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Sabu Thomas - One of the best experts on this subject based on the ideXlab platform.
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Thermal and electrical properties of Phenol Formaldehyde foams reinforcing with reduced graphene oxide
Polymer Composites, 2020Co-Authors: P Sandhya, M.s. Sreekala, Abderrahim Boudenne, Bertrand Garnier, Didier Rouxel, Moothetty Padmanabhan, Nandakumar Kalarikkal, Sabu ThomasAbstract:In this study, Phenol Formaldehyde/reduced graphene oxide (PF/RGO) foam nanocomposites were prepared. Here, RGO was obtained by the reduction of graphene oxide using an eco-friendly reducing agent potato starch. The scanning electron microscopic images of RGO reinforced foams exhibited smaller cells with thick cell walls as compared to neat PF foam that confirms the incorporation of filler material. The thermal and dielectric properties of the PF/RGO foams were improved with increasing the wt% of RGO. The incorporation of RGO improved the thermal conductivity of the PF matrix (11.3% for 0.15 wt% of RGO) to a small extent. The prepared foams are efficient thermal insulation materials as well as efficient electrical conductors.
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electrical properties of banana fiber reinforced Phenol Formaldehyde composites
Journal of Applied Polymer Science, 2008Co-Authors: Seena Joseph, Sabu ThomasAbstract:The electrical properties of banana fiber-reinforced Phenol Formaldehyde composites have been studied with special reference to fiber loading, fiber treatments, and hybridization with glass fibers. The dielectric constant decreased with frequency and fiber loading. Treatments with silanes, NaOH and acetylation, latex treatment, heat treatment, and cyanoethylation decreased the dielectric constant value. The dielectric constant is higher for banana/PF composites than that of glass/PF composites. In hybrid composites, the dielectric constant decreased with increase in glass fiber concentration. The volume resistivity of banana fiber-reinforced Phenol Formaldehyde composites decreased with frequency and fiber loading. Chemical modifications in the fiber increased the volume resistivity of the composites. Volume resistivity of banana/glass hybrid composites increased with increase in glass fiber content. Layered composites with glass fiber at periphery were found to have higher volume resistivity than other layering patterns. The loss factor decreased by the chemical treatments and in hybrid composites it decreased with increase in volume fraction of glass fibers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
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environmental durability of banana fiber reinforced Phenol Formaldehyde composites
Journal of Applied Polymer Science, 2006Co-Authors: Seena Joseph, Zachariah Oommen, Sabu ThomasAbstract:We explored the environmental aging behavior of banana-fiber-reinforced Phenol Formaldehyde (PF) composites. The composites were subjected to water aging, thermal aging, soil burial, and outdoor weathering. The effects of chemical modification and hybridization with glass fibers on the degradability of the composites in different environments were analyzed. The extent of degradation was measured by changes in the weight and tensile properties after aging. Absorbed water increased the weight of water-aged composites, and chemical treatments and hybridization decreased water absorption. The tensile strength and modulus of the banana/PF composites were increased by water aging, whereas the strength and modulus of the glass/PF composites were decreased by water aging. As the glass-fiber loading was increased in the hybrid composites, the increase in strength by water aging was reduced, and at higher glass-fiber loadings, a decrease in strength was observed. The tensile properties of the composites were increased by oven aging. The percentage weight loss was higher for soil-aged samples than for samples weathered outdoors. The weight loss and tensile strength of the glass/PF composites and banana/glass/hybrid/PF composites were much lower than those of the banana/PF composites. Silane treatment, NaOH treatment, and acetylation improved the resistance of the banana/PF composites on outdoor exposure and soil burial. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2521–2531, 2006
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the role of interfacial interactions on the mechanical properties of banana fibre reinforced Phenol Formaldehyde composites
Composite Interfaces, 2005Co-Authors: Seena Joseph, Peter Koshy, Sabu ThomasAbstract:Banana fibre has been modified with silane treatments, acetylation, cyanoethylation, latex treatment and mercerization to improve the interfacial bonding with Phenol Formaldehyde (PF) resin. Scanning electron microscopy was used to study the morphology of the banana fibre. The tensile properties of the modified fibre were compared with the untreated fibre and it was found that the tensile strength and modulus of the fibre were decreased by all the treatments except cyanoethylation. Tensile, flexural and impact performance of Phenol Formaldehyde composites reinforced with various treated fibres were analyzed and compared with that of untreated fibre composite. The tensile and flexural properties of the fibre-reinforced composites were found to be increased by all the modifications except latex coating. Incorporation of heat-treated, vinyl silane-treated and acetylated fibre-reinforced PF composites was found to have higher impact strength than that of untreated fibre/compsites. The tensile fractographs of ...
