This study investigated the inhibition effect of nanoscale silver–copper particle (20 nm) against Coriolus versicolor and Gloeophyllumtrabeum. Poplar wood samples (Populus L.) were vacuum-impregnated using aqueous nano-AgCu solutions at concentrations of 0.01 %, 0.02 %, 0.03 %, 0.05 %, 0.075 %, and 0.1 %. Alkaline copper quaternary (ACQ, 0.1 %), boric acid (0.2 %) and untreated control group (CK) were employed for comparisons. Decay resistance and leachability were studied. The anti-fungi effects were compared between nano-AgCu, nano-Ag, Ag+ (silver nitrate), Cu2+ (copper nitrate), and a composite of Ag+–Cu2+. Nano-AgCu particle exhibited effective resistance to fungi after 12 weeks of exposure. The threshold retention of the nano-AgCu against C. versicolor and G. trabeum on poplar wood was 0.19 kg m−3 and 0.62 kg m−3, respectively. The silver–copper nanoparticles demonstrated excellent leach resistance, and the inhibition effect was retained after leaching. The nano-AgCu particle provided better antifungal effects than single ions or metal nanoparticles. This study illustrates the potential of using nano-AgCu particle as an efficient wood preservative compared to commercial water-soluble preservatives.
本研究探讨了纳米银铜微粒（20 纳米）对 Coriolus versicolor 和 Gloeophyllum trabeum 的抑制作用。使用浓度为 0.01 %、0.02 %、0.03 %、0.05 %、0.075 % 和 0.1 % 的纳米银铜水溶液对杨木样本（杨树）进行真空浸渍。碱性季铵盐铜（ACQ，0.1 %）、硼酸（0.2 %）和未经处理的对照组（CK）被用来进行比较。研究了抗腐烂性和浸出性。比较了纳米银铜、纳米银、Ag+（硝酸银）、Cu2+（硝酸铜）和 Ag+-Cu2+ 复合材料的抗真菌效果。纳米 AgCu 粒子在暴露 12 周后表现出对真菌的有效抵抗力。纳米银铜在杨木上对 C. versicolor 和 G. trabeum 的阈值保留分别为 0.19 kg m-3 和 0.62 kg m-3。纳米银铜粒子表现出优异的耐浸出性，浸出后仍能保持抑制效果。与单一离子或金属纳米粒子相比，纳米银铜粒子具有更好的抗真菌效果。这项研究表明，与商用水溶性防腐剂相比，纳米银铜微粒具有作为高效木材防腐剂的潜力。
{"title":"Poplar wood treated with nano-silver–copper particles: fungal degradation and leaching analysis","authors":"Xiwei Wang, Tengfei Yi, Hongxue Luo, Yanran Qi, Fengbiao Yao, Yiliang Liu, Yongfeng Li","doi":"10.1515/hf-2023-0128","DOIUrl":"https://doi.org/10.1515/hf-2023-0128","url":null,"abstract":"This study investigated the inhibition effect of nanoscale silver–copper particle (20 nm) against <jats:italic>Coriolus versicolor</jats:italic> and <jats:italic>Gloeophyllum</jats:italic> <jats:italic>trabeum</jats:italic>. Poplar wood samples (<jats:italic>Populus</jats:italic> L.) were vacuum-impregnated using aqueous nano-AgCu solutions at concentrations of 0.01 %, 0.02 %, 0.03 %, 0.05 %, 0.075 %, and 0.1 %. Alkaline copper quaternary (ACQ, 0.1 %), boric acid (0.2 %) and untreated control group (CK) were employed for comparisons. Decay resistance and leachability were studied. The anti-fungi effects were compared between nano-AgCu, nano-Ag, Ag<jats:sup>+</jats:sup> (silver nitrate), Cu<jats:sup>2+</jats:sup> (copper nitrate), and a composite of Ag<jats:sup>+</jats:sup>–Cu<jats:sup>2+</jats:sup>. Nano-AgCu particle exhibited effective resistance to fungi after 12 weeks of exposure. The threshold retention of the nano-AgCu against <jats:italic>C. versicolor</jats:italic> and <jats:italic>G. trabeum</jats:italic> on poplar wood was 0.19 kg m<jats:sup>−3</jats:sup> and 0.62 kg m<jats:sup>−3</jats:sup>, respectively. The silver–copper nanoparticles demonstrated excellent leach resistance, and the inhibition effect was retained after leaching. The nano-AgCu particle provided better antifungal effects than single ions or metal nanoparticles. This study illustrates the potential of using nano-AgCu particle as an efficient wood preservative compared to commercial water-soluble preservatives.","PeriodicalId":13083,"journal":{"name":"Holzforschung","volume":"30 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140301534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Humins are heterogeneous and polydisperse furanic macromolecules derived from sugar biorefinery. Improving wood properties by humination has become of interest recently. This study examined the photodegradation stability of European pine sapwood microveneers modified with humins at different concentrations of citric acid (CA) and succinic acid (SA) as reaction catalysts, e.g., 1.5 %, 3 %, and 4.5 % wt.