Modified Phenol Formaldehyde Resin Research Articles

By the force of decay: A green strategy to fabricate white rot fungal degraded wood for sustainable oil/water separation

Two species of white rot fungi, Coriolus versicolor（Cv）and Fomes fomentarius (Ff), were successfully applied to selectively degrade lignin of balsa wood, which caused weight loss of 15.66% and 9.66% respectively. Subsequently, the remained wood template was impregnated with 1 wt% cuprous oxide modified phenol formaldehyde resin and 4.8 wt% Stearic acid (STA, C17H35COOH), which was endowed with superhydrophobicity, high oil absorption capacity and filtration efficiency up to 8.97 g/g and 95% respectively. It was first time discovered that the absorption capacity of as prepared wood was not decreased but improved with the increase of the recycle times. Characterized by absorption efficiency of chloroform increased from the initial 5.69–8.97 g/g after 84 times repeat oil absorption process. While, the filtration efficiency for chloroform remains above 95% even after 84 cycles. Furthermore, the as modified balsa wood performed desirable photocatalytic degradation efficiency toward methylene blue (MB) more than 95% even after 84 cycles, this multifunctional aspect enhances the material's applicability for various environmental remediation purposes. This work proposed a novel, green and facile strategy to fabricate sustainable oil/water separation material, which has potential to be applied to oil/water separation industry.

Modified phenol formaldehyde resin with sodium silicate as a low-cure wood adhesive

Phenol-formaldehyde (PF) resin is a common adhesive in the plywood industry with the main advantage of its water resistance and high bonding strength. However, PF has unfavorable high curing temperatures which becomes of cost concern. In the present work, sodium silicate was used to modify the resin properties to lower its curing temperature. The amount of sodium silicate was varied in a range of 0% to 25% (w/w) in terms of sodium silicate to phenol. The thermal properties of the modified resin and its bonding strength were investigated. The experimental result showed that the presence of sodium silicate can increase crosslink density which leads to higher bonding strength. In addition, the presence of sodium silicate resulted in a lower curing temperature and reduced curing activation energy. The addition of 25% (w/w) sodium silicate could increase the bonding strength by more than 200% and decrease the curing temperature by about 35 °C. The improved processability and energy consumption offer advantages for the effective application of phenol-formaldehyde, particularly in the wood industry.

Enhancing and toughening bamboo interfacial bonding strength by reactive hyperbranched polyethyleneimine modified phenol formaldehyde resin adhesive

Phenol formaldehyde (PF) resin adhesives are widely used in the production of bamboo-based composites owing to their excellent bonding strength and durability. However, the inherent brittleness of cured PF resin may result in notable stress concentration at the interface between PF resin and bamboo bonding, leading to the generation of cracks. In this study, a hyperbranched compound polyethyleneimine (PEI) with high reaction activity was incorporated into a PF resin adhesive to toughen the adhesive and the bonding interface. And the effects of PEI incorporation on the properties of the adhesive and the bonding performance between PF resin and bamboo were comprehensively investigated. The results showed that introduction of flexible PEI chains could effectively facilitated stress transfer, avoiding stress concentration, thus enabling efficient energy release and play a toughening effect. In addition, PEI could react with PF resin and bamboo components during hot pressing, forming a three-dimensional network structure and enhancing the bonding interface, which was proved by FT-IR and XPS analysis. When 1 wt% PEI was incorporated, the bending strength and Charpy impact toughness of the modified PF resin was significantly increased by 38.88% and 76.02%, respectively, compared with the pure PF resin. While the dry and wet shear strength of the bamboo composite bonded by the PEI modified PF resin were also obviously increased. This study is expected to address the problem of cracking in the bonding interface of bamboo composite, and endow the composites with high strength and durability, which can prolong its service life and contribute to the healthy and sustainable development of the bamboo industry.

Effects of the Addition of Amino-Terminated Highly Branched Polyurea on Curing Properties of Phenol-Formaldehyde Resin.

