Silane Treatment Research Articles

Fully bio-based agro-waste soy stem fiber reinforced bio-epoxy composites for lightweight structural applications: Influence of surface modification techniques

Present days, the world needs more sustainable and eco-friendly materials to replace and reduce the use of synthetic materials to prevent pollution. In this regard, the agro-waste after soy cultivation is identified as a sustainable resource of raw material and can be used as reinforcement in polymer matrices. The current research focuses on the effect of surface modification in agro-waste soy stem fibers and their composites. The fibers were collected, cleaned, processed, and subjected to chemical treatment. The chemical analysis showed an increased ratio of cellulose % in the soy fibers when compared to untreated fibers. The silane treatment showed improvement in the thermal stability of soy fibers and reduced the coefficient of thermal expansion in silane treated composite. The X-ray diffraction test shows that there was a 22.57% increase in the crystalline index due to oxalic acid treatment. The chemical treatments also influenced the crystal size of the soy fibers which had direct impact on the water absorption nature of the developed composites. The mechanical performance of the composites is evaluated through tensile, flexural, impact, and interlaminar shear strength according to the ASTM. The silane treated fibers in the composites showed a better mechanical performance compared to untreated and other chemical treatment. However, oxalic acid treatment showed better mechanical performance when compared to traditional NaOH treatment. The increase in wettability nature influenced the mechanical strength and water-resistant nature of the composite. The complete results state that the silane treatment on the soy stem fiber showed the best performance followed by the oxalic acid and alkali treatment when compared to the raw fibers. From the results, it is observed that the Agro-waste soy fiber is a sustainable and renewable resource of raw material that can be used as reinforcements in polymer matrices for lightweight structural applications.

Sustainable Characterization of Silane Treated and Untreated Psidium Guajava Stem Natural Fibers Based Automobile Brake Pads

ABSTRACT The present study deals with the extraction and characterization of untreated and silane-treated natural fibers from stems of Psidium guajava (Guava plants) for automobile brake pad applications. The extraction of fibers was done from the Psidium guajava plant stems by the retting process followed by silane treatment. The untreated and silane-treated Psidium guajava fibers were analyzed for chemical, physical, and crystalline properties. These fibers were used in the brake pad composite developed using conventional industrial processes and analyzed for various performance characteristics as per industrial standards. The tribological performance of the developed brake pads was measured using the Chase test following IS 2742 Part-4 of 1994 or SAE J661:2012. It was found that silane-treated Psidium guajava fibers had acrystalline index of 42%, while it was 27% for untreated Psidium guajava fibers. The brake pads developed using silane-treated Psidium guajava fibers showed ahigher hardness of 99, while it was 90 for untreated Psidium guajava fibers proving better results upon the usage of silane-treated Psidium guajava fibers in brake pads. Scanning Electron Microscope studies of Chase tested brake pads that elucidated the plateau formations and back transfers.

Avaliação dos tratamentos de superfície na resistência de união entre dois pinos de fibra de vidro e uma resina composta

Introduction: The aim of this study was to evaluate the influence of different surface treatment methods on glass-fiber posts relative to their bond strength with the composite resin and to evaluate the types of failures that occurred. Materials and Methods: Thirty-six posts from WhitepostDC (FG group) and Exacto Conics (AG group) were used, divided into: Control FG-1 and AG-1 groups – application of silane, according to manufacturers’ specifications; FG-2 and AG-2 groups – conditioning with 10% hydrogen peroxide and silanization; FG-3 and AG-3 groups – aluminum oxide blasting for 10 seconds and silaniza-tion. The composite resin was added in 2-mm increments, each increment was photopolymerized for 40 seconds, until the entire length of the matrix was filled. Then, the assembly (fiber post and composite resin) was sectioned into three portions (cervical, middle and apical) (n = 18). Samples were submitted to the bond strength analysis by a push-out test in a Universal Testing Machine and the failure types were evaluated with a 30 × magnification with an optical micro-scope. Data were submitted to the analysis of variance, the Tukey test, and the chi-square test with a 5% significance level. Results: For AG groups, the treatment with silane (23.10 MPa) resulted in statistically greater bond strength than the treatments with peroxide (17.19 MPa) and blasting (16.28 MPa). It was found that the bond strength was statistically higher in the middle third (21.16 MPa) than in the apical third (12.55 MPa) for the peroxide treatment. The mixed-type failure had the highest prevalence (57.01%). Conclusion: Silane treatment showed statistically greater bond strength values, when the Angelus brand was tested.

