The influence of silane coupling agent composition on the surface characterization of fiber and on fiber-matrix interfacial shear strength (original) (raw)
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Effect of Glass Fiber Surface Treatments on Mechanical Strength of Epoxy Based Composite Materials
Journal of Colloid and Interface Science, 2002
Sizing glass fibers with silane coupling agents enhances the adhesion and the durability of the fiber/polymer matrix interface in composite materials. There are several tests to determine the interfacial strength between a fiber and resin, but all of them present difficulties in interpreting the results and/or sample preparation. In this study, we observed the influence of different aminosilanes fiber coatings on the resistance of epoxy-based composite materials using a very easy fractographic test. In addition, we tried a new fluorescence method to get information on a molecular level precisely at the interface. Strength was taken into account from two standpoints: (i) mechanical strength and (ii) the resistance to hydrolysis of the interface in oriented glass-reinforced epoxy-based composites. Three silanes: γ -aminopropyltriethoxysilane, γ -Aminopropylmethyldiethoxysilane, and γ -Aminopropyldimethylethoxysilane were used to obtain different molecular structures at the interface. It was concluded that: (i) the more accessible amine groups are, the higher the interface rigidity is; (ii) an interpenetrating network mechanism seems to be the most important for adhesion and therefore to the interfacial strength; and (iii) the higher the degree of crosslinking in the silane coupling layer is, the higher the hydrolytic damage rate is. C 2002 Elsevier Science (USA)
Journal of Materials Science, 2008
In this study, effects of fiber surface treatments on mechanical behavior and fracture mechanism of glass fiber/epoxy composites were investigated experimentally. To change the composition of the glass and regenerate to the hydroxyl groups, activation pretreatment of heat cleaned woven glass fabric was performed using (v/v) HCl aqueous solution at different concentrations before silane treatment. The treatment of silanization of heat cleaned and acid activated glass fibers with c-glycidoxypropyltrimethoxysilane were performed. In this work, short beam shear test has been conducted to determine the performance of the acid treatment and the silane treatment in terms of the interlaminar shear strength. The silane coating on the heat cleaned glass fibers increased the interlaminar shear strength of the composite. However, the silane coating on the acid activated glass fibers did not improve the interlaminar shear strength of the composite. In addition, the strengths of the glass fabric specimens in tension and flexure were investigated. When the glass fibers are first treated with HCl solution and then with silane coupling agent, the tensile strengths of the composites decreased significantly. Scanning electron photomicrographs of fractured surfaces of composites were performed to explain the failure mechanisms in the composite laminates broken in tension.
Fibers
The increasing efforts aimed to design structures with reduced weight and better mechanical performances has led in recent years to a growing use of fiber reinforced polymer materials in several fields such as marine. However, these materials can be composed of chemically very different elements and, hence, may be difficult to joint. This research aims to improve the adhesion between a thermoplastic matrix of polyamide reinforced with short carbon fibers (PA12-CR) and a carbon fiber reinforced epoxy matrix (CFRP). Two different silane coupling agents, (3-Aminopropyl)trimethoxysilane (AM) and (3-Glycidyloxypropyl)trimethoxysilane (EP), were applied, through the spray deposition method, on the PA12-CR substrate to create a reactive layer between the adherents. Different deposition methods and coupling agents curing conditions were also investigated. The wettability of the PA12-CR surface as well as the chemical modifications induced by silane treatments were investigated through conta...
Effect of nanoclay addition on the fiber/matrix adhesion in epoxy/glass composites
Journal of Composite Materials, 2011
Various kinds of organo-modified clays were dispersed at different amounts in an epoxy matrix. After clay addition, the viscosity of the epoxy resin resulted still acceptable for a possible usage as matrices for fiber-reinforced composites. The formation of intercalated microstructures led to substantial improvements of the thermal (glass transition temperature) and mechanical (fracture toughness) properties of the epoxy matrix. E-glass fiber/matrix interfacial shear strength was evaluated by the single-fiber microdebonding method. The introduction of organo-modified clays led to the formation of a stronger fiber-matrix interface, with an increase of the interfacial shear strength of about 30%. Concurrently, the evaluation of the fiber/matrix contact angle revealed an improved wettability when organo-modified clays were added.