In this work, a highly branched polyurea (HBP-NH2) similar to urea structure was introduced to phenol-formaldehyde (PF) resin to accelerate itscuring speed The results of gel time and bonding strength were combined to obtain a good modified additional stage and amount of HBP-NH2. The relative molar mass changes of HBP-NH2-modified PF resin were investigated by gel permeation chromatography (GPC). The effects of HBP-NH2 on the curing of PF resin were investigated by differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The effect of HBP-NH2 on the structure of PF resin was also investigated by nuclear magnetic resonance carbon spectroscopy (13C-NMR). The test results show that the gel time of the modified PF resin was reduced by 32% and 51% at 110 °C and 130 °C, respectively. Meanwhile, the addition of HBP-NH2 increased the relative molar mass of PF resin. The bonding strength test showed that the bonding strength of modified PF resin increased by 22% after soaking in boiling water (93 °C ± 2) for 3 h. The DSC and DMA analysis indicated that the curing peak temperature decreased from 137 °C to 102 °C, and the curing rate of the modified PF resin was also faster than that of the pure PF resin. The 13C-NMR results showed that HBP-NH2 in the PF resin reacted to produce a co-condensation structure. Finally, the possible reaction mechanism of HBP-NH2 for the modification of PF resin was given.

Sinteza fenolne smole ojačane nanočesticama TiO2 i njezin utjecaj na gorivost lamelirane drvne građe (LVL)

In this study, phenol-formaldehyde (PF) resin has been modified with titanium dioxide nanoparticles (nano-TiO2) at a varying ratio from 0.05 wt.% to 1.5 wt.% to enhance the thermal properties and combustion performance of the resins. The effect of the nano-TiO2 modification on the properties (chemical or thermal) of the resins was determined by Fourier to transform infrared (FT-IR) and thermal analysis (TGA) techniques. In addition, the combustion performance of laminated veneer lumber (LVL) samples bonded with the PF resin modified with nano-TiO2 was tested. The result of the FT-IR analysis indicated that the modified PF resins had match peaks to the reference PF resin. These similarities of the peaks supported that the modified PF resins were successfully synthesise with phenol, formaldehyde, and nano-TiO2. The PF resins modified by nano-TiO2 demonstrated better thermal stability than the reference resin. The nano-TiO2 modified PF resin exhibited a favourable influence on the combustion characteristics of LVL. In consequence, PF resin modified with nano-TiO2 could be used as a combustion retardant adhesive in the wood industry.

Synthesis and characterization of green phenolic resin with olive oil mill wastewater

Olive oil mill wastewater (OMW), a by-product of the olive oil industry, each year is generated millions of tons all over Mediterranean countries. Uncontrolled disposal of the OMW leads to massive environmental problems including soil and water pollution. In this experimental study, the OMW was used to partly replace clean water for getting prepared formaldehyde solution. Then, phenol and formaldehyde solutions were synthesized under alkali conditions to obtain more green phenol–formaldehyde (PF) resin. The effect of the OMW substitution level on the chemical and thermal properties of PF resin was examined by the Fourier transform infrared (FT-IR) spectral and thermogravimetric (TGA) analysis, respectively. Moreover, the bonding strength of each PF resin was evaluated under dry and wet conditions. It was found that FT-IR measurements showed that the PF resin containing various amounts of the OMW had a chemical structure very similar to the PF resin. The thermogravimetric analysis demonstrated that the low‐molecular‐weight organics in the OMW had negatively affected the thermal stability of the modified PF resins. In addition, the wood samples bonded with the PF resin containing up to 30 wt% OMW met the minimum requirements of interior and exterior bonding performance according to standard EN 12765. The OMW could be replaced by clean water up to 30 wt% for the production of green phenolic resin.

Relevance between Cassava Starch Liquefied by Phenol and Modification of Phenol-Formaldehyde Resin Wood Adhesive.

