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The phenols and ammonia–nitrogen compounds in semi-coking wastewater are used to react with formaldehyde to generate phenolic resin and curing agent urotropine, so as to achieve the resourceful preparation of thermosetting phenolic resin. The effects of pH value of wastewater, reaction time, reaction temperature, formaldehyde addition amount and other conditions on the quality of phenolic resin were investigated. Response surface methodology was used to optimize the preparation conditions of phenolic resin, and the effect of ammonia on the preparation of phenolic resin was explored. Moreover, solid content, carbon yield, gel time and viscosity of the prepared phenolic resin were determined. The experimental results showed that the quality of phenolic resin prepared when the pH value of wastewater was 9.5, the reaction time was 2.5 h, the reaction temperature was 140 °C, and the additive amount of formaldehyde was 1.4 mL, phenolic resin with best quality could be obtained. The solid content of phenolic resin prepared is 94.25%, the carbon yield is 40.02%, the gel time is 92 s, and the viscosity is 1.50 × 104 mPa·s. This study has solved the problems such as high chemical oxygen demand (COD), high ammonia–nitrogen, as well as difficult degradation and treatment. [ABSTRACT FROM AUTHOR]

Phenolic resin pyrolytic carbons were obtained by catalytic pyrolysis of phenolic resin at 500 °C, 600 °C, 700 °C, and 800 °C for 3 h in an argon atmosphere using copper nitrate as a catalyst precursor. The effects of copper salts on the pyrolysis process of phenolic resin as well as the structural evolution and oxidation resistance of phenolic resin pyrolytic carbons were studied. The results showed that copper oxide (CuO) generated from the thermal decomposition of copper nitrate was reduced to copper (Cu) by the gas generated from the thermal decomposition of the phenolic resin. Carbon nanofibers with tapered structures were synthesized by Cu catalysis of pyrolysis gas at 500–800 °C. The catalytic pyrolysis of phenolic resin with Cu increased the graphitization degree and reduced the pore volume of the phenolic resin pyrolytic carbons. The combined action improved the oxidation resistance of phenolic resin pyrolytic carbons. [ABSTRACT FROM AUTHOR]

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Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, blends of silicone rubber (SR) and benzoxazine (BZ) were prepared accompanied by ethylene propylene diene monomer grafted with maleic anhydride (EPDM‐g‐MA) as the compatibilizing agent. A total of 3 phr MA grafted EPDM showed the most favorable grafting efficiency and relatively lower gel content. Results showed that 8 phr (EPDM‐g‐MA) was the optimal compatibilizer content in the 85/15 SR/BZ blend, which was used for further studies. Morphological studies proved that the greatest reduction in the dispersed droplet size (from 1.32 to 0.23 μm) occurred at this optimal compatibilizer loading (8 phr). The lowest difference between the glass transition temperatures of the blend components was observed at the 8 phr compatibilizer content, which was confirmed by DMTA. The mechanical and curing characteristics of compatibilized and uncompatibilized blends were also studied. The results evinced that the tensile strength of the compatibilized samples was higher than that of the uncompatibilized blends. Thermal studies on the 85/15 SR/BZ blend and nanocomposites containing 1, 3, and 5 phr polyhedral oligomeric silsesquioxane (POSS) nanoparticles revealed that the thermal stability of nanocomposites containing 1 and 3 phr POSS was superior to that of the nanocomposite with 5 phr POSS. [ABSTRACT FROM AUTHOR]

AbstractIn this study phenolic resin (Phen)-loaded PCS (Phen-PCS) films were prepared and quartz fiber/Phen-PCS composites based on the resin films were also prepared. The quartz fiber/Phen-PCS composites were prepared by impregnating 2.5 Dimension (2.5D was an arrangement of fibers) quartz fibers using the resin film infusion (RFI) process. The properties of the composites were investigated. The study demonstrated that the density of the composites, after curing gradually increased with the increase in PCS. The flexural strength of the composites exhibited a trend of increasing and then decreasing after curing and pyrolysis at 1100 °C under an N2 atmosphere. The flexural strength of the composites reached 13.73 MPa when the addition of PCS was 30% of the phenolic resin, representing an increase of 74.23% compared to that of the composites without PCS. The porosity was found to be as low as 2.3% after curing and 2.1% after pyrolysis. X-ray diffraction (XRD) analysis and infrared spectroscopy tests demonstrated that ceramicization products, such as SiO2 and SiC, were produced after pyrolysis of the composites containing PCS. This transformation significantly enhanced the ablation resistance of the composites. Butane flame tests were performed, and the lowest line and mass ablation rates were 0.026 mm/s and 0.196 mg/s after curing. The results of the study revealed the potential of PCS as a precursor to improve the mechanical properties and heat resistance of composites, which offers promising material options for high-temperature applications. [ABSTRACT FROM AUTHOR]

A crystalline and non-crystalline composite of pure carbon was proposed, which is a carbon whiskers reinforced porous glassy carbon composite, where crystalline carbon whiskers support the microscopic pores of non-crystalline glassy carbon matrix. Two allotropes of carbon were produced simultaneously and compounded together in a single high temperature treatment of thermosetting phenolic resin, with aluminum oxide (Al2O3) as a catalyst. A synchronous growth theory was proposed to explain the growth mechanism. In the pyrolysis process of phenolic resin to generate porous glassy carbon, hydrocarbon gas was produced and trapped in the generated pores. By the same time, the hydrocarbon gas in pores was decomposed and grew carbon whiskers by catalysis of Al2O3. With linear thermal expansion coefficient from 2.0∙10−6 to 3.8∙10−6 K−1, thermal conductivity from 1.763 to 2.518 W∙m−1 K−1, specific heat capacity from 0.396 to 0.752 J∙g−1 K−1, thermal diffusivity from 6.115 to 4.598 mm2 s−1, between room temperature (RT) and 500 °C, the Vickers hardness is at 65 MPa, and the fracture toughness is at 0.329 Mpa∙m1/2 in RT. The carbon whiskers reinforced porous glassy carbon composite keeps a balance between thermophysical and mechanical properties, showing its application value in thermal insulation materials and high temperature structure materials.

