Andrzej Antczak - Academia.edu (original) (raw)

Papers by Andrzej Antczak

Przemysl Chemiczny

ABSTRACT

Annals of WULS, Forestry and Wood Technology

The study of selected properties of pine wood (Pinus sylvestris L.) subjected to acetylation. In ... more The study of selected properties of pine wood (Pinus sylvestris L.) subjected to acetylation. In the paper pine wood was subjected to acetylation with acetic anhydride and mixture of acetic anhydride and glacial acetic acid (50:50)v/v. After modification process density, WPG index, water absorbability, volume swelling and colour of wood were carried out and compared with results obtained for unmodified pine wood. Based on the obtained results the density of acetylated pine wood was increased for each group of samples. The highest WPG index was obtained for previously dried wood modified with acetic anhydride (15.6%) or mixture of acetic anhydride and glacial acetic acid (10.5%). Acetylation process with acetic anhydride or mixture of acetic anhydride and glacial acetic acid of samples, which were extracted (in chloroform-ethanol 93:7w/w mixture) and dried before modification, had beneficial effect on water absorbability of pine wood. These samples after 1001h (about 42 days) of soak...

Polymers

The influence of bacterial cellulose gel film pretreatment methods on the efficiency of enzymatic... more The influence of bacterial cellulose gel film pretreatment methods on the efficiency of enzymatic hydrolysis was investigated. An increase in the efficiency of enzymatic hydrolysis due to liquid hot water pretreatment or steam explosion was shown. The glucose yield of 88% was obtained from raw, non-purified, bacterial cellulose treated at 130 °C. The results confirm the potential of bacterial cellulose gel film as a source for liquid biofuel production.

Wood Research

The concentration of selected heavy metals: chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni)... more The concentration of selected heavy metals: chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni), copper (Cu) and zinc (Zn) in 5-year-old wood of Populus trichocarpa before and after steam explosion (SE) and liquid hot water (LHW) pretreatments was studied. The concentration of the above heavy metals in the liquid fraction obtained after pretreatments was also studied. The studied problem of heavy metals in lignocellulosic biomass is an interesting and important issue in the context of bioethanol production technology. An X-ray fluorescence spectrometer (XRF) was used to analyse the concentration of heavy metals. The change of concentration of the tested elements in wood biomass after pretreatment was small (except for iron). On the other hand, the average concentration of iron in wood biomass of a 5-year-old Populus trichocarpa, after SE and LHW with duration of the pretreatments 15 and 60 min, increased about 24-fold to 28-fold, comparing to its average concentration in native wood. During the pretreatment process, wood biomass absorbed the iron that at high temperatures passed from the pretreatment equipment to the solution. The average concentration of the elements under research in liquid fraction obtained during SE and LHW of wood biomass with duration of the pretreatments 15 and 60 min was at a low level.

Annals of WULS, Forestry and Wood Technology, 2020

The study of selected properties of black poplar wood (Populus nigra L.) subjected to furfurylati... more The study of selected properties of black poplar wood (Populus nigra L.) subjected to furfurylation and polymerization in lumen. The aim of this work was studying black poplar wood (Populus nigra L.) selected properties modified with furfuryl alcohol and styrene. Maleic anhydride and glicydyl methacrylate were used as cross-linking agents. For modified wood samples the index of WPG, density, hardness, water absorbability, colour change and volume swelling were tested. Each test results were compared with values for unmodified black poplar wood. During furfurylation process density of poplar wood samples increased up to 1.3 times. Addition of maleic anhydride to furfurylation process caused increase of WPG index about 5-6 % and at the same time slightly decrease of wood Brinell hardness. Water absorbability and volume swelling of furfurylated poplar wood after 10080 min (168 h) of soaking in water were reduced more than 50% relative to unmodified wood. Polymerization in lumen with us...