Effect of silane modified smectite clay on the hydration, intercalation of PCE superplasticizers, and mechanical strength of cement composites

Clays have emerged as potential partial replacements for cement, allowing for a reduction in global CO2 emissions without sacrificing strength. However, smectite clay minerals such as montmorillonite (MMT) have dramatic shrink and swell properties, which hampers the consistency of cement paste and generates micro cracks at the interface. In addition, MMT shows strong adsorption and intercalation of poly carboxylate-based superplasticizer because of numerous active sites in their interlayer, which affects the properties of fresh and hardened concrete. In this study, the interlayer alkali cation exchanged by (3-Aminopropyl) triethoxysilane. Silane treatment increased the interlayer spacing and hydrophobicity of MMT. In addition, the shrink and swell index showed 84 % reduction. Cement pastes with silane-modified clay showed needle shaped hydration products and less portlandite content. The mortar fabricated with silane treated MMT showed improved consistency and higher mechanical strength.

Improvement of commercial carbon/high density polyethylene conductive composite plate with an aqueous silane treatment for soluble lead flow batteries

In this paper, γ-aminopropyltrimethoxysilane is used to improve the properties of commercial carbon/HDPE conductive composite plate. The surface chemistry of carbon fillers are characterized using X-ray Photoelectron Spectroscopy. Carbon fillers (natural flake graphite, carbon black and short carbon fiber) are treated by hydrolysis of silane to improve their compatibility with polyethylene. High-speed shearing and two-screw rotating are performed to distribute carbon fillers into the matrix. Finally the carbon/HDPE conductive composite is prepared using a hot press. Compared with the sample without silane treatment, the conductivity and flexible strength of composite plate can be enhanced by addition of hydrolyzed γ-aminopropyltrimethoxysilane, especially treated with the concentration of 2 wt% aqueous silane solution. The conductivity of NFG57.5%CB11.5%SCF4%/HDPE27% composite increases from 41.2 S/cm to 82.6 S/cm, and its bending strength from 49.3 MPa to 65.6 MPa. The sample treated with the concentration of 2 wt% silane exhibits a better electrochemical corrosion resistance than other samples treated with 0 wt%, 1.0 wt%, 3.0 wt% and 4.0 wt% silane. As the electrode of lead methanesulfonate flow batteries, the conductive composite treated with 2 wt% silane has the highest energy efficiency than other sample since due to its high conductivity, which is confirmed by electrochemical impedance spectroscopy.

Alkali and epoxy-silane surface modified pine cone flour reinforced polypropylene/poly (lactic acid) blend: viscoelastic and morphological characterization

The main aim of this work was to study the effect of surface modification on the characteristics of local Pine cone flour (PCF) and on the interfacial adhesion in polypropylene/poly(lactic acid)/Pine cone (PP/PLA/PCF) blend composites. For this purpose, alkali, silane, and a combination of both treatments were applied to impart a hydrophobic character to the PCF flour. Treated and untreated flour samples were subjected to several investigations, such as Fourier transform infrared spectroscopy (FTIR), X-rays diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The results revealed a reduction in the contents of hemicellulose, lignin, and wax upon treatments, as evidenced by the disappearance or reduction in the intensity of some characteristic bands, such as that related to the carbonyl groups (C = O) at 1730 cm−1. Also, the treatments were seen to enhance the surface roughness, thermal stability, and crystallinity of the flour, as a result of greater exposure to cellulose. The dynamic mechanical analysis (DMA) showed that the storage modulus of blend composites with modified flour is higher than that of the unfilled blend. In this sense, the Alkali-GPTMS 5%-PCF composite exhibited a higher value by 20, 9, and 16% compared to Untreated-, Alkali-, and GPTMS-PCF composites, respectively. Surface treatments increased the interfacial adhesion, as it was perceived from the decrease in the height of tan δ peak owing to PP/PLA/PCF blend composites. Finally, the combination of both silane and alkali treatments was found to provide composites with a more cohesive microstructure owing to the improved compatibility.

