Influence Of Silane Research Articles

Influence of silane and polyethylene glycol functionalization of boron nitride nanosheets on mechanical and thermal properties of epoxy nanocomposites: Machine and deep learning forecasting

AbstractThe influence of hexagonal boron nitride (hBN) nanosheet surface modification on epoxy nanocomposites' mechanical and thermal properties were investigated. An innovative approach was developed for synthesizing hBN nanosheets (hBNNs) via optimized ultrasonic‐assisted liquid‐phase exfoliation (UALPE), followed by functionalization with 3‐aminopropyltriethoxysilane (APTS) and polyethylene glycol (PEG600) for nanocomposite preparation. Compared to unmodified epoxy, nanocomposites containing 0.3 wt% of pristine hBNNs exhibited significant enhancements in flexural strength (125.28 MPa) and tensile strength (53.35 MPa), with respective increases of 40.57% and 43.23%. PEG‐hBNNs improved flexural and tensile strengths to 136.83 and 58.57 MPa, respectively. The most substantial enhancements were observed with APTS‐hBNNs, yielding flexural and tensile strengths of 174.13 and 63.53 MPa, reflecting increases of 95.37% and 70.50%, attributed to better interfacial interactions and a more effective crack deflection mechanism. Thermal stability analyses revealed superior performance of modified hBNNs epoxy nanocomposites, increasing 8.2°C and 6.3°C at 50 wt% degradation as compared to the unmodified system, owing to enhanced physical barrier properties. Structural and morphological analyses validated the successful exfoliation and modification of hBNNs. Predictive models utilizing machine and deep learning (DL) techniques, particularly DL with the adaptive moment estimation (ADAM) optimizer, effectively forecasted mechanical properties, achieving high R2 values.HIGHLIGHTS 0.3 wt% modified hBNNs epoxy nanocomposite showed the highest mechanical strength Improved thermal stability of epoxy nanocomposite by modification of hBNNs Improved crack deflection mechanism in the presence of surface‐modified hBNNs Deep learning with ADAM optimizer showed high R2 and low prediction loss

Influence of silanes on the hydration of cement by separating the cement into its individual phases

AbstractCementitious materials can be treated with organosilicon compounds (silanes) to achieve a water‐repellent effect. However, the influence of silanes on cement hydration is still not fully understood. For this reason, we studied the hydration of the main Portland cement phase (C3S ‐ tricalcium silicate) and the interaction with iBTES (isobutyltriethoxysilane), iOTES (isooctyltriethxysilane) and nOTES (n‐octyltriethoxysilane) by isothermal calorimetry and in‐situ X‐ray diffraction (XRD). The results show that C3S hydration is initially retarded and subsequently accelerated by iBTES and iOTES. In addition to the hydration process, the crystal growth of the portlandites (calcium hydroxide) is also affected by the silanes. The XRD results indicate that the portlandites grow significantly more plate‐like. In this context, the influence of the silanes on the portlandite crystallization was therefore also recorded in a special experimental setup. From the scanning electron microscope images it can be shown that all portlandite crystals grown in the presence of silanes have a platelike morphology. This is due to the fact that the hexagonal surfaces of the portlandite are covered by silanes and thus the growth direction of the crystals is affected. The modified portlandite crystals indicate that silanes also influence the microstructure of the cement paste and therefore its chemical and mechanical properties.