Annals of WULS, Forestry and Wood Technology, 2020

Comparison of the chemical composition of domestic common hornbeam (Carpinus betulus L.) wood and... more Comparison of the chemical composition of domestic common hornbeam (Carpinus betulus L.) wood and exotic yakal (Shorea astylosa Foxw.) wood. The study was carried out to compare the chemical composition of domestic hornbeam wood with exotic yakal wood, which is an endemic species occurring in the Philippines. Species of similar structural structure occurring in different areas were studied. Extractives, cellulose (including α-cellulose), holocellulose (including hemicelluloses), lignin and ash contents were analyzed. The obtained results indicated lower content of cellulose, α-cellulose, lignin, extractives and ash in hornbeam wood as compared to yakal wood. On the other hand, a much higher amount of hemicelluloses (by 12 percentage points) was found in hornbeam wood. Probably, the main reason for the differences in the chemical composition of wood were different habitat and climatic conditions, in which the studied species were growing.

In order to specify the influence of the environmental pollution on non-metals accumulation in Sc... more In order to specify the influence of the environmental pollution on non-metals accumulation in Scots pine trees, studies of nitrogen, sulfur, phosphorus and chlorine content were performed on samples obtained from pine stems gained from the Ist, IInd and IIIrd zone of industrial damages (tree degradation). Samples were collected from butt-end, middle and top sections of the stem in sapwood, heartwood adjacent sapwood, heartwood and in bark. Significant influence of the environmental pollution caused by nitrogen industrial plant on the nitrogen content was denoted. Nitrogen content was decreased (in relation to samples from non-polluted area) especially in sapwood and bark. Additionally, chlorine content both in wood and bark was increased.

Annals of WULS, Forestry and Wood Technology, 2021

Effects of soaking aqueous ammonia pretreatment on chemical composition and enzymatic hydrolysis ... more Effects of soaking aqueous ammonia pretreatment on chemical composition and enzymatic hydrolysis of corn stover. The aim of this research was to investigate the effect of applying two different temperatures of the soaking aqueous ammonia treatment on the chemical composition and enzymatic hydrolysis yield of the corn stover. Native corn stover as well as solid fractions after 20 h of alkali pretreatment performed at 15% ammonia solution and at 50 °C or 90 °C were analysed in terms of cellulose, holocellulose, lignin and extractives content. Both untreated and treated samples were subjected to the enzymatic hydrolysis and hydrolysates were examined with a high performance liquid chromatography (HPLC). Results indicated a significant development of enzymatic digestibility of the SAA treated biomass. Furthermore, a 38.7% and a 68.9% delignification levels in the biomass treated with ammonia at respectively 50 °C and 90 °C process comparing to the raw material were achieved.

Annals of WULS, Forestry and Wood Technology, 2020

Changes in poplar (Populus trichocarpa) wood porous structure after liquid hot water (LHW) pretre... more Changes in poplar (Populus trichocarpa) wood porous structure after liquid hot water (LHW) pretreatment. The aim of this research was to investigate the effect of applying different hydrothermal pretreatment conditions on the porous structure of poplar wood. Porosity is recognised as an important factor considering efficiency of an enzymatic hydrolysis as a step of bioethanol production. Native poplar wood as well as solid fractions after pretreatment performed at different temperatures (160 °C, 175 °C and 190 °C) were analysed. Porous structure was examined with an inverse size-exclusion chromatography (ISEC) method. Results indicated a significant development of the porous structure of the biomass with increasing porosity along with the growing temperature of the LHW process. The temperature of 190 °C was chosen as the most promising condition of poplar wood LHW pretreatment in terms of the efficiency of the subsequent steps of bioethanol production. The obtained results were cons...

