Novolak Phenol Research Articles

Preparation and characterization of lignin copolymerized phenolic resins with superior stiffening effect for natural rubber composites

The development of lignin-derived functional additives for rubber composites has gained growing importance in light of biomass valorization. This work aims at preparing phenolic novolak resin with lignin as one building block for reinforcing natural rubber. A one-pot two-step synthetic approach involving phenolation and copolymerization was developed to prepare lignin-phenol-formaldehyde resins (LPF), wherein 30 wt% of phenol was substituted by lignin. With increasing the ratio of formaldehyde/phenol functionality (F/P), resins show increased molecular weight, elevated glass transition temperature and declined curing activity. The resin with F/P of 0.68/1 exhibits a higher stiffening effect compared to the control without lignin. This enhancement is attributed to lignin's ability to form a hyperbranched structure with multiple phenolic arms as implied by GPC results, acting as a crosslinking hub and facilitating the formation of an effective network. Furthermore, we introduced cardanol with a flexible alkene chain to prepare cardanol-lignin-phenol-formaldehyde resins (CLPF). The CLPF15 resin with cardanol/lignin/phenol of 15/30/55 wt% achieves the maximum stiffening effect due to improved compatibility with natural rubber. This study provides insights into the design and optimization of lignin-copolymerized resins for enhancing the mechanical properties of rubber composites.

New Chemically Amplified Positive Photoresist with Phenolic Resin Modified by GMA and BOC Protection.

In this paper, a chemically amplified (CA) i-line photoresist system is described including a phenolic resin modified with glycidyl methacrylate (GMA) addition and protected with di-tert-butyl dicarbonate (BOC group), here called JB resin. JB resin with different degrees of BOC protection was synthesized and characterized with ultraviolet spectrophotometry, Fourier transform infrared spectroscopy and gel permeation chromatography. These resins were also evaluated in CA resists by formulating the JB resin with a photoacid generator (PAG) and tested at 405 nm and 365 nm exposure wavelengths. The BOC protection ratio at approximately 25 mol% of the Novolak phenol group showed the best performance. The resist showed high sensitivity (approximately 190 mJ/cm2), high resolution and good alkali developer resistance with reliable repeatability, indicating the great practical potential of this JB resist system.

Preparation and electrochemical performance of activated carbon microspheres from recycled novolak phenol formaldehyde

In this study, an attempt is made to obtain porous activated carbon microspheres (ACMs) as supercapacitor electrodes by recycling waste novolak phenol formaldehyde (NPF) resins. These NPF-ACMs were prepared by a three-step procedure of hydrothermal synthesis, carbonization, and activation in turn. The effects of temperature, time, and sodium dodecyl sulfonate (SDS) addition on NPF-based microspheres were studied by the orthogonal method. The optimal preparation process of NPF-based microspheres was the following: 230 °C, 4 h, and a mass ratio of SDS: NPF of 24:1 by hydrothermal synthesis. Based on the above optimal conditions, NPF-ACMs were made, the yield of the microspheres after carbonization and chemical activation are 54% and 38%, and their electrochemical properties were analyzed. The NPF-ACMs had uniform size, a high surface area of 2528 m2 g−1, good dispersion, a low impedance of 0.46 Ω, highest specific capacitance of 118.6 F g−1 at 0.5 A g−1, good rate capability with 79% retention from 0.1 to 10 A g−1. Moreover, it showed high capacitance retention of 99.5% after 1000 cycles at a scan rate of 5 mV s−1. The results showed that waste NPF can be used as promising ACMs of the electrode material to increase its utilization value.

