The effects of fillers and extenders on the cure properties of phenol–formaldehyde resin as determined by the application of thermal techniques

Waage, S. K.; Gardner, Douglas J.; Elder, Thomas

doi:10.1002/app.1991.070420131

Cited by 21 publications

(18 citation statements)

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“…At this particulate loading, the flexural strength, flexural modulus, maximum flexural strain and fracture toughness are 29.1 MPa, 3.005 GPa, 0.014mm/mm and 13.8 MPa m respectively; the cost would be reduced by 5 %. The fracture toughness was greatly reduced after 5 % particulate loading and this contradicts to Waage et al had found in their study, in which fillers were found to alter stress distribution in adhesive joints, thus improving fracture toughness [23]. Some extenders may be required to improve the fracture toughness of composites used in this study.…”

Section: Resultscontrasting

confidence: 76%

“…The viscosity of neat resin used in this study was 3,240 cps therefore for the same particle loading, the initial viscosity of the filler-resin mixture of this resin is likely to higher than its counterpart and the maximum percentage by weight of filler that could be added to this resin for ease of casting would be less. The maximum particle (pecan shell flour) loading used by Waage et al was 40% and the viscosity of the mixture was 15,400 cps, while that (SLG) in this study was 35 % and the viscosity of the mixture was 13,360 cps [23,25]. If Figure 10 were extrapolated, it can be found that the viscosity of SLG filled phenolic resin would be over 20,000 cps and would not be suitable for casting [24,25].…”

Section: Resultsmentioning

confidence: 74%

“…At this viscosity, workability of the filled resin would be good. The viscosity of neat resin used by Waage et al was 2,650 cps and it was found that if the initial viscosity of filler-resin mixture is greater than 6000 cps, difficulties will be encountered in achieving adequate adhesive distribution when spraying flakes [23]. The viscosity of neat resin used in this study was 3,240 cps therefore for the same particle loading, the initial viscosity of the filler-resin mixture of this resin is likely to higher than its counterpart and the maximum percentage by weight of filler that could be added to this resin for ease of casting would be less.…”

Section: Resultsmentioning

confidence: 99%

“…The differential scanning calorimetry (DSC) showed a single exothermic peak that was not influenced to a great extent by the fillers or extenders [23].…”

Section: By Viewingmentioning

confidence: 99%

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Relationship between different mechanical properties of phenol formaldehyde SLG-reinforced composites

2011

Journal of Reinforced Plastics and Composites

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Phenol formaldehyde was filled with Envirospheres, ceramic hollow spheres (SLG) to increase the tensile strength, fracture toughness and flexural strength. This article varies the percentages by weight of the SLG in the composites which are then subjected to the relevant mechanical tests. The results show that composite with 7.5 wt% of the SLG produces the optimum combinations of tensile properties, flexural properties, fracture toughness, and cost with a reasonable fluidity for casting. It is hoped that the discussion and results in this work would not only contribute towards the development of SLG-reinforced phenolic composites with better material properties, but also useful for the investigations of fracture toughness, tensile properties, and flexural properties in other composites.

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Section: Resultscontrasting

confidence: 76%

Section: Resultsmentioning

confidence: 74%

Section: Resultsmentioning

confidence: 99%

“…The differential scanning calorimetry (DSC) showed a single exothermic peak that was not influenced to a great extent by the fillers or extenders [23].…”

Section: By Viewingmentioning

confidence: 99%

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Relationship between different mechanical properties of phenol formaldehyde SLG-reinforced composites

2011

Journal of Reinforced Plastics and Composites

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“…This pattern of changes in dynamic viscosity and curing time of adhesive compositions are appropriate and can be explained by the interaction of resorcinol or PRF resin with PF resin by forming cross-links (Urbanik et al, 1997). Such cross-links increase the molecular weight of polymer, which respectively leads to the increasing of viscosity of the adhesive composition and to the fast curing (Waage et al, 1991).…”

Section: Rezultati I Raspravamentioning

confidence: 99%

Properties of Modified Phenol-Formaldehyde Adhesive for Plywood Panels Manufactured from High Moisture Content Veneer