Effect of Silane-Containing Universal Adhesives on the Bonding Strength of Lithium Disilicate.

The purpose of this study was to investigate the effect of silane-containing universal adhesives on the bonding strength of lithium disilicate. Two-hundred-and-forty lithium disilicate blocks were divided into 16 groups according to the following surface treatments: hydrofluoric acid (HF)-treated or not, silane-treated or not, and the type of universal adhesive used (All-Bond Universal (ABU); Prime & bond (PB); Clearfil Universal Bond (CU); Single bond Universal (SBU)). After surface treatment, resin discs were bonded to each lithium disilicate using dual-cure resin cement. Bonded specimens were stored in distilled water for 24 h and then subjected to microtensile bond strength (μTBS) test. Failure modes were examined under stereomicroscope. Microscopic observation of bonded interfaces was analyzed using scanning electron microscopy. The μTBS data were statistically analyzed. Regardless of silane treatment, all groups treated with HF showed higher bonding strengths compared to those that were not treated with HF (p < 0.05). In groups treated with HF, the bonding strength increased after silane application (p < 0.05) except PB and CU (p > 0.05). Adhesive failures were dominant in all groups, but some mixed failures were observed in ABU treated with HF and silane. While most of the specimens that were not treated with silane after HF application only showed loose bonding between the ceramic and resin cement due to partial gaps, the specimens treated with silane application after HF showed a tight ceramic–resin interface. In conclusion, the silane in universal adhesives did not effectively improve the bonding strength between lithium disilicate and resin cement.

Contribution to a Circular Economy Model: From Lignocellulosic Wastes from the Extraction of Vegetable Oils to the Development of a New Composite.

The present works focuses on the development of a novel fully bio-based composite using a bio-based high-density polyethylene (Bio-HDPE) obtained from sugar cane as matrix and a by-product of extraction of chia seed oil (CO) as filler, with the objective of achieving a circular economy model. The research aims to revalorize an ever-increasing waste stream produced by the growing interest in vegetable oils. From the technical point of view, the chia seed flour (CSF) was chemically modified using a silane treatment. This treatment provides a better interfacial adhesion as was evidenced by the mechanical and thermal properties as well as field emission scanning electron microscopy (FESEM). The effect of silane treatment on water uptake and disintegration rate was also studied. On the other hand, in a second stage, an optimization of the percentage of treated CSF used as filler was carried out by a complete series of mechanical, thermal, morphological, colour, water absorption and disintegration tests with the aim to evaluate the new composite developed using chia by-products. It is noteworthy as the disintegration rate increased with the addition of CSF filler, which leads to obtain a partially biodegradable wood plastic composite (WPC) and therefore, becoming more environmentally friendly.

Effectiveness of Silanization and Plasma Treatment in the Improvement of Selected Flax Fibers' Properties.

The study investigated the effectiveness of the combination of chemical and physical methods of natural fibers’ modification. The long flax fibers were subjected to various types of modification. These were silanization, plasma modification and a combination of these methods. For the silanization process, two types of silanes were used: amino- and vinylsilane. The application of structurally different compounds allowed us to acquire knowledge about the effect of the modifier structure on its properties. Various properties of flax fibers were investigated, comparing the results before and after different modification processes. The flammability of prepared samples were tested by pyrolysis combustion flow calorimeter (PCFC). In the effect of the natural fibers’ modifications, flammability was reduced even by 30%. The thermal stability of modified fibers increased. The FTIR tests of the gases released during thermal degradation of the tested fibers allowed us to determine the important compounds and prove a lower degree of flax-fiber decomposition after modification. Flax fibers were also tested to evaluate their physical properties (linear mass, average diameter, aspect ratio and hygroscopicity). Changes in surface morphology were observed by scanning electron microscope (SEM). The properties of natural fibers improved significantly, thus contributing to an increase in their suitability for the use in composites.

Organic Non-Wettable Superhydrophobic Fullerite Films.