%. The photostability of huminated wood was assessed after 48 h, 96 h, and 144 h of exposure to the accelerated weathering test by means of mass loss and finite-span tensile strength. The results were compared with unmodified and also unweathered samples. The FT-IR spectroscopy showed apparent changes in the chemical structure of wood by humination modifications. The weight percentage gains of the samples increased with increasing the concentration of the catalyst. While no differences were observed between the samples after two weeks of the water leaching. The strength losses of weathered microveneers were, however, mostly reduced by humin-based formulas containing catalysts, where the microveneers modified with 1.5 % and 3 % CA showed respectively 32 % and 41 % lower strength loss values than the unmodified samples after 144 h of weathering. Overall, the results showed a high potential for humins to protect wood against photodegradation.
{"title":"Photodegradation stability of huminated European pine (Pinus sylvestris L.) microveneers","authors":"Amir Ghavidel, Reza Hosseinpourpia","doi":"10.1515/hf-2024-0006","DOIUrl":"https://doi.org/10.1515/hf-2024-0006","url":null,"abstract":"Humins are heterogeneous and polydisperse furanic macromolecules derived from sugar biorefinery. Improving wood properties by humination has become of interest recently. This study examined the photodegradation stability of European pine sapwood microveneers modified with humins at different concentrations of citric acid (CA) and succinic acid (SA) as reaction catalysts, e.g., 1.5 %, 3 %, and 4.5 % wt.%. The photostability of huminated wood was assessed after 48 h, 96 h, and 144 h of exposure to the accelerated weathering test by means of mass loss and finite-span tensile strength. The results were compared with unmodified and also unweathered samples. The FT-IR spectroscopy showed apparent changes in the chemical structure of wood by humination modifications. The weight percentage gains of the samples increased with increasing the concentration of the catalyst. While no differences were observed between the samples after two weeks of the water leaching. The strength losses of weathered microveneers were, however, mostly reduced by humin-based formulas containing catalysts, where the microveneers modified with 1.5 % and 3 % CA showed respectively 32 % and 41 % lower strength loss values than the unmodified samples after 144 h of weathering. Overall, the results showed a high potential for humins to protect wood against photodegradation.","PeriodicalId":13083,"journal":{"name":"Holzforschung","volume":"36 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140171060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lukas Sommerauer, Matthew Konkler, Gerald Presley, Thomas Schnabel, Alexander Petutschnigg, Barbara Hinterstoisser
Bark residues from Douglas fir are an abundant resource that is currently used primarily in low-value energy recovery or is landfilled. Bark extractives are rich in diverse compounds like terpenes, fatty acids, phenols, and sugars with potential uses in a variety of high value applications. The study explores the potential of enzymatic hydrolysis to improve phenolic compounds from Douglas fir bark. It also assesses differences in chemical composition among rhytidome, phloem, and comingled bark fractions from an industrial waste pile. Phloem fractions exhibit higher yields of extractives, rhytidome fractions have elevated lignin levels, while the comingled fraction lies between the two except in ash content which was higher than in the separated fractions. Fungal decay tests with Gloeophyllum trabeum and Coniophora puteana on extract treated wood suggest potential for growth inhibition in extracts, about 58–31 % and 30–7% mass loss (in average) respectively, but due to high mass loss at low concentrations an enzymatic modification approach seems crucial for enhanced inhibition. Growth responses in whole-cell fermentation approach display variability depending on the participating microorganisms. Enzymatic hydrolysis with beta-glucosidase improved the antioxidant properties of bark extracts and holds promise for altering the chemical composition and enhancing bioactivity.