Glass fiber reinforced phenolic composites (GFRP) are an advanced composite material with good processability, fatigue resistance, corrosion resistance and stability, and are widely used in the production of structural parts for aircraft and ships. Our research described in this article explores the performance changes of GFRP in different aging media with prolonged aging time using GFRP with different fiber/matrix ratios. The research results indicated that aging time had the most significant impact on the various properties of the composite materials among all variables. With the extension of aging time, the bending strength of our composite materials decreased significantly, with a maximum decrease of 33%. The water absorption rate gradually increased and tended to stabilize, but the thermal decomposition temperature remained at 300 °C, and the mass residual rate remained stable at around 61% with little change. As the content of GF was increased, the aging of the composite gradually slowed down, and the rate of decline in its bending strength gradually decreased. In addition, the influence of different aging media on the performance was also studied, and it was found that the presence of NaCl in artificial seawater could cause changes in the osmotic pressure at the interface of the composite materials and the sea water, thus exacerbating interface damage and affecting the material's performance. [ABSTRACT FROM AUTHOR]

[Display omitted] • Carbon nanofibrous membranes were prepared for adsorptive separation of VOCs. • The membranes showed hierarchical porous structures and functional surfaces. • The membranes possessed comparable adsorption quantities and fast kinetics. • The membranes exhibited good reusability and dynamic adsorption performance. Volatile organic compounds (VOCs) in the air pose great health risks to humans and the environment. Adsorptive separation technology has proven effective in mitigating VOC pollution, with the adsorbent being the critical component. Therefore, the development of highly efficient adsorbent materials is crucial. Carbon nanofibers, known for their physical–chemical stability and rapid adsorption kinetics, are promising candidates for removing VOCs from the air. However, the relatively simple porous structures and inert surface chemical properties of traditional carbon nanofibers present challenges in further enhancing their application performance further. Herein, a hierarchical porous carbon nanofibrous membrane was prepared using electrospinning technology and a one-step carbonization & activation method. Phenolic resin and polyacrylonitrile were used as co-precursors, with silica nanoparticles serving as the dopant. The resulting membrane exhibited a specific surface area of up to 1560.83 m2/g and surfaces rich in functional O-/N- groups. With a synergistic effect of developed micro- and meso -pores and active chemical surfaces, the carbon nanofibrous membrane demonstrated excellent adsorption separation performance for various VOCs, with comparable adsorption capacities and fast kinetics. Moreover, the membrane displayed remarkable reusability and dynamic adsorption performance for different VOCs, indicating its potential for practical applications. [ABSTRACT FROM AUTHOR]

This work mainly studied the influence of SiC and Si3N4 composite fillers on the ablation performance of silica/phenolic composites. The effect of Si3N4 content on the mechanical and ablative properties of the composites was investigated, and the bridging effect between the two different ceramic fillers was analyzed. The results indicated that the mechanical properties and ablation properties of the composite were improved due to the combined effect of the SiC and Si3N4. When the content of Si3N4 was 36phr, the flexural strength at room temperature was 114.6 MPa, the flexural strength after 1200 °C treatment was 18.38 MPa, and the linear ablation rate was 0.011 mm/s in the 1600 °C oxyacetylene ablation test for 30s, while the flexural strength without Si3N4 at room temperature was 105.4 MPa, the flexural strength after 1200 °C treatment was 10.35 MPa, and linear ablation rate was 0.061 mm/s in the 1600 °C oxyacetylene ablation test for 30s. The bridges between the Si3N4 and SiC ceramic fillers can form SiO2, SiCN and Si2N2O in the high temperature environment, which helps fill the pores on the surface of the composite, forming an effective protective layer structure and improving the high temperature and erosion resistance of the composites. [ABSTRACT FROM AUTHOR]

Carbon fiber paper (CFP) is one of the most widely used gas diffusion layer materials for proton exchange membrane fuel cells (PEMFC) due to its excellent properties such as high conductivity, high strength, high air permeability and corrosion resistance. In this study, CFP was prepared using the phenolic resin (PF) in-pulp addition method. The effect of PF content on the properties of hot-pressed paper (HPP) and CFP was investigated. The results showed that when the dosage of polyethylene oxide (PEO) was 1.5 wt%, the flocculation effect of PEO on PF was basically complete, and the water filterability and retention of carbon fiber pulp were relatively optimal. After HPP was carbonized into CFP, the hydrophobicity, average pore size, porosity, and air permeability increased, while the resistivity and tensile strength decreased. With the increase of PF content, the tensile strength of CFP gradually increased, while the average pore size, porosity, air permeability and resistivity decreased. When the PF content was 250 wt%, the average pore size of CFP was 36.5 μm, the water contact angle was 127°, the porosity was 69.7%, the air permeability was 7.81 × 103 mL mm/(cm2·h·mmHg), the resistivity was 21.1 mΩ cm, and the tensile strength was 15.7 MPa. In addition, the CFP prepared using PF in-pulp addition method had a relativity uniform pore size distribution and high air permeability. Therefore, this work shows that the CFP prepared using this technique exhibits excellent comprehensive performance, and enables the manufacturing of CFP to be more efficient, low-cost, and environmentally friendly. [Display omitted] • Carbon fiber paper was prepared efficiently using the phenolic resin in-pulp addition method. • Polyethylene oxide exhibits strong adsorption ability on phenolic resin in carbon fiber pulp. • The melting temperature of phenolic resin is a critical point in the preparation process of carbon fiber paper. • Carbon fiber paper possesses a relatively uniform pore size distribution and high air permeability. [ABSTRACT FROM AUTHOR]