Modification of Physical, Mechanical and Electrical Properties of Reinforced Epoxy Phenol Novolac with Nano Cobalt Acrylate and Carbon Nanotubes

The research associated with optimal manufacturing procedure for composites strengthened with carbon nanotubes has became an important stage inside the early levels of discovery of fantastic physical properties of carbon nanotubes. The particular increasing interest has been brought by swift developments in nanotechnology and composites production techniques. This particular document brings together a study of two processes for production reinforced epoxy phenol novolak (EPN) with multi wall carbon nanotubes (MWCNT) and nano cobalt acrylate and evaluation of their physical properties. Shear mixing method and solution process are techniques that were used to produce plates and thin films of composites containing different weight fractions of unpurified and purified multiwall nanotubes. The first method consist in processing the pure combination of (EPN) and nanotubes in a reactor and the subsequent technique utilizes ultrasound to improve dispersion of nanotubes in the matrix through solvent medium. In this case, solution process showed a better dispersion of the encouragement in the matrix, but physical qualities did not show significant improvements. Mechanical qualities, for instance tensile strength, Young's modulus, fracture toughness, and hardness do not show relevant improvements. The explanation for this behavior is the poor adhesion at the interface carbon nanotube-matrix, attributable to tendency of MWNTs to agglomerate into bundles, which generate discontinuities in the last composite. The electrical Conductivity measurements indicate a percolating network formed only by inner metallic tubes of the nano composite.

Wood‐derived phenol novolaks and their wood/epoxy biocomposites

ABSTRACTGuaiacol novolak (GCN) and wood‐tar creosote novolak (WCN) were synthesized by the reactions of wood‐derived guaiacol and creosote with formalin, respectively, and used as hardeners of sorbitol polyglycidyl ether (SPE). Thermal and mechanical properties of the cured resins (SPE‐GCN and SPE‐WCN) and their biocomposites with wood flour (WF) were compared with those of the materials prepared by using a petroleum‐based phenol novolak (PN). Although tan δ peak temperatures of SPE‐GCN and SPE‐WCN were lower than that of SPE‐PN, that (58.5–70.8°C) of SPE‐GCN/WF(40–50 wt %) was higher than that (56.6–57.0°C) of SPE‐PN/WF(40–50 wt %). Tensile moduli of all the biocomposites increased by the addition of WF, while tensile strengths were rather reduced. When the biocomposites with the same WF content were compared, tensile modulus of SPE‐GCN/WF was higher than that of SPE‐PN/WF. The 5% weight loss temperatures (346–291°C) of SPE‐GCN and SPE‐GCN/WF were comparable to those (338–284°C) of SPE‐PN and SPE‐PN/WF. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41347.

環状フェノール・ノボラック (2)

環状フェノール・ノボラック (2)

環状フェノール・ノボラック (1)

環状フェノール・ノボラック (1)

Preparation and characterization of novolak phenol formaldehyde resin from liquefied brown‐rotted wood

AbstractThe brown‐rotted wood was liquefied in phenol with phosphoric acid as catalyst and the resulting liquefied products were condensed with formaldehyde to yield novolak liquefied wood‐based phenol formaldehyde resin (LWPF). The results showed that brown‐rotted wood could be more easily liquefied than sound wood in phenol. The residue content of liquefied wood decreased continually with the progress of brown‐rot decay. Both water wash and neutralization and water wash slightly improved the thermofluidity and curing properties of LWPF with a small reduction of LWPF yield. An increase in phenol to wood (P/W) ratio from 2 to 3 slightly improved the flow property of LWPF, but with an accompanied by 20% deduction in the product yield. Increased liquefaction time from 30 min to 60 min showed no significant influence on the resulting LWPF. The moldings fabricated from LWPF yielded higher charpy impact, flexural and flexural modulus strength but yielded lower temperature deflection under load than that of the commercial novolak resin. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Synthetic tannins structure by MALDI‐TOF mass spectroscopy