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a comparison of the mechanical properties of Phenol Formaldehyde composites reinforced with banana fibres and glass fibres
Composites Science and Technology, 2002Co-Authors: Seena Joseph, Peter Koshy, M.s. Sreekala, Zachariah Oommen, Sabu ThomasAbstract:Composites were fabricated using banana fibre and glass fibre with varying fibre length and fibre loading. The analysis of tensile, flexural and impact properties of these composites revealed that the optimum length of fibre required for banana fibre and glass fibre are different in Phenol Formaldehyde resole matrix. Both banana fibre and glass fibre reinforced composites show a regular trend of increase in properties with fibre loading. Interfacial shear strength values obtained from single fibre pull out test reveal that the interlocking between banana fibre and Phenol Formaldehyde resin is much higher than that between glass and Phenol Formaldehyde resin. SEM studies were carried out to evaluate fibre/matrix interactions. Finally the experimental tensile strength were compared with the theoretical predictions.
Runcang Sun - One of the best experts on this subject based on the ideXlab platform.
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structure property relationships for technical lignins for the production of lignin Phenol Formaldehyde resins
Industrial Crops and Products, 2017Co-Authors: Bo Pang, Sheng Yang, Wei Fang, Tongqi Yuan, Dimitris S Argyropoulos, Runcang SunAbstract:Abstract The synthesis and performance of a lignin-Phenol-Formaldehyde resin are significantly related to the properties of the lignin used. In an effort to provide a fundamental understanding of lignin structure-property relations for lignin-Phenol-Formaldehyde resin synthesis and application, two distinct technical lignins were examined as-obtained from an acidic (L1) and an alkaline (L2) organosolv pulping of bamboo. These samples were thoroughly characterized and the structural and compositional features of them were charted. The content of β-O-4′ linkages in L1 were 23.83 per 100Ar, followed by some β-β′ linkages (1.27 per 100Ar). However, almost all the side-chain linkages in L2 were cleaved. The purities of the two lignins both exceeded 81.0%, but significantly more extractives were found to be present in L2. Subsequently, two lignin-Phenol-Formaldehyde resins were successfully synthesized using L1 and purified L2 at a substitution rate of 50% to Phenol. The high content of extractives contaminating L2, especially long-chain hydrocarbon derivatives, severely affected the synthesis of lignin-Phenol-Formaldehyde resin. The successful removal of this fraction was necessary before the material could be put to use.
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lignin Phenol Formaldehyde resin adhesives prepared with biorefinery technical lignins
Journal of Applied Polymer Science, 2015Co-Authors: Sheng Yang, Tongqi Yuan, Yue Zhang, Runcang SunAbstract:In this study, four biorefinery technical lignins were used to synthesize lignin–Phenol–Formaldehyde (LPF) resin adhesives with a proposed formulation that was designed based on accurate analysis of the active sites in lignin with 31P nuclear magnetic resonance (NMR). The properties of the LPF resin adhesives and the plywoods prepared with them were tested. The structural features and curing behavior of the LPF resin adhesives were thoroughly investigated by solution- and solid-state 13C NMR. Results indicated that the proposed formulation exhibited favorable adaptability for all four of these technical lignins for synthesis of LPF resin adhesives. High-performance plywood with low emissions of Formaldehyde could be successfully prepared with the synthesized LPF resin adhesives. All the LPF resin adhesives exhibited similar structure and curing behavior with the commercial Phenol–Formaldehyde (CPF) resin adhesive. However, the LPF resin adhesives showed relatively higher curing temperatures as compared with the CPF resin adhesive. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42493.