2014

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• This paper presents the results of laboratory investigations of bonding high moisture content (15 %) birch veneers (Betula pubescens Ehrh.) with the use of modifi ed phenol-formaldehyde (PF)resin et al., 1993) that consisted of an alkaline insoluble but swellable dispersed PF phase, an alkaline soluble continuous phase and propylene carbonate additive. Some systems of fi lling with pecan shell fl our and two furfural-process residues were tested (Sellers et al., 1990). One of them involves mixing a high molecular weight resin with alkylene carbonates or phenol-resorcinol-formaldehyde resins (Clarke et al., 1990). The wood porosity is one of the main physical indexes in wood science. Bonding of wood elements with higher moisture content is a diffi cult process; the details of the penetration of the hardening adhesives into the porous wood skeleton are rather complicated. It is strongly infl uenced by factors as wood species, grain orientation and surface roughness, adhesive factors as type of adhesive, solid content and viscosity, and process factors as applied pressure and temperature, which have the most signifi cant infl uence on the bonding performance (Kamke and Lee, 2007; Varivodina et al., 2010). An analytical model to predict the penetration of adhesives into hardwood was proposed . The model considers a dimensional capillary fl uid transport of a hardening adhesive through a single, straight vessel with diffusion of solvent through the walls of the vessel. Adhesive penetration follows the path of lowest resistance into the porous structure, either by gross penetration or by cell wall penetration. The bond line morphologies and the adhesive penetration into the wood structure were evaluated (Haas, 2012) after determining the hardening characteristics of adhesives.The viscoelastic characteristics of wood play an important role in compression and densifi cation. At high temperature and high moisture content, wood exhibits plastic behaviour that can be characterized as inconvenient. Temperature and conditions of pressing process affect the change of relative density and creep deformation, as well as properties of the resulting pressed plywood material. The dependence of inelastic behaviour of the gross wood on the elastic properties of the cell wall allows the time, temperature, and moisture dependence to be modelled with classical linear viscoelastic theory of amorphous polymers. Time-temperature-moisture relationship was shown (Wolcott et al., 1994) to be applicable to stress relaxation data collected for temperatures between 39 and 99 °C and moisture contents between 3 and 16 %.The bond strength of thermosetting PF adhesives is developing during the hardening process carried out in a hot-press at stated pressure, temperature and for a defi ned period of time. Pressure parameters are infl uenced by several factors as thickness of the composite, thermal conductivity, or moisture content of the material. Pressure must be kept till strength of cured adhe- INTRODUCTION1. UVOD

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Activation energy and curing behavior of resol‐ and novolac‐type phenolic resins by differential scanning calorimetry and thermogravimetric analysis

Lee

Kim

et al. 2003

J of Applied Polymer Sci

102

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ABSTRACT:The thermal behavior, thermal degradation kinetics, and pyrolysis of resol and novolac phenolic resins with different curing conditions, as a function of the formaldehyde/phenol (F/P) molar ratio (1.3, 1.9, and 2.5 for the resol resins and 0.5, 0.7, and 0.9 for the novolac resins) were investigated. The activation energy of the thermal reaction was studied with differential scanning calorimetry at five different heating rates (2, 5, 10, 20, and 40°C/min) between 50 and 300°C. The activation energy of the thermal decomposition was investigated with thermogravimetric analysis at five different heating rates (2, 5, 10, 20, and 40°C/min) from 30 to 800°C. The low molar ratio resins exhibited a higher activation energy than the high molar ratio resins in the curing process. This meant that less heat was needed to cure the high molar ratio resins. Therefore, the higher the molar ratio was, the lower the activation energy was of the reaction. As the thermal decomposition of the resol resins proceeded, the activation energy sharply decreased at first and then remained almost constant. The activation energy of the thermal decomposition for novolac resins with F/P ϭ 0.5 or F/P ϭ 0.7 was almost identical in all regions, whereas that for novolac resins with F/P ϭ 0.9 gradually decreased as the reaction proceeded.

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The effects of fillers and extenders on the cure properties of phenol–formaldehyde resin as determined by the application of thermal techniques

Cited by 21 publications

References 4 publications

Relationship between different mechanical properties of phenol formaldehyde SLG-reinforced composites

Relationship between different mechanical properties of phenol formaldehyde SLG-reinforced composites

Properties of Modified Phenol-Formaldehyde Adhesive for Plywood Panels Manufactured from High Moisture Content Veneer

Activation energy and curing behavior of resol‐ and novolac‐type phenolic resins by differential scanning calorimetry and thermogravimetric analysis

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