Flexural Properties of Phenolic Resin Reinforced with Glass Powder: Preliminary Results
TL;DR: In this article, a research centre on composites, University of Southern Queensland (USQ), filled phenol formaldehyde with glass powder to increase its flexural strength for civil and structural applications.
Abstract: Phenol formaldehyde was filled with glass powder to increase its flexural strength for civil and structural applications by a research centre on composites, University of Southern Queensland (USQ). To reduce costs, the centre wishes to fill in as much glass powder as possible subject to maintaining sufficient strength of the composites in structural applications. This project varies the percentage by weight of the glass powder in the composites from 5 to 30%. The specimens were then subjected to flexural tests. The results show that composite with 17.5% by weight of the glass hollow spheres produces the highest flexural strength and flexural modulus combined with a very good fluidity for casting. The maximum flexural strain was achieved with pure resin.
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TL;DR: Inverse gas chromatography results showed that the sisal fibers and the tannin-phenolic thermoset have close values of the dispersive component and also have predominance of acid sites (acid character) at the surface as mentioned in this paper.
Abstract: A tannin–phenolic resin (40 wt% of tannin, characterized by 1 H nuclear magnetic resonance (NMR) and 13 C NMR, Fourier transform infrared, thermogravimetry, differential scanning calorimetry) was used to prepare composites reinforced with sisal fibers (30–70 wt%). Inverse gas chromatography results showed that the sisal fibers and the tannin–phenolic thermoset have close values of the dispersive component and also have predominance of acid sites (acid character) at the surface, confirming the favoring of interaction between the sisal fibers and the tannin–phenolic matrix at the interface. The Izod impact strength increased up to 50 wt% of sisal fibers. This composite also showed high storage modulus, and the lower loss modulus, confirming its good fiber/matrix interface, also observed by SEM images. A composite with good properties was prepared from high content of raw material obtained from renewable sources (40 wt% of tannin substituted the phenol in the preparation of the matrix and 50 wt% of matrix was replaced by sisal fibers).
67 citations
TL;DR: In this paper, new hollow glass microspheres and carbon nanotubes (CNTs) were added to an epoxy matrix to obtain some new, different epoxy composites to compare with a traditional one.
16 citations
TL;DR: In this article, the thermal properties of sawdust reinforced vinyl ester resin composites post-cured in microwaves have been measured and evaluated with a view to benefit the civil and construction industry as the materials used in the industry.
Abstract: The mechanical properties of sawdust reinforced vinyl ester resin composites post-cured in microwaves have been measured and evaluated in earlier studies. This basic but critical and important data have caused interests in the relevant industry in Australia. This study is therefore carried out to measure and evaluate the thermal properties of the composites with a view to benefit the civil and construction industry as the materials are used in the industry. The original contributions of this paper are that samples post-cured in microwaves, irrespective of the percentage by weight and particle size of sawdust, have higher glass transition temperatures than their counterparts post-cured in an oven; these imply that the stiffness of the samples post-cured in microwaves are higher than their peers. From previous study, it was discovered that the fracture toughness increased with increasing particulate loading. These properties are vital in civil engineering applications because civil structures need composites with high rigidity and fracture toughness. It is hoped that the discussions and results in this work would not only contribute towards the development of sawdust reinforced vinyl ester composites with better material properties, but also useful for the investigations of thermal and mechanical properties in other composites.
7 citations
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TL;DR: In this article, the effects of particle size, particle/matrix interface adhesion and particle loading on the stiffness, strength and toughness of such particulate polymer composites are reviewed.
Abstract: There have been a number of review papers on layered silicate and carbon nanotube reinforced polymer nanocomposites, in which the fillers have high aspect ratios. Particulate–polymer nanocomposites containing fillers with small aspect ratios are also an important class of polymer composites. However, they have been apparently overlooked. Thus, in this paper, detailed discussions on the effects of particle size, particle/matrix interface adhesion and particle loading on the stiffness, strength and toughness of such particulate–polymer composites are reviewed. To develop high performance particulate composites, it is necessary to have some basic understanding of the stiffening, strengthening and toughening mechanisms of these composites. A critical evaluation of published experimental results in comparison with theoretical models is given.