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characterization and Phenolation of biorefinery technical lignins for lignin Phenol Formaldehyde resin adhesive synthesis
RSC Advances, 2014Co-Authors: Sheng Yang, Tongqi Yuan, Jialong Wen, Runcang SunAbstract:Technical lignins are cheap, abundant and renewable Phenolic substances that have been attracting increasing attention. In this study, the structural features and active sites of four technical lignins obtained from different biorefinery processes were thoroughly characterized. Their suitability for partial incorporation into a Phenol–Formaldehyde (PF) resin adhesive was also evaluated. Phenolation treatment under alkaline conditions was conducted to enhance the reactivity of the technical lignins. Composition analysis indicated that all four technical lignins had a high purity (>88%). 13C nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC) analyses revealed that the technical lignins from different original feedstocks and biorefinery processes had different structural features, but all of these technical lignins could be used in the synthesis of a lignin–Phenol–Formaldehyde (LPF) resin adhesive. The structural features and active sites of the different technical lignins before and after Phenolation treatment were determined using quantitative two-dimensional heteronuclear single-quantum correlation (2D HSQC) and 31P NMR spectroscopies. The results confirmed that the Phenolation treatment under alkaline conditions could effectively increase the number of active sites on the technical lignins and could be easily included in the synthesis process of LPF resin adhesives.
Martin Feng - One of the best experts on this subject based on the ideXlab platform.
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bark extractives based Phenol Formaldehyde resins from beetle infested lodgepole pine
Journal of Adhesion Science and Technology, 2013Co-Authors: Yong Zhao, Ning Yan, Martin FengAbstract:In this study, Phenol–Formaldehyde (PF) resins derived from the bark extractives were synthesized and characterized. Bark of lodgepole pine (Pinus contorta Dougl.) infested by mountain pine beetle (Dendroctonus ponderosae Hopkins) was first extracted with 1% NaOH. The bark extractives with and without acid-neutralization were then dried to the solid state. The neutralized and non-neutralized extractives were used to partially replace petroleum-based Phenol for synthesizing the bark extractives-PF resins. In comparison with a commercial PF resin and a laboratory made PF resin (Lab PF), the bark extractive-PF resins were found to have higher molecular weights, higher viscosities, and shorter gel times. Acid neutralization of the bark extractives increased the molecular weight of the extractives and modified the performance and curing behavior of the resulting bark extractive-PF resins. Bark extractive-PF resins (BEPF) showed a similar level of post-cured thermal stability to that of the lab PF at higher tem...
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thermal degradation characteristics of Phenol Formaldehyde resins derived from beetle infested pine barks
Thermochimica Acta, 2013Co-Authors: Yong Zhao, Ning Yan, Martin FengAbstract:In this study, Phenol–Formaldehyde (PF) resins were synthesized using both bark extractives and Phenol-liquefied barks from mountain pine beetle (Dendroctonus ponderosae Hopkins) infested lodgepole pine (Pinus contorta Dougl.). The thermal stability and thermal degradation kinetics of the bark-derived PF resins were investigated by thermogravimetric analysis (TGA). The structural changes in the bark-derived PF resins at different stages of the thermal degradation were studied using the Fourier Transform Infrared Spectroscopy (FTIR). Thermal stability of the post-cured bark-derived PF resins were similar to that of the lab PF resin but differed significantly from that of the post-cured commercial PF resin. Bark-derived PF resin made from bark extractives differed significantly in thermal stability and thermal degradation kinetics from the bark-derived PF resin made from the Phenol-liquefied bark. The bark-derived PF resin made from the bark extractives showed a higher thermal stability.
