Phenolic Resin Research Articles

A tough, strong, and fast-curing phenolic resin enabled by quercetin-functionalized hyperbranched polymer

Phenolic resins are widely utilized in outdoor and structural wood-based panels; however, their high curing temperatures and brittleness have constrained their potential applications. This study developed a fast-curing phenolic resin (HPAQ/PF) with enhanced toughness and strength, achieved by incorporating a quercetin-functionalized hyperbranched polymer (HPAQ) into a phenol-formaldehyde (PF) resin. The HPAQ was synthesized by grafting biomass-derived quercetin onto an amino-terminated hyperbranched polymer. The phloroglucinol structure of quercetin, in conjunction with the amino groups, significantly accelerated the curing process of the HPAQ/PF resin. Consequently, the gel time was reduced from 593s to 274s, while the initial and maximum curing temperatures decreased from 155.6°C and 202.4°C to 128.7°C and 171.7°C, respectively. The moisture uptake value of the HPAQ/PF resin was reduced from 28% to 7% compared to the PF resin. The boiling water bonding strength and debonding work of the HPAQ/PF resin were measured at 1.75MPa and 0.780J, respectively, which were 51% and 105% higher compared to the 1.16MPa and 0.380J of the PF resin. These improvements were attributed to the enhanced compatibility and strong interfacial interactions between HPAQ and the PF chains, as well as the unique branched structure and intramolecular cavities of HPAQ. This study presents a simple and effective approach to enhance the curing speed and toughness of phenolic resins.

Dandelion inspired multi-functional superhydrophobic bamboo scrimber with desirable humidity resistance

Bamboo scrimber is high value added biomass fiber composites from natural bamboo due to its excellent multiple properties. However, the hydrophilicity of bamboo scrimber make it being susceptible to mold, fungi decay, colour changing and cracking during outdoors application. Therefore, wind blowing dandelion inspired multi-functional superhydrophobic bamboo scrimber was fabricated by spraying solution of Cu2O nanoparticles (NPs) modified phenol formaldehyde (PF) resin, immersing ethanol solution of stearic acid, followed by growth of copper stearate nanowires. The superhydrophobic bamboo scrimber exhibited desirable chemical and mechanical durability, liquid permeability, ultraviolet resistance, self-cleaning and anti-fouling properties, as well as mold resistance. More importantly, the modified bamboo scrimber performed best humidity resistance over 136 days under relative humidity of 85% in this field, which can be attributed to the dense nanostructure of copper stearate nanowires. Furthermore, a specific bamboo cellulose crystalline model from natural bamboo to bamboo scrimber was firstly proposed to support the improvement of hardness. This work provide an biomimetic strategy for bamboo scrimber superhydrophobic modification, and it’s also innovative to promote the high value development of biomass composites.

Cathodic catalyst from lemon peel-based hydrogel for application in a SCMFC

In this investigation, a hydrogel has been prepared with the filling of lemon peel powder (LP) at three different concentrations of 1, 1.5, and 2 g (CS-PF/LP1, CS-PF/LP1.5, and CS-PF/LP2), in a mixture of phenol formaldehyde resin and chitosan, and they are pyrolyzed at 700°C to get soluble metal and nitrogen-doped carbon as cathode catalysts for oxygen reduction reaction (ORR). Several analytical characterization results confirmed the presence of inherent metallic content (or soluble metal) in the LP power. Among the three, CS-PF/LP1 provides the maximum surface area of 259.38 m2g-1, which is confirmed by the BET analysis. Additionally, the highest conductivity and catalytic activity of CS-PF/LP1 are also confirmed by electrochemical analysis. Thus, CS-PF/LP1 was selected to be used in a single-chamber microbial fuel cell (SCMFC) as a cathode catalyst. A maximum power density of 170.67 mWm-2 is obtained for CS-PF/LP1 which is 5.70 times higher than the base catalyst (without LP). Therefore, the present work uses LP, a waste material to develop a porous carbon material that can be used as an efficient cathode catalyst using solely the soluble metals of LP, for ORR in SCMFC for efficient power generation.

