Cure kinetics of aqueous phenol–formaldehyde resins used for oriented strandboard manufacturing: Analytical technique

Lei, Yong; Wu, Qinglin; Lian, Kun

doi:10.1002/app.23756

Cited by 41 publications

(43 citation statements)

References 22 publications

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“…The excellent properties of PF resin include high mechanical, thermal, and weather stability [1]. However, the lower curing rate and required higher curing temperature compared to other thermosetting adhesives limit the application of PF resins for use in impregnating resins or adhesives [2,3]. Many attempts have been made to accelerate the curing rate or lower the curing temperature, including testing of various catalysts or additives to alter the reaction kinetics, such as carboxylic acid esters [4,5], anhydrides [6], amides [7], carbonate [8], and metallic ions [9].…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Mechanism of Metal-Mediated Polymerization of Phenolic Resins

Zhao

Zhang

et al. 2016

Polymers

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Phenol-formaldehyde (PF) resin is a high performance adhesive, but has not been widely developed due to its slow curing rate and high curing temperature. To accelerate the curing rate and to lower the curing temperature of PF resin, four types of metal-mediated catalysts were employed in the synthesis of PF resin; namely, barium hydroxide (Ba(OH) 2 ), sodium carbonate (Na 2 CO 3 ), lithium hydroxide (LiOH), and zinc acetate ((CH 3 COO) 2 Zn). The cure-acceleration effects of these catalysts on the properties of PF resins were measured, and the chemical structures of the PF resins accelerated with the catalysts were investigated by using Fourier transform infrared (FT-IR) spectroscopy and quantitative liquid carbon-13 nuclear magnetic resonance ( 13 C NMR). The results showed that the accelerated efficiency of these catalysts to PF resin could be ordered in the following sequence: Na 2 CO 3 > (CH 3 COO) 2 Zn > Ba(OH) 2 > LiOH. The catalysts (CH 3 COO) 2 Zn and Na 2 CO 3 increased the reaction activity of the phenol ortho position and the condensation reaction of ortho methylol. The accelerating mechanism of (CH 3 COO) 2 Zn on PF resin is probably different from that of Na 2 CO 3 , which can be confirmed by the differences in the differential thermogravimetric (DTG) curve and thermogravimetric (TG) data. Compared to the Na 2 CO 3 -accelerated PF resin, the (CH 3 COO) 2 Zn-accelerated PF resin showed different peaks in the DTG curve and higher weight residues. In the synthesis process, the catalyst (CH 3 COO) 2 Zn may form chelating compounds (containing a metal-ligand bond), which can promote the linkage of formaldehyde to the phenolic hydroxyl ortho position.

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Section: Introductionmentioning

confidence: 99%

Synthesis and Mechanism of Metal-Mediated Polymerization of Phenolic Resins

Zhao

Zhang

et al. 2016

Polymers

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“…29 After obtaining the processing parameters of prepregs, it was important to determine the degree of conversion achieved by the resin after being under such conditions. It must be taken into account that a disadvantage of phenolic resins is that they exhibit a complex process of polymerization reactions with the evolution of water and formaldehyde.…”

Section: Prepreg Processing Designmentioning

confidence: 99%

Development of carbon fiber/phenolic resin prepregs modified with nanoclays

Asaro

Rivero

Manfredi

et al. 2015

Journal of Composite Materials

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This work is focused on the study of the main variables involved in the development of phenolic/carbon prepregs and how these variables are affected by the incorporation of nanoclays. For this, phenolic resin was obtained from phenol and formaldehyde, performing the reaction under basic conditions and with formaldehyde excess. Resin curing kinetics was studied by means of Fourier transform infrared spectroscopy measurements. Organo-modified clay was added to the phenolic resin in order to evaluate their effect on the general performance of the material. Carbon fiber/phenolic resin and carbon fiber/clay modified phenolic resin prepregs were obtained by hand-layup and vacuum bagging. Prepregs were characterized in terms of fiber content, flexural stiffness, and degree of tack. In both the cases, intermediate fiber volume content, nearly 50%, was obtained. The addition of 5 wt% of clay to the phenolic resin did not produce a significant change on the prepregs stiffness but increased the degree of tack, which implies that the incorporation of such particles was useful to enhance the prepregs properties. Composite materials were obtained by compression molding of the prepregs obtained, and were characterized by its fiber content, mechanical behavior with the three-point bending test and its thermal degradation by thermogravimetry. High fiber content composites materials were obtained, nearly 75% by volume. However, modified composites showed lower fiber content, which resulted in a decrease of the flexural modulus and strength. In relation to thermal degradation, the addition of nanoclay did not change the behavior of the materials.

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“…A literature search did not reveal any information on room-temperature PF kinetics, although these have been studied at higher temperatures (Lee et al 2003;Lei et al 2006), even in systems containing lignin (Pan et al 2008;Pérez et al 2009). Therefore, kinetic studies have been carried out at 25°C as part of these studies.…”

Section: Reaction Kineticsmentioning

confidence: 99%

Phenol Formaldehyde Revisited—Novolac Resins for the Treatment of Degraded Archaeological Wood

2014

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Archaeological wood is usually severely degraded. The Norwegian Viking Age Oseberg find exemplifies problems arising due to past conservation treatments and the need for new types of preservatives. Phenol formaldehyde (PF) has been investigated as a consolidant for alum‐treated wood. X‐ray tomography has revealed that it is possible to obtain a porous structure inside the wood, ensuring ethical acceptability by allowing re‐treatment. In order to understand the curing mechanics, the kinetics of the initial condensation reaction were elucidated at room temperature. It was found that a second‐order reaction using both phenol and formaldehyde concentrations is the most probable mechanism.

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Cure kinetics of aqueous phenol–formaldehyde resins used for oriented strandboard manufacturing: Analytical technique

Cited by 41 publications

References 22 publications

Synthesis and Mechanism of Metal-Mediated Polymerization of Phenolic Resins

Synthesis and Mechanism of Metal-Mediated Polymerization of Phenolic Resins

Development of carbon fiber/phenolic resin prepregs modified with nanoclays

Phenol Formaldehyde Revisited—Novolac Resins for the Treatment of Degraded Archaeological Wood

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