A novel type of phenol-formaldehyde (PF) resin was prepared by utilizing the liquefaction products liquefied by phenol under acidic conditions and then reacted with formaldehyde under alkaline conditions. The relationship between the liquefaction behavior of cassava starch and the properties of modified PF resin wood adhesive was studied. The effects of the liquid–solid ratio of phenol to cassava starch, sulfuric acid usage, and liquefaction time on the liquefaction residue rate and relative crystallinity of cassava starch were determined. The results showed that the bonding strength of modified PF resin decreased gradually with the decrease of the liquid–solid ratio. It was a great surprise that bonding strength still met the requirement of the national standard of 0.7 MPa when the liquid–solid ratio was 1.0. The detailed contents were analyzed through FT-IR, SEM, and XRD. In terms of the utilization of bio-materials for liquefaction to synthesize wood adhesive, cassava starch may be superior to the others.

The Manufacturing of Composite Materials in the Matrix of Modified Phenol-Formaldehyde Resins

The Manufacturing of Composite Materials in the Matrix of Modified Phenol-Formaldehyde Resins

Wood–Polymer Duroplastics Based on Modified Phenol–Formaldehyde Resins

Wood–Polymer Duroplastics Based on Modified Phenol–Formaldehyde Resins

Incorporation of In Situ Synthesized Nano-Copper Modified Phenol-Formaldehyde Resin to Improve the Mechanical Properties of Chinese Fir: A Preliminary Study.

Phenol-formaldehyde (PF) resin, modified using nano-copper with varying contents (0 wt%, 1 wt%, 3 wt%), was manufactured to improve the mechanical properties of Chinese fir. The morphology, chemical, micromechanical and micromechanical properties of the samples were determined by transmission electron microscopy (TEM), atomic force microscopy (AFM), environmental scanning electron microscopy (ESEM), Fourier transform infrared spectroscopy (FTIR), nanoindentation (NI) and traditional mechanical testing. The TEM and AFM results indicated that the in situ synthesized nano-copper particles were well-dispersed, and spherical, with a diameter of about 70 nm in PF resin. From the FTIR chemical changes detected by FTIR inferred that the nano-copper modified PF resin penetrated into the Chinese fir cell walls and interacted with the acetyl groups of hemicellulose by forming a crosslinked structure. Accordingly, the micro-mechanical properties of the Chinese fir cell walls were enhanced after treatment with nano-copper modified PF resin. The filling of the PF-1-Cu resin (1 wt% nano-copper) in the wood resulted in 13.7% and 22.2% increases in the elastic modulus (MOE) and hardness, respectively, of the cell walls. Besides, the impact toughness and compressive strength of the Chinese fir impregnated with PF-1-Cu resin were 21.8% and 8.2% higher than that of the PF-0-Cu resin. Therefore, in situ synthesized nano-copper-modified PF resin is a powerful treatment method for Chinese fir due to improved diffusive properties and reinforcement of the mechanical properties.

Improving Performance of Phenol-Formaldehyde Resins Modified/Blended with Phenol-Rich Pyrolysis Bio-Oil

AbstractIn this study, we compare the panel performance of plywood made with phenol-formaldehyde (PF) resins modified and blended with phenol-rich bio-oil produced from pyrolysis of biomass. The modified PF resins were synthesized with phenol-rich bio-oil at phenol substitutions of 10, 25, 50, and 75 percent. The blended PF resins were prepared by blending control PF resin with phenol-rich bio-oil at 4, 13, 23, and 38 percent by weight. These resins were examined with Fourier-transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) and evaluated as plywood binders. The results indicated that the apparent viscosities of modified PF resins were similar to those of control PF resin, while the apparent viscosities of blended PF resins increased with the addition of phenol-rich bio-oil. As the amount of phenol-rich bio-oil increased, the gel times of both modified and blended PF resins decreased first and then increased. FTIR results showed that modified PF resins with up to 25 percent substitution had FTIR spectra similar to those of control PF resin, while blended PF resins with a higher amount of added bio-oil had spectra more like those of bio-oil. TGA results showed that at temperatures of 25°C to 400°C, both modified and blended PF resins with high bio-oil content had better thermal stability than the control PF resin. Panel tests showed that modifying or synthesizing PF resin with phenol-rich bio-oil up to 50 percent increased both dry and wet bond strength. Blending PF resin with phenol-rich bio-oil up to 13 percent increased both dry and wet bond strength compared with control PF resin.