AbstractThe structure, polymeric nature, and oligomers distribution of six types of commercial synthetic tannins (syntans) were determined by MALDI‐TOF mass spectrometry. The syntans examined were: (i) polycondensation oligomers of sulfonated phenol and 4,4′‐dioxydiphenylsulfone with formaldehyde and sodium bisulfite; (ii) sodium salts of polycondensation oligomers of phenol and sulfonated phenol with formaldehyde and urea; (iii) sodium salts of polycondensation oligomers of sulfonated phenol with formaldehyde and urea; (iv) sodium and ammonium salts of polycondensation oligomers of sulfonated naphtalene with formaldehyde; and (v) a sulfonated phenolic novolak resin. The oligomers distribution indicated that the relative abundance of oligomers from trimer to higher degrees of polymerization varied from 70% to more than 90% according to the different syntans tested. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Physicomechanical and thermal properties of moldings made from liquefied wood‐based novolak PF resins under various hot‐pressing conditions

AbstractThe wood powder of Cryptomeria japonica (Japanese cedar) was liquefied in phenol, with H2SO4 and HCl as a catalyst. The liquefied wood was used to prepare the liquefied wood‐based novolak phenol formaldehyde (PF) resins by reacting with formalin. Furthermore, novolak PF resins were mixed with wood flour, hexamethylenetetramine, zinc stearate as filler, curing agent, and lubricating agent, respectively, and hot‐pressed under 180 or 200°C for 5 or 10 min to manufacture moldings. The results showed that physicomechanical properties of moldings were influenced by the hot‐pressing condition. The molding made with hot‐pressing temperature of 200°C for 10 min had a higher curing degree, dimensional stability, and internal bonding strength. The thermal analysis indicated that using a hot‐pressing temperature of 180°C was not sufficient for the liquefied wood‐based novolak PF resins to completely cure. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Preparation and properties of calix[4]arene-based epoxy resins

Calix[4]arene macrocycles are the subject for increasing interest in the field of supramolecular chemistry and hostguest chemistry as basic skeletons for the synthesis of host compounds for ions or neutral molecules. Although quite a large number of reports exists on the molecular calix[4] arenes, those on polymeric precursors are limited. Recently, calix[4]arene-based polymers have just begun to receive attention, as these new polymers may then be processed into materials suitable for the chemical sensor devices such as ion selective electrodes and filtration/extraction membranes. There is some structural analogy between polymeric linear phenolic novolak molecules and calixarenes which could also be called ‘cyclic phenol resin’. Thus it seems promising to further enhance the sensitivity of calixarene derivatives by applying various techniques, which are generally used to reduce the required dose of commonly used novolak resin. Up to now, this method has not been applied to the non polymeric class of calixarenes. In the microelectronic process, the smallest obtainable structure size as well as the line edge roughness is strongly influenced by the size of the typical novolak based polymeric resist molecules. Therefore, the search for prospective nonpolymeric resist materials has become a high interest. In this paper, various glycidyl calix[4]arene derivatives were prepared using ECH under different conditions, and their curing behavior and thermal properties were examined using epoxy systems with 4,4'-diaminodiphenylmethane and boron trifluoride-isopropylamine as a crosslinker and a cationic catalyst, respectively.

A phosphate-based epoxy resin for flame retardance: synthesis, characterization, and cure properties

A phosphorus-containing oligomer, bis(3-hydroxyphenyl) phenyl phosphate (BHPP), was synthesized through the reaction of phenyl dichlorophosphate and 1,3-dihydroxybenzene, and characterized by elemental analysis, Fourier transform IR spectroscopy, and 1H NMR and 31P NMR spectroscopy. Consequently, the phosphate-based epoxy resins with a phosphorus content of 1 and 2 wt % were prepared via the reaction of diglycidyl ether of bisphenol-A with BHPP and bisphenol-A, and were confirmed with Fourier transform IR spectroscopy and gel permeation chromatography. Phenolic melamine, Novolak, and dicyanodiamide were used as curing agents to prepare the thermoset resins with the control and the phosphate-based epoxy resins. Thermal properties and thermal degradation behavior of these thermoset resins were investigated by using differential scanning calorimetry and thermogravimetric analysis. The thermoset resins cured with phenolic melamine exhibited higher glass-transition temperatures than the other cured resins owing to the high rigidity of their molecular chain. Thermogravimetric analysis studies demonstrated that the decomposition temperatures of the thermoset resins cured with Novolak were higher than those of the others. A synergistic effect from the combination of the phosphate-based epoxy resin and the nitrogen-containing curing agent can result in a great improvement of the flame retardance for their thermoset resins.

