electrode and enhances the wetting of the electrolyte within the electrode. In this work, graphite with 15 wt% silicon monoxide was used as an electrode with trisiloxane-modified binder showing much improved electrochemical performance with better mechanical integrity compared to the benchmark electrode. The cell with modified binder exhibited remarkable cycling stability up to 400 cycles at 0.2 C-rate. A detailed study on the role of the trisiloxane additives on the physicochemical properties of electrode materials has also been elucidated. The prospects of employing these additives for similar high-volume expansion electrodes are also discussed.

Preparation and properties of silane cross-linked polyethylene nanocomposite foams: The effect of silane and nanoclay type and content

In this study, silane grafted and moisture cross-linked low density polyethylene nanocomposite foams were prepared by melt mixing and batch foaming process and the effects of silane content, nanoclay content, foaming agent concentration and clay type (clay modified with vinyltriethoxysilane (VTES) and amino-propyltriethoxysilane on foaming efficiency and foam properties were investigated. The morphology and the efficiency of silane modification of modified clay were characterized by series of tests, including X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and thermogravimetric analysis (TGA). The results of Fourier transform infrared and thermogravimetric analysis showed that the silane modifiers were bonded to the surface of nanoclay through both physical and chemical bonds. According to XRD, these modifiers caused characteristic peak of clay to shift to lower angles, and make an increase in basal spacing. Gel content, density, scanning electron microscopy, compression, creep and rheological tests were used to determine the effect of different parameters on properties of cross-linked polyethylene foams. Results indicated that silane content has the significant effect on stress-strain behavior in compression mode. Compression set and creep deformation were affected by cell size and gel content. Furthermore, the rheological properties including complex viscosity, storage and loss modulus of unformed samples increased with the addition of silane and nanoclay content.

Effect of soil hydrophobicity on soil-water retention curve of a silt loam soil

Soil wettability is an important property that affects the behaviour of fine-grained soils. Previous studies have shown that hydrophobicity induced by organic or silane additives may affect the soil-water retention curve (SWRC). However, current findings regarding the effect of hydrophobicity on the SWRC are controversial. Previously, organic or silane additives were assumed to change only the soil wettability. Nevertheless, this study shows that polyvinyl alcohol (PVA) can change the hydrophobicity, pore size distribution (PSD), and specific surface area (SSA) of soil, thus affecting the SWRC. PVA-treated soil is hydrophobic when cured at 20 ℃, but hydrophilic when cured at 100 ℃. No thermal degradation is indicated in the PVA at 100 ℃ based on thermogravimetric analysis and a comparison of mass loss, and the sole difference between the PVA-treated soils cured at 20 and 100 ℃ is their wettability. This study managed to make the hydrophobicity caused by PVA to become an independent variable separated from the PSD and SSA by controlling the ambient temperature. The wetting and drying curves are measured under isopiestic humidity control in the high-suction domain (2.7–298.7 MPa), whereas pressure plates are used for the drying curves in the low-suction domain (0–800 kPa). The results obtained indicate that soil hydrophobicity significantly accelerates drainage when the matric suction is between 100 and 400 kPa, and an increase in PVA content increases the water retention capacity of soil. When the matric suction exceeds 2.7 MPa, the effect of soil hydrophobicity on the SWRC of the soil weakens. At this time, the SWRC is dominated by the van der Waals force, and the SSA contributes significantly to the process. Additionally, this study enables some controversial findings from previous studies to be explained, which is of great significance in soil and agriculture sciences.