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biobased Phenol Formaldehyde resins derived from beetle infested pine barks structure and composition
ACS Sustainable Chemistry & Engineering, 2013Co-Authors: Yong Zhao, Ning Yan, Martin FengAbstract:In this study, two types of biobased bark-derived Phenol Formaldehyde (PF) resins, namely, liquefied bark-PF and bark extractive-PF, were synthesized from acid-catalyzed Phenol-liquefied bark and b...
Sheng Yang - One of the best experts on this subject based on the ideXlab platform.
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structure property relationships for technical lignins for the production of lignin Phenol Formaldehyde resins
Industrial Crops and Products, 2017Co-Authors: Bo Pang, Sheng Yang, Wei Fang, Tongqi Yuan, Dimitris S Argyropoulos, Runcang SunAbstract:Abstract The synthesis and performance of a lignin-Phenol-Formaldehyde resin are significantly related to the properties of the lignin used. In an effort to provide a fundamental understanding of lignin structure-property relations for lignin-Phenol-Formaldehyde resin synthesis and application, two distinct technical lignins were examined as-obtained from an acidic (L1) and an alkaline (L2) organosolv pulping of bamboo. These samples were thoroughly characterized and the structural and compositional features of them were charted. The content of β-O-4′ linkages in L1 were 23.83 per 100Ar, followed by some β-β′ linkages (1.27 per 100Ar). However, almost all the side-chain linkages in L2 were cleaved. The purities of the two lignins both exceeded 81.0%, but significantly more extractives were found to be present in L2. Subsequently, two lignin-Phenol-Formaldehyde resins were successfully synthesized using L1 and purified L2 at a substitution rate of 50% to Phenol. The high content of extractives contaminating L2, especially long-chain hydrocarbon derivatives, severely affected the synthesis of lignin-Phenol-Formaldehyde resin. The successful removal of this fraction was necessary before the material could be put to use.
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lignin Phenol Formaldehyde resin adhesives prepared with biorefinery technical lignins
Journal of Applied Polymer Science, 2015Co-Authors: Sheng Yang, Tongqi Yuan, Yue Zhang, Runcang SunAbstract:In this study, four biorefinery technical lignins were used to synthesize lignin–Phenol–Formaldehyde (LPF) resin adhesives with a proposed formulation that was designed based on accurate analysis of the active sites in lignin with 31P nuclear magnetic resonance (NMR). The properties of the LPF resin adhesives and the plywoods prepared with them were tested. The structural features and curing behavior of the LPF resin adhesives were thoroughly investigated by solution- and solid-state 13C NMR. Results indicated that the proposed formulation exhibited favorable adaptability for all four of these technical lignins for synthesis of LPF resin adhesives. High-performance plywood with low emissions of Formaldehyde could be successfully prepared with the synthesized LPF resin adhesives. All the LPF resin adhesives exhibited similar structure and curing behavior with the commercial Phenol–Formaldehyde (CPF) resin adhesive. However, the LPF resin adhesives showed relatively higher curing temperatures as compared with the CPF resin adhesive. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42493.
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characterization and Phenolation of biorefinery technical lignins for lignin Phenol Formaldehyde resin adhesive synthesis
RSC Advances, 2014Co-Authors: Sheng Yang, Tongqi Yuan, Jialong Wen, Runcang SunAbstract:Technical lignins are cheap, abundant and renewable Phenolic substances that have been attracting increasing attention. In this study, the structural features and active sites of four technical lignins obtained from different biorefinery processes were thoroughly characterized. Their suitability for partial incorporation into a Phenol–Formaldehyde (PF) resin adhesive was also evaluated. Phenolation treatment under alkaline conditions was conducted to enhance the reactivity of the technical lignins. Composition analysis indicated that all four technical lignins had a high purity (>88%). 13C nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC) analyses revealed that the technical lignins from different original feedstocks and biorefinery processes had different structural features, but all of these technical lignins could be used in the synthesis of a lignin–Phenol–Formaldehyde (LPF) resin adhesive. The structural features and active sites of the different technical lignins before and after Phenolation treatment were determined using quantitative two-dimensional heteronuclear single-quantum correlation (2D HSQC) and 31P NMR spectroscopies. The results confirmed that the Phenolation treatment under alkaline conditions could effectively increase the number of active sites on the technical lignins and could be easily included in the synthesis process of LPF resin adhesives.