Lightweight and high-strength insulation materials have important application prospects in the aerospace, metallurgical, and nuclear industries. In this study, a highly porous silica fiber reinforced phenolic resin matrix composite was prepared by vacuum impregnation and atmospheric drying using quartz fiber needled felt as reinforcement and anhydrous ethanol as a pore-making agent. The effects of curing agent content on the structure, composition, density, and thermal conductivity of the composite were studied. The mechanical properties of the composite in the xy direction and z direction were analyzed. The results showed that this process can also produce porous phenolic resin (PR) with a density as low as 0.291 g/cm3, where spherical phenolic resin particles are interconnected to form a porous network structure with a particle size of about 5.43 μm. The fiber-reinforced porous PR had low density (0.372~0.397 g/cm3) and low thermal conductivity (0.085~0.095 W/m·K). The spherical phenolic resin particles inside the composite were well combined with the fiber at the interface and uniformly distributed in the fiber lap network. The composite possessed enhanced mechanical properties with compressive strength of 3.5–5.1 MPa in the xy direction and appeared as gradual compaction rather than destruction as the strain reached 30% in the z direction. This research provides a lightweight and high-strength insulation material with a simple preparation process and excellent performance. [ABSTRACT FROM AUTHOR]

Ablative composites serve as sacrificial materials, protecting underlying materials from high-temperature environments by endothermic reactions. These materials undergo various phenomena, including thermal degradation, pyrolysis, gas generation, char formation, erosion, gas flow, and different modes of heat transfer (such as conduction, convection, and radiation), all stemming from these endothermic reactions. These phenomena synergize to form a protective layer over the underlying materials. Carbon, with its superb mechanical properties and various available forms, is highlighted, alongside phenolics known for good adhesion and fabric ability and elastomers valued for flexibility and resilience. This study focuses on recent advancements in carbon-and-phenolic and carbon-and-elastomeric composites, considering factors such as erosion speed; high-temperature resistance; tensile, bending, and compressive strength; fiber–matrix interaction; and char formation. Various authors' calculations regarding the percentage reduction in linear ablation rate (LAR) and mass ablation rate (MAR) are discussed. These analyses inform potential advancements in the field of carbon/phenolic and carbon/elastomeric ablative composites. [ABSTRACT FROM AUTHOR]

Copyright of Plastics Science & Technology / Suliao Ke-Ji is the property of Plastics Science & Technology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Without using fossil resources such as petroleum and coal, which are likely to be depleted and have a large load on the environment, we studied the improvement of the performance of phenolic resin using lignin‐based natural material, which is a non‐fossil resource that is less likely to cause environmental problems. Using modified lignin with polyethylene glycol, the modified lignin phenolic novolac resin was synthesized, and the properties of the phenolic resin molding material and molded article containing the modified lignin were evaluated. As a result, it was found that the phenolic resin into which the modified lignin was introduced not only has excellent moldability, but also excellent heat resistance, mechanical strength, and electrical insulation, and can achieve both heat resistance and flexibility. [ABSTRACT FROM AUTHOR]

Copyright of Bearing is the property of Bearing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Silicon (Si) is a promising anode material for next-generation lithium-ion batteries (LIBs) with its high theoretical specific capacity (4200 mAh/g). However, Si anode has a huge volume change rate (> 300%) and high cost compared to graphite, which limits the commercial application of Si anode. Carbon coating can effectively tackle the volume change and poor conductivity during cycling of Si anode. In this work, aluminum–silicon alloy was firstly etched by hydrochloric acid. Followed by a mixture with pyrolysis of phenolic resin, the carbon layer outside the silicon particles was deposited during heat treatment process. The carbon-coated porous silicon-carbon (Si/C) anode material demonstrates excellent electrochemical performance and porous structure, which relieves mechanical stress and inhibits volume expansion. The results show that Si/C present well electrochemical performance at a sintering temperature of 800 ℃. Specially, the Si/C anode delivers a high specific capacity of 1394.4 mAh/g at the current density of 0.5 A/g with 46.1% retention. Nitrogen-doped silicon carbon composite material (Si/NC) was synthesized to further improve the performance of Si/C anodes. The characterizations confirm good crystallinity, uniform carbon coating on silicon surfaces, and even distribution of Si, C, and N elements. Simultaneously, a highly stable reversible capacity of 1218.3 mAh/g with 42.7% retention over 300 cycles at a current density of 0.5 A/g was obtained. This research can provide an alternative approach for high-energy and low-cost silicon-based anodes for LIBs. [ABSTRACT FROM AUTHOR]

It is crucial to develop high porosity and permeability carbon fiber paper for improving the performance of proton exchange membrane fuel cell. Herein, Porous carbon paper with gradient structure (GCP) was prepared by the process of impregnation with a solution of phenolic resin /carbon black composites, overlayer molding, carbonization and graphitization. Specially, conductive carbon black was modified by silane coupling agent (KH-550) and in-situ polymerization with phenolic resin to improve its dispersion uniformity. The microstructure, porosity, gas permeability, electric resistance and mechanic properties of the as-prepared GCP are characterized. The resultant GCP has a gradual transition of porosity from bottom layer to top layer, which constitutes diffusion channels conducive to the transport of gas and liquid. In addition, GCP exhibits superior gas permeability, conductivity, corrosion resistance and tensile strength over commercial carbon paper (CCP). It has potential application prospects for further improving the performance of fuel cells. [ABSTRACT FROM AUTHOR]

