Papers by Keyword: Phenolic Resin

Abstract: To improve the heat absorbed and scattered properties of quartz fiber tile, porous phenolic resin impregnated quartz fiber tile composite for ablator and thermal insulator was prepared by impregnating the quartz fiber tile with ethanol solution of phenolic resin, and then drying and cured. The phenolic resin impregnated quartz fiber tile ablative composite is a new heat protection composite material with lower density, lower heat conductivity and low mass ablation. It can be used as the widespread thermal protection system of the aero craft in the high heat flux, high temperature and extreme condition. The thermal property and ablation property of the composites were studied respectively. The ablation property of PICA was evaluated by the oxyacetylene ablation experiment. The microstructure morphology of specimen before and after ablation was viewed by SEM. The thermogravimetric analysis of the ablator was taken from room temperature to 800°C.

Abstract: Carbon nanotubes (CNTs) with 20-40 nm in diameter and several micro-meters in length were prepared through catalytic pyrolysis of phenol resin at 400-1000 °C under Ar atmosphere using nickel nitrate as a catalyst precursor. Microstructure and morphology of pyrolysed resin were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the onset and optimal growth temperatures of CNTs were 400 and 800 °C respectively. Moreover, the optimal weight ratio of Ni catalyst to phenol resin was 0.75%.

Abstract: In order to solve the problem that low thermal conductivity of the plastics for the heat of LED, SiC/Phenolic resin for the heat of LED were fabricated combining powder metallurgy. The effects of particles diameters, content and adding nanoparticles on thermal conductivity of the fabricated composites were investigated, the mechanical properties were also characterized. The experimental results showed that the materials were obtained, and the insulation performance of the fabricated SiC/Phenolic resin was higher than the industry standard one, the thermal conductivity reached 4.1W/(m·k)^-1. And the bending strength of the fabricated composites was up to 68.11MPa. The problem of low thermal conductivity of the material is expected to be solved. In addition, it is meaningful for improving LED life.

Abstract: Coconut coir husk (CCH) was chosen to extract it lignin due to high lignin content comparable with other natural fibre. The lignin was extracted and its utilization in production of phenolic resin was investigated. The percentage extracted lignin obtained in this studied was 38.1% which indicated the high yield of lignin. Two phenolic resins were prepared, which are phenol-formaldehyde resin and lignin-formaldehyde resin. The functional group present in the lignin and both phenolic resins were further analyzed using the Fourier Transform Infrared Spectroscopy (FTIR). The findings from the infrared spectra of the lignin-formaldehyde resin were similar to the phenol-formaldehyde resin. These indicate that lignin can be partially used as phenol in phenolic resin synthesis.

Abstract: In this study, unsaturated polyester resin (UP) is blended with resole type phenolic resin (PF) to develop a material with good flame retardancy. The UP/PF resin blends are expected to show good compatibility when compounded with natural fibers which in this research is kenaf fiber. The thermal properties were investigated by thermogravimetric analysis (TGA). The char yields of the UP/PF blends reinforced kenaf composite increased with PF content. The degradation temperature of the composite at 50% weight loss rose to 410.13°C as the PF content was increased to 40%. The result shows with additional of PF to UP resin enhance the thermal stability of the composite. Meanwhile the mechanical performance of UP/PF kenaf composite were evaluated and compared with neat UP and PF reinforced with kenaf fiber using tensile and impact testing. The mechanical properties of all resin blends at different mixing proportions slightly decrease by increasing the phenolic content but shown an improvement as compared to the PF kenaf fiber composite. The fracture surface morphology of the tensile testing samples of the composites was performed by scanning electron microscopy (SEM).

Abstract: Composite development is very intense to replace heavy and expensive metallic materials. One application of composite is a brake pad for vehicle. The composite for brake lining is consisted of various components which are divided into reinforcement, binder, friction modifier and filler. Composite in this study is made with variation in weight of graphite, NBR, fly-ash and phenolic resin. The hardness test was carried out to investigate the mechanical properties of the composite. Observation of the composite surface was carried out using SEM. The hardness test shows that an appropriate composition of the phenolic, fly-ash and NBR was result in high hardness value of fly-ash/phenolic composite.