{"title":"Douglas fir bark: composition, extracts utilization and enzymatic treatment for enrichment of bioactive constituents","authors":"Lukas Sommerauer, Matthew Konkler, Gerald Presley, Thomas Schnabel, Alexander Petutschnigg, Barbara Hinterstoisser","doi":"10.1515/hf-2023-0130","DOIUrl":"https://doi.org/10.1515/hf-2023-0130","url":null,"abstract":"Bark residues from Douglas fir are an abundant resource that is currently used primarily in low-value energy recovery or is landfilled. Bark extractives are rich in diverse compounds like terpenes, fatty acids, phenols, and sugars with potential uses in a variety of high value applications. The study explores the potential of enzymatic hydrolysis to improve phenolic compounds from Douglas fir bark. It also assesses differences in chemical composition among rhytidome, phloem, and comingled bark fractions from an industrial waste pile. Phloem fractions exhibit higher yields of extractives, rhytidome fractions have elevated lignin levels, while the comingled fraction lies between the two except in ash content which was higher than in the separated fractions. Fungal decay tests with <jats:italic>Gloeophyllum trabeum</jats:italic> and <jats:italic>Coniophora puteana</jats:italic> on extract treated wood suggest potential for growth inhibition in extracts, about 58–31 % and 30–7% mass loss (in average) respectively, but due to high mass loss at low concentrations an enzymatic modification approach seems crucial for enhanced inhibition. Growth responses in whole-cell fermentation approach display variability depending on the participating microorganisms. Enzymatic hydrolysis with beta-glucosidase improved the antioxidant properties of bark extracts and holds promise for altering the chemical composition and enhancing bioactivity.","PeriodicalId":13083,"journal":{"name":"Holzforschung","volume":"17 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140108179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Helena C. Quilter, Regis Risani, Suzanne Gallagher, Michael Robertson, Armin Thumm, Hayden P. Thomas, Robert Abbel
The bark of Pinus radiata offers an underutilized source of high-value renewable chemicals such as extractable polyphenols and lipophilic compounds (waxes and suberin). Here, the depolymerization and extraction of suberin from P. radiata bark and its repolymerization to form novel polyesters are reported. Three different strategies were evaluated for repolymerization of the suberin monomers, with starting materials and products characterized using chemical and thermal analysis techniques. The inclusion of comonomer (1,12-dodecanediol) to provide stoichiometric balance improved the conversion, product yield, solubility and increased molecular weight. Enzymatic polymerization conditions gave the highest yield, while the highest molecular weight was achieved using titanium butoxide, demonstrating that polymerization conditions could be varied to target desired product properties. Products were hydrophobic, as shown by contact angles, ϴ ≥ 90° after 30 s. This work highlights opportunities for utilizing suberin to add value to a P. radiata bark biorefinery concept. Potential future applications include its use as a starting material for novel bio-based polymers that can serve as water-repellent surfaces and coatings, replacing established products derived from fossil resources.