Annals of WULS, Forestry and Wood Technology, 2020

Inhibitory compounds formation after liquid hot water (LHW) pretreatment of corn stover as an alt... more Inhibitory compounds formation after liquid hot water (LHW) pretreatment of corn stover as an alternative to wood lignocellulosic feedstock for bioethanol production. Thus far, corn stover has been perceived as a promising lignocellulosic alternative to wood intended for bioethanol procurement, however it should be recognised also as a potential future component in a mixed biomass system. The aim of this research was to investigate the effect of applying different hydrothermal treatment conditions on the potential inhibitory compounds formation from corn stover. An analysis of selected inhibitory compounds formed after pretreatment performed at different temperatures (160°C, 175°C, 190°C and 205°C) was carried out. Furfural, simple sugars and lignin were some of the inhibitors examined with HPLC and UV-VIS spectrophotometric methods. Furthermore, the chemical composition of organic extracts obtained from native and LHW pretreated biomass was analyzed qualitatively with GC-MS method ...

Energies, 2020

Biomass pretreatment is a mandatory step for the biochemical conversion of lignocellulose to chem... more Biomass pretreatment is a mandatory step for the biochemical conversion of lignocellulose to chemicals. During pretreatment, soluble compounds are released into the prehydrolyzate that inhibit the enzymatic hydrolysis step. In this work, we investigated how the reaction conditions in steam explosion pretreatment of beechwood (severity: 3.0–5.25; temperature: 160–230 °C) influence the resulting amounts of different inhibitors. Furthermore, we quantified the extent of enzyme inhibition during enzymatic hydrolysis of Avicel in the presence of the prehydrolyzates. The amounts of phenolics, HMF, acetic acid and formic acid increased with increasing pretreatment severities and maximal quantities of 21.6, 8.3, 43.7 and 10.9 mg/gbeechwood, respectively, were measured at the highest severity. In contrast, the furfural concentration peaked at a temperature of 200 °C and a severity of 4.75. The presence of the prehydrolyzates in enzymatic hydrolysis of Avicel lowered the glucose yields by 5–26...

BioResources, 2018

The potential of fast-growing poplar species was evaluated for bioethanol production. The yields ... more The potential of fast-growing poplar species was evaluated for bioethanol production. The yields of glucose and xylose from acid and enzymatic hydrolysis were compared. The hydrolysis processes were performed on raw and extracted wood. The extracted wood was obtained by action of a chloroform and 96% ethanol (93:7 w/w) mixture. Additionally, to enhance the enzymatic hydrolysis efficiency, a liquid hot water (LHW) pretreatment was used. The acid hydrolysis turned out to be a good method to verify the biomass potential for bioethanol production. After acid hydrolysis of raw and extracted biomass, high total sugars yields were obtained (between 626.2 to 808.5 mg/g raw or extracted biomass), while in the case of enzymatic hydrolysis the total sugars yields were very low (between 45.5 to 68.9 mg/g raw or extracted biomass). The LHW pretreatment greatly enhanced the enzymatic digestibility of the studied wood. The average glucose yield from enzymatic hydrolysis was up to 602.0 mg/g pretreated biomass and was higher than that from acid hydrolysis (the maximum yield was 566.9 mg/g extracted biomass). As a result of the LHW pretreatment, up to 91.3% of the hemicelluloses were removed from the solid fraction. From the obtained glucose and xylose results, it was concluded that Populus trichocarpa wood had a higher potential for bioethanol production than P. deltoides x maximowiczii wood. The presence of extractives (low molecular substances) in raw poplar wood (up to 2.8%) had a low impact on the yield from acid and enzymatic hydrolysis.

BioResources, 2012

Two hyperbranched polyglycerols (HBPGs) and one oligoglycerol containing bisphenol A in the core ... more Two hyperbranched polyglycerols (HBPGs) and one oligoglycerol containing bisphenol A in the core of the molecule were synthesized from glycerol carbonate and applied as polyols in 2-component polyurethane adhesive systems. It was shown that mechanical performance of the joints made in solid wood depended on the hydroxyl functionality of the polyglycerol as well as on the type of the isocyanate used as a crosslinker. The shear strengths of the best-performing joints exceeded that of the substrate. Eventually, it was proved that hyperbranched polyglycerols might be convenient glycerol-derived raw materials for polyurethane adhesives.