Investigation of Impact Behaviour of Sisal Fiber Reinforced Phenol Formaldehyde Composites

Short Sisal fiber reinforced Phenol Formaldehyde resin composites are prepared with varied fiber lengths (5 mm and 10 mm) and for varied weight fraction (20%, 25% and 30%) of the fibers. Here in this work, Sisal fiber is used as reinforcement. Since it is abundantly available in nature and majority of it is getting wasted without being used as reinforcement in engineering applications. Over the last thirty years composite materials, plastics and ceramics have been the dominant emerging materials. The 10 mm fiber length reinforced composite shown improved mechanical properties than 5 mm fiber length reinforced composite. Increase in impact strength is seen when the fiber content in the composite is increased from 20% to 25% and 25% to 30%. The fiber strength, for different fiber lengths and fiber volume fraction, the work of fracture is proportional to the fiber length and fiber volume fraction. Although results show increment in impact strength with fiber volume fraction, proportionality is not demonstrated. This suggests that there are other mechanisms that affect the impact strength of the composites. Crack propagation is the predominant toughening mechanism in notched impact test. Improvement in impact strength characterizes that fibers as stress transferring medium are able to absorb impact energy effectively. Good interaction with crack increases the energy needed for further crack formation and propagation. The exceptional case could be due to low fiber content and relatively short fiber length so that the energy is not dissipated effectively. Weak interfacial bonding of natural fibers is mainly due to incompatibility of hydrophobic matrix and hydrophilic fiber. High moisture absorption causes dimensional changes of natural fibers as well.

Enhanced tribological performance of PLA/CNC composites: A comparison with phenolic resin and nylon

PLA has been developed to replace plastic because it is degradable. For more advanced applications, more research is needed on PLA. This study investigates the tribological properties of phenolic resin, nylon, and PLA/CNC composites under varying sliding distances and loads. Both phenolic resin and nylon demonstrate exceptional wear resistance and stable friction coefficients. PLA/CNC composites exhibit improved wear resistance, showing a 17% reduction in friction coefficient at a 3 wt.% CNC content. While the wear volume of PLA/CNC composites increases with sliding distance, the addition of CNC enhances PLA’s self-lubricating properties and overall wear resistance. The correlation between dissipated energy and wear volume confirms that higher CNC content significantly improves the durability of PLA. These findings suggest that CNC has considerable potential as an additive to enhance the tribological performance of PLA composites, making it a valuable material for various applications requiring superior wear resistance.

Largely enhanced damping performance of nitrile rubber/ethylene–vinyl acetate blends via phenolic resin-induced phase separation

The low glass transition temperature (Tg) and narrow effective damping temperature range (EDTR) greatly restrict the application of common vulcanized rubbers in fields relating to high temperature environmental condition due to the greatly reduced damping performances. In this work, phenolic resin (PR) was incorporated into nitrile rubber/ethylene–vinyl acetate (NBR/EVM) blends through melt-compounding processing, and the microstructure and damping performance changes induced by PR were comparatively investigated. The results show that PR induces the phase separation of the blends and most of PR particles selectively locate in the NBR component. Molecular dynamics simulation confirms that more hydrogen bonds form in the ternary blends, and reduced free volume fraction is also achieved. The ternary blends show good high-temperature damping performances, and apparently enhanced Tg (up to 17.7 °C) and EDTR (82.6 °C, from −2.6 to 80 °C) are also achieved. Additionally, the ternary blends exhibit good mechanical properties, including higher ductility and larger fracture energy, and better energy dissipation ability. This work provides an alternative resolution way to enhance the damping performances of the common vulcanized rubbers at high temperatures.