Influence of Silanes on Carbonation of Calcium Sulfoaluminate Cement Produced from Solid Industrial Wastes

Production of calcium sulfoaluminate (CSA) cement from solid industrial wastes consumes enormous amounts of wastes and provides an environmentally friendly binder for the construction sector. However, carbonation of CSA cement is much faster than that of portland cement. Silane was used to reduce water absorption of portland cement concrete and thus promote its carbonation resistance. To clarify the effect of silane on carbonation resistance of CSA cement prepared from solid industrial wastes, three silanes, including glycidoxypropyltrimethoxysilane (GOPTS), vinyltrimethoxysilane (VTMS), and dodecyltrimethoxysilane (DTMS), were employed in this research. Their influence on early-age hydration and water absorption of CSA cement mortar was investigated. Accelerated carbonation was performed. The results show that GOPTS and VTMS retarded early-age hydration of CSA cement and slightly decreased 28-day compressive strength, whereas DTMS had less influence. All three silanes decreased water absorption of mortar. However, they bring about more pores larger than 200 nm, which would facilitate the spread of CO2 in mortar. Nevertheless, other than silane’s effect on water absorption and the pore structure of mortar, carbon chain length of silane determines the carbonation resistance of CSA cement mortar. DTMS accelerates carbonation due to its long chain, but, GOPTS and VTMS, with shorter chains, promote resistance of mortar.

Wood flour‐high density polyethylene composites: Influence of silanization and esterification on mechanical properties

AbstractSilanization and esterification are strategies used to treat wood flour (WF) to produce surface functionalized hydrophobic WF leading to an improvement in dispersion and compatibility between wood phase and polymer phase. Silanization involves functionalization of alkyl groups by coupling trimethoxy (propyl) silane (MPS), and esterification functionalizes WF with ester groups, using acetic anhydride (Ac). Modified WF was incorporated into recycled high‐density polyethylene (HDPE) to form reHDPE/mod‐WF composite system. Both modifications produced highly hydrophobic WF surfaces which improved the dispersion in the reHDPE matrix; resulting in a significant difference in impact strength, specifically at 20 wt% filler, from 74.5 Jm−1 to 146.3 Jm−1 and 113.5 Jm−1, that is, up to 96% and 52% for MPS‐WF and Ac‐WF, respectively. However, filler agglomeration higher than 20 wt% reduces the composite impact strength. The results herein demonstrate that alkyl‐functionalized WF show excellent dispersion in the reHDPE system and is the preferred technique to improve system mechanical resilience as compared to esterification.

Influence of silane on hydration characteristics and mechanical properties of cement paste

In the present study, silane coupling agents (SCAs) were used as admixture in cement paste. The influence on the cement hydration in different stages as well as the mechanical properties were well investigated. Results demonstrated that silanes play a role of retardant in cement paste at the very early age, the proposed mechanism laid in the attraction force between the intermediate hydrolysis products of silanes and the cement hydrated products. The intermediate hydrolysis products can form a gel-like barrier covering the cement hydrated products and were further proved by the designed pre-hydrolysis experiments using calorimeter and Fourier transform infrared spectroscopy (FTIR). However, cement paste modified by silane would have denser structure compared to neat paste as a result of reaction between polycondensated silane and CH after 28 days of curing, leading lower porosity, higher hydration degree and better mechanical performance.

Bond Strength of Composite Resin Restoration Repair: Influence of Silane and Adhesive Systems

The aim of this study is to evaluate the effect of silane (Si) application and different adhesive systems on the bond strength of composite resin repair. One hundred composite truncated cone-shaped specimens were prepared and submitted to 5,000 thermal cycles to simulate existing restorations. Their top surfaces were airborne particle abraded with aluminum oxide, etched with phosphoric acid, and divided into two groups (n = 50) with or without Si application. Each group was divided into five subgroups (n = 10) according to the adhesive system applied: Solobond Plus Primer and Adhesive (SPA)-two-bottle, Solobond Plus adhesive (SA), Admira Bond (A)-one bottle, Futurabond DC (FDC)-self-etch, and Futurabond M (FM)-self-etch. New composite resin was applied over the bonded area. A control group was prepared to evaluate the cohesive strength of the composite resin. Specimens were submitted to tensile stress. Data were analyzed with two-way analysis of variance (ANOVA), and the Tukey and Dunnett tests. Si application reduced the bond strength of all adhesives (p = 0.001). Groups SA and SPA showed higher bond strengths in relation to other groups (p = 0.01). Groups FDC + Si, FM, FM + Si, and A + Si showed smaller mean bond strength values than that of the control group (p < 0.05). Previous Si application reduced bond strength values. The two-bottle adhesive showed better results than one-bottle or self-etching systems for composite resin repairs. The kind of adhesive system applied for composite resin repairs has a great influence on bond strength values. The use of Si in this situation is not recommended.

