Papers by Keyword: Phenolic Resin

Abstract: Phenolic resins are thermosetting material that is commercially produced via the condensation process of phenol and formaldehyde. However, due to the usage of petro-based materials in the production of phenolic resins, several approaches have been made, and one of the approaches is by substituting the raw materials, especially phenol, with lignin. In this study, acetosolv lignin was used to produce lignin-formaldehyde (LF) and compared with phenol-formaldehyde (PF) resin. The resinification reaction was conducted at 85 °C for 4h. The functional group, curing behavior and the shear strength of the resins was analyzed using FTIR-ATR, DSC and Universal Testing Machine, respectively. The formation of PF and LF resins was confirmed by the presence of the methylene bridge functional group at 1460 cm^-1. The curing curve shows the shift of LF resin to a higher temperature compared to the PF resin. Furthermore, the evaluation of bonding strength shows that LF resin possesses a low shear strength compared to PF resin. However, both resins pass to be adhesives for the manufacture of plywood panels based on standard JIS K-6852.

Abstract: The present research reports the influences of variant phenolic resin concentrations on the thermo-mechanical and ablation characteristics of ethylene propylene diene monomer (EPDM) elastomer. Backface temperature acclivity (BTA), charring rates, and insulation indexes were executed for the fabricated composite specimens. It was noticed that BTA was enhanced while linear/radial/mass ablation rates were significantly diminished with increasing concentration of phenolic resin (PR) in base matrix (elastomeric polymer). The composite (30wt%PR/EPDM) has 25% high thermal endurance compared to virgin EPDM composite. Thermal conductivity was increased with increasing PR to EPDM ratio. PR incorporation has remarkably enhanced the ultimate tensile strength of the EPDM elastomer. An efficient improvement in elastomeric hardness was also observed with increasing PR contents in EPDM matrix. Scanning Electron Microscopy (SEM) results showed the porosity generation and polymer melting during ablation.

Abstract: Hot molding is one of the most important processes for the manufacture of friction materials in automotive brake systems. That is because it has direct impacts on the physical and mechanical properties. Porosity and compressibility affect properties like brake vibration. This then affects brake noise. Therefore, the objective of this work was to study the effects of hot molding conditions on the porosity and compressibility of friction materials. The crucial parameters; molding pressure, temperature and holding time were varied in the hot molding process. Porosity and compressibility were investigated and analyzed in relation to the manufacturing parameters using statistical analysis. The results and the correlation coefficients (R²) show that molding pressure and holding time are the most significant effects on porosity and compressibility. They indicate that the hot molding parameters can adequately explain porosity and compressibility.

Abstract: Phenolic resin can be formed from the powder of cashew nut shell waste (CNSW), phenoland sulfuric acid. In this study, the powder of CNSW, phenol and sulfuric acid were mixed withvarious ratios in the reactions for formation of phenolic resin at 150oC during 180 minutes. Theformation of phenolic resin was evaluated by the non-reactive residue of CNSW, which was used tofind the best composition. The molecular mass and the separation of the constituents in the sampleswere also identified by gel permeation chromatography (GPC). The samples with optimizedcomposition were characterized molecular structures and functional groups using Fourier transforminfrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR).

Abstract: In this paper, the modified phenolic resin-based adhesive was prepared by dissolving different components. After low temperature curing, SiC samples were bonded by the binder. The samples were treated at different temperatures (400°C, 800°C, 1200°C, 1500°C) under an inert atmosphere. The bonding strength of samples was tested after heat treatment at room temperature. The results showed that the bonding strength of the B₄C modified phenolic resin (PF) based adhesive is the highest. When the heat treatment temperature was above 1200°C, the bond strength increased with the additive amount of boron carbide at room temperature. The microstructures of the samples were observed by optical microscope and scanning electron microscope. The effects of the modified filler and heat treatment temperature on the bonding strength of the phenolic resin based adhesive were investigated. The bonding strength of boron carbide-modified phenolic resin-based binder was tested under high temperature. It was found that the bond strength at high temperature was lower than that at room temperature, and the bond strength decreased with the increase of temperature.