{"title":"Synthesis of hydrophobic biopolyesters from depolymerized Pinus radiata bark suberin","authors":"Helena C. Quilter, Regis Risani, Suzanne Gallagher, Michael Robertson, Armin Thumm, Hayden P. Thomas, Robert Abbel","doi":"10.1515/hf-2023-0104","DOIUrl":"https://doi.org/10.1515/hf-2023-0104","url":null,"abstract":"The bark of <jats:italic>Pinus radiata</jats:italic> offers an underutilized source of high-value renewable chemicals such as extractable polyphenols and lipophilic compounds (waxes and suberin). Here, the depolymerization and extraction of suberin from <jats:italic>P. radiata</jats:italic> bark and its repolymerization to form novel polyesters are reported. Three different strategies were evaluated for repolymerization of the suberin monomers, with starting materials and products characterized using chemical and thermal analysis techniques. The inclusion of comonomer (1,12-dodecanediol) to provide stoichiometric balance improved the conversion, product yield, solubility and increased molecular weight. Enzymatic polymerization conditions gave the highest yield, while the highest molecular weight was achieved using titanium butoxide, demonstrating that polymerization conditions could be varied to target desired product properties. Products were hydrophobic, as shown by contact angles, <jats:italic>ϴ</jats:italic> ≥ 90° after 30 s. This work highlights opportunities for utilizing suberin to add value to a <jats:italic>P. radiata</jats:italic> bark biorefinery concept. Potential future applications include its use as a starting material for novel bio-based polymers that can serve as water-repellent surfaces and coatings, replacing established products derived from fossil resources.","PeriodicalId":13083,"journal":{"name":"Holzforschung","volume":"37 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140105268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Johannes Karthäuser, Andreas Treu, Erik Larnøy, Holger Militz, Gry Alfredsen
Phenol-formaldehyde (PF) resins can be impregnated and cured in situ to improve the woods dimensional stability and decay resistance. In search of renewable alternatives, the substitution of phenol by lignin cleavage products (LCP) has been discussed. However, the different chemical nature may affect the performance of the resin against fungal decay, formaldehyde emission, and equilibrium moisture content. In this study, 30 % (w/w) of the phenol in PF resins were substituted by LCP obtained from microwave-assisted pyrolysis. Scots pine sapwood was modified with the resin. The decay resistance against Rhodonia placenta, Gloeophyllum trabeum, and Trametes versicolor was determined. Additionally, effects of specimen organisation within the Petri dish, different substrates, length of leaching, and type of inoculum were studied. Further, the materials water vapor sorption properties and formaldehyde emission were determined. All modifications effectively reduced fungal decay. With 10 % weight percent gain (WPG), initial decay was detected, while 20 % WPG and 30 % WPG provided efficient protection. The substitution of phenol increases the formaldehyde emission. While further reduction in formaldehyde in the resin admixture or formaldehyde scavengers may be required, the method described herein can be used to partly replace fossil-based phenol, while maintaining good fungal resistance.
{"title":"Resistance against fungal decay of Scots pine sapwood modified with phenol-formaldehyde resins with substitution of phenol by lignin pyrolysis products","authors":"Johannes Karthäuser, Andreas Treu, Erik Larnøy, Holger Militz, Gry Alfredsen","doi":"10.1515/hf-2023-0119","DOIUrl":"https://doi.org/10.1515/hf-2023-0119","url":null,"abstract":"Phenol-formaldehyde (PF) resins can be impregnated and cured <jats:italic>in situ</jats:italic> to improve the woods dimensional stability and decay resistance. In search of renewable alternatives, the substitution of phenol by lignin cleavage products (LCP) has been discussed. However, the different chemical nature may affect the performance of the resin against fungal decay, formaldehyde emission, and equilibrium moisture content. In this study, 30 % (w/w) of the phenol in PF resins were substituted by LCP obtained from microwave-assisted pyrolysis. Scots pine sapwood was modified with the resin. The decay resistance against <jats:italic>Rhodonia placenta, Gloeophyllum trabeum</jats:italic>, and <jats:italic>Trametes versicolor</jats:italic> was determined. Additionally, effects of specimen organisation within the Petri dish, different substrates, length of leaching, and type of inoculum were studied. Further, the materials water vapor sorption properties and formaldehyde emission were determined. All modifications effectively reduced fungal decay. With 10 % weight percent gain (WPG), initial decay was detected, while 20 % WPG and 30 % WPG provided efficient protection. The substitution of phenol increases the formaldehyde emission. While further reduction in formaldehyde in the resin admixture or formaldehyde scavengers may be required, the method described herein can be used to partly replace fossil-based phenol, while maintaining good fungal resistance.","PeriodicalId":13083,"journal":{"name":"Holzforschung","volume":"37 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140074415","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Thi Tham Nguyen, Cong Chi Tran, Thi Vinh Khanh Nguyen, Trong Kien Nguyen, Zefang Xiao, Yanjun Xie
