Weathering of wood modified with the N-methylol compound 1,3-dimethylol-4,5-dihydroxyethyleneurea

Xie, Yanjun; Krause, Andreas; Mai, Carsten; Militz, Holger; Richter, Klaus; Urban, Karol; Evans, Philip D.

doi:10.1016/j.polymdegradstab.2004.08.017

Cited by 93 publications

(54 citation statements)

References 24 publications

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“…The N content in the treating solution was not determined, but it is assumed that the modified veneers release water-soluble degradation products prior to mineralisation. A similar degradation process of DMDHEU-modified veneers due to weathering has been shown previously, where the ML of DMDHEU occurred faster than the ML of veneer (Xie et al 2005). N loss is consistent with ML and tensile strength reduction.…”

Section: Change In Nitrogen Content Of Dmdheumodified Veneerssupporting

confidence: 85%

“…As reported previously (Xie et al 2005(Xie et al , 2007Xiao et al 2010), the process of chemical modification reduced wet tensile strength by up to 50%, especially at high chemical concentrations (see values at 0 h incubation time in …”

Section: Tensile Strength Of Woodsupporting

confidence: 77%

“…The proportion of DMDHEU in treated veneers was calculated as described previously (Xie et al 2005). …”

Section: Methodsmentioning

confidence: 99%

“…As the carbon content of Scots pine sapwood amounts to 47.4% (Xie et al 2005), the Fenton system should produce 10.6 mmol l -1 CO 2 , if the ML would be completely due to mineralisation. However, approximately 8.0 mmol l -1 was actually produced (Figure 5c), indicating that at least 2% of decomposed cell wall fragments remained in the solution.…”

Section: Gas Production By the Fenton Systemmentioning

confidence: 99%

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Degradation of chemically modified Scots pine (Pinus sylvestris L.) with Fenton reagent

Xie¹,

Xiao²,

Mai

2014

Holzforschung

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Abstract:The Fenton reaction is supposed to play a key role in the initial wood degradation by brown rot fungi. Wood was modified with 1,3-dimethylol-4,5-dihydroxyethyleneurea (DMDHEU) and glutaraldehyde (GA) to various weight percentage gains in order to study if these types of modifications are able to reduce wood degradation by Fenton reagent. Veneers modified with higher concentrations (1.2 and 2.0 mol l -1 ) of both chemicals exhibited minor losses in mass and tensile strength during treatment with Fenton reagent, which shows restrained oxidative degradation by hydroxyl radicals. The decomposition rate of H 2 O 2 was lower in the Fenton solutions containing modified veneers than in those containing unmodified controls. More CO 2 evolved in systems containing unmodified veneers than in systems with modified veneers, indicating that modification protected wood from mineralisation. The reason for the enhanced resistance of modified wood to the Fenton reaction is attributed to impeded diffusion of the reagent into the cell wall rather than to inhibition of the Fenton reaction itself. The results show that wood modification with DMDHEU and GA is able to restrain the degradation of wood by the Fenton reaction and can explain why modified wood is more resistant to brown rot decay.

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Section: Change In Nitrogen Content Of Dmdheumodified Veneerssupporting

confidence: 85%

Section: Tensile Strength Of Woodsupporting

confidence: 77%

“…The proportion of DMDHEU in treated veneers was calculated as described previously (Xie et al 2005). …”

Section: Methodsmentioning

confidence: 99%

Section: Gas Production By the Fenton Systemmentioning

confidence: 99%

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Degradation of chemically modified Scots pine (Pinus sylvestris L.) with Fenton reagent

Xie¹,

Xiao²,

Mai

2014

Holzforschung

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“…Different investigations have found that the deterioration is primarily related to the decomposition of lignin (Hon and Minemura 2001;Bekhta and Niemz 2003;George et al 2005;Pandey 2005a;Sharratt et al 2009;Popescu et al 2011;Teacǎ et al 2013;Calienno et al 2014;Bonifazi et al 2015). Free phenoxyl radicals are created during lignin degradation, and these further react with oxygen to produce carbonyl chromophoric groups (Tolvaj and Faix 1995;Colom et al 2003;Xie et al 2005;Gou and Guan 2010;Rosu et al 2010). These are then responsible for the color change of wood.…”

Section: Introductionmentioning

confidence: 99%

Effects of Air Relative Humidity and Temperature on Photodegradation Processes in Beech and Spruce Wood

Tolvaj¹,

Popescu²,

Molnár³

et al. 2015

BioResources

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Spruce and beech samples were irradiated by UV light in humid (100% air humidity) and dry conditions to clarify the effects of vapor on photodegradation. UV-irradiated samples were also soaked in distilled water for comparison. The color change and the IR absorption spectra were measured. The wet condition generated considerably greater discoloration than did the dry condition. The intensity of the color change was higher at elevated temperature (53 °C) than at 32 °C. The results showed that the presence of water as vapor increased the degradation of lignin. The nonconjugated carbonyl groups absorbing around 1760 cm -1 were found not to be stable, and the number of these chemical groups decreased in the presence of vapor when compared against the dry condition. The rising temperature amplified this degradation effect.

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Chemical Modification of Solid Wood

Gérardin

2016

Lignocellulosic Fibers and Wood Handbook

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Weathering of wood modified with the N-methylol compound 1,3-dimethylol-4,5-dihydroxyethyleneurea

Cited by 93 publications

References 24 publications

Degradation of chemically modified Scots pine (Pinus sylvestris L.) with Fenton reagent

Degradation of chemically modified Scots pine (Pinus sylvestris L.) with Fenton reagent

Effects of Air Relative Humidity and Temperature on Photodegradation Processes in Beech and Spruce Wood

Chemical Modification of Solid Wood

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