The study indicated that the phenolic resin pyrolysis carbon showed a gradual decrease in microdomain and domain sizes, as well as inter-domain compactness with increasing carbonization temperature (1200–1600 °C) and time (1–3 h). We determined that with an increase in carbonization temperature and time, the reduction and disappearance of organic groups such as C C, CH 2 , and C– O –C led to a gradual transformation of carbon microcrystals from structures of a larger size, with a certain curvature of more defects to smaller short straight shapes with fewer defects. This also led to a tendency of assimilation within the domains, an increase of inter-domain differences, and difficulty of further merging and growing smaller microdomains and domains. The β-SiC nanoparticles with a controllable particle size in the range of 30–200 nm, as well as controllable dispersibility, were successfully synthesized by reacting the coke with silicon. With further heat treatment at 600 °C for 6 h in air, the wrapped 2.0–3.6 nm amorphous phase homogeneous structure silicon oxide film was prepared on the SiC nanoparticles surface, which improved the oxidation resistance of the SiC nanoparticles. We determined that the reduction in microdomain and domain sizes, and an increase in inter-domain grain boundary defects, was one of the main reasons for promoting the exfoliation of microdomain and domain structures during the synthesis process to generate dispersed single smaller SiC nanoparticles. [ABSTRACT FROM AUTHOR]

Herein we report the formulation of phenolic resin–based adhesive to join SiC substrates for a wide range of application temperatures. The formulation consists of phenolic resin as a binder and a mixture of B4C, Al2O3, Y2O3, Si, and SiO2 powders as active filler. The X‐ray diffraction, thermogravimetric analysis, porosity, and scanning electron microscopy analysis were carried out to understand the reactions occurring within this adhesive during its exposure to application temperatures. These results were also used to understand thermal stability and morphological changes that are involved in the formulated adhesive during its application. The shear strength values of lap joints of SiC substrates made with this phenolic adhesive after exposure to temperatures between 200 and 1500°C were studied to evaluate its adhesive capacity. Obtained SiC joints with this adhesive have shown an excellent lap shear strength value of 24 MPa after its cure. These joints were also found to be intact with good shear strength values of more than 5 MPa even after exposure to temperatures ranging from 200 to 1500°C. The results further confirm that the adhesive is potentially viable for joining SiC segments for their application at a wide range of temperatures in oxidative environments. [ABSTRACT FROM AUTHOR]

In this study, a novel fabrication method was used to synthesize phenolic resin/phosphate hybrid coatings using aluminum dihydrogen phosphate (Al(H2PO4)3, hereafter denoted as Al), SC101 silica sol (Si) as the primary film-forming agent, and phenolic resin (PF) as the organic matrix. This approach culminated in the formation of Al+Si+PF organo–inorganic hybrid coatings. Fourier-transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) results confirmed the successful integration of hybrid structures within these coatings. The crystalline structure of the coatings post-cured at various temperatures was elucidated using X-ray diffraction (XRD). Additionally, the surface and cross-sectional morphologies were meticulously analyzed using scanning electron microscopy (SEM), offering insights into the microstructural properties of the coatings. The coatings' porosities under diverse thermal and temporal regimes were quantitatively evaluated using advanced image processing techniques, revealing a significant reduction in porosity to a minimum of 5.88% following a thermal oxidation process at 600 °C for 10 h. The antioxidant efficacy of the phosphate coatings was rigorously assessed through cyclic oxidation tests, which revealed their outstanding performance. Specifically, at 300 °C across 300 h of cyclic oxidation, the weight losses recorded for phosphate varnish and the phenolic resin-infused phosphate coatings were 0.15 mg·cm−2 and 0.09 mg·cm−2, respectively. Furthermore, at 600 °C and over an identical period, the weight reduction was noted as 0.21 mg·cm−2 for phosphate varnish and 0.085 mg·cm−2 for the hybrid coatings, thereby substantiating the superior antioxidation capabilities of the phenolic resin hybrid coatings in comparison to the pure phosphate varnish. [ABSTRACT FROM AUTHOR]

Over a century ago, phenolic formaldehyde (PF) resin was developed and continues to increase in yield due to its diverse applications. However, PF resin is a thermosetting plastic lacking fluidity and moldability, which are nondegradable in natural environments, leading to severe threats to fossil resources as well as global environmental crises. As a result, recycling PF resin is extremely important. In this review, we provide the recent advances in the recycling of PF resin, which includes mechanical recycling, chemical recycling, and utilization of carbon-based materials. The advantages and disadvantages of each strategy are evaluated from a green chemistry perspective. This article aims to attract interest in PF resin design, synthesizing, application and recycling, offering useful suggestions. [ABSTRACT FROM AUTHOR]

The structure and property relationships of graft copolymers from natural rubber (NR) and polymethyl methacrylate (PMMA) crosslinked with a phenolic resin were investigated. The NR grafted with PMMA (NR-g-PMMA) having different grafting levels was initially prepared by emulsion polymerization before compounding and vulcanization. Then, proton nuclear magnetic resonance and transmission electron microscopy were used to verify the resultant NR-g-PMMAs. The graft copolymers crosslinked with phenolic resin exhibited improvements in various properties. Tensile modulus and tensile strength increased at least 18 and 95%, respectively, over the un-grafted counterpart and further improved with grafting percentage, while the elongation at break decreased accordingly. Storage modulus in rubbery plateau increased while tanδ peak height decreased with PMMA content. Moreover, the thermal stability of the graft copolymers was also improved over that of the plain NR at least 23 °C, depending on MMA contents. These improvements are tentatively attributed to the strong adhesion between NR and PMMA phases, based on interactions between the functional groups of PMMA and hydrogen bonding between phenolic resin crosslinker and PMMA. The results clearly suggest that the phenolic resin could be an effective crosslinker for NR-g-PMMA. [ABSTRACT FROM AUTHOR]