Honeycomb Molding - Forming Thermoplastic Sandwich Structures for Interior Applications

Trains play an important role in the sustainable mobility of the future. The changes in the market are reflected in the number of newly approved series by the German Federal Railway Authority (EBA); 226 new designs and redesigns of train cars were approved for use on German rails in 2019. Phenol-formaldehyde resins are used extensively specifically for railcar interiors. However, phenol-formaldehyde resins release carcinogenic vapors during and even after production if not completely sealed. As a result, European production standards and requirements have been increased, making the material less economical and increasingly difficult to enter the market. Further bans aimed at lower formaldehyde release limits are currently being considered by the European Union's Committee for Risk Assessment (RAC) and Committee for Socioeconomic Analysis (SEAC). In order to develop and design alternative materials, it is important to meet the requirements for stiffness, light weight, insulation and sustainability simultaneously. This research aim is therefore to develop a new class of material for interior components with improved stiffness, lower weight, lower CO2 footprint and no health hazards. The approach is to develop advanced composite sandwich panels that retain the ability to be molded into complex structures for interior applications. This is done through a thermoplastic honeycomb core structure that is manufactured directly from sheet material and fiber reinforced organo-sheets as the outer layers. The base matrix for all layers is kept uniform for better recyclability and consists of polycarbonate (PC) with sufficient flame retardant properties to provide an environmentally friendly alternative to existing phenolic resin and aramid epoxy honeycomb solutions while still complying with the security norms.

An organic-inorganic dual network built in fast-growing wood veneers to improve the flame retardant and mechanical properties of plywood

Fast-growing wood is widely used in plywood production due to its short growth cycle and low cost. However, its loose fiber structure, inferior material quality, and high flammability significantly limit the application range of plywood products and hinder high-value utilization. This paper reports a simple method for modifying fast-growing wood veneers. We modified phenolic resin with Mg(OH)₂@nano-silica composite particles and impregnated it into the veneers, constructing an organic-inorganic hybrid dual-network structure on both the surface and interior of the veneers. The plywood prepared from the modified veneers exhibited a bending strength of 115.6 MPa, a modulus of elasticity of 9.7 GPa, and a wet shear strength of 2.1 MPa, representing increases of 86.1%, 47.0%, and 90.9%, respectively, compared to plywood made from unmodified veneers. Additionally, the peak heat release rate decreased by 15.3%, and the ignition time was extended to 26 seconds. The uniformly distributed inorganic network effectively mitigated stress concentration and, together with the phenolic resin, formed an efficient thermal insulation layer, enhancing the flame retardancy of the material. This study offers a simple and effective treatment method for reinforcing fast-growing wood veneers, promoting the use of fast-growing wood in high-performance applications.

Synthesis of Phosphorus-containing Modifier based on Phenolic Epoxy Resin and its Application in Flexible Poly(vinyl chloride)/Magnesium Hydroxide Composites

Synthesis of Phosphorus-containing Modifier based on Phenolic Epoxy Resin and its Application in Flexible Poly(vinyl chloride)/Magnesium Hydroxide Composites

Optimization of crosslinked network structure of cured phenolic resin with high char yield

Optimization of crosslinked network structure of cured phenolic resin with high char yield

Controlled fabrication of hierarchical porous carbon nanospheres with high doped nitrogen content for high-performance adsorbent of biomacromolecule

Constructing nitrogen-doped porous carbons with high specific surface area, rapid mass transfer channels, and positive charge is a crucial requirement for high-performance adsorbents. Herein, by the kinetic self-assembly synthesis strategy, we prepared nitrogen-doped hierarchical porous carbon spheres (N-HPCS) with adjustable pore structure, high specific surface area, and high nitrogen doping content (8.88 %). By using ethylenediamine as an assisted polymerization and assembly agent, the hydrolysis and condensation rate of tetraethyl orthosilicate (TEOS) as the silica source and the condensation rate of 3-aminophenol and formaldehyde as the phenolic resin precursor were controlled by adjusting ammonia volume as the alkaline catalyst to tune kinetic self-assembly of silica and phenolic resin components, thus achieving their simultaneous or sequential nucleus and growth. After carbonization and selective silica etching, three types of carbon nanospheres with center-radial pores, hollow center-radial pores and hollow structure were obtained. High nitrogen doping content endowed the nanospheres with positive charge. Through adsorption experiments on the bovine serum albumin (BSA) and Hemoglobin (Hb) as typical biological macromolecules, hollow carbon nanospheres with center-radial pores exhibited excellent adsorption performance for BSA(622.34 mg g−1) and Hb(759.96 mg g−1). Our fabricated N-HPCS may become a potential candidate for high-performance adsorption materials.