Fabrication of nano-cupric oxide in phenol–formaldehyde resin adhesive: effect of cupric chloride concentration on resin performance

The potential for simultaneously incorporating nano-copper oxide (CuO) while synthesizing phenol–formaldehyde (PF) resin using different concentrations of cupric chloride (CuCl2) was studied. Curing kinetics, resin morphology, as well as physical and mechanical properties of oriented strand boards produced using the modified PF resin were evaluated. Nano-CuO showed a positive effect on the PF resin curing reactions that was characterized by a significant decrease in the activation energy within conversion degree of 65%. X-ray photoelectron spectrometric analysis showed that bivalent CuO was present in the modified PF resin. Laser scattering particle analysis showed that more than 40% of CuO was in the nanoparticle range. Four types of nano-CuO crystal structures were observed. Incorporation of nano-CuO derived from a 40% concentration of CuCl2 into the PF resin gave a 74% increase in perpendicular MOR. 2-h thickness swelling of PCu-0.5 was improved significantly. The findings of this work have potential application to the engineered wood composites manufacturing.

Properties of Oriented Strandboard Produced Using Phenol-Formaldehyde Resin Synthesized with Bio-Oil of Lignocellulosic Wastes

The main objective of the present study was to modify phenol-formaldehyde (PF) resin by using bio-oil obtained by pyrolysis with and without alkali catalyst (potassium carbonate: K2CO3) (10 to 50 weight %) and determine technological properties oriented strandboard (OSB) panels produced using the modified PF resin formulations. The pine sawdust was used as a raw material of bio-oil. The chemical characterization of bio-oils was determined by GC-MS analysis. The OSB panels were produced with the bio-based PF resins and then their technological properties were determined. As the amount of potassium carbonate catalyst increased up to 20 wt% in the PF resin, 24-h thickness swelling of OSB panels decreased from 15.4 to 14.3%, but further increment in the potassium carbonate catalyst content increased the thickness swelling (22.8%). The IB strength of the OSB specimens with PF resin with 10 wt% bio-oil produced with catalyst or pyrolysis process was found the same (2.18 N/mm2) and it was higher than the reference value (1.97 N/mm2). As the amount of bio-oil was increased to 20 wt%, the difference in the IB values between treated OSB and reference OSB was negligible. However, above the 20 wt% bio oil, it was observed a decreasing trend in the IB values. The bending strength and bending modulus of the OSB specimens containing 20 wt% bio-oil were also found to be higher than those of the reference OSB specimens. It was concluded that the PF resin synthesized using bio-oil of (20 wt%) produced with and without alkali catalyst could be successfully used in the production of the OSB.

The simultaneous preparation of nano cupric oxide (CuO) and phenol formaldehyde (PF) resin in one system: aimed to apply as wood adhesives

To reduce the cost of nano copper oxide (CuO) modified phenol-formaldehyde (PF) resin, the PF resin synthesis and the preparation of the nano CuO were carried out simultaneously in one system. The modified PF resins were evaluated via X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectrometry (EDXS), and thermogravimetry (TG). Physical and mechanical properties of oriented strand board (OSB) prepared using these modified PF resins were also evaluated. XPS results proved that nano CuO was present in the modified PF resin. XRD data showed that the derived nano CuO has a face-centered cubic structure. The minimum particle size of nano CuO was below 10 nm and the distribution of CuO was uniform as seen in TEM and EDXS images. TG analysis illustrated that the main degradation peak of the modified PF resins narrowed and shifted to a lower temperature by introducing nano CuO. Though the physical and mechanical properties of OSB decreased slightly, values were still within the requirements set by the appropriate Chinese Standard; this means that the modified PF resin has potential to be applied in engineered wood composites manufacturing.