Copyright of Refractories / Naihuo Cailiao is the property of Naihuo Cailia (Refractories) Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Rare Metals is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A novel class of hybrid composites was prepared containing carbon fibers along with carbon nanotubes and silicon carbide particles in phenolic resin for improved mechanical performance. The loading of carbon fibers was ~60 wt% while carbon nanotubes and silicon carbide particles were reinforced in the fractions of 0.1 wt% and 5 wt%, respectively. Individually reinforced composites containing 0.1 wt% carbon nanotubes and 5 wt% silicon carbide particles were also manufactured for comparison with hybrid composites. Microstructural and mechanical property characterization was performed using electron microscopy and mechanical testing, respectively. Uniform dispersion of nanometer-scale carbon nanotubes and micrometer-scale silicon carbide particles was observed under microscopy. The pooled effect of carbon nanotubes and silicon carbide particles significantly increased the tensile, compressive, and flexural performance of composites while carbon nanotubes offered greater weight fraction value improvement than silicon carbide particles. [ABSTRACT FROM AUTHOR]

Nanocarbons including carbon nanotubes, graphene oxide, reduced graphene oxide and particularly graphene have unique properties such as high mechanical strength, thermally stable, highly conducting, high friction stability and lower specific wear rates, which can potentially provide synergically improved performance of advanced engineering materials and technologies for various fields of applications such as automotive, aerospace, and other industrial components. Development of phenolic resin‐based nanocomposites comprised of nanocarbon material remained as a research focus to outperform different properties of conventional material based components. In application, phenolic resin is the most popular binder in frictional components development such as brake pads, brake linings, and clutch facings, particularly used in many of light and medium automotive brake pad applications. Specifically, the present review study aims to provide thorough discussion on the mechanical, tribological, and thermal performances of phenolic resin‐based nanocomposites containing nanocarbon as a property modifier by comparing with the neat phenolic resin or with the composite containing other micro ingredients. As per presented overview, the analysis shows the significant improvement in some required application‐based properties of phenolic resin‐based nanocomposites such as tensile strength, young's modulus, impact strength, specific wear rate reduction, residue yield, and thermal conductivity due to the inclusion of nanocarbon, where the content of nanocarbons ranges about 0.5 wt% to 5 wt%. Hence nanocomposites synthesized using phenolic resin matrix with nanocarbons fillers found to have better mechanical strength, better wear resistance, and thermal stabilities when compared to pure phenolic resin and other composites. [ABSTRACT FROM AUTHOR]

In this work polyurethane (PU) and phenolic foam (PF) panels were mechanically grinded and incorporated within an expanded polyurethane matrix utilized for thermal insulation, in order to reduce the use of virgin material and to promote a circular re-utilization of recycled materials. As observed by scanning electron microscopy, the formulations containing both recyclates showed a rather homogeneous cell structure, however their presence led to a strong reduction of the closed porosity. This reflected in a slight increase in the thermal conductivity, reaching maximum values of 0.030 W/m∙K in foams with 7.5%wt of PF particles. The introduction of the recyclates slightly improved the thermal stability of the PU foams and led to a general decrease in flexural and compression properties. Cone calorimetry tests demonstrated that the inclusion of PF particles reduced the peak heat release rate up to 28 % compared to neat PU foam, enhancing the fire safety of the insulating panels.

In order to enhance the toughness of mining polymer foam, polyethylene glycol (PEG), an organic material, was added to modify the toughening effect of foam. The effect of PEG modification with different molecular weight was studied by scanning electron microscope, thermogravimetric test, oxygen index test, cone calorimetric test, compressive strength test, foaming and curing time test. The results show that: PEG with different molecular weight can effectively increase the compressive strength of phenolic resin foam and reduce its pulverization rate. When the molecular weight of PEG is 1 000, the addition of 6% has the best toughening effect, the compressive strength reaches 0.155 MPa, and the pulverization rate decreases to 1.3%. Adding a certain amount of PEG can effectively increase the foaming ratio of phenolic resin, but at the same time, it will increase the shrinkage and curing time of its foam. The pore structure of PEG modified phenolic resin foam is more uniform, and the pore size of foam is also more uniform, mainly because the PEG that does not react with the phenolic resin plays the role of surfactant, and can better mix the curing agent with the resin. Compared with the thermal stability of phenolic resin foam with different PEG molecular weight, the larger the molecular weight, the worse the thermal stability of phenolic resin foam with more PEG molecular weight.

Polyvinyl chloride (PVC) is a kind of plastic widely used in different industries, and it is a hard and brittle polymer that requires the use of plasticizers to improve processability. Phthalates are small molecule plasticizers of PVC, which are easy to volatilize and migrate while improving the processing properties of PVC. We propose alternatives based on phenolic resin prepolymer modified by cardanol (CPF), which were added to PVC as reactive plasticizer and can improve the processability of PVC. The effects of CPF on the rheological properties and migration resistance of plasticized PVC were studied, and the changes in the physical properties of blends were also discussed. The results showed that the viscosity of PVC melt can be reduced by two orders of magnitude by adding 30 wt% prepolymers at 180°C compared with PVC without CPF, which indicated that CPF can be used to reduce the processing temperature of PVC. The test results of migration resistance showed that the mass loss rate of the blend with 30 wt% prepolymers was less than 1 wt% after curing, however, the mass loss rate of the blend with 30 wt% dioctyl phthalate (DOP) was more than 12% after 5 days of testing. When the PVC/CPF mass ratio was between 60/40-70/30, the maximum values of tensile strength and elastic modulus are 64.4 MPa and 3.2 GPa, respectively, which showed the addition of CPF could significantly improve the tensile strength and elastic modulus of the blend system compared with PVC without CPF. Especially, the thermal stability of CPF is better than that of DOP, CPF exhibits the maximum thermal decomposition temperature (410°C), higher than that of DOP (170°C), which can adapt to higher processing temperature. [ABSTRACT FROM AUTHOR]