Cross Couplings of Cinnamates to Benzo‐Fused Oxanorbornadienes

AbstractPotential exo‐specific [3+2] cascade cyclizations between o‐Br‐substituted cinnamates (CM−Br) and benzo‐fused 7‐oxa‐norbornadiene (Bz‐OND) by Pd‐mediated catalysis were explored both in racemic and asymmetric methods. A systematic study on Pd(II) catalysts, silane additives, carbonate bases, solvents, chiral diphosphines within a reaction temperature range of 60–80 °C were carried out. The best combination was between methyl o‐Br‐cinnamate and Bz‐OND catalyzed by Pd(OAc)2/dppf and /DM‐BINAP, respectively, in CH3CN at 80 °C. The desired racemic and optically active Bz‐OND‐fused indanes bearing 1‐carbonylmethylidene (CBM) unit were thus afforded in 95 % and 71 % yields and with enantioselectivities of up to 43 % ee. The optimal asymmetric recipe can be applied to alkyl, aryl cinnamates, 4‐substituted, and 5‐substituted o‐bromo‐cinnamates. Exclusive hydrogenations from the exo‐face of the CBM alkene units can be readily done by Pd(0)/charcoal in EtOAc, affording the product complementary to the direct Rh(I)‐catalyzed cyclization.

Analytical study of silane-based and wax-based additives on the interfacial bonding characteristics between natural rubber modified binder and different aggregate types

The modification of asphalt binder with natural rubber latex (NR) significantly improves the rutting and fatigue resistance of asphalt mixtures. However, NR-modified binder is prone to low workability and wettability due to its high viscosity. Therefore, this research focuses on examining the influences of silane and wax-based additives on the wettability of natural rubber-modified binders and the binder-aggregates adhesion performances. In this study, experimental and analytical approaches were used. The contact angles of asphalt binder were measured using a goniometer through the sessile drop method with three solvents: deionised water, formamide, and glycerol. The C++ algorithm was adopted to compute the surface free energy (SFE) elements of the asphalt binder. Analytical methods were employed to analyse the results based on the Young-Dupre equation, followed by linear regression to establish a correlation between the compatibility ratio (CR) and the SFE components. The results inferred that modified asphalt binders with additives possessed improved moisture resistance, wherein dry work adhesion values were less than 210 ​mJ/m2 under granite interfaces, whereas the limestone interface exhibited higher dry adhesion values of 340 ​mJ/m2 and below. Similar performance results were observed under wet adhesion conditions; with granite wet adhesive values observed below 120 ​mJ/m2, while limestone wet adhesion values were ascertained below 180 ​mJ/m2 for all tested samples and conditions. According to the spread–ability coefficient results, the limestone interface has greater spread-ability than granite interfaces. Meanwhile, compatibility ratio values indicated better compatibility of 1.9 or higher for tested samples under granite interfaces, whereas compatibility values of 1.7 and below were observed under limestone interfaces. Among the SFE components studied for correlation with CR, the acidic SFE component demonstrated excellent correlations (with R2 values greater than 0.91) under all ageing conditions. An inclusion of micro-level additive enhanced binder adhesion properties, resulting in a more resilient asphalt pavement.

Influence of different processing atmospheres on curing and adhesive strength of cyanoacrylates

Cyanoacrylate adhesives cure within seconds due to water in a normal atmosphere, which can lead to problems in processing and in large-area bonding. The aim of this work is therefore to overcome the problem by using a water-free process atmosphere. In the scope of this work, a standard argon protective atmosphere and a novel argon/silane atmosphere are compared with an air atmosphere. To validate the influence of the atmosphere the adhesive strength is investigated by tensile tests as well as the curing process via Raman spectroscopy. In order to explain differences in curing and strength the fracture surfaces of selected samples are examined by confocal microscopy. While the argon atmosphere shows slower curing and thus longer processing capability, only low tensile strengths after 72 h are achieved. The novel oxygen-free argon/silane atmosphere shows a similar delayed cure, but the tensile strengths achieved after 72 h are comparable to those in air. The addition of silane thus allows a more flexible processing without disadvantages in the final mechanical strength.