Wood Science and Technology, 2021

In this paper, the influence of physicochemical pretreatment methods on the chemical composition,... more In this paper, the influence of physicochemical pretreatment methods on the chemical composition, enzymatic hydrolysis efficiency and porosity of fast-growing Populus trichocarpa wood was compared. Among the pretreatment methods, the liquid hot water (LHW) and steam explosion (SE) were used, which were performed at three different temperatures (160 °C, 175 °C and 190 °C) and two residence times (15 min and 1 h). The chemical composition, enzymatic hydrolysis and porosity analysis were done for native wood and solid fraction obtained after LHW and SE pretreatments. The porosity analysis was performed by inverse size exclusion chromatography method. Additionally, inhibitors of hydrolysis and fermentation processes in the liquid and solid fractions obtained after pretreatments were examined. Based on the results, it was found that the tested pretreatments caused the greatest changes in the chemical content of hemicelluloses. It was found that after LHW and SE pretreatments up to 99.1% ...

BioResources, 2014

This study aimed to determine glucose and xylose content by acid hydrolysis of wood samples, both... more This study aimed to determine glucose and xylose content by acid hydrolysis of wood samples, both unmodified and thermally modified (modification time was 2, 6, 10 hours), using high performance liquid chromatography. Optimization of the hydrolysis process on the native ash wood samples showed that 3 h was the best time in the hydrolysis process. After that time, 58.8% of glucose and 20.8% of xylose were obtained. In turn, chromatographic analysis showed incomplete hydrolysis of ash wood samples, which were modified in a nitrogen atmosphere, especially at shorter times (2 and 6 h) of modification. With longer modification times (10 h), the hydrolysis of ash wood samples was completed. The above mentioned problem was caused mainly by the increase of cellulose crystallinity degree. The decrease of this parameter was observed only after 10 h of thermal modification, which would facilitate the process of acidic hydrolysis. Additionally, it was observed that the thermal modification of ash wood at 190 °C in a nitrogen atmosphere for 10 h caused a drastic decrease in the xylose content (from 20.8% to 8.0%) and only a slight decrease in the glucose content (from 58.8% to 54.9%).

Przemysl Chemiczny

ABSTRACT

Annals of WULS, Forestry and Wood Technology

The study of selected properties of pine wood (Pinus sylvestris L.) subjected to acetylation. In ... more The study of selected properties of pine wood (Pinus sylvestris L.) subjected to acetylation. In the paper pine wood was subjected to acetylation with acetic anhydride and mixture of acetic anhydride and glacial acetic acid (50:50)v/v. After modification process density, WPG index, water absorbability, volume swelling and colour of wood were carried out and compared with results obtained for unmodified pine wood. Based on the obtained results the density of acetylated pine wood was increased for each group of samples. The highest WPG index was obtained for previously dried wood modified with acetic anhydride (15.6%) or mixture of acetic anhydride and glacial acetic acid (10.5%). Acetylation process with acetic anhydride or mixture of acetic anhydride and glacial acetic acid of samples, which were extracted (in chloroform-ethanol 93:7w/w mixture) and dried before modification, had beneficial effect on water absorbability of pine wood. These samples after 1001h (about 42 days) of soak...

Polymers

The influence of bacterial cellulose gel film pretreatment methods on the efficiency of enzymatic... more The influence of bacterial cellulose gel film pretreatment methods on the efficiency of enzymatic hydrolysis was investigated. An increase in the efficiency of enzymatic hydrolysis due to liquid hot water pretreatment or steam explosion was shown. The glucose yield of 88% was obtained from raw, non-purified, bacterial cellulose treated at 130 °C. The results confirm the potential of bacterial cellulose gel film as a source for liquid biofuel production.