Present work aims to analyze the effect of including carbon-based nano materials in the thermosetting polymer based composite in terms of their tribological properties based on critical assessment of several literature data in this field of research. In particular, nanocarbon materials such as carbon nano tubes (CNT), graphene oxides (GO), and graphene are effectively being incorporated in to various polymers as a reinforcement agent to develop polymer nanocomposite based brake pad material. Phenolic and epoxy resins are found to be the most popular thermosetting polymers in practice and research for brake pad material development. Accordingly, the role of nanocarbon which is responsible for the stable coefficient of friction and reduced wear rate due to its inclusion in to phenolic and epoxy resins-based polymer composite have been studied in the present work. As per the present meta-analysis of tribological properties for nanocarbon based phenolic and epoxy resins polymer composite, the analyses showed that an average of around 65% specific wear rate reduction using 5 wt% graphene inclusions in the phenolic based polymer composite as compared to the 5 wt% graphitebased phenolic polymer composite. While in other case a wear rate reduction of 70%, 85%, and 94% were also achieved using 1.5 wt% CNT, 5.3 wt% graphene, and amino treated 0.2 wt% GO respectively in epoxy resin-based polymer composite as compared to pure epoxy resin in all the cases. Moreover, nanocarbon potential in reduction of wear rate for both phenolic and epoxy resin based nanocomposites are found practically evident while maintaining the stable coefficient of friction. Finally the nanocarbon found to be highly potential in affecting the tribological properties with limited amount addition in both phenolic and epoxy polymer composites, while at the same time it is also found that the nanocarbon effect may not pop up in same way when many ingredients added in the phenolic and epoxy polymer composites. [ABSTRACT FROM AUTHOR]

Owing to economic reasons and the morphology of the surface of particles, carbothermal reduction is a suitable method for the synthesis of the desired materials. In this research, ZrC nanopowder was synthesized using phenolic resin as the carbon source and ZrO2 powder as the source of zinc by the carbothermal method. ZrO2 powder was milled for 1, 2, 3, 4, 6, and 7 h followed by combining with phenolic resin and ethanol with stoichiometric and nonstoichiometric ratios, and then the samples were pyrolyzed for 60 min at 800°C. Then, the samples were heat treated in an argon atmosphere in two stages at 1,600°C for 60 and 90 min. XRD and FE‐SEM were used to investigate the microstructure of the samples. By increasing the molar ratio and increasing the heat treatment time, the ZrC phase content in the samples increased so that the highest amount of ZrC phase was observed in the samples with the carbon to zirconium ratios of 1:6 and 1:9 and the holding time of 90 min. By increasing the heat treatment time, the average size of ZrC particles increased from 130 to 180 nm and the size of crystallites increased from 36 to 46 nm. [ABSTRACT FROM AUTHOR]

Although various aerogels with electromagnetic wave (EMW) absorbing properties have been extensively explored, the development of aerogels with excellent wave absorption performance, low density, and great heat resistance has still met profound challenges. Herein, polysilazane hybrid phenolic resin aerogels (PRVS aerogels) were prepared using the vinyl addition reaction of polysilazane and cross‐linking reaction between polysilazane and phenolic resin. A SiOCN ceramic aerogel with multistage pore structure was prepared via a simple and quick freeze‐drying method and polymer‐derived ceramic (PDC) methods. The SiOCN ceramic aerogels exhibited low density (0.15–0.27 g/cm3), good heat‐shielding (thermal conductivity in the range of 0.03–0.04 W/(m·K)), and excellent wave absorption performance (i.e., RL was about –31.6 dB@16.48 GHz and EAB was 3.85 GHz when the thickness of the ceramic aerogel was 1.2 mm). Hence, the ceramic aerogel absorbing materials could meet the requirements of "wide absorption bandwidth, strong reflection loss, lightweight and thi thickness". Moreover, the mechanism of low weight, heat insulation, and wave absorption properties of the aerogels were also investigated. We believe this work is of great significance in ceramic aerogels prepared by traditional polymers, which may provide new opportunities for new ceramic aerogels with applications ranging from EMW absorption to aerospace and information technology. [ABSTRACT FROM AUTHOR]

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In this research, the effect of adding aluminum oxide nanoparticles on the flexural strength of glass/phenolic composites that were exposed to water environment was experimentally investigated. To make glass/phenolic composites, IL‐800 phenolic resin, H002 hardener, T400 bidirectional glass fibers and Al2O3 nanoparticles were used. Four‐layer composite plates were made by hand layup method. Beam‐shaped samples were extracted from the plates with the help of laser cutting method. Rectangular composite beams made of glass/phenolic and Al2O3/glass/phenolic were subjected to three‐point flexural test. The moisture absorption test was continued until the amount of water absorption reached a constant level. Bending test was performed on the samples before and after immersion in water. Based on the results, the average flexural strength of the samples after water absorption shows a decrease of about 15%. This parameter is equal to 118.96 MPa for glass/phenolic composite samples immersed in water, and by adding 0.25 wt% of Al2O3 nanoparticles into the matrix material of glass/phenolic composite samples, the flexural strength reaches 142.54 MPa, which shows an increase of 19.82% compared to samples without nanoparticles. Furthermore, the amount of flexural modulus decreases after water absorption, and the addition of nanoparticles in the base material can compensate this reduction. Scanning electron microscopy images illustrate that the addition of Al2O3 nanoparticles into the phenolic resin can enhance the strength of matrix material and improve the adhesion of glass fibers to the resin. Highlights: Addition of nano Al2O3 reduces water absorption of glass/phenolic composites.Nano Al2O3 improves composite flexural strength after water absorption.Addition of nano Al2O3 increases the adhesion between the layers of the specimens. [ABSTRACT FROM AUTHOR]