Design of PEI and Amine Modified Metakaolin-Brushite Hybrid Polymeric Composite Materials for CO2 Capturing

In this paper, the properties of organic-inorganic hybrid polymer materials, which were synthesized from an aluminosilicate inorganic matrix with the addition of brushite and aminosilane grafted on one side and PEI covalently bonded composites on the other side, were examined. The synthesized organic-inorganic hybrid polymers were examined in terms of a structural, morphological, thermo-gravimetric, and adsorption-desorption analysis and also as potential CO2 capturers. The structural and phase properties as well as the percentage contents of the crystalline and amorphous phase were determined by the X-ray diffraction method. The higher content of the amorphous phase in the structure of hybrid polymers was proven in metakaolin and metakaolin-brushite hybrid samples with the addition of amino silane and with 1,000,000 PEI in a structure. The DRIFT method showed the main band changes with the addition of an organic phase and inorganic matrix. Microstructural studies with the EDS analysis showed a uniform distribution of organic and inorganic phases in the hybrid geopolymers. The thermo-gravimetric analysis showed that organic compounds are successfully bonded to inorganic polymer matrix, while adsorption-desorption analysis confirmed that the organic phase completely covered the surface of the inorganic matrix. The CO2 adsorption experiments showed that the amine-modified composites have the higher capture capacity, which is 0.685 mmol·g-1 for the GM10 sample and 0.581 mmol·g-1 for the BGM10 sample, with 1,000,000 PEI in the structure.

Gas Phase Reaction of Silane with Water at Different Temperatures and Supported by Plasma.

The interaction of silane and water is discussed controversially in literature: some authors suggest monosilane and water react kinetically and sufficiently fast enough to remove water, while others state the reaction occurs only at elevated temperatures. This question is of technological interest for the removal of unavoidable water residues in Ar gases. Thermodynamic calculations show that virtually complete removal of water is expected with superstoichiometric silane addition. However, mass spectrometric and infrared spectroscopic experiments give evidence that the addition of monosilane to such an Ar gas at room temperature is unable to remove residual water, which disagrees with some current hypotheses in the literature. This holds even for very high SiH4 concentrations up to 2 vol.-%. Silane reacts with water above temperatures of 555 °C, initiated by the thermal decomposition of silane. A cold dielectric barrier discharge-plasma used for silane and water dissociation enhances reactivity similar to elevated temperatures. Fourier-transformed infrared spectroscopy points toward silanol generation at temperatures between 400 and 550 °C, while quadrupole mass spectrometry indicates the creation of SiOH+, SiHOH+, SiH2OH+, and SiH3OH+. Cold plasmas generate smaller amounts of SiOH+, SiHOH+, and SiH2OH+ compared to elevated temperatures. Reaction products are hydrogen and nanoscaled particles of non-stoichiometric silicon oxides. The silicon-oxide particles produced differ in elemental composition and shape depending on the prevailing water content during decomposition: SiO x generated with residual water appears with relatively smooth surfaces, while the addition of water supports the formation of significantly rougher particle surfaces. Higher initial water contents correlate with higher oxygen contents of the particles.

Approach to achieve controlled particle size synthesis of non-polar functionalised siloxane particles using a one-pot synthesis

The homogeneous addition of functional silanes dissolved in a co-solvent such as ethanol has been shown to change particle growth mechanisms as well as control over particle size and dispersity, especially for non-polar silanes. Highly monodisperse size-controlled silica particles from 50 to over 1000 nm bearing thiol, vinyl, phenyl, propyl, cyanopropyl and chloropropyl R group functionality were synthesised directly from the corresponding single organosilane source. Observing particle growth over time revealed that it proceeded by a conventional Stöber process, where silane monomers and oligomers add to nucleation sites, resulting in particle growth. Scale-up of the homogeneous mixing approach produced gram quantities of particles without affecting size, size dispersion or functionality under good mixing. The presence and functionality of the surface R groups were confirmed by a simple second addition of reactive molecules to the particle synthesis liquor, resulting in theoretical maximum attachment densities.