Abstract: In this paper, reaction bonded silicon carbide (RBSC) was prepared by silicon infiltration with silicon carbide and carbon black as raw materials. The effects of the mixing methods with different binders on density of green body were compared. The influences of phenolic resin content, forming pressure, sintering temperature of samples on the performance of green body, mechanical microstructure and properties of RBSC were studied. The result shows that the density of green body by wet-mixing with alcohol-soluble binder (phenolic resin) was much better than semi-dry-mixing with usual water-soluble binders (polyvinyl alcohol and carboxy methyl cellulose sodium). The bending strength of green body prepared with phenolic resin at the content of 12 wt.% reached to the maximum value. The density of RBSC increased generally with phenolic resin content increasing at temperature range from 1550 to 1650 °C. The bending strength of RBSC increased firstly and then decreased with phenolic resin content increasing at a sintering temperature of 1600 °C. The optimum condition for fabricating RBSC was sintering at 1600 °C with 12 wt.% phenolic resin, the density, porosity and bending strength of the obtained RBSC was 3.06 g·cm^-3, 0.05% and 370±54 MPa, respectively.

Abstract: Carbon fibre reinforced carbon composites (C/C) are characterised by their excellent thermal, chemical and mechanical properties. The intrinsic porosity and fibre reinforcement grant them an excellent damage tolerance. The production of complex structures is time consuming and very expensive. An innovative approach to this topic is the integration of simple geometric ceramic composite materials within complex polymer structures. The motivation of this contribution is to investigate the influence of hexamethylenetetramine as hardener (hardener content: 4, 8, 12 and 16 %) and curing parameters (tempered and non-tempered) on the microstructure and mechanical properties of the porous C/C composites. During the course of this contribution, selected carbon fibre reinforced polymer (CFRP) composites with different porosities were produced while adjusting the resin or hardening agent-ratio, as well as the processing parameters. Subsequent to the curing of the CFRP samples, porous C/C composites were produced by means of a pyrolysis process. The final part of the contribution is comprised of the microstructural analysis by light microscopy and the explanation of the flexural strengths, by utilising a “three-point-bending test”.

Abstract: In this work, the improvement of thermal and ablative properties of the phenolic resin by the addition of silicon carbide (SiC) and montmorillonite (MMT) were studied. The phenolic composites were fabricated by hot compression. The thermal stabilities, mechanical properties and ablative properties of the neat phenolic resin and the SiC/MMT phenolic composites were examined using a Lloyd universal testing machine, thermogravimetric analysis (TGA) and ablation tests (an oxyacetylene torch), respectively. Mass ablation rates were measured after flame exposure. The results showed that SiC/MMT provided the higher thermal stabilities and lower ablation rates to the phenolic resin.

Abstract: This research aims to study the effect of the functionalization of the multiwall carbon nanotubes (MWCNTs) on the mechanical property improvement of phenolic composites for bipolar plate applications in proton exchange membrane fuel cells (PEMFC). The MWCNTs were oxidized by strong acid and silanized by silane coupling agent in order to enhance the interfacial adhesion between the MWCNTs and matrix and were used as reinforcement in the phenolic composites. The silanized MWCNTs was found to improve the mechanical properties of the composites; however, they caused the decrease of electrical conductivity due to the wrapping of the MWCNTs with non-conductive silane molecules. Nevertheless, the conductivity of more than 100 S/cm is maintained to meet the DOE requirement of materials for use as bipolar plates.

Abstract: Modified phenolic resin-based adhesive is used as the high temperature binder, which is prepared by adding different additives, zirconium diboride, boron carbide as modified fillers, and H3PO4, AlPO4 as curing agents. The influence of additives for phenolic resin-based adhesive on bond property of SiC ceramic was studied after heat treatment at 400 oC , 800 oC , 1200 oC , 1600 oC. The results show that the improvement of adhesion property for curing agents is not obvious. B4C modified phenolic resin-based adhesive exhibits better adhesion performance than ZrB2 modified phenolic resin-based adhesive. Bonding property of B4C modified phenolic resin-based adhesive is best at 1200 oC , and the adhesive strength is reduced above 1200 oC along with rising of the heat treatment temperature. Because of the formation of shrinkage micro-defects of phenolic resin, bond strength exists a sharp decline after 1200 oC heat treatment.