Polymer materials such as epoxy and phenolic resin are widely used in the field of thermal management materials because of their good electrical insulation properties, chemical stability and easy processing properties. However, the low inherent thermal conductivity of polymer materials limits their wide application. Tn this work, multi-scale spherical AU ()3 particles were introduced into phenolic resin (PF) matrix to improve its heat transfer performance. We focused on the study of the influence of AU ()3 particle size and AU ()s loading on thermal conductivity and thermal stability of PF composites. The results show that the thermal conductivity of the AUO3/PF composite is up to 1.611 W/(m • K) at the total fillers loading is 75 wt% (the weight ratio of AU ()3 particles with large and small sizes is 1: 1), which is nearly 8 times higher than that of pure PF. At the same time, the thermal conductivity achieved is higher than that of PF composites with only small particles or large particles added. This is attributed to the fact that when the multi-scale spherical AU ()3 particle hybridized, the AU ()s particles with small particle size filled the gaps between the AU ()s particles with large particle size, constructing more heat transfer pathways in the matrix. The TG results show that the thermal stability of PF composites with AU ()3 fillers is improved, and the maximum decomposition temperature of AU ()3 / PF composites is increased from 51 7 °C to 543 °C. Therefore, our work provides a new idea for the preparation of high-performance polymer composites. [ABSTRACT FROM AUTHOR]

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Rubber compounds with high friction coefficients are widely used in safety shoes, functional shoes, etc. However, in the presence of a liquid lubrication layer, friction coefficients between rubber compounds and the opposing surface are generally very low. In this work, friction coefficients of rubber compounds are improved by a two‐pronged method. First, micron silicon carbides (SiC) with irregular shape and knife‐edge are selected as fillers to improve the plowing friction in dry state, and to improve the adhesive friction in wet state via piercing the liquid lubrication layer. Second, tackifying phenolic resin is added to increase the damping performance of rubber compounds, so as to improve the hysteresis friction in both dry and wet states. The results show that the comprehensive static and dynamic friction properties of rubber compounds are the best in both dry and wet states (0.5 wt% sodium dodecyl sulfate solution or 90 wt% glycerol solution), when SiC size is 7–14 μm and SiC content is 75–90 phr. Phenolic resin can increase the loss factor (tanδ) and loss modulus (E") of rubber compounds, and improve the static and dynamic friction coefficients in wet state (90 wt% glycerol solution). At the same time, it can improve the hardness of rubber compounds and reduce the relative content of SiC, thus reducing the static and dynamic friction coefficients of rubber compounds in dry and wet states (0.5 wt% sodium lauryl sulfate aqueous solution). In general, the optimal content of phenolic resin is 10–15 phr. Highlights: Rubber friction coefficients improved via both adhesion and hysteresis friction.Irregular silicon carbides pierce liquid layer to improve adhesive friction of rubber.Phenolic resin increases hysteresis friction of rubber via damping property. [ABSTRACT FROM AUTHOR]

Bamboo is a fast-growing plant with properties such as low cost, abundant resources, and good carbon sequestration effect. However, the swift growth of bamboo resources generates an immense quantity of processing waste, which is necessary to effectively utilize bamboo processing waste. The leftovers from bamboo processing can be reutilized by fast pyrolysis to prepare renewable bio-oil. In this study, bamboo bio-oil was partially substituted for phenol to synthesize phenolic resin with different substitution rates under the action of an alkaline catalyst, and then to serve as the adhesive to produce bamboo scrimber. Bamboo bundles were impregnated with synthetic bio-oil phenolic resin to create bamboo scrimber, which was subsequently hot-pressed. The research shows that modified phenolic resins with a bio-oil substitution rate of under 30% have good physical and chemical properties, while the free aldehyde content of phenolic resin with 40% bio-oil substitution exceeds the limit value (0.3%) specified in the Chinese National Standard. The thermal stability of phenolic resins was also increased after bio-oil modification, indicated by the movement of the TG curve to higher temperature ranges. It was found that the bamboo scrimber prepared with 20% BPF resin adhesive had the best comprehensive properties of a good mechanical strength, hydrophobicity, and mildew resistance, particularly with an elastic modulus of 9269 MPa and a static bending strength of 143 MPa. The microscopic morphology showed that the BPF resin was well impregnated into the interior of the bamboo bundle and had a compact bonding structure within the bamboo scrimber. The anti-mold performance experiment found that the bio-oil-modified resin increased the anti-mold level of the bamboo scrimber from slightly corrosion-resistant to strong corrosion-resistant. The conclusions obtained from this study have a good reference value for achieving the comprehensive utilization of bamboo, helping to promote the use of all components, reduce the production cost of bamboo scrimber, and improve its mildew resistance performance. This provides new ideas for the development of low-cost mildew resistant bamboo scrimber novel materials. [ABSTRACT FROM AUTHOR]

The use of asbestos in brake pads is being eliminated due to its carcinogenic effect. Due to this, there is a need for better alternative in the brake pad material to replace asbestos fibers. This leads to the development of more natural fibers/filler-based brake pads which are safer to the environment, cheaper, and readily available. Moreover, bio fillers-based brake pads have shown excellent performance compared to asbestos. This paper addresses the different composition of brake pad materials and manufacturing techniques. Common binders like epoxy resin, Phenolic resin-based brake pads were analyzed and its effect on the mechanical, tribological, and thermal performance were critically analyzed. Also, the performance of metal matrix-based brake pad has been analyzed in detail. It has been observed that utilizing natural fibers as a reinforcement provides an excellent braking performance compared to metallic and carbon fiber-based brake pads. This research will open new avenues towards "Net Zero." [ABSTRACT FROM AUTHOR]