Chemical modification is an efficient strategy for improving wood quality; however, for some fast-grown wood species unwanted shrinkage occur upon treatment with alkaline solution. This study was devised to reveal the shrinkage behavior of poplar and radiata pine woods treated with 5, 10, 15 and 20 % alkaline sodium silicate (SS) solutions. Wood treated with sodium hydroxide (SH) solution adjusting to the same pH as the specific SS solution was used as a reference sample. The weight loss, chemical components analysis, and confocal microscopy revealed that treatments with SS caused considerable reductions in hemicellulose and acid-insoluble lignin (AIL) of poplar wood up to 51 % and 21 %, respectively. In contrast, such reductions of the SS-treated radiata pine wood were only 13 % and 2 %, respectively. Consequently, shrinkage of poplar wood in the tangential- and radial-directions reached up to 22 % and 11 % respectively. However, such shrinkage for radiata pine was less than 2 % in either direction. The crystallinity index of poplar and radiata pine woods after treatment increased up to 35.3 % and 4.8 %, respectively, attributable to removal of the amorphous fraction. The scanning electron microscopy displayed that treatments had minor effect on the cell structure of radiata pine, but brought about significant collapse of poplar cells. The above results show that radiata pine is more chemically stable to alkaline treatment than poplar.
{"title":"Shrinkage of poplar and radiata pine wood after treatment with sodium silicate and sodium hydroxide","authors":"Thi Tham Nguyen, Cong Chi Tran, Thi Vinh Khanh Nguyen, Trong Kien Nguyen, Zefang Xiao, Yanjun Xie","doi":"10.1515/hf-2023-0097","DOIUrl":"https://doi.org/10.1515/hf-2023-0097","url":null,"abstract":"Chemical modification is an efficient strategy for improving wood quality; however, for some fast-grown wood species unwanted shrinkage occur upon treatment with alkaline solution. This study was devised to reveal the shrinkage behavior of poplar and radiata pine woods treated with 5, 10, 15 and 20 % alkaline sodium silicate (SS) solutions. Wood treated with sodium hydroxide (SH) solution adjusting to the same pH as the specific SS solution was used as a reference sample. The weight loss, chemical components analysis, and confocal microscopy revealed that treatments with SS caused considerable reductions in hemicellulose and acid-insoluble lignin (AIL) of poplar wood up to 51 % and 21 %, respectively. In contrast, such reductions of the SS-treated radiata pine wood were only 13 % and 2 %, respectively. Consequently, shrinkage of poplar wood in the tangential- and radial-directions reached up to 22 % and 11 % respectively. However, such shrinkage for radiata pine was less than 2 % in either direction. The crystallinity index of poplar and radiata pine woods after treatment increased up to 35.3 % and 4.8 %, respectively, attributable to removal of the amorphous fraction. The scanning electron microscopy displayed that treatments had minor effect on the cell structure of radiata pine, but brought about significant collapse of poplar cells. The above results show that radiata pine is more chemically stable to alkaline treatment than poplar.","PeriodicalId":13083,"journal":{"name":"Holzforschung","volume":"27 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140057691","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The glass transition temperatures (Tg) of native, residual, and technical lignins are important to lignocellulose pulping, pulp processing and side stream utilization; however, how the structural changes from native to residual and technical lignin influences Tg has proven difficult to elucidate. Since the Tg of macromolecules is greatly influenced by the molecular weight, low-molecular-weight fractions, such as milled wood lignin (MWL), are poor representatives of lignin in the cell wall. To circumvent this problem, lignins of both high yield and purity were isolated from Norway spruce and softwood kraft pulp using the enzymatic mild acidolysis lignin (EMAL) protocol. Technical softwood kraft lignin was also fractionated into groups of different molecular weights, to acquire lignin that spanned over a wide molecular-weight range. A powder sample holder for dynamic mechanical analysis (DMA), was used to determine the Tg of lignins, for which calorimetric methods were not sensitive enough. The Tgs of EMAL were found to be closer to their in situ counterparts than MWL.