Aqueous bifunctionalization of cellulose nanocrystals through amino and alkyl silylation: functionalization, characterization, and performance of nanocrystals in quartz microflotation

Surface modifications of cellulose nanomaterials can be used to tailor their surface charge and hydrophilicity-hydrophobicity characteristics. Additionally, it can facilitate the selective interaction of nanocelluloses with other solid particles to further expand their applicability in different fields. For instance, cellulose nanocrystals (CNC) with amphiphilic features are potential green alternatives in mineral processing such as particle flotation. In the present study, aqueous, one- and two-step silylation of CNCs with amino and alkyl silanes was considered to create a novel bifunctionalized CNCs that contained both positively charged amino silane moieties and hydrophobic alkyl chains. Especially, the effects of reaction conditions and different reaction routes on the silylation were investigated, and the electric surface potential and hydrophobicity of CNCs were determined. The bifunctionalization conducted by the simultaneous addition of an amino silane and alkyl silane led to a high reaction efficiency, and the grafting amount was notably higher than that obtained with the sequential reactions with individual reagents. After the functionalization, the hydrophobicity of the CNCs was strongly altered, leading to water contact angles of up to 135° on CNC films. However, the silylation with amino silanes slightly affected the ζ-potential of the functionalized CNCs. Due to the relatively low ζ-potential, the interaction and orthokinetic attachment of CNCs onto quartz surfaces were insufficient, resulting in a limited flotation recovery in microflotation using a Hallimond tube.

Effects of Silane Treatment on Physical and Mechanical Properties of Particleboards Prepared with Urea Formaldehyde

In this study, the effect of silane on particleboard physical and mechanical properties was investigated. Silane was mixed in particleboards with two different methods. In the first method, silane was mixed with wood chips namely as a pretreatment of wood chips. In the second method, silane was mixed with urea-formaldehid adhesive. The amounts of silane used in both methods were 1 %, 2 % and 3 % of the particles based on the dry weight. Urea formaldehyde with 65 % solid content was used as adhesive. Ammonium sulfate (1 %) was added as a hardener to the used adhesive. The target density of three-layer particleboards manufactured was 550 kg/m3. The properties of particleboards evaluated include thickness swelling, bending properties and internal bond strength. Results indicate that particleboards thickness swelling values increase with the use of silane. Overall, pretreatment of the wood particles provided better mechanical properties than the addition of silane to the adhesive solution. Flexure strength and flexure modulus of particleboards were significantly improved by use of silane. Pretreatment of particles with 2 % silane yielded the best improvement of modulus of rupture and modulus of elasticity. For the particleboards prepared with pretreated wood chips with silane, the highest increase of the flexure modulus and flexure strength was 20 % and 40 %, respectively. Pretreatment of wood particles with 3 % of silane nearly doubled internal bond strength of the particleboards. Silane pretreatment can be an alternative method for the improvement of particleboard mechanical properties.

Strength and Moisture-Related Properties of Filter Paper Coated with Nanocellulose

The aim of this study was to assess selected properties of coatings incorporating nanocellulose, with the potential of being applied as a surface modification for cellulosic and lignocellulosic materials, particularly for applications within biodegradable packaging. Cellulose nanocrystal (CNC) and cellulose nanofibril (CNF) coatings were produced and applied on both sides of pure cellulose samples in the form of filter paper with a Mayer bar. Selected organosilicon compounds, albumin, and the TEMPO reagent were used as additional modifying substances. Coating parameters were determined, such as water contact angle, water absorption, hygroscopicity, and tensile strength. The presence of the coatings resulted in a significant increase in water vapor absorption by the substrate. Nanocellulose coatings proved to be sensitive to the water vapor and showed no barrier properties against it. However, the samples coated with nanocellulose had a noticeably lower tendency to absorb liquid water. The samples coated with modifying substances had a contact angle of ≥90°, proving that such coatings were an additional barrier to the penetration of liquid water. In the case of cellulose material coated with nanocellulose (i.e., without the addition of silane), there was no barrier effect established, thereby allowing full wetting of the substrate. The nanocellulose coatings increased the tensile strength of the samples. This increase was observed for all tested coating variants. The results obtained offer several potential routes to the manufacture of more environmentally friendly coatings and packaging materials.