Use of UF-bonded recycling particle- and fibreboards in MDF-production

Roffael, E.; Dix, B.; Behn, C.; Bär, G.

doi:10.1007/s00107-009-0376-3

Cited by 19 publications

(12 citation statements)

References 9 publications

(3 reference statements)

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“…Urea, ammonia and oligomeric decay products of UF resin can react with formaldehyde and act as formaldehyde scavengers. Thus, various studies reported significantly reduced formaldehyde content and emission of the recycled MDF (Roffael et al 2010b;2016;Behn 2018). Similarly, the formaldehyde emission determined by perforator method of the recycled panels was lower than that of virgin panels throughout the different generations of this study.…”

Section: Physico-mechanical and Chemical Properties Of The Mdf Panelsmentioning

confidence: 99%

Repeated thermo-hydrolytic disintegration of medium density fibreboards (MDF) for the production of new MDF

Buschalsky

Mai

2021

Eur. J. Wood Prod.

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Medium density fibreboards (MDF) are currently not recycled after service life, but various publications report on recycling by the disintegration of MDF using various techniques and the properties of obtained recovered fibres (RF). In this study, the main aim was to put back RF into the MDF manufacturing process as closed-loop recycling using repeated thermo-hydrolytic disintegration. Compared to previous studies, the focus was on the recycling of MDF with a relatively low F:U molar ratio (1.11). Urea–formaldehyde-bonded MDF with a target density of 700 kg m−3 was subjected to thermo-hydrolytic disintegration in an autoclave using only water at 95 °C for 20–30 min. Afterwards, the properties of RF and virgin fibres (VF), of MDF produced thereof and the composition of the disintegration water (DW) were determined. The nitrogen content (NC) revealed that RF contained about 30% of the initially applied UF. The pH of the DW hardly changed during recycling and it contained considerable amounts of reducing sugars. Using RF did not result in higher formaldehyde emissions than VF. Compared to earlier studies using a higher formaldehyde content (higher F:U ratio), MDF bonded with modern UF resins can be disintegrated under clearly milder disintegration conditions with respect to temperature and time. The properties of recycled MDF were similar to those of reference MDF; up to 100% RF could be used without severely deteriorating the strength and increasing formaldehyde emissions from these panels.

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Section: Physico-mechanical and Chemical Properties Of The Mdf Panelsmentioning

confidence: 99%

Repeated thermo-hydrolytic disintegration of medium density fibreboards (MDF) for the production of new MDF

Buschalsky

Mai

2021

Eur. J. Wood Prod.

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“…Lately, there has been a growing interest in utilizing oligosaccharides in different applications such as biodegradable oxygen barrier films [38][39][40], emulsifiers [41][42][43][44][45][46][47], thermoplastics [48], hydrogels [49], coatings, or adhesives [50]. The remaining fibrous fraction, on the other hand, might be suitable for production of new fiberboards [51][52][53][54][55][56][57], cellulose nanocrystals [58,59], bioethanol [60,61], biogas, and bio-oil using pyrolysis [62,63]; however, utilization as reinforcement and filler material in wood-plastic compounds (WPCs) [64][65][66] and particleboards [67] has also been proposed.…”

Section: Introductionmentioning

confidence: 99%

Fractionation of Waste MDF by Steam Refining

Hagel

Saake

2020

Molecules

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In view of the expected increase in available waste medium-density fiberboard (MDF) and the current insufficient and unsatisfactory disposal capacities, efficient ways of recycling the waste material need to be developed. In this study, the potential of steam refining as a method to hydrolyze the resins, isolate fibers, and obtain a hemicellulose-rich extract available for further utilization in the context of a biorefinery was assessed. Two different MDF waste samples, as well as poplar (Populus spp.) and spruce (Picea spp.) wood chips for benchmarking, were treated over a severity range from 2.47 to 3.95. The separated fiber and extract fractions were analyzed with regard to yield, content of carbohydrates, acids, degradation products, and nitrogen. A fiber fraction of more than 70% yield and an extract containing up to 30% of carbohydrates for further processing can be gained by steam-refining waste MDF. At low severities, most of the nitrogen-based compounds are solubilized. Increasing the severity leads to a decrease in nitrogen in the extract as the nitrogen compounds are converted into volatiles. A non-hydrolysable resin residue remains on the fibers, independent of the treatment severity. In comparison to the benchmark samples, the extract fraction of waste MDF shows a high pH of 8 and high amounts of acetic and formic acid. The generation of furfural and 5-hydroxymethylfurfural (5-HMF) on the other hand is suppressed. Distinct differences in carbohydrate hydrolysis behavior between waste MDF and conventional wood can be observed. Especially, the mannose-containing constituents seem to be resistant to hydrolysis reactions in the milieu created in MDF fractionation.

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“…Wan et al [13] mentioned that there have been developed several methods for reconstituting the waste from PBs and other medium density fiberboards (MDF) in order to solve the problem of recycling the wood composites. The processing can be chemically thermomechanical [14,15], hydrothermal [16][17][18], chemical [19] or mechanical [20][21][22][23][24]. According to Wan et al [13], it was confirmed by research results that common types of urea-formaldehyde (UF) 2 of 16 and phenol-formaldehyde (PF) resins are suitable for manufacturing PBs and MDF from recycled wood materials using conventional technology.…”

Section: Introductionmentioning

confidence: 99%

Particleboards from Recycled Wood

Iždinský

Vidholdová

Reinprecht

2020

Forests

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The effective recovery of wood waste generated in wood processing and also at the end of wood product life is important from environmental and economic points of view. In a laboratory, 16 mm-thick three-layer urea–formaldehyde (UF)-bonded particleboards (PBs) were produced at 5.8 MPa and 240 °C and with an 8 s/mm pressing factor, using wood particles prepared from (1) fresh spruce wood (C), (2) a mixture of several recycled wood products (R1), and (3) recycled faulty PBs bonded with UF resin (R2). Particles from spruce wood were combined with particles from R1 or R2 recyclates in weight ratios of 100:0, 80:20, 50:50 and 0:100. In comparison to the control spruce PB, the PBs containing the R1 recyclate from old wood products were characterized by lower thickness swelling after 2 and 24 h (TS-2h and TS-24h), lower by 18 and 31%; water absorption after 2 and 24 h (WA-2h and WA-24h), lower by 33 and 28%; modulus of rupture in bending (MOR), lower by 28%; modulus of elasticity in bending (MOE), lower by 18%; internal bond (IB), lower by 33%; and resistance to decay determined by the mass loss under the action of the brown-rot fungus Coniophora puteana (Δm), lower by 32%. The PBs containing the R2 recyclate from faulty PBs were also characterized by a lower TS-2h and TS-24h, lower by 45% and 59%; WA-2h and WA-24h, lower by 61% and 51%; MOR, lower by 37%; MOE, lower by 17%; and IB, lower by 33%; however, their biological resistance to C. puteana was more effective, with a decreased Δm in the decay test, lower by 44%.

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Use of UF-bonded recycling particle- and fibreboards in MDF-production

Cited by 19 publications

References 9 publications

Repeated thermo-hydrolytic disintegration of medium density fibreboards (MDF) for the production of new MDF

Repeated thermo-hydrolytic disintegration of medium density fibreboards (MDF) for the production of new MDF

Fractionation of Waste MDF by Steam Refining

Particleboards from Recycled Wood

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