M.s. Sreekala - One of the best experts on this subject based on the ideXlab platform.
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Thermal and electrical properties of Phenol Formaldehyde foams reinforcing with reduced graphene oxide
Polymer Composites, 2020Co-Authors: P Sandhya, M.s. Sreekala, Abderrahim Boudenne, Bertrand Garnier, Didier Rouxel, Moothetty Padmanabhan, Nandakumar Kalarikkal, Sabu ThomasAbstract:In this study, Phenol Formaldehyde/reduced graphene oxide (PF/RGO) foam nanocomposites were prepared. Here, RGO was obtained by the reduction of graphene oxide using an eco-friendly reducing agent potato starch. The scanning electron microscopic images of RGO reinforced foams exhibited smaller cells with thick cell walls as compared to neat PF foam that confirms the incorporation of filler material. The thermal and dielectric properties of the PF/RGO foams were improved with increasing the wt% of RGO. The incorporation of RGO improved the thermal conductivity of the PF matrix (11.3% for 0.15 wt% of RGO) to a small extent. The prepared foams are efficient thermal insulation materials as well as efficient electrical conductors.
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a comparison of the mechanical properties of Phenol Formaldehyde composites reinforced with banana fibres and glass fibres
Composites Science and Technology, 2002Co-Authors: Seena Joseph, Peter Koshy, M.s. Sreekala, Zachariah Oommen, Sabu ThomasAbstract:Composites were fabricated using banana fibre and glass fibre with varying fibre length and fibre loading. The analysis of tensile, flexural and impact properties of these composites revealed that the optimum length of fibre required for banana fibre and glass fibre are different in Phenol Formaldehyde resole matrix. Both banana fibre and glass fibre reinforced composites show a regular trend of increase in properties with fibre loading. Interfacial shear strength values obtained from single fibre pull out test reveal that the interlocking between banana fibre and Phenol Formaldehyde resin is much higher than that between glass and Phenol Formaldehyde resin. SEM studies were carried out to evaluate fibre/matrix interactions. Finally the experimental tensile strength were compared with the theoretical predictions.
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water sorption in oil palm fiber reinforced Phenol Formaldehyde composites
Composites Part A-applied Science and Manufacturing, 2002Co-Authors: M.s. Sreekala, M G Kumaran, Sabu ThomasAbstract:Abstract Water sorption kinetics in oil palm fiber reinforced Phenol Formaldehyde (PF) composites and oil palm/glass hybrid fiber reinforced PF composites was investigated. The influence of fiber loading, relative volume fractions of fibers in hybrid composites and fiber surface modifications on the kinetic and thermodynamic parameters of water sorption by the composites were also studied. Water sorption at four different temperatures was analysed and compared. Composite with 10 wt% fiber loading exhibits maximum water uptake. Hybridisation of the oil palm fiber with glass considerably decreased the water sorption by the composite. The concentration dependency of the diffusion coefficient was analysed and discussed.
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utilization of short oil palm empty fruit bunch fiber opefb as a reinforcement in Phenol Formaldehyde resins studies on mechanical properties
Journal of Polymer Engineering, 1996Co-Authors: M.s. Sreekala, Sabu ThomasAbstract:The brittle thermosetting plastic, Phenol-Formaldehyde, was reinforced with oil palm empty fruit bunch fiber. Composites were prepared from resol type Phenol-Formaldehyde resin. Hand lay up technique followed by compression molding was used for composite preparation. Fiber lengths of 20, 30, 40 and 50 mm were used for composite fabrication. The effect of fiber length and fiber loading on the mechanical properties was studied. Tensile, flexural and impact properties of the composites were analyzed. The experimental results were compared with the theoretical predictions. Scanning electron micrographs of the fracture surfaces were taken to analyze the fiber-matrix adhesion, fiber pull-out and fiber surface topography. Finally, the properties of the composites were compared to those of other natural fiber filled PF composites.