On Porosity of Carbon Aerogels from Sol-Gel Polymerization of Phenolic Novolak and Furfural

Carbon aerogels were prepared by sol-gel polymerization of phenolic novolak and furfural followed by supercritical drying and pyrolysis. The porosity and morphologies of carbon aerogels were characterized by nitrogen adsorption, apparent density, He- pycnometer method, and transmission electronic microscopy (TEM). Effect of ratios of phenolic novolak to furfural (Ra) and total concentration of reactants (C) in sol-gel step on porosity and morphologies of carbon aerogels was investigated. The carbon aerogels synthesized are rich in meso- and macropores. The Ra determines the cross-linking density of polymers, thereby the compatibility of the polymers, and ultimately the shrinkage of gels in the drying and pyrolysis. The network sizes and the porosity of organic and carbon aerogels are mainly determined by Ra. The C has no effect on volume shrinkage of gels in drying and pyrolysis and has only dilute effect in determining bulk density of organic and carbon aerogels, and ultimately the porosity of carbon aerogels. Conversion of mesopores to micro- and macropores is observed, which is related to combination of C and Ra, and determines the partition of micro-, meso- and macropores.

Preparation and properties of epoxy resins cured with silyl esters of phenol novolak and cresol novolak

The curing agents of epoxy resin, trimethylsilyl ethers of phenol novolak (TMSPN) and cresol novolak (TMSCN) were prepared by refluxing phenol novolak and cresol novolak respectively, with the mixture of hexamethyldisilazane and chlorotrimethylsilane in THF. The curing reaction of epoxy resin with these curing agents and the thermal properties of cured resins were examined. The Tg values of epoxy resins cured with TMSPN were a little higher than those cured with TMSCN. The maximum of Tg is 118°C for TMSPN-cured epoxy resin against 112°C for TMSPN-cured epoxy resin. The water absorption of hydrophobic epoxy resins cured with TMSPN was a little lower than those cured with TMSCN. The clear decrease of water absorption is attributed to the difficulty of the micro-void formation caused by the more tight primary structures of TMSPN. The water absorption at 25°C containing trimethylsilyl groups is about one-tenth of that of epoxy resins cured with conventional curing agents and even one-half of that of the epoxy resins cured with active esters. The low water absorption is attributed to the presence of trimethylsilyl groups, which are more hydrophobic than ester groups, and to the absence of hydroxyl groups of the cured resins.

Relations between the solubility speed and the electrical conductivity of phenol novolak polymer solutions

Relations between the solubility speed of phenol novolak resins which are typical photoresist base polymers, with the ac-electrical conductivity of their polymer solutions were studied. Strong correlations between these quantities were found. These relations were found to be affected by the concentration of the solution and the measured temperature. It is suggested to use such relations to predict the solubility speed of photosensitive novolak polymers by measuring their ac-electrical conductivity instead of measuring the solubility speed directly.

High-pressure synthesis of diamond from phenolic resin

Two kinds of phenolic resin, novolak and resols, have been studied with an addition of cobalt at pressures between 2 and 4 GPa and at temperatures from 1300 to 1900 °C, all under thermodynamically graphite-stable conditions. Diamond was synthesized from these resins which had been pre-fired at 500–1000 °C. From such resins, carbon precursors carrying a great number of radicals, being nearly free of hydrogen and oxygen, and turbostratic in structure, can be constructed. The pressure–temperature conditions suitable for the diamond synthesis were dependent on the pre-firing temperatures. The cobalt served as a catalyst–solvent, similar to the case of conventional diamond synthesis from graphite under diamond-stable conditions. Well-defined single crystals cubo-octahedral in shape, measuring 0.3–0.7 mm across and classified as type Ib were obtained.