A long-standing quest in material science has been the development of non-wettable superhydrophobic films based on a single organic material, without the requirement of fluorination or silane treatment. Here, such films and coatings, which are developed using colloidal gels of fullerite C60 and C70 nanocrystals, are described. It is illustrated that despite the high surface energy of these van der Waals molecular crystals their gelation can create films having self-affine fractal surfaces with multiscale roughness. Water droplets on resulting surfaces of fullerite films bead like a pearl resting in a Fakir state with contact angle exceeding 150°. The films are extremely water repellent and non-wettable; when submerged in water they stay dry up to 3 h even at a water depth of two feet and exhibit the plastron effect. A series of experiments are presented to provide comprehensive inspection of water droplet dynamics on these films. These include rolling, bouncing, squeezing, freezing, melting, evaporating; along with acidic and alkaline tests. Non-wettable films of such materials are unique as fullerites get photosensitized instantaneously generating extremely high yields (≈100%) of singlet oxygen (1 O2 ) that can destroy viruses and bacteria; thereby enabling their use in rheology, water purification, and medicinal devices.

Long-term surface modification of PEEK polymer using plasma and PEG silane treatment

Despite the several advantages of the Polyetheretherketone (PEEK) polymer, its wide application is limited due to its hydrophobic nature and poor surface adhesion performance. The plasma treatment can effectively transform the hydrophobic surface to hydrophilic. However, their effects are for a short duration, and the modified surfaces gradually lose their wetting and surface adhesion properties. In this work, we have reported a combined effect of plasma and PEG Silane treatment for permanent hydrophilic modification and improved adhesion strength of PEEK surfaces. The time-dependent changes in the contact angles, XPS, and ATR-FTIR spectra results were carefully recorded to investigate the surface properties of the modified surfaces. It was observed that the functional groups and polar component of surface energy played a pivotal role in long-term modification of PEEK surfaces. The Plasma and PEG Silane treated PEEK surface retained a very low contact angle and high content of hydroxide, carboxylic acid, and peroxide groups as compared to the plasma-treated PEEK surfaces. The lap shear test confirms the long-term effects of Plasma and PEG Silane treatment on adhesion properties with high bonding strength after 48 days of sample storage, which was dropped for Plasma treated surface just after 7 days of storage.

Establishing selection criteria of water repellent sandy soils for use in impervious layer of engineered slope

In this study, the selection criteria of water-repellent sandy soils for use in the impervious layer of engineered slopes were examined. First, the hydrophobization of six kinds of sandy soils was performed via the silane treatment. Laboratory experiments to assess hydrophobicity and water-shielding performance—namely the water drop penetration time (WDPT) test, the contact-angle measurement test, and the water infiltration head (WIH) test—were conducted. Based on the required thickness and the required particle number of water-repellent soils, the mean particle sizes of sandy soils that achieved acceptable water-shielding performance were determined. It was found that a Cc value of less than 1.0 or a D40 value of less than 2.0 mm allowed good water-shielding performance in sandy soils. Lastly, some of the measured WIH values agreed with the results estimated by the capillary rise model, and the application of the particle size to this model was discussed.

Comparison of Chemically Treated&lt;i&gt; Luffa cylindrica&lt;/i&gt; Using Fourier Transform Infrared Spectroscopy (FTIR) and Thermal Analysis

The world as we probably are aware of is confronting a major problem known as environmental pollution, therefore, leading to global warming. Researchers from around the world have been focusing on green composites to improve the general effect of polymer pollution leading to environmental pollution. This need has constrained numerous researchers to concentrate on making composites utilizing natural fibers and biodegradable polymers. Moreover, natural fibers are cheaper to purchase, have great mechanical properties, biodegradability and demand lower amount of production energy. This paper focuses on one of the natural fibers known asLuffa Cylindrica(LC). Chemical surface treatments are necessary in order to get the best adhesion possible between the polymer and fiber which leads to better mechanical properties. Therefore, in this paper sodium hydroxide, silane and acetylation chemical surface treatments were performed. Furthermore, with the help of Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA) and Derivative Thermogravimetry (DTG) it was predicted that all the chemical surface treatments were successful. With the help of the results it was predicted that these specific chemical surface treatments showed removal of hemicellulose and lignin. Furthermore, with the help of thermal analysis it was predicted that silane treated samples showed highest amount of thermal resistance whereas, acetylated samples predicted lowest.