Wood Research

The concentration of selected heavy metals: chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni)... more The concentration of selected heavy metals: chromium (Cr), manganese (Mn), iron (Fe), nickel (Ni), copper (Cu) and zinc (Zn) in 5-year-old wood of Populus trichocarpa before and after steam explosion (SE) and liquid hot water (LHW) pretreatments was studied. The concentration of the above heavy metals in the liquid fraction obtained after pretreatments was also studied. The studied problem of heavy metals in lignocellulosic biomass is an interesting and important issue in the context of bioethanol production technology. An X-ray fluorescence spectrometer (XRF) was used to analyse the concentration of heavy metals. The change of concentration of the tested elements in wood biomass after pretreatment was small (except for iron). On the other hand, the average concentration of iron in wood biomass of a 5-year-old Populus trichocarpa, after SE and LHW with duration of the pretreatments 15 and 60 min, increased about 24-fold to 28-fold, comparing to its average concentration in native wood. During the pretreatment process, wood biomass absorbed the iron that at high temperatures passed from the pretreatment equipment to the solution. The average concentration of the elements under research in liquid fraction obtained during SE and LHW of wood biomass with duration of the pretreatments 15 and 60 min was at a low level.

Annals of WULS, Forestry and Wood Technology, 2020

The study of selected properties of black poplar wood (Populus nigra L.) subjected to furfurylati... more The study of selected properties of black poplar wood (Populus nigra L.) subjected to furfurylation and polymerization in lumen. The aim of this work was studying black poplar wood (Populus nigra L.) selected properties modified with furfuryl alcohol and styrene. Maleic anhydride and glicydyl methacrylate were used as cross-linking agents. For modified wood samples the index of WPG, density, hardness, water absorbability, colour change and volume swelling were tested. Each test results were compared with values for unmodified black poplar wood. During furfurylation process density of poplar wood samples increased up to 1.3 times. Addition of maleic anhydride to furfurylation process caused increase of WPG index about 5-6 % and at the same time slightly decrease of wood Brinell hardness. Water absorbability and volume swelling of furfurylated poplar wood after 10080 min (168 h) of soaking in water were reduced more than 50% relative to unmodified wood. Polymerization in lumen with us...

Annals of WULS, Forestry and Wood Technology, 2020

Comparison of the chemical composition of domestic common hornbeam (Carpinus betulus L.) wood and... more Comparison of the chemical composition of domestic common hornbeam (Carpinus betulus L.) wood and exotic yakal (Shorea astylosa Foxw.) wood. The study was carried out to compare the chemical composition of domestic hornbeam wood with exotic yakal wood, which is an endemic species occurring in the Philippines. Species of similar structural structure occurring in different areas were studied. Extractives, cellulose (including α-cellulose), holocellulose (including hemicelluloses), lignin and ash contents were analyzed. The obtained results indicated lower content of cellulose, α-cellulose, lignin, extractives and ash in hornbeam wood as compared to yakal wood. On the other hand, a much higher amount of hemicelluloses (by 12 percentage points) was found in hornbeam wood. Probably, the main reason for the differences in the chemical composition of wood were different habitat and climatic conditions, in which the studied species were growing.

In order to specify the influence of the environmental pollution on non-metals accumulation in Sc... more In order to specify the influence of the environmental pollution on non-metals accumulation in Scots pine trees, studies of nitrogen, sulfur, phosphorus and chlorine content were performed on samples obtained from pine stems gained from the Ist, IInd and IIIrd zone of industrial damages (tree degradation). Samples were collected from butt-end, middle and top sections of the stem in sapwood, heartwood adjacent sapwood, heartwood and in bark. Significant influence of the environmental pollution caused by nitrogen industrial plant on the nitrogen content was denoted. Nitrogen content was decreased (in relation to samples from non-polluted area) especially in sapwood and bark. Additionally, chlorine content both in wood and bark was increased.

Annals of WULS, Forestry and Wood Technology, 2021

Effects of soaking aqueous ammonia pretreatment on chemical composition and enzymatic hydrolysis ... more Effects of soaking aqueous ammonia pretreatment on chemical composition and enzymatic hydrolysis of corn stover. The aim of this research was to investigate the effect of applying two different temperatures of the soaking aqueous ammonia treatment on the chemical composition and enzymatic hydrolysis yield of the corn stover. Native corn stover as well as solid fractions after 20 h of alkali pretreatment performed at 15% ammonia solution and at 50 °C or 90 °C were analysed in terms of cellulose, holocellulose, lignin and extractives content. Both untreated and treated samples were subjected to the enzymatic hydrolysis and hydrolysates were examined with a high performance liquid chromatography (HPLC). Results indicated a significant development of enzymatic digestibility of the SAA treated biomass. Furthermore, a 38.7% and a 68.9% delignification levels in the biomass treated with ammonia at respectively 50 °C and 90 °C process comparing to the raw material were achieved.