Influence of silane on the structure of polystyrene prepared by sol-gel coatings via UV curing

Light, heat, oxygen, moisture, ozone, atmospheric pollution and biological effects are the most important effectives wreak to chemical degradation in the polymer structure. In result of chemical degradation on the polymer consist of problems such as discoloration, brittleness, surface cracks, perspiration, crumbling, smell, surface acidity. In this work, it is aimed to improve the problem of the polystyrene (PS) material against chemical degradation. For this reason, PS is coated with silica sol-gel hybrid coating. Silica sol-gel was synthesized by using vinyltrimethoxysilane (VTMS) as a cross-linker and tetraethylorthosilicate (TEOS) as a silica source. Firstly, four different pre-treatment technique (oven, vacuum oven, lyophilizer and freezing) was studied to determine the most suitable pre-treatment technique for coating on PS substrate of sol-gel prepared with initial formulation (S1). A freezing technique gave the best results for coating sample. The change of surface colour of coated PS was measured by CIE L*a*b* methods. Secondly, the most suitable curing agent (Irgacure 184, Irgacure 819, Darocur 1173 and TiO 2 as crystalline anatase phase) was determined to coat the sol-gel on PS. It was determined to the lowest yellowing of PS surface hybrid coated as UV curing of TEOS sol modified by VTMS and TiO 2 as photo-initiators. Finally, the chemical and morphological structure of the coated PS samples was determined by FT-IR and SEM instruments, respectively.

Effect of silane/nano-silica on the mechanical properties of basalt fiber reinforced epoxy composites

The present study explains the role of surface modification of constituent materials on composite material performance. The influence of silane and nano-hybrid coatings on mechanical properties of basalt fibers and composite materials on their base was investigated. Infrared spectroscopy indicated that modification of basalt fiber surface and nano-SiO2 was successfully applied. The surface modification leads to the significant increase in the tensile strength of basalt fibers compared to the non-coated fibers. The tensile strength of silane-treated fibers was established 23% higher than the non-coated fibers, indicating that silane plays a critical role in the strength retention of basalt fibers. Also it was pointed out that silane coupling agents can be used for the preparation of the nano-hybrid coating. Addition of SiO2 nanoparticles into the fiber surface was incorporated to enhance the interfacial bonding of basalt fiber reinforced epoxy composite.

Influence of silane and heated silane on the bond strength of lithium disilicate ceramics - An in vitro study.

Objectives:To evaluate the effect of silane application and silane heat treatment on lithium-disilicate ceramic when bonded to composite resin.Methods:Twelve blocks of lithium-disilicate (LD) ceramic were fabricated and bonding surfaces were etched using 9.5% hydrofluoric acid (90 seconds). Three experimental groups resulted from the various surface treatment combinations, which included, no silane application (NS) (controls), silane application (S) and silane heat treatment (HS) (100°C for 5 minutesutes). Ceramic and composite resin blocks were bonded using an adhesive resin and light cured restorative composite as a luting agent, under standard conditions. A total of 90 specimen sticks (8 x 1mm²) were subjected to micro-tensile bond strength testing. The means of micro-tensile bond strength (µ-tbs) of the study groups were analyzed using t-test and ANOVA. The tested specimens were analyzed for mode of failure using scanning electron microscopy (SEM).Results:The highest µ-tbs value (42.6 ±3.70 MPa) was achieved for LD ceramics with heat-dried silane. Both silane application and heat treatment of silane resulted in significant (p<0.05) improvements in micro-tensile bond strength of LD ceramics when bonded to resin composite.Conclusions:The application of silane and its heat treatment showed significant improvement in bond strength of lithium disilicate ceramic when bonded to composite.