Investigation of alumina doped 45S5 glass as a bioactive filler for experimental dental composites

AbstractThis study aimed to investigate the effects of inclusion of Al2O3‐doped bioactive glass (BG) and silane treatment on physical properties and bioactivity behavior of resin‐based experimental dental composites (EDCs). Melt‐derived 45S5 BG and alumina doped 45S5 BG were prepared and incorporated into EDCs with and without silanization. EDCs prepared were subjected to three‐point bending, microhardness, water sorption (WS), solubility (S), and bioactivity tests. Using non‐silanized Al2O3‐doped BG in EDCs resulted in improved flexural strength (FS), flexural modulus (FM), and microhardness and decreased bioactivity compared to EDCs containing non‐silanized BG. There was no significant difference (p &lt; 0.05) between WS and S results of non‐silanized glass containing EDCs. Using silanized BG and Al2O3‐doped BG resulted in improved FS and FM, decreased WS, S, and bioactivity. Addition of Al2O3‐doped BG as a possible bioactive filler to EDCs improved mechanical performance while slightly decreasing bioactivity compared to BG containing EDCs.

Improved Hydrophobicity of Macroalgae Biopolymer Film Incorporated with Kenaf Derived CNF Using Silane Coupling Agent.

Hydrophilic behaviour of carrageenan macroalgae biopolymer, due to hydroxyl groups, has limited its applications, especially for packaging. In this study, macroalgae were reinforced with cellulose nanofibrils (CNFs) isolated from kenaf bast fibres. The macroalgae CNF film was after that treated with silane for hydrophobicity enhancement. The wettability and functional properties of unmodified macroalgae CNF films were compared with silane-modified macroalgae CNF films. Characterisation of the unmodified and modified biopolymers films was investigated. The atomic force microscope (AFM), SEM morphology, tensile properties, water contact angle, and thermal behaviour of the biofilms showed that the incorporation of Kenaf bast CNF remarkably increased the strength, moisture resistance, and thermal stability of the macroalgae biopolymer films. Moreover, the films’ modification using a silane coupling agent further enhanced the strength and thermal stability of the films apart from improved water-resistance of the biopolymer films compared to unmodified films. The morphology and AFM showed good interfacial interaction of the components of the biopolymer films. The modified biopolymer films exhibited significantly improved hydrophobic properties compared to the unmodified films due to the enhanced dispersion resulting from the silane treatment. The improved biopolymer films can potentially be utilised as packaging materials.

Silane treatment of drop-on glass-beads and their performance in two-component traffic paints

In this research, the surface of drop-on glass beads (GBs) was first etched, then modified using 3- trimethoxy silyl propyl methacrylate (MS) and trimethoxy vinyl silane (VS) through a sol-gel process to improve GBs’ adhesion to the two-component methyl methacrylate-based traffic paints (known as cold plastic paints). The etching was conducted in acidic, neutral, and basic conditions. Acidic etching condition was selected for the further experiments considering the highest number of OH groups provided by etching reaction on the surface of GBs. The FTIR and 13C-NMR spectroscopy were utilized to characterize chemical composition, and Atomic Force Microscopy (AFM) was used to evaluate the surface roughness / topography of the pretreated and silane-treated GBs. The amount of silane coated on the surface of the GBs was determined using thermogravimetric analysis (TGA). The dispersion of silane compounds on the surface of the treated GBs was assessed using Energy Dispersive X-Ray Analysis (EDXA). Neat and silane-treated GBs were then sprayed on freshly applied cold plastic paint samples using a designed lab spray device. Optical microscopy was used to evaluate the proper embedment depth of the GBs onto the surface of the paint samples. The abrasion test was performed in dry and wet conditions to evaluate the adhesion strength of neat and silane-treated GBs to the paint surface in normal and rainy weather. The coefficient of retroreflected luminance (RL) and the luminance coefficient under diffuse illumination (Qd) were measured to characterize the night and day retroreflective performance of cold plastic paints containing treated and untreated GBs. The abrasion test results showed the least weight loss in the paint markings containing drop-on VS-treated GBs (VS.GBs) in comparison to neat and MS-treated GBs (MS.GBs). This was assigned to increase in adhesion strength and interfacial interactions between VS.GBs and the polymeric matrix. The measured values of RL and Qd also confirmed the excellent maintenance of drop on VS.GBs on the surface of the two-component traffic paints.