2,767 citations
TL;DR: In this paper, an epoxy silane coupling agent on the glass fibre in a glass/phenolic composite resulted in a significantly higher interlaminar shear strength (ILSS) and flexural strength than an aminosilane.
Abstract: Low-temperature acid-cured resole phenolic resins and glass-fibre-reinforced polymer (GRP) composites containing resole matrices are inherently fire-retardant materials that evolve low levels of smoke and combustion products in a fire. The mechanical properties, particularly interlaminar shear strength (ILSS), of glass/phenolic composites are low compared with those of glass/polyester composites, and this is discussed in terms of the compatibility between the reinforcing fibres and resin matrix, the influence of the phase-separated water microdomains which result in voids in the phenolic matrix, and the resin strength. An epoxy silane coupling agent on the glass fibre in a glass/phenolic composite resulted in a significantly higher ILSS and flexural strength than an aminosilane, which is recommended for use with thermally cured glass/phenolic composites, or a methacrylyl-functional silane, which is preferred for use with glass/polyester and glass/vinyl ester composites. The ILSS of the glass/phenolic composites decreased after exposure to water at elevated temperature; this is attributed to a deterioration of the interfacial region and is independent of the silane coupling agent used on the glass reinforcement.
62 citations
TL;DR: In this article, three groups of phenolic matrix composites were investigated: powder (glass, ceramic and carbon black) filled phenolic resin, graphite fiber reinforced phenolic resins, and graphite fibre/glass particle reinforced (G/g-P) composites.
Abstract: Three groups of phenolic matrix composites were investigated in this study: (1) powder (glass, ceramic and carbon black) filled phenolic resin, (2) graphite fiber reinforced phenolic resin, and (3) graphite fiber/glass powder reinforced phenolic resin. In the first part of this study, the three-point bending test method was used to measure the mechanical properties of these composites. The graphite fiber/10 wt% glass powder filled phenolic composite exhibited higher flexural strength and flexural modulus than the unfilled graphite fiber reinforced phenolic resin composite. Samples were examined using an optical microscope and scanning electron microscope (SEM). The amount of wedge-shaped voids could be greatly reduced by introducing the glass powder to the phenolic resin. The filler acted to delay crack propagation by deflecting the crack such that it propagated along the interface of the carbon fiber and the matrix. In the second part of this study, the effects of temperature (up to 500°C) on the mechanical properties of graphite fiber reinforced phenolic (G/P) and graphite fiber/glass particle reinforced (G/g-P) composites were investigated. The results show that G/g-P composites exhibited higher flexural strength and flexural modulus than the G/P composites at exposure temperatures up to 360°C. The thermal stresses induced due to heating in the composite were analyzed by the Thick-Cylinder Model (TCM) and Selsing's model. At temperatures above 300°C, tensile thermal stresses tended to promote the formation of micro-cracks at the fiber/matrix interface, which degraded the properties of G/P composites. Debonding between the glass particle and the matrix occurred at a temperature above 360°C, which greatly degraded the properties of G/ g-P composites.
62 citations
Journal Article•
TL;DR: In this paper, Lapinus fiber reinforced structural composites with randomly distributed fibres in a plane were studied via three point bend tests and SAE J661a friction tests, and a positive correlation was observed between flexural moduli and fibre volume fraction.
Abstract: The flexural and frictional properties of Lapinus fibre-reinforced phenolic friction materials at different fibre loadings have been studied via three point bend tests and SAE J661a friction tests, respectively. A positive correlation was observed between flexural moduli and fibre volume fraction for these materials. The empirical constant in the Halpin-Tsai model is about 0.22 for this material compared with 0.375 for some other fibre reinforced structural composites with randomly distributed fibres in a plane. The coefficient of friction of the composites fell in the range of 0.1 to 0.5 and the minimum friction was found in materials with volume fraction of 0.024 to 0.05 fibre loading. These two fibre loadings also showed a more stable coefficient of friction than the other fibre loadings did over the wide range of temperatures in the second fade test. A minimum volumetric wear was found in the material with 0.05 fibre loading during the wear test. The wear mechanisms at different fibre loadings have also been discussed.
23 citations