The influence of silane and silane–PMMA coatings on the in vitro biodegradation behavior of AE42 magnesium alloy for cardiovascular stent applications

Silane–PMMA-coated AE42 magnesium alloy with improved corrosion resistance and hemocompatibility for cardiovascular stent applications.

硅烷添加剂Y9669对STN液晶取向剂性能的影响

硅烷添加剂Y9669对STN液晶取向剂性能的影响

Influence of surface modified nanoclay on electrochemical properties of PVDF-HFP composite electrolytes

Polymer electrolyte membranes have prepared for dye sensitized solar cells based on Polyvinylidene fluoride-co-hexaflouropropylene (PVDF-HFP) filled with silane modified Sodium montmorillonite (Na-MMT) nanofillers. Na-MMT nanoclay has modified using Aminopropyltrimethoxysilane and it is confirmed by FTIR and XRD. The XRD patterns of PVDF-HFP/Si-NaMMT proved that Si-NaMMT layers were completely exfoliated within the PVDF-HFP matrix. The influence of silane modified clay on the degree of crystallinity of the polymer matrix was studied by using DSC. The Electrochemical studies indicated that the addition of surface modified nanoclay increases the ionic conductivity up to 6.45 × 10−4 S/cm for 4 wt%, whereas the ionic conductivity about 1.14 × 10−4 S/cm with the addition of unmodified counterpart as the filler into the PVDF-HFP. The solid state dye sensitized solar cell has been fabricated by using silane modified Na-MMT/PVdF-HFP polymer nanocomposites electrolyte and Eosin-Y as a sensitizer. The photovoltaic characteristics showed an enhancement in open circuit voltage (Voc) from 0.26 to 0.32 V.

The influence of silanes on hydration and strength development of cementitious systems

The influences of three types of silane (tetraethoxysilane (TEOS), 3-aminopropyltriethoxysilane (APTES), N-2-aminoethyl-3-aminopropyltrimethoxysilane (AEAPTMS)) on flowability, strength development and hydration kinetics of cement pastes and mortars are systematically investigated. Results show that: 1) three silanes exhibit a dispersing effect on cement pastes indicated by the increased flowability of fresh cement pastes, among which AEAPTMS shows the strongest dispersing power; 2) AEAPTMS and APTES retard cement hydration by extending the induction period and reducing the hydration degree at certain ages determined by isothermal calorimetry, measurements of non-evaporable water amount and portlandite content in hydration products at ages before 90days; 3) AEAPTMS and APTES show positive effect on the toughness of mortars after 7day curing; and 4) three silanes act differently on strength growth at various ages, which should be a result that is counterbalanced by their influences on hydration kinetics, pore structure, composition and morphology of hydration products.

Effect of silane coupling agent on the curing, tensile, thermal, and swelling properties of ethylene‐propylene‐diene monomer rubber (EPDM)/mica composites

The influence of silane (bis[3‐triethoxysilylpropyl] tetrasulfide) coupling agent on the properties of ethylene‐propylene‐diene monomer rubber (EPDM)/mica composites was studied. Both EPDM/mica composites with silane and those without silane were compounded by using a two‐roll mill at various filler loadings (i.e., 100/0, 100/10, 100/30, 100/50, 100/70). The tensile and thermal properties as well as the fracture surfaces of the composites were investigated by using an Instron Universal Testing Machine, a thermal gravimetric analyzer, and a field emission scanning electron microscope. The results indicated that the optimum cure time (t90) and scorch time (ts2) values were shorter, whereas the maximum torque (MH) value was slightly higher, for EPDM/mica composites with silane compared to those without silane. The tensile properties, modulus at 100% elongation, and modulus at 300% elongation increased for the composites made with silane, and the optimum filler loading for those properties was 50 parts by weight per hundred parts of rubber. In addition, thermal stability and swelling ratio for both composites improved with increased filler loading. However, the composites with silane showed better thermal stability and swelling ratio because of stronger linkage at the rubber‐filler boundary, which promoted filler dispersion. J. VINYL ADDIT. TECHNOL., 20:116–121, 2014. © 2014 Society of Plastics Engineers