Abstract: Phenolic resin modified with methylvinylcyclosilazanes (MVSZ) were prepared and their flame-retardant properties were investigated, and results exhibited that the Limited Oxygen Index (LOI) values increased with the content increasing of MVSZ, and the LOI reach to 40.8, when the content of MVSZ was 26.0%. The flame-retardant and mechanical properties of polyester fabrics reinforced phenolic resin modified with silazanes (PFMS) composites were measured, the results indicated that the LOI and flexural strength were enhanced compared with those of phenolic resins composites.

Abstract: SiC/SiC ceramics consist of silicon carbide fibres embedded in a silicon carbide matrix. As an alternative to classic CVI and PIP routes, Liquid Silicon Infiltration (LSI) was chosen as a technique with short process times to obtain composites with low porosity. Silicon carbide composites show good thermal shock resistance, a low coefficient of thermal expansion and excellent physical and chemical stability at elevated temperatures and are therefore regarded as promising candidates for various applications in jet engines and in power engineering. To build up the matrix, different phenolic resin based carbon precursors were infiltrated in fibre preforms and thermally cured, pyrolysed and siliconized. The aim is to obtain a high carbon yield during pyrolysis and to control the pore morphology in a way that the following liquid silicon infiltration leads to a complete reaction of the carbon matrix with silicon to SiC. The siliconization behaviour and conversion into SiC in dependence of pore morphology and chosen precursor is analysed.At the same time a functional fibre coating has to be developed which protects the fibres from liquid silicon and simultaneously provides a weak fibre matrix bonding. A LPCVD-SiN_x fibre coating has been chosen and is investigated in fibre composites especially in terms of protection and reactivity in different atmospheres during pyrolysis and siliconization.

Abstract: Fibre-reinforced ceramic composite materials offer excellent thermal, mechanical and chemical properties. Due to their intrinsic fibre structure and porosity, they offer a great damage tolerance. Therefore, they provide superb attenuation characteristics, as do polymer composites. The current compound systems consisting of ceramic components feature a rather low capacity for energy absorption in relation to their weight; this is a fact in dire need of a fundamental change. In regards to the development of new hybrid ceramic/polymer material compounds basic research of the material design and binding behaviour of the different components is necessary. The advantage of this development allows for a selective implementation of positive characteristics of one component in an integrated compound-system. This opens up completely new possible are-as of application, such as wear and tear resistant and chemically inert, energy absorbing elements for the construction of reactors or areas of medical technology. During the investigation, a few selected fibre-reinforced ceramic composite materials with a specific porosity were produced, while adjusting the amount of resin/hardening agent used, as well as modifying other parameters. This was followed by tests regarding the wetting with a polyurethane component. The characterisation and analysis of the hybrid compounds on a microscopic scale is achieved by means of optical microscopic examinations. The characterisation of the mechanical attenuation characteristics on the other hand is realised by means of DM(T)A. The flexural strength is determined by utilising a “three-point-bending test”.

Abstract: Specific phenolic resin samples have been developed as the carbon precursor for SiC/C composites. Liquid phenolic resins suitable for fiber-infiltration in the resin transfer moulding (RTM) process are synthesized by using versatile combination of the aromatic component (phenol, naphthalen-2-ol) with various formaldehyde equivalents such as methanal, 1,3,5,7tetraazatricyclo [3.3.1.1^3,7] decane (urotropine), and 1,3,5-trioxane, under different reaction conditions. Room temperature liquid resoles (RTLR) are obtained by using an excess of the formaldehyde component over phenol (≥2) under basic conditions. Upon heating RTLR can form a crosslinked network even without addition of a hardening reagent. In addition, novolacs are synthesized under acidic conditions using a phenol/formaldehyde ratio ≥1. Nitrogen-containing resins contain nitrogen due to reaction of phenol with urotropine. Novolacs and nitrogen-containing resins are solids at room temperature and not self-curing. To infiltrate these both resins into SiC fibers in the RTM process, they are dissolved in 2furanmethanol (furfuryl alcohol FA) and urotropine which is added as curing-agent. Both, the molecular weight and the amount of the dissolved phenolic resin have an influence on the viscosity and the carbon yield after pyrolysis which is important for this application. The aim was to create different phenolic resins for the fabrication in the RTM process and to characterize the carbon after pyrolysis with respect to the structure and porosity as these are key parameters to generate a stoichiometric SiC matrix by LSI.