97/00197 The effect of benzoyl peroxide on solvent liquefaction of coal

Gel permeation chromatography was applied to the measurement of molecular weight distribution of the preasphaltenes in liquefied products from Victorian brown coal. When polar solvents such as N-methyl-2-pyrrolidone were used as elution solvents, two major peaks were separately observed at different retention times, reflecting the polarity of their components. By applying a new calibration method to the polar and non-polar components in the preasphaltenes, using a novolak phenol resin and polystyrenes respectively, the molecular weights of both components were estimated to be distributed around 103. According to the present evaluation, a high liquefaction temperature was found to be effective in reducing the polar components in the preasphaltenes.

Chromatographic characterization of preasphaltenes in liquefied products from Victorian brown coal

Gel permeation chromatography was applied to the measurement of molecular weight distribution of the preasphaltenes in liquefied products from Victorian brown coal. When polar solvents such as N-methyl-2-pyrrolidone were used as elution solvents, two major peaks were separately observed at different retention times, reflecting the polarity of their components. By applying a new calibration method to the polar and non-polar components in the preasphaltenes, using a novolak phenol resin and polystyrenes respectively, the molecular weights of both components were estimated to be distributed around 10 3. According to the present evaluation, a high liquefaction temperature was found to be effective in reducing the polar components in the preasphaltenes.

褐炭液化重質生成物の構造解析 プレアスファルテンのキャラクタリゼーション

Molecular weight distributions of heavy products are very important factors necessary to understand the mechanism of coal liquefaction reaction. GPC is a promising method for heavy organic materials such as preasphaltenes (benzene insoluble-pyridine soluble fractions) derived from coal. In this paper, GPC analysis was applied to characterize the preasphaltenes using N-methyl-2-pyrolidinone (NMP), which is a preferable solvent for the preasphaltenes, as an elution solvent in GPC.In the GPC analysis of the preasphaltenes, two characteristic peaks were observed in the region of the molecular weight of 103 and 105-7 correlated by polystyrene standards. A peak corresponding to 105-7 shifted to the lower-molecular-weight region after addition of LiBr into the solvent. Besides the preasphaltenes, phenol novolak resin showed the same GPC profile using NMP as the solvent. These results suggested that the origin of the peak in the higher-molecular-weight region was the oxygen-containing polar components in the preasphaltenes. The peak separation and the peak shift after LiBr addition were also observed in the reversed phase liquid chromatography of preasphaltenes and phenol resin using NMP as the solvent. It was therefore suggested that the peak observed in the higher-molecular-weight region was ascribed to the decrease of the interaction between polar components and the column packings, because of the enhanced ionic properties of the polar components caused by NMP. Therefore, it was realized that the evaluation of the molecular weight distributions of these polar components was needed to analyze the preasphaltenes, and the phenol resin was one of the promising candidates for the standards to be used in the correlation of molecular weight.

The multilayer adsorption probability and potential energy from a binary liquid mixture onto a silica particle surface

The probability and potential energy of multilayer adsorption from a binary liquid mixture of o-cresole novolak epoxy resin and phenol novolak resin onto treated surfaces of silica particles have been obtained from the immobilized layer estimated from the viscosity measured with a capillary. The predominant adsorption types have been found to be physical adsorption for nontreated silica and chemical adsorption for silica treated with phenyl oxazoline, according to the probability calculated by assuming physical adsorption, chemical adsorption, and adhesion. However, neither chemical nor physical adsorption acquires activity for silica treated by phenyl oxazoline blocked by phenyl glycidyl ether. The kinetic energy of an adsorptive molecule which is consumed by the rotation angular momentum of silica particles in a capillary fluid flow has been estimated from the adsorption and desorption energy values, and its value was found to be two or three times larger than the bonding energy. In contrast to this, the consumption of the kinetic energy of an adsorptive molecule during energy transfer to a solid silica surface by collision and also during energy transfer to a special molecular structure in the liquid near the solid surface was much larger.