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Showing 1 to 20 of 34 for “"Phenol-formaldehyde"”.
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Production of phenol-formaldehyde resin composites
… the production of industrial laminates based on phenol-formaldehyde resins, with a view of suggesting ways of improving the process economics and/or the physical properties of the final product. Aspects of impregnation, drying, and lamination were investigated. The resins used in all experiments …
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Evaluation of Phenol Formaldehyde Resin Cure Rate
… to characterize the cure rate of two commercial phenol-formaldehyde adhesives. Two methods are used, parallel-plate rheometry and dielectric spectroscopy. Viscosity data from a parallel-plate rheometer may be used to track the advance of polymerization as a function of temperature. This data can …
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Organic Fillers in Phenol-Formaldehyde Wood Adhesives
… wood composites are typically manufactured using phenol-formaldehyde resols (PF) that are formulated with wheat flour extender and organic filler. Considering that this technology is several decades old, it is surprising to learn that many aspects of the formulation have not been the subject of …
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Interaction of phenol-formaldehyde condensates with isoprene rubber
… with the interaction between p-tertiary butyl phenol-formaldehyde condensates and isoprene rubber under conditions resembling those used in industrial vulcanization processes, and involves investigations of reaction rates, mechanisms of reactions and structures produced. The work is an …
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Investigation of the Wood/Phenol-Formaldehyde Adhesive Interphase Morphology
This work addresses the morphology of the wood/ Phenol-Formaldehyde (PF) adhesive interphase using yellow-poplar. In this case, morphology refers to the scale or dimension of adhesive penetration into wood. The objective is to develop methods for revealing ever smaller levels of wood/resin …
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Cure of aqueous phenol-formaldehyde resin at elevated water vapor pressures
… research was to enhance our knowledge of aqueous phenolformaldehyde resin cure as it is affected by the elevated water vapor pressures that occur during hot-pressing of a wood-based composite. Microdielectric spectroscopy (DEA) was used to monitor the cure reaction, and thermomechanical analysis …
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Structural Determination of Copolymers from the Cross-catalyzed Reactions of Phenol-formaldehyde and Polymeric Methylenediphenyl Diisocyanate
… and pMDI prepolymers. The electronic behavior of phenolic monomers as perturbed by alkali metal hydroxides in an aqueous environment was studied with 1H and 13C NMR. Changes in electronic structure and thus reactivity were related to solvated ionic radius, solvent dielectric constant, and their …
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Effect of Cellulose Nanocrystals on the Rheology, Curing Behavior, and Fracture Performance of Phenol-Formaldehyde Resol Resin
… additives, on the properties and performance of phenol–formaldehyde (PF) adhesive resin. The steady-state viscosity of a commercial PF resol resin and three CNC–resin mixtures, containing 1–3 wt % CNCs, based on solids content, was measured with a rheometer as a function of shear rate. The …
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Modified Phenol-Formaldehyde Resins for C-Fiber Reinforced Composites: Chemical Characteristics of Resins, Microstructure and Mechanical Properties of their Composites
This work correlates the chemistry of phenol-formaldehyde (PF) resins, its functionalities with their microstructural and mechanical properties in composite materials. The main focus is put on the development of the pores in dependence on the chemical composition of the resins and their influence …
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Response of mat conditions and flakeboard properties to steam- injection variables
… and Populus tremuloides) flakeboard. Two resins, phenol formaldehyde and polymeric MDI, were used. Steam-injection press schedules varied from low steam input to high steam input by adjusting steam pressure, steam time, and the density range for steam-injection during press closing. …
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The evaluation of an organophosphate thermosetting resin for use in a high temperature resistant composite and a study of chemistry of ionomer cements
… to improve the high temperature performance of phenol-formaldehyde thermosets by modification of their structure with inorganic phosphate groups. Transesterification of tri-phenyl phosphate with resorcinol has given a resorcinol phosphate resin, which cured with hexamethylenetetramine. A pilot …
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Characterizing the Durability of PF and pMDI Adhesive Wood Composites Through Fracture Testing
… of fracture testing. The relative durability of phenol-formaldehyde (PF) and isocyanate (pMDI) adhesives was compared using a 2-hour boil test and an environmental test. The feasibility of using oriented strandboard (OSB), oriented strand lumber (OSL) and parallel strand lumber (PSL) for the DCB …
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Comparison of soy-flour hydrolysates for wood adhesive systems
… focused on soy flour adhesives due to increased phenol prices and environmental concerns related to the use and exposure to formaldehyde. Soy protein isolates can be modified in highly caustic alkaline solutions to reduce viscosity and improve adhesive properties, but the price of isolates is …
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The effect of hot-pressing parameters on resin penetration and flakeboard layer properties
The area of penetration of phenol-formaldehyde resin into aspen (<i>Populus tremuloides</i>) and Douglas-fir (<i>Pseudotsuga menziesii</i>) flakes, and the layer properties of yellow poplar (<i>Liriodendron tulipifera</i>) flakeboard were investigated to determine how they were influenced by …
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Wood liquefaction in the presence of phenol with a weak acid catalyst and its potential for novolac type wood adhesives
Wood liquefaction was conducted using phenol as a reagent solvent with oxalic acid as a catalyst. A series of studies were done on liquefied wood, liquefied wood residues, novolac-type liquefied wood resins, and bio-composites fabricated from liquefied wood resin. The results of the liquefied wood …
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Investigating the Surface Energy and Bond Performance of Compression Densified Wood
… boiling of one half of all fracture samples. Phenol formaldehyde film (PF-film) and polymeric diphenylmethane diisocyanate (pMDI) were the two different adhesives used to bond fracture samples. Hygro-thermal samples bonded with PF-film had significantly higher fracture toughness than control …
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An Improved Method for the Fracture Cleavage Testing of Adhesively-Bonded Wood
… as the degree of cure increased for a phenol formaldehyde adhesive, and yielded maximum strain energy release rate (SERR) values of 370 - 560 J/m2. A second study showed performance differences between two polymeric diphenylmethane diisocyanate (pMDI) adhesives and one polyurethane …
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Aspects of Wood Adhesion: Applications of 13C CP/MAS NMR and Fracture Testing
Phenol Formaldehyde (PF) and polymeric isocyanate (pMDI) are the two main types of adhesives used in the production of structural wood-based composites. Much is unknown about various aspects of adhesion between these two types of resins and wood. The present research describes the development of …
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Filler effects in resole adhesive formulations
… on how organic fillers affect the properties of phenol-formaldehyde resole (PF) resins that are formulated for veneer applications like plywood and laminated veneer lumber. The PF formulations studied in this work used fillers that were derived from walnut shell (Juglans regia), alder bark (Alnus …
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Wetting and Penetration Behavior of Resin/Wood Interfaces
… than aqueous resins, with exception of urea-formaldehyde. Wetting and penetration of pMDI was studied on 5 wood species using the Lucas-Washburn equation. The wetting behaviors exhibited grain and species effects, which had implications on the resin availability for flake/strand-based …
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