Development of a Renewable Hybrid Resin System by Blending Isocyanate with Novolac Phenolic Resins

Abstract The objective of this study was to develop a performance-competitive bio-based hybrid resin system composed of methylene diphenyl diisocyanate (MDI) resin and novolac phenol-formaldehyde (PF) resin for engineered wood panel manufacturing. A novolac PF resin and a bio-oil–modified PF resin were blended with MDI at weight ratios of PF to MDI of 85:15, 75:25, 50:50, and 25:75, respectively. The obtained hybrid resins were examined with Fourier-transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA), and evaluated as plywood binders. The results indicated that the gel times and viscosities of hybrid resins were closely related to the weight ratio of PF resin to MDI. At a ratio lower than 75:25, the viscosities of hybrid resins were appropriate for plywood application. FTIR results showed some reactions between the novolac PF resin and MDI. TGA results showed that reacting novolac PF resin with MDI resin possibly increased the thermal stabilities of hybrid resins in the temperature range of 150°C to 300°C. Panel performance tests showed that blending novolac PF resin with MDI increased both the dry and the wet bonding strength of panels at the optimal ratio of 50:50. Replacing phenol with bio-oil of the hybrid resin had the trend of reducing the hybrid resin gel time and increasing panel dry and wet bonding strength.

Studies on Synthesis, Characterization of Modified Phenol Formaldehyde Resin and Metal Adsorption of Modified Resin Derived From Lignin Biomass

This study was related to development of economically viable method of extraction of lignin from saw dust in order to produce lignin modified phenolic resin and ecofriendly adhesives (bio-based resin). This study cover to improve the mechanical properties by modification of phenol formaldehyde resole resin using some additives such as boric acid, sulfuric acid and lignin biomass. The synthesis and metal adsorption capacity of resin derived from lignin biomass were explored. Lignin sample was extracted from sawdust of Acacia sp. collected from Batticaloa region by alkali extraction method called delignification process. Qualitative tests were carried out on the extracted alkali lignin and it was used to prepare modified resin. Resin synthesized by using lignin substitution phenol and allowed to condensation reaction in the presence of sodium hydroxide. Boron-modified phenol formaldehyde resin was prepared by using boric acid with formalim method. The above reaction was performed for four hours by refluxing with toluene. Which was produced a high viscous massive resin with 90% yield. The absorbtion peak of B-O bond at 1362cm-1 was observed at IR spectra. Rise in solid mass content leads to produce smooth resin surface without causing cracks and bubbling. Phenol formaldehyde resin was modified into their sulfonated forms to increase their ion exchange capacity, since the ion exchange capacity of virgin resin was found to be zero. Conductivity property shown by sulfonated resin(121mS/cm). The synthesized Lignin based PF resin was used to study the metal adsorption capacity of Cd2+ in aqueous solution. The adsorption capacity of heavy metal Cd2+ ion shown by lignin modified resin (55%) and lignin (86%). In this study sawdust lignin could be best substitution for phenol in synthesis of Phenol-Formaldehyde resin. It’s better due to their sustainability, environmental control, low production cost and their ability to adsorb heavy metals. Phenolic resin was modified with boric acid to improve thermal resistance property and to get smooth resin surface.