Chemistry of Materials, 1999
Microscopic dynamics of the interfacial layer and macroscopic mechanical properties of [3-(acryloxy)propyl]trimethoxysilane (APMS) at a polymer-silica interface were studied using NMR and three-point bending tests. Wide-line deuterium NMR studies of deuterium-enriched [3-(acryloxy)propyl]trimethoxysilane-d (APMS-d), showed that when chemically bonded to silica, the acrylic group of APMS moved rapidly at the interface with air, more slowly when coated with a poly(methyl methacrylate) (PMMA) overlayer, and slowest when copolymerized with methyl methacrylate. A two-component line shape was found for the coated composite and these were assigned to relative immobile and mobile surface groups. From three-point bend tests, the PMMA/glass-fiber composite, made from glass laminates treated with APMS, had almost two times the flexural strength of a composite made from glass laminates not treated with APMS. Electron micrographs of the fracture surfaces revealed that the untreated fibers were smooth, while those from the APMS-treated glass were rougher, indicating the presence of polymer at the interface.
Composite Interfaces, 2020
In this work, the surface of nano/micro-E-glass fibril (nGF) was modified with an amine silane coupling agent before applying as toughener for epoxy resin. The chemical structure and composition of silanized glass fibril (s-nGF) were also confirmed and compared with virgin nano/micro-glass fibrils. The curing reaction of epoxy samples with various s-nGF contents was performed at room temperature. Many characteristics of composite samples were also examined such as mechanical properties, fracture energy, thermal stability, and morphology. The experimental testing indicated that the s-nGF helps to improve the mechanical, thermal stability as well as the fracture energy of epoxy resin. The morphology observation also indicated that the s-nGF prevented the crack growth inside the epoxy matrix as the main reason of the enhancing fracture energy of epoxy resin with the presence of s-nGF.
Polymer Composites, 2009
In this work, the influence of the nature of the reinforcement surface on the interfacial morphologies developed in E‐glass fibers/polystyrene (PS)‐modified epoxy composites has been studied. Different surface modifications of the fibers were considered. In a complementary way, morphological analysis and nanoindentation measurements were carried out using atomic force microscopy to subsequently correlate the interfacial structure with the morphologies observed. In every composite, reaction‐induced phase separation happened with a morphology composed of PS‐rich domains immersed in an epoxy‐rich phase. However, depending on the surface modification of the glass fibers, different distributions of PS‐rich domains at the interfaces were obtained. The results were interpreted in terms of a gradual phase separation process because of stoichiometric gradients from the glass fibers surface to the matrix bulk caused by specific segregation of one of the components of the reactive epoxy mixtur...
Journal of Polymer Science: Polymer Physics Edition
The mechanical performances of fiberglass reinforced plastics (FRP) are quite different when the glass fibers are treated with vinyl (VS) and methacryl (r-MPS) functional silane coupling agents. We have studied the structural basis for this difference on the molecular level using Fourier transform infrared spectroscopy (FT-IR). A high-surface-area silica powder is used to study the coupling agent/matrix interface. Both VS and y-MPS can react with styrene a t the interface. However, when E-glass fiber is used as a substrate, only y-MPS polymerizes in the coupling agent interphase which consists of many layers of coupling agent molecules while the major portion of the VS does not polymerize in the interphase. The effect of glass surfaces, with and without a coupling agent, on the curing of the polyester resin has also been studied. Silane coupling agents participate in the curing of the polyester resin while untreated E-glass fiber surfaces inhibit the polymerization resulting in different structures from the bulk matrix.
Polymer Composites, 2014
Wiley Samper Madrigal, MD.; Petrucci, R.; Sánchez Nacher, L.; Balart Gimeno, RA.; Kenny, JM. (2015). Effect of silane coupling agents on basalt fiber-epoxidized vegetable oil matrix composite materials analyzed by the single fiber fragmentation technique. Polymer Composites. 36(7):ABSTRACT The fiber-matrix interfacial shear strength (IFSS) of biobased epoxy composites reinforced with basalt fiber was investigated by the fragmentation method. Basalt fibers were modified with four different silanes, (3-aminopropyl)trimethoxysilane, [3-(2aminoethylamino)propyl]-trimethoxysilane, trimethoxy[2-(7-oxabicyclo[4.1.0]hept-3yl)ethyl]silane and (3-glycidyloxypropyl)trimethoxysilane to improve the adhesion between the basalt fiber and the resin. The analysis of the fiber tensile strength results was performed in terms of statistical parameters. The tensile strength of silane-treated 1 Corresponding author: Tel.: 96 652 84 21; Fax: 96 652 84 33