Influence of silanes on the wettability of anodized titanium

A facile method was adapted to make superhydrophobic (SHP) titanium in which a synergistic combination of surface roughness and surface chemistry was utilized. In the first step, titanium was mechanically polished and pickled followed by anodization. The next step was to dip coat the samples with silane solution and then were cured at 110°C. Influence of different synthesis parameters such as silane concentration, number of dip coating and curing temperature on water contact angle (WCA) was studied and conditions were optimized to achieve a WCA of 150°. The wetting properties of the samples were elucidated using contact angle meter and the water just rolled off the modified titanium surface with a slight tilting. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to study the morphology and surface roughness of the silane coated titanium samples. Grazing incidence X-ray diffraction (GIXRD), energy dispersive spectroscopy (EDS), attenuated total reflection-infrared spectroscopy (ATR-IR) and X-ray photoelectron spectroscopy (XPS) were used to analyze the chemical composition of the coatings which confirmed the presence of silicon along with titanium and oxygen. Immersion studies in sea water and nitric acid medium for 15 days indicated the stability of the coatings with minimal variations in contact angle.

Influence of silanes on the shear bond strength of resin cements to zirconia.

To test the shear bond strength of self-adhesive and conventional resin cements to zirconia after the application of different types of silanes with/without aging. Three hundred and sixty zirconia specimens were randomized into 10 groups (n = 36). Five groups were assigned to the self-adhesive resin cement RelyX-Unicem (RXU) and five groups to the conventional resin cement Panavia 21 (PAN). The groups were further assigned to the following pretreatments: Monobond-S (M), Alloy Primer (AP), Clearfil (C), Experimental Universal Primer (EUP), or without silane (control group). Twelve specimens of each of the cements were tested after water storage for 24 hours (initial shear bond strength). The remaining 24 samples were aged (1,500 cycles, n = 12; or 13,500 cycles, n = 12). The shear bond strength was measured (Universal Testing Machine; 1 mm/min, Zwick Roell Z010). Data were analyzed with one-way ANOVA followed by post-hoc Scheffé tests. Student's t test was applied to test the differences between the two cements (P < .05). The initial bond strength of RXU was increased by the application of the different silanes. The silanes had less influence on the initial bond strength of PAN. Aging reduced the bond strength of RXU significantly in combination with two of the silanes (AP, 0 ± 0 MPa; C, 4.1 ± 0.9 MPa; P < .05). Aging led to a significant reduction of the bond strength values of PAN with the primers AP (2.9 ± 0.4 MPa) and EUP (2.5 ± 0.5 MPa; P < .05). The present study indicates that the bond strength of the self-adhesive resin cement was positively influenced by the pretreatment of the zirconia surface with different silanes. Aging led to a decrease of the bond strength of both types of cements, irrespective of most of the silanes used.

Effect of Silane Coupling Agent on the Curing, Tensile, Thermal, and Swelling Properties of EPDM/Mica Composites

In this work, the influence of silane (bis (3-triethoxysilylpropyl) tetrasulfide) or Si69 coupling agent on properties of EPDM/mica composites was studied. Both EPDM/mica composites with silane and without silane were compounded using two roll mill at various filler loading (i.e., 100/0, 100/10, 100/30, 100/50, 100/70). The tensile and thermal properties as well as fracture surfaces of composites were tested using Instron Universal Testing Machine, Thermal Gravimetric Analysis (TGA) and Emission Scanning Electron Microscope (SEM). The results indicated that the optimum cure (t90), scorch time (ts2) value was lower, while maximum torque (MH) value slightly higher for EPDM/mica composites with silane compared to EPDM/mica composites without silane. The tensile properties, M100 and M300 value increased for EPDM/mica composites in the presence of silane and the optimum filler loading for those properties occurred at 50 phr. In addition, thermal stability and swelling ratio for both composites improved with increasing filler loading. However, EPDM/mica composites with silane show better thermal stability and swelling ratio due to stronger linkage taking place at the rubberfiller boundary and it promotes filler dis-agglomeration.