Effect of Silane Coupling Agent on Flexural Strength and Hardness of Wheat Straw Polystyrene Composites

In the present research work, the effect of silane treatment along with alkali treatment on flexural strength, flexural modulus, and hardness investigated. Wheat straw as a filler was added (5%, 10%, 15% and 20%) to polystyrene matrix to prepare wheat straw polystyrene composite. The wheat straw fibre was first treated with 20% NaOH and 1% silane coupling agent to prepare wheat straw polystyrene composite. The compounding process was carried out in twin-screw extruder and samples were prepared by the compression moulding process. There was an increase in flexural modulus (214%), flexural strength (44%), and hardness (28%) of composite with the addition of alkali and silane treated wheat straw fibre.

Impact of Silane Treatment on Characterization of Ipomoea Staphylina Plant Fiber Reinforced Epoxy Composites

ABSTRACT In this work, the influence of silane treatment on characterization of Ipomoea staphylina plant fiber composites reinforced with epoxy matrix are studied. The silane treated I. staphylina fiber reinforced composites (ISFRCs) are fabricated through hand layup and compression molding methods. The composites are subjected to characterization techniques, such as tensile strength, flexural strength, thermo-gravimetric analysis, differential scanning calorimetry, Fourier transform infra-red spectroscopy, X-ray diffraction studies, and field emission scanning electron microscopy analysis. Results revealed that the silane treatment has a significant influence on characterization of ISFRCs.

Effects of anodizing surface treatment on the mechanical strength of aluminum alloy 5083 to fibre reinforced composites adhesive joints

In this study, the anodizing process based on the use of tartaric sulfuric acid solution (TSA) was carried out on metal substrate to evaluate for the first time its effect on the adhesion strength and corrosion resistance of aluminium alloy (i.e., AA5083) to fibre (i.e., basalt or glass) reinforced composite adhesive joints for nautical applications. Furthermore, some TSA anodized samples were soaked in a NaOH solution to investigate the influence of this post-immersion step on the joint performances. With the aim to improve the fibre-matrix adhesion in the composite substrate thus further increasing the overall mechanical response of the joint, glass and basalt fibres were treated with a silane coupling agent solution. The corrosion behaviour of the aluminium alloy was studied by electrochemical techniques. Samples morphology was analysed by scanning electron microscopy, while the interaction between aluminium alloy substrate and epoxy resin was studied through contact angle analysis and resin uptake tests. The effectiveness of the silane treatment was examined by means of Fourier transform infrared spectroscopy and quasi-static tensile tests carried out on dry glass and basalt fabrics. The mechanical response of the resulting joints was evaluated by means of quasi-static tensile tests in accordance to ASTM D3528 standard.

Impact of Alkali and Silane Treatment on Hemp/PLA Composites’ Performance: From Micro to Macro Scale

This study investigated the effect of hemp fiber pretreatments (water and sodium hydroxide) combined with silane treatment, first on the fiber properties (microscale) and then on polylactide (PLA) composite properties (macroscale). At the microscale, Fourier transform infrared, thermogravimetric analysis, and scanning electron microscopy investigations highlighted structural alterations in the fibers, with the removal of targeted components and rearrangement in the cell wall. These structural changes influenced unitary fiber properties. At the macroscale, both pretreatments increased the composites’ tensile properties, despite their negative impact on fiber performance. Additionally, silane treatment improved composite performance thanks to higher performance of the fibers themselves and improved fiber compatibility with the PLA matrix brought on by the silane couplings. PLA composites reinforced by 30 wt.% alkali and silane treated hemp fibers exhibited the highest tensile strength (62 MPa), flexural strength (113 MPa), and Young’s modulus (7.6 GPa). Overall, the paper demonstrates the applicability of locally grown, frost-retted hemp fibers for the development of bio-based composites with low density (1.13 to 1.23 g cm−3).