Modeling the Dynamic Properties of Multi-Layer Glass Fabric Sandwich Panels.

Sandwich panels are key components of many lightweight structures. They are often subjected to time-varying loads, which can cause various types of vibrations that adversely affect the functionality of the structure. That is why it is of such importance to predict the dynamic properties of both the panels and the structures made of them at the design stage. This paper presents finite element modeling of the dynamic properties (i.e., natural frequencies, mode shapes, and frequency response functions) of sandwich panels made of glass fabric impregnated with phenolic resin. The model reproducing the details of the panel structure was built using two-dimensional, quadrilateral, isoparametric plane elements. Afterwards, the model was subjected to an updating procedure based on experimentally determined frequency response functions. As a result, the average relative error for natural frequencies achieved numerically was 5.0%. Finally, a cabinet model consisting of the analyzed panels was built and experimentally verified. The relative error between the numerically and experimentally obtained natural frequencies was on average 5.9%.

Influence of Silicon Carbide Incorporation on Thermal and Ablation Properties of Carbon Fabric-Phenolic Resin Composites

To shield re-entry spacecraft from the extreme heat experienced during hypersonic flight through a planet's or the earth's atmosphere, thermal protection systems (TPS) were developed. This work involved the fabrication of composites using a polyacrylonitrile (PAN) based carbon fabric (Cf)-phenolic resin matrix (PR) modified with different weight percentages (wt.%) of silicon carbide (SiC), namely 0 wt.% (Cf/PR), 1wt.%, 3wt.%, and 5wt.%. The composites were prepared using the hydraulic hot press method. The manufactured composites were analyzed for their thermal conductivity and resistance to ablation using an oxyacetylene torch test. Furthermore, the ablated composites underwent X-ray diffraction (XRD), revealing a SiO2 compound layer on the ablated composite surface. The experimental results demonstrated that the Cf/PR composites modified with 3wt.% of SiC exhibited superior characteristics. The composites consist of 3wt.% Cf/PR-SiC exhibited a thermal conductivity value of 0.57 W/m K. Additionally, these composites showed a noticeable decrease in the mass ablation rate (MAR) at 0.0052 mm/sec and linear ablation rates (LAR) at 0.025061 gm/sec. This study proposed an effective way to improve the thermal and ablation characteristics of TPS materials.

The Effect of Fractional Composition on the Graphite Matrices' Porosity.

Synthetic graphite of complex fractional composition was mixed with phenolic resin as a binder and pore-forming component. The mixtures were pressed and subsequently heat-treated to obtain porous matrices. The structural transformations of phenolic resin by heating up to 900 °C in oxygen and inert gas media were studied and the patterns of amorphization of fixed carbon formed on the walls of the pore system during carbonization were investigated. We found regularities in the changes in matrix volume density in the function of the open porosity and the average pore diameter. It is shown that, in order to obtain graphitized carbon matrices with a density of 1 g/cm3 and an open porosity of at least 50%, it is necessary to introduce no more than 20% of phenolic resin into the molding powder with an equal content of 60, 100 and 250 μm graphite fractions. This allows for high intensity and completeness of bulk silicon infiltration.

Thermal stability and anti-ablation performance of plasma spray coated-YSZ on Al2TiO5 modified novel ablative carbon-phenolic composites

