Wood modification with phenol urea formaldehyde (PUF) resin: the influence of wood species selection on the dimensional stability

Kupfernagel, Carlo; Spear, Morwenna; Pitman, Andrew J.; Ormondroyd, Graham

doi:10.1007/s00107-022-01893-5

Cited by 5 publications

(2 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The results indicate, that there is a high correlation between the density and the solution uptake; lower density favors higher solution uptakes and vice versa. These observations are in line with results described elsewhere (Kupfernagel et al 2022). To con rm the in uence of the density on the solution uptake, the density was depicted as a function of the solution uptake (Fig.…”

Section: Wood Treatmentsupporting

confidence: 94%

Substituting phenol in phenol-formaldehyde resins for wood modification by phenolic cleavage products from vacuum low-temperature microwave-assisted pyrolysis of softwood kraft lignin

Karthäuser

Biziks²,

Frauendorf

et al. 2023

Preprint

View full text Add to dashboard Cite

Wood modification using phenol-formaldehyde resins (PF resins) is a well-known and commercialized method to improve, amongst others, the dimensional stability and the durability of wood. However, phenol is mainly obtained from non-renewable resources, and the substitution of phenol by renewable resources has been a topic of research interest for years. Due to the high availability of technical lignins, lignin-derived cleavage products are promising candidates. In this study, organic cleavage products obtained from vacuum low-temperature microwave-assisted pyrolysis of softwood kraft lignin were used to substitute up to 45% of phenol in PF resins. The curing behavior and the free formaldehyde content of the resins was studied. Pine sapwood was treated with these resins by a vacuum pressure treatment, and the weight percent gain, leaching, and dimensional stability of the species were examined. Selected samples were analyzed with microscopy. The results indicate that up to 30% substitution of phenol by lignin-based organic products does not lead to significantly inferior wood modifications. At a substitution of 45%, the performance decreases, most likely due to the lower reactivity of the lignin cleavage products compared to pure phenol. The method described in this study could be a way to improve the environmental footprint of wood modification by PF resins.

show abstract

Section: Wood Treatmentsupporting

confidence: 94%

Substituting phenol in phenol-formaldehyde resins for wood modification by phenolic cleavage products from vacuum low-temperature microwave-assisted pyrolysis of softwood kraft lignin

Karthäuser

Biziks²,

Frauendorf

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…Another method of wood densification involves impregnation, injecting low-molecular-weight thermosetting resins or other chemically modifying substances into wood pores under vacuum pressure. This process, followed by heat curing, enhances the wood's density and strength (Kupfernagel et al 2022). The deformation resulting from thermal compression densification via physical mechanical pressure is difficult to fix.…”

Section: Introductionmentioning

confidence: 99%

Effect of Urea-High-Temperature Combined Treatment on the Dimensional Stability of Densified Fast-Growing Wood

Wang,

Wei,

Wang

et al. 2024

Preprint

View full text Add to dashboard Cite

Due to the continuous depletion of timber resources and the increasing ecological awareness among people, large-scale fast-growing artificial forests have become a key solution to address the imbalance between timber supply and demand. In recent years, the problem of low density and mechanical strength of fast-growing timber has been addressed through timber densification. However, densified timber still faces issues such as high moisture absorption and poor dimensional stability. Urea molecules can expand the volume of the non-crystalline region of cellulose to protect the cell wall structure of timber from damage during the densification process. In this paper, an effective modification strategy was proposed to prepare lightweight high-strength wood through the synergistic effect of urea vacuum impregnation treatment and high temperature densification, which solved the problem of poor dimensional stability of densified wood. Research results indicate that when the concentration of urea solution is at 50%, the maximum weight gain of the timber samples reaches 17.76%. After densification treatment, the absolute dry density of the test samples increased by more than 0.031g/cm3. Timber treated with a 50% urea solution and processed at 170°C demonstrates good dimensional stability, with a radial swelling rate of only 0.79% under a relative humidity of 65%. Therefore, the joint modification of wood using urea and high-temperature treatment is an effective and environmentally friendly method, presenting broad prospects for development.

show abstract

Utilizing pyrolysis cleavage products from softwood kraft lignin as a substitute for phenol in phenol-formaldehyde resins for modifying different wood species

Karthäuser,

Biziks,

Roggatz

et al. 2024

Eur. J. Wood Prod.

View full text Add to dashboard Cite

Phenol-formaldehyde resins can be used for wood modification through an impregnation process and subsequent curing within the wood cell wall. Phenol is gained from non-renewable resources, and its substitution by renewable chemicals has been a research goal. A promising example for renewable phenol substituents are lignin-derived organic chemicals. Phenol-formaldehyde resins with such substitutions have been studied, however, knowledge of their application for wood modification is deficient. While there are attempts to modify pine and beech wood with this method, studies on other wood species are scarce. Considering the increasing use of different wood species in wood industry, determining the influence of the wood species on the modification quality is an important research goal. Therefore, in this study, vacuum-pressure impregnation of five wood species – Scots pine sapwood (Pinus sylvestris), Norway spruce (Picea abies), European beech (Fagus sylvatica), Silver birch (Betula pendula), and European aspen sapwood (Populus tremula) – with phenol-formaldehyde resins is described. Here, up to 45% of the phenol in the synthetic resin is substituted by vacuum low-temperature microwave-assisted pyrolysis cleavage products from commercial softwood kraft lignin. The solution uptake, weight% gain, leaching, and anti-swelling efficiency of the modified wood are analyzed and compared. The results indicate that up to 30% of the phenol can be substituted without significant decreases in the performance of the modification. The method gives comparable results for most of the wood species described herein, with exception of beech wood, for which the modification had a lower quality. The results could help to develop more environmentally friendly wood modification methods for several common European wood species.

show abstract

Wood modification with phenol urea formaldehyde (PUF) resin: the influence of wood species selection on the dimensional stability

Cited by 5 publications

References 37 publications

Substituting phenol in phenol-formaldehyde resins for wood modification by phenolic cleavage products from vacuum low-temperature microwave-assisted pyrolysis of softwood kraft lignin

Substituting phenol in phenol-formaldehyde resins for wood modification by phenolic cleavage products from vacuum low-temperature microwave-assisted pyrolysis of softwood kraft lignin

Effect of Urea-High-Temperature Combined Treatment on the Dimensional Stability of Densified Fast-Growing Wood

Utilizing pyrolysis cleavage products from softwood kraft lignin as a substitute for phenol in phenol-formaldehyde resins for modifying different wood species

Contact Info

Product

Resources

About