原生木质素、残留木质素和工业木质素的玻璃化转变温度（T g）对木质纤维素制浆、纸浆加工和副流利用非常重要；然而，从原生木质素到残留木质素和工业木质素的结构变化如何影响 T g 却很难阐明。由于大分子的 T g 受分子量影响很大，因此低分子量馏分（如碾磨木质素 (MWL)）不能很好地代表细胞壁中的木质素。为了避免这一问题，我们采用酶法温和酸解木质素（EMAL）方案从挪威云杉和软木牛皮浆中分离出了高产率和高纯度的木质素。技术软木牛皮浆木质素也被分成了不同分子量的组，以获得跨越宽分子量范围的木质素。使用动态机械分析（DMA）的粉末样品架来测定木质素的 T g，因为热量测定法对其不够灵敏。结果发现，EMAL 的 T gs 比 MWL 更接近其原位对应物。
{"title":"The glass transition temperature of isolated native, residual, and technical lignin","authors":"Åke Henrik-Klemens, Fabio Caputo, Roujin Ghaffari, Gunnar Westman, Ulrica Edlund, Lisbeth Olsson, Anette Larsson","doi":"10.1515/hf-2023-0111","DOIUrl":"https://doi.org/10.1515/hf-2023-0111","url":null,"abstract":"The glass transition temperatures (<jats:italic>T</jats:italic> <jats:sub>g</jats:sub>) of native, residual, and technical lignins are important to lignocellulose pulping, pulp processing and side stream utilization; however, how the structural changes from native to residual and technical lignin influences <jats:italic>T</jats:italic> <jats:sub>g</jats:sub> has proven difficult to elucidate. Since the <jats:italic>T</jats:italic> <jats:sub>g</jats:sub> of macromolecules is greatly influenced by the molecular weight, low-molecular-weight fractions, such as milled wood lignin (MWL), are poor representatives of lignin in the cell wall. To circumvent this problem, lignins of both high yield and purity were isolated from Norway spruce and softwood kraft pulp using the enzymatic mild acidolysis lignin (EMAL) protocol. Technical softwood kraft lignin was also fractionated into groups of different molecular weights, to acquire lignin that spanned over a wide molecular-weight range. A powder sample holder for dynamic mechanical analysis (DMA), was used to determine the <jats:italic>T</jats:italic> <jats:sub>g</jats:sub> of lignins, for which calorimetric methods were not sensitive enough. The <jats:italic>T</jats:italic> <jats:sub>g</jats:sub>s of EMAL were found to be closer to their <jats:italic>in situ</jats:italic> counterparts than MWL.","PeriodicalId":13083,"journal":{"name":"Holzforschung","volume":"11 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140034304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Carbon fraction (CF) of trees is essential for quantifying forest carbon (C) stocks. Considerable attention has been paid to CF variations at various levels with the exception of inter- and intra-growth rings. Herein, the inter- and intra-growth ring variation of CF in Pinus tabuliformis was investigated. Elemental analysis was performed to obtain CF values of the earlywood and latewood in each growth ring of the xylem. Patterns of CF variation at the growth ring level were evaluated using mixed-effect models. The results showed that latewood CF, 50.6 %, was significantly higher than earlywood CF, 49.9 % (p < 0.01). In particular, inter-growth ring variations of CF differed between heartwood and sapwood, as well as between juvenile wood and mature wood. CF values decreased nonlinearly with cambium age toward the heartwood or juvenile wood, with estimated least-squares means of 50.4 % and 51.8 %, respectively. While CF values were almost unaltered in sapwood, and slightly decreased in mature wood, with estimated least-squares means of 50.0 % and 50.2 %, respectively. It indicates that patterns of CF variation between juvenile wood and mature wood are important to estimate the C stock of P. tabuliformis. This research provides insights into C uptake dynamics to support forest management and wood utilization.