Influence of silane and solvated bonding agents on the bond strength to glass‐fibre posts

The combined use of silane and solvated bonding agents on the bond strength to glass-fibre posts was investigated. A model Bis-GMA/HEMA adhesive was formulated with no solvent, 30% of ethanol or 80% of acetone. The surfaces of rectangular-shaped posts were silanated or not and one of the agents was applied, except for the control group. Cylinders of resin cement (RelyX ARC, 3M ESPE, Saint Paul, MN, USA) were built-up on the surfaces (n = 20) and submitted to shear testing. All groups showed higher bond strengths when the surfaces were silanated. When no silanization was carried out, the use of bonding agents, either solvated or non-solvated, increased the bond strengths. All groups treated with both silane and bonding agent showed higher bond strengths than the group that was only silanated. Control and ethanol-based adhesives were similar, whereas the acetone-based agent yielded higher bond strengths. Adhesive failures were predominant. Combination of silane and adhesive enhanced the bond to fibre posts.

Influence of silanization on voltammetry at electrodes modified with silica films of controlled porosity formed by electrochemically initiated sol-gel processing

Silica sol-gel (SG) films with templated pores were deposited on glassy carbon (GC) electrodes by an electrochemically initiated process. Generation-4 poly(amidoamine), PAMAM, dendrimer was included in the tetraethoxysilane precursor to facilitate pore formation. The PAMAM adsorbs to the GC, which blocks SG formation at those sites on the electrode. The pore size was 10 ± 5 nm. After removal of the PAMAM, cyclic voltammetry of Fe(CN)6 3− and Ru(NH3)6 3+ at pH 6.2 showed that the residual negative charge on the silica attenuated the current for the former and increased the current for the latter, presumably by electrostatic repulsion and ion-exchange preconcentration, respectively. This premise was supported by repeating the measurements at the isoelectric point. Methylation of the silanol sites was used to eliminate the charge of the SG. At the end-capped SG, the voltammetry of Fe(CN)6 3− and Ru(NH3)6 3+ yielded currents that were independent of pH over the range 2.1 to 7.2. Circumventing the need for the silanization by using (3-glycidyloxypropyl)trimethoxysilane as the sol-gel precursor failed because the oxygen plasma treatment to remove the PAMAM attacked the organically modified sol-gel backbone. The resulting modified electrode mitigated the influence of proteins on the voltammetry of test species and stabilized functionalize nanoparticle catalysts under hydrodynamic conditions.

The Influence of Growth Conditions on the Annealing of Irradiation Induced EH&lt;sub&gt;6,7&lt;/sub&gt; Defects in 4H-SiC

Nitrogen doped 4H-SiC epitaxial layers grown by hot-wall chemical vapor deposition were investigated by deep level transient spectroscopy after irradiation with 6 MeV electrons or 1.6 MeV protons. The influence of silane and propane flows used during the epilayers growth on the behaviour of radiation induced EH6,7 levels is studied. Samples grown under different conditions were investigated: 1 sample grown in steps of different C/Si ratio obtained by changing the propane flow only; 1 sample grown in steps of different C/Si ratio obtained by changing the silane flow only; 2 samples grown with a C/Si ratio of 1.5 but with different flows of propane and silane. These investigations revealed that the low thermal stability of EH6,7 (the defects anneal out at temperatures as low as 750K) is due to the magnitude of silane flow used during the growth irrespective of the C/Si ratio. A possible structure of the EH6,7 defect is discussed.