Abstract Despite ongoing challenges, ablative thermal protection systems are among the most promising methods for safeguarding spacecraft during re-entry thermal protection systems (TPS). A novel aluminium titanate (Al2TiO5/AT) and a highly efficient thermal barrier of coating (TB/TBCs) made from yttria-stabilized zirconia (YSZ), powder, but deposited using the plasma spray technique on polyacrylonitrile (PAN)-based carbon fiber fabric(C)-reinforced with resorcinol phenol formaldehyde resin (RF) composites (C-RF)) would be a potential candidate for TPS applications. This study investigates the composites with varying wt.% of AT that were developed, namely 0 wt.% (YSZ-C-RF), 1 wt.%, 3 wt.%, and 5 wt.% (YSZ-AT-C-RF) by utilizing a hot press moulding machine. Thermal stability and ablation performance of unmodified C-RF with modified YSZ-C-RF and YSZ-AT-C-RF composites are examined through thermogravimetric analysis (TGA) and oxyacetylene torch test/OAT (4.0 MW/m2 for 60 sec). Also, the phase composition and microstructure of the ablated surface are determined by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The TBC of YSZ has an obvious influence on the residual weight ratios at high temperatures in C-RF and also plays a positive role in increasing thermal stability under nitrogen atmosphere for enhancing ablation resistance concerning YSZ-C-RF. The mass and linear ablation rates (MAR and LAR) of the composites after modifying the surface by YSZ-coated particles are reduced by 82.98% and 15.65%, respectively. Similarly, the introduction of AT particles and TBC of YSZ results in evidence of improving the thermal stability and the ablation resistance in varying wt.% of YSZ-AT-C-RF composites. The primary optimum AT weight loading for enhancing ablation resistance in YSZ-C-RF composites is 1wt.%. The modification of 1wt.% AT particles and YSZ-Coated particles reduce MAR and LAR by 54.79% and 61.94%, respectively. This work offers a meaningful method to remarkably enhance the ablation performance of the modified C-RF and YSZ-AT-C-RF composites.

Aramid nanofiber-modified carbon paper to enhance adaptability and performance of proton exchange membrane fuel cells

This study developed a novel method to enhance the comprehensive performance of carbon paper (CP) by using aramid nanofibers (ANF) modified phenol formaldehyde resin (PF). The effect of ANF modification ratios (0 wt%, 0.6 wt%, 1.2 wt%, 1.8 wt%, 2.4 wt%) on ANF dispersion in PF impregnation solution, PF thermal stability, and PF carbon matrix structure were investigated. Compared to unmodified PF, ANF-modified PF matrix carbon exhibited increasingly regular and ordered structures, with the ID/IG value decreasing from 2.16 to 2.02. Furthermore, with ANF modification ratio increasing, the tensile strength, flexural strength, porosity and gas permeability of CP exhibited a pattern of initial increase followed by a decrease, and when increasing to 1.8 %, reaching the optimal values of 14.28 MPa, 531.61 MPa, 85.94 %, and 2520 L·m−2·s−1, respectively. The limiting power density of proton exchange membrane fuel cells (PEMFCs) assembled with 1.8 wt% ANF-modified CP gradually increased with different assembly torques of 2, 4 and 6 N·m, reaching maximum values of 0.86, 0.98, and 1.1 W·cm−2, respectively. Therefore, the novel ANF modification method of CP provides new insights into enhancing PEMFCs assembly adaptability, potentially addressing issues related to low mechanical stability and poor pore structure affecting PEMFCs performance.

Effect of Resin Content on the Properties of Roofing Tile for Building Materials

The production process of roofing tile materials uses among other materials thermosetting adhesive resins normally urea formaldehyde (UF), phenol formaldehyde (PF), di-isocyanate (PMDI) at various content mixtures, 3wt%, 5wt%, 7wt%, 9w% and 11wt% with a usual thickness of 6 mm. The fibers, adhesives, and other materials are then placed into a steel mold with the standard dimensions of 400 mm x 400 mm, to be then hydraulically pressed at high pressure and the required temperature. Overall, PMDI synthetic adhesives have better physical and mechanical properties than PF synthetic adhesives, however the thermal properties of UF and PF synthetic adhesives are better than PMDI. The physical properties testing were density, humidity content, absorption of water, thickness inflated and water permeability. The mechanical properties such as modulus of rupture (MOR) and modulus of elasticity (MOE), impact strength and tensile strength are all measured according to JIS A 5908-2003, ASTM D 256-2006a,TIS 535-2556 and ASTM D1037-12.The testing for the thermal conductivity, thermal resistivity and solar reflectance were done according to ASTM C177-2010 and ASTM E 891-87. The type of resin content and adhesive used had a significant impact on the physical, mechanical and thermal properties of the roofing tile materials of showed in the results of the analysis of variance (p >0.05). The produced roofing tile has an improved thermal conductivity and heat insulation which can be a substitute for hazardous asbestos based roofing materials.