{"title":"Inter- and intra-growth ring variations of wood carbon fractions in Pinus tabuliformis","authors":"Yupei Wei, Chang Zheng, Lingyu Ma, Xiaomei Jiang, Yafang Yin, Juan Guo","doi":"10.1515/hf-2023-0115","DOIUrl":"https://doi.org/10.1515/hf-2023-0115","url":null,"abstract":"Carbon fraction (CF) of trees is essential for quantifying forest carbon (C) stocks. Considerable attention has been paid to CF variations at various levels with the exception of inter- and intra-growth rings. Herein, the inter- and intra-growth ring variation of CF in <jats:italic>Pinus tabuliformis</jats:italic> was investigated. Elemental analysis was performed to obtain CF values of the earlywood and latewood in each growth ring of the xylem. Patterns of CF variation at the growth ring level were evaluated using mixed-effect models. The results showed that latewood CF, 50.6 %, was significantly higher than earlywood CF, 49.9 % (<jats:italic>p</jats:italic> < 0.01). In particular, inter-growth ring variations of CF differed between heartwood and sapwood, as well as between juvenile wood and mature wood. CF values decreased nonlinearly with cambium age toward the heartwood or juvenile wood, with estimated least-squares means of 50.4 % and 51.8 %, respectively. While CF values were almost unaltered in sapwood, and slightly decreased in mature wood, with estimated least-squares means of 50.0 % and 50.2 %, respectively. It indicates that patterns of CF variation between juvenile wood and mature wood are important to estimate the C stock of <jats:italic>P. tabuliformis</jats:italic>. This research provides insights into C uptake dynamics to support forest management and wood utilization.","PeriodicalId":13083,"journal":{"name":"Holzforschung","volume":"176 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139751942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Daniel Konopka, Benjamin Grohmann, Jens Gecks, Wolfram Scheiding, Michael Kaliske
The hygroscopic and moisture-dependent mechanical characteristics of small-leaved lime wood (Tilia cordata) were investigated experimentally. This study includes sorption, swelling and shrinkage experiments, as well as tension and compression tests in the three principal anatomical directions at four relative humidity levels. Four sample groups from trees of three different locations in Germany were used. The findings are comparable to those of earlier studies. The hygro-expansion anisotropy is relatively small. Young’s moduli at tension/compression decreased by about 52 %/64 % in radial, 19 %/48 % in tangential and 16 %/58 % in longitudinal direction for an increase of moisture content from 10 % (65 % RH) to 20 % (95 % RH). Tension strengths/compression yield stresses decreased by about 25 %/45 % in radial, 9 %/42 % in tangential, and 32 % (compression) in longitudinal direction, respectively. These parameters increased with an increasing density. Based on the mechanical tests, Young’s modulus, tension strength and compression yield stress were derived as density- and moisture-dependent material model parameters. Shear modulus and shear strength were estimated by a theoretical approach. The experimental and modelling study was accompanied by a literature survey on characteristics of lime wood relevant for hygro-mechanical material modelling.