Abstract Nanocarbons including carbon nanotubes, graphene oxide, reduced graphene oxide and particularly graphene have unique properties such as high mechanical strength, thermally stable, highly conducting, high friction stability and lower specific wear rates, which can potentially provide synergically improved performance of advanced engineering materials and technologies for various fields of applications such as automotive, aerospace, and other industrial components. Development of phenolic resin‐based nanocomposites comprised of nanocarbon material remained as a research focus to outperform different properties of conventional material based components. In application, phenolic resin is the most popular binder in frictional components development such as brake pads, brake linings, and clutch facings, particularly used in many of light and medium automotive brake pad applications. Specifically, the present review study aims to provide thorough discussion on the mechanical, tribological, and thermal performances of phenolic resin‐based nanocomposites containing nanocarbon as a property modifier by comparing with the neat phenolic resin or with the composite containing other micro ingredients. As per presented overview, the analysis shows the significant improvement in some required application‐based properties of phenolic resin‐based nanocomposites such as tensile strength, young's modulus, impact strength, specific wear rate reduction, residue yield, and thermal conductivity due to the inclusion of nanocarbon, where the content of nanocarbons ranges about 0.5 wt% to 5 wt%. Hence nanocomposites synthesized using phenolic resin matrix with nanocarbons fillers found to have better mechanical strength, better wear resistance, and thermal stabilities when compared to pure phenolic resin and other composites.

A novel class of hybrid composites was prepared containing carbon fibers along with carbon nanotubes and silicon carbide particles in phenolic resin for improved mechanical performance. The loading of carbon fibers was ~60 wt% while carbon nanotubes and silicon carbide particles were reinforced in the fractions of 0.1 wt% and 5 wt%, respectively. Individually reinforced composites containing 0.1 wt% carbon nanotubes and 5 wt% silicon carbide particles were also manufactured for comparison with hybrid composites. Microstructural and mechanical property characterization was performed using electron microscopy and mechanical testing, respectively. Uniform dispersion of nanometer-scale carbon nanotubes and micrometer-scale silicon carbide particles was observed under microscopy. The pooled effect of carbon nanotubes and silicon carbide particles significantly increased the tensile, compressive, and flexural performance of composites while carbon nanotubes offered greater weight fraction value improvement than silicon carbide particles.

Phenolic resin pyrolytic carbons were obtained by catalytic pyrolysis of phenolic resin at 500 °C, 600 °C, 700 °C, and 800 °C for 3 h in an argon atmosphere using copper nitrate as a catalyst precursor. The effects of copper salts on the pyrolysis process of phenolic resin as well as the structural evolution and oxidation resistance of phenolic resin pyrolytic carbons were studied. The results showed that copper oxide (CuO) generated from the thermal decomposition of copper nitrate was reduced to copper (Cu) by the gas generated from the thermal decomposition of the phenolic resin. Carbon nanofibers with tapered structures were synthesized by Cu catalysis of pyrolysis gas at 500–800 °C. The catalytic pyrolysis of phenolic resin with Cu increased the graphitization degree and reduced the pore volume of the phenolic resin pyrolytic carbons. The combined action improved the oxidation resistance of phenolic resin pyrolytic carbons.

The effects on the stability under accelerated degradation of phenolic resin used for the corrosion inhibition of metallic surfaces in aeronautical and nuclear spare parts are evaluated by nonisothermal chemiluminescence (CL) at four different heating rates: 5, 10, 15, and 20 °C min-1. The simulation of the interface interaction between the metallic bodies and protection layers is achieved by the addition of metallic oxides as corrosion promoters: Gd2O3, CeO2, Pr2O3, MgO, MnO2, Cr2O3, and In2O3. These metallic atoms may be the main alloying elements that are present in the compositions of special application products. The presence of a specific peak in the CL spectra between 160 and 177°C proves the oxidation activity of filler in the connection of electronic interference. The differences between the emission intensities of the studied formulations certify the unlike contributions of alloying components. The heating rate plays also the role of oxidation factor that influences the refreshing surrounding atmosphere. The present results define the thermal technological limits of peculiar operation conditions for any metallic item subjected to a high level of warranty. The initiation of degradation in phenolic resin is done by γ-irradiation when free fragments are provided for the interaction with metallic structures. The development of oxidation is analyzed by the modification of CL emission intensities from room temperature to 250°C. The diminution of this process parameter over 200°C is found an essential factor for the preservation of surface integrity. [ABSTRACT FROM AUTHOR]

Phenolic resin(PF) is commonly used as a binder in Al 2 O 3 -SiC-C bricks; however, it reduces the strength and accelerates the damage after carbonisation under temperatures of 300–800 °C. To improve the medium-temperature mechanical properties of Al 2 O 3 -SiC-C bricks, the mechanism of silica sol modify PF was analyzed, and silica sol modified phenolic resin (PFS) was introduced into Al 2 O 3 -SiC-C bricks to explore the effect of PFS on the mechanical properties of Al 2 O 3 -SiC-C bricks. The results showed that the silanol groups (Si-OH) in the silica sol can react with the hydroxyl groups (-OH) in the PF to form a Si-O-C bond, which makes PFS have a higher residual carbon rate and greater thermal stability. Overall, the introduction of PFS enhances the mechanical properties of the Al 2 O 3 -SiC-C bricks. When the content of silica sol in PFS is 10 wt%, the cold modulus of rupture and compressive strengths increased by 62.6% and 22.1%, respectively. [ABSTRACT FROM AUTHOR]

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