Processing Variable Optimization of Plywood Hot Pressed with Ba2+-Modified Phenol-Formaldehyde Resin by a Response Surface Method

Abstract Ba(OH)2 was added in the synthesis of phenol-formaldehyde resin to realize a low-temperature and fast-bonding process for plywood production. Plywood bonding was investigated by studying a number of parameters, such as the glue spread, the amount of curing agent, and the temperature and duration of the hot-pressing process. The plywood bonding strength was characterized by the shear strength of the adhesive layer, and a mathematical model describing the process and the response was developed using a central composite design and response surface methods. The variance analysis revealed that the newly developed model was reliable, with a high signal-to-noise ratio. All the factors and their interactions were analyzed to optimize the bonding process. Thus, seven optimized processes were obtained from the model, and the optimal process conditions were revealed (glue spread: 277.8 g/m2; amount of curing agent: 3.5%; hot-pressing temperature: 108°C; and hot-pressing duration: 34.99 s/mm). The results from repeated average shear strength experiments of five veneer testing samples (1.64 MPa) verified the reliability of the optimized technics.

The similar in-situ polymerization of nano cupric oxide preparation and phenol formaldehyde resin synthesis: The process and mechanism

The process and mechanism of phenol-formaldehyde (PF) resin synthesis and nano copper oxide (CuO) preparation simultaneously in the same reaction vessel were studied in this paper. Curing kinetics, molecular structure changes as well as the bonding performance of the modified PF resin was investigated. The results indicated that loading levels of the derived nano CuO at 4% and 8% reduced the apparent activation energy of the PF resin and accelerated both the addition and condensation reactions, while changes of reaction enthalpy were consistent of these results. With the introduction of the derived nano CuO, the chemical shifts of all samples were generally offset to the low field for the solvent effect. A complexation reaction between copper ions and oxygen on the phenolic hydroxyl groups had an influence on phenoxy carbons as shown by NMR. Quantitative analysis indicated that nano CuO had a positive effect on para substituted reaction and thus enhanced both the addition and the condensation reactions. Though the shear strength under several test conditions decreased slightly, values were within the requirements set by the appropriate Chinese Standard.

Dynamic mechanical thermal analysis (DMTA) of aqueous phenol formaldehyde (PF) resin modified by nano copper oxide (CuO)

To improve the bio-resistance of engineered wood composites products via gluing process, aqueous phenol formaldehyde (PF) resin was modified using nano CuO containing alkane surfactant and polyvinyl alcohol (PVA) 17-99. The modified PF system was analyzed by dynamic mechanical thermal analysis, and the mechanical properties of the bonded plywood panels including tensile strength, modulus of rupture (MOR), modulus of elasticity (MOE) and shear strength under five test conditions were also evaluated. The results indicated that the addition of nano CuO incorporating PVA 17-99 separated the gel point and vitrification point in the curve of tan δ, which is related to the delaying of moisture loss in modified PF resin during the curing process. The modification showed adverse effect on tensile strength but only a minimal influence on MOR and MOE. Additionally, PVA 17-99 reduced the water resistance of cured PF resins. However, with the test conditions of dipping in 100 °C water for 6 h, then drying for 20 h at 63 °C in air, followed by dipping in 100 °C water for 4 h, PVA consolidated the re-curing effect on the PF resin and compensated the strength loss from hydrolysis. Thus, the modified PF system not only guaranteed bio-resistance of glued wood composites via CuO, but also has the potential for developing self-curing wood composites being applied as structural construction materials.

Synthesis and ceramic conversion of novel silazane modified phenol formaldehyde resin

Novel silazane modified phenol formaldehyde (SPF) resins were synthesized by reacting varying amounts of 1, 3, 5-trimethyl-1', 3', 5'-trivinylcyclotrisilazane (CTS) with phenol formaldehyde (PF) resin. For the selection of an appropriate pyrolysis condition, polymer-to-ceramic conversion of SPF was carried out at 1450 °C and 1650 °C under argon and nitrogen atmosphere. The pyrolysis conditions significantly affected the evolution of ceramic phases, excess carbon and morphology which were thoroughly investigated through XRD, Raman and FESEM techniques. This study establishes silazane modified phenol formaldehyde as a new class of preceramic polymer for high-temperature applications. The study also reveals that nitrogen atmosphere is a more suitable gas atmosphere than argon atmosphere for preparation of desired C/Si3N4/SiC ceramics with higher ceramic yield.