{"title":"Short-term hygro-mechanical behaviour of lime wood (Tilia cordata) in principal anatomical directions","authors":"Daniel Konopka, Benjamin Grohmann, Jens Gecks, Wolfram Scheiding, Michael Kaliske","doi":"10.1515/hf-2023-0029","DOIUrl":"https://doi.org/10.1515/hf-2023-0029","url":null,"abstract":"The hygroscopic and moisture-dependent mechanical characteristics of small-leaved lime wood (<jats:italic>Tilia cordata</jats:italic>) were investigated experimentally. This study includes sorption, swelling and shrinkage experiments, as well as tension and compression tests in the three principal anatomical directions at four relative humidity levels. Four sample groups from trees of three different locations in Germany were used. The findings are comparable to those of earlier studies. The hygro-expansion anisotropy is relatively small. Young’s moduli at tension/compression decreased by about 52 %/64 % in radial, 19 %/48 % in tangential and 16 %/58 % in longitudinal direction for an increase of moisture content from 10 % (65 % RH) to 20 % (95 % RH). Tension strengths/compression yield stresses decreased by about 25 %/45 % in radial, 9 %/42 % in tangential, and 32 % (compression) in longitudinal direction, respectively. These parameters increased with an increasing density. Based on the mechanical tests, Young’s modulus, tension strength and compression yield stress were derived as density- and moisture-dependent material model parameters. Shear modulus and shear strength were estimated by a theoretical approach. The experimental and modelling study was accompanied by a literature survey on characteristics of lime wood relevant for hygro-mechanical material modelling.","PeriodicalId":13083,"journal":{"name":"Holzforschung","volume":"11 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139752045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Babar Hassan, Lesley Francis, R. Andrew Hayes, Maryam Shirmohammadi
Resin production in wood tissues is a regular feature of pine wood species, including southern pine. High resin contents of southern pine wood may increase wood resistance against decay fungi. The current study investigated the effect of resin contents in southern pine wood on decay resistance by exposing non-extracted heartwood, mixed wood (sapwood + heartwood), and sapwood blocks with varying resin content to brown rot, Fomitopsis ostreiformis in a laboratory decay test. Matching blocks of each wood type were successively extracted in a Soxhlet using three solvents to determine resin content and were exposed to decay fungus in parallel. Results showed that mass losses in non-extracted heartwood and mixed wood depended on resin content levels, and very shallow or no mass losses were observed in blocks containing more than 31 % resin content. Sapwood experienced high mass losses, but the presence of resinous extractives significantly increased the decay resistance. All solvent-extracted blocks experienced high mass loss (53–55 %). Scanning electron microscopy showed that penetration of brown rot hyphae and cell damage depended on the resin contents of blocks. Most of the identified compounds through GC-MS belonged to oleoresins, among which monoterpene hydrocarbons, oxygenated monoterpenoids, and sesquiterpenes were more abundant in heartwood than sapwood.
{"title":"Decay resistance of southern pine wood containing varying amounts of resin against Fomitopsis ostreiformis (Berk.) T. Hatt.","authors":"Babar Hassan, Lesley Francis, R. Andrew Hayes, Maryam Shirmohammadi","doi":"10.1515/hf-2023-0106","DOIUrl":"https://doi.org/10.1515/hf-2023-0106","url":null,"abstract":"Resin production in wood tissues is a regular feature of pine wood species, including southern pine. High resin contents of southern pine wood may increase wood resistance against decay fungi. The current study investigated the effect of resin contents in southern pine wood on decay resistance by exposing non-extracted heartwood, mixed wood (sapwood + heartwood), and sapwood blocks with varying resin content to brown rot, <jats:italic>Fomitopsis ostreiformis</jats:italic> in a laboratory decay test. Matching blocks of each wood type were successively extracted in a Soxhlet using three solvents to determine resin content and were exposed to decay fungus in parallel. Results showed that mass losses in non-extracted heartwood and mixed wood depended on resin content levels, and very shallow or no mass losses were observed in blocks containing more than 31 % resin content. Sapwood experienced high mass losses, but the presence of resinous extractives significantly increased the decay resistance. All solvent-extracted blocks experienced high mass loss (53–55 %). Scanning electron microscopy showed that penetration of brown rot hyphae and cell damage depended on the resin contents of blocks. Most of the identified compounds through GC-MS belonged to oleoresins, among which monoterpene hydrocarbons, oxygenated monoterpenoids, and sesquiterpenes were more abundant in heartwood than sapwood.","PeriodicalId":13083,"journal":{"name":"Holzforschung","volume":"73 1 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139668421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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