A Novel Approach to the Development of Natural Resin‐Based Biopolymer in the Presence of a Reusable Catalyst: Characterization and Modeling of Material Properties

ABSTRACTThe rise in environmental and health concerns has led to increasing attention to nature‐derived materials. Natural resin (NR) is secreted by pine trees, and it is a great monomer source for synthesizing biopolymers. The objective of this study is to produce terpene rosin phenolic resin (TRPR) from NR, turpentine, and phenol by applying a novel polymerization technique. An environmentally friendly and reusable catalyst (Amberlyst15) was chosen instead of traditional ones. TRPR samples were chemically characterized using Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), and gel permeation chromatography (GPC) analysis. The average molecular weight (Mw) of TRPR was detected as 560 g/mol. Artificial neural network (ANN) modeling was designed with three inputs (pressure, temperature, and terpene/NR ratio) and four outputs (reaction yield, acid value, saponification value, and softening point). The highest TRPR yield was obtained with a terpene/NR ratio of (1/2) at 80°C and under 3 atm. The lowest acid and saponification values were calculated as 90.54 and 100.11 mg KOH/g, respectively. The softening point of TRPR reached 80°C and it was suggested for use in the paper, ink, and adhesive industries.

Investigation of Mechanical Properties of Short Sisal Fiber Reinforced Phenol Formaldehyde and Vinyl Ester Composites

Composite materials are replacing standard Engineering metals and alloys for many applications. Here in this work, Sisal fiber is used as reinforcement. Since it is abundantly available in nature and majority of it is getting wasted without being used as reinforcement in engineering applications. Short Sisal fiber reinforced Phenol Formaldehyde and Vinyl Ester resin composites are prepared with varied fiber lengths (5 mm and 10 mm) and for varied weight fraction (20%, 25% and 30%) of the fibers. The short Sisal fibers are treated with 5% of Sodium Hydroxide (NaOH) solution. In the present work, the effect of the fiber treatment, fiber length and fiber loading on the mechanical properties are investigated. The results show that the Alkali Treated Sisal fiber reinforced composites have better mechanical properties than untreated composites. The 10 mm fiber length reinforced composite shown improved mechanical properties than 5 mm fiber length reinforced composite. Increase in mechanical properties is seen when the fiber content in the composite is increased from 20% to 25% and 25% to 30%. The 30% weight of the Sisal fiber reinforced composite has shown higher values of mechanical properties.

Preparation of phenol-formaldehyde composite modified with chitosan for the simultaneous removal of antibiotics and heavy metal ions in waters

In current study, a new adsorbent based on aminated phenol-formaldehyde composite was prepared using chitosan as modifier. Various techniques were adopted to characterize the morphology and structure of the prepared adsorbent. Due to the abundant amino groups, the obtained adsorbent presented satisfactory adsorption performance towards fluoroquinolones (FQs) and heavy metal ions (including Cu2+, Cd2+ and Pb2+) by means of multiple forces including electrostatic, H-bonding, π-π stacking interactions (for FQs) and chelating force (for heavy metal ions). Studies about the adsorption kinetics, isotherm and thermodynamics were performed to inspect the adsorption behaviors of studied FQs and heavy metal ions on the new adsorbent. After optimizing the adsorption parameters, the obtained adsorbent were employed to remove FQs, Cu2+, Cd2+ and Pb2+ in various environmental waters. The removal rates for FQs and heavy metal ions were 91.8–98.6 % and 94.4–98.5 %, respectively, which were significantly higher than that obtained on unmodified phenol-formaldehyde resin (20.7–49.0 % for FQs and 35.1–43.0 % for heavy metal ions). At the same time, the adsorbent exhibited good preparation repeatability in different batches, acceptable stability and reusability. The current study well demonstrated the potential application of the new adsorbent in the simultaneous removal of organic and inorganic pollutants from aqueous waters.