Annals of WULS, Forestry and Wood Technology, 2020

Changes in poplar (Populus trichocarpa) wood porous structure after liquid hot water (LHW) pretre... more Changes in poplar (Populus trichocarpa) wood porous structure after liquid hot water (LHW) pretreatment. The aim of this research was to investigate the effect of applying different hydrothermal pretreatment conditions on the porous structure of poplar wood. Porosity is recognised as an important factor considering efficiency of an enzymatic hydrolysis as a step of bioethanol production. Native poplar wood as well as solid fractions after pretreatment performed at different temperatures (160 °C, 175 °C and 190 °C) were analysed. Porous structure was examined with an inverse size-exclusion chromatography (ISEC) method. Results indicated a significant development of the porous structure of the biomass with increasing porosity along with the growing temperature of the LHW process. The temperature of 190 °C was chosen as the most promising condition of poplar wood LHW pretreatment in terms of the efficiency of the subsequent steps of bioethanol production. The obtained results were cons...

Annals of WULS, Forestry and Wood Technology, 2020

Inhibitory compounds formation after liquid hot water (LHW) pretreatment of corn stover as an alt... more Inhibitory compounds formation after liquid hot water (LHW) pretreatment of corn stover as an alternative to wood lignocellulosic feedstock for bioethanol production. Thus far, corn stover has been perceived as a promising lignocellulosic alternative to wood intended for bioethanol procurement, however it should be recognised also as a potential future component in a mixed biomass system. The aim of this research was to investigate the effect of applying different hydrothermal treatment conditions on the potential inhibitory compounds formation from corn stover. An analysis of selected inhibitory compounds formed after pretreatment performed at different temperatures (160°C, 175°C, 190°C and 205°C) was carried out. Furfural, simple sugars and lignin were some of the inhibitors examined with HPLC and UV-VIS spectrophotometric methods. Furthermore, the chemical composition of organic extracts obtained from native and LHW pretreated biomass was analyzed qualitatively with GC-MS method ...

Energies, 2020

Biomass pretreatment is a mandatory step for the biochemical conversion of lignocellulose to chem... more Biomass pretreatment is a mandatory step for the biochemical conversion of lignocellulose to chemicals. During pretreatment, soluble compounds are released into the prehydrolyzate that inhibit the enzymatic hydrolysis step. In this work, we investigated how the reaction conditions in steam explosion pretreatment of beechwood (severity: 3.0–5.25; temperature: 160–230 °C) influence the resulting amounts of different inhibitors. Furthermore, we quantified the extent of enzyme inhibition during enzymatic hydrolysis of Avicel in the presence of the prehydrolyzates. The amounts of phenolics, HMF, acetic acid and formic acid increased with increasing pretreatment severities and maximal quantities of 21.6, 8.3, 43.7 and 10.9 mg/gbeechwood, respectively, were measured at the highest severity. In contrast, the furfural concentration peaked at a temperature of 200 °C and a severity of 4.75. The presence of the prehydrolyzates in enzymatic hydrolysis of Avicel lowered the glucose yields by 5–26...

BioResources, 2018

The potential of fast-growing poplar species was evaluated for bioethanol production. The yields ... more The potential of fast-growing poplar species was evaluated for bioethanol production. The yields of glucose and xylose from acid and enzymatic hydrolysis were compared. The hydrolysis processes were performed on raw and extracted wood. The extracted wood was obtained by action of a chloroform and 96% ethanol (93:7 w/w) mixture. Additionally, to enhance the enzymatic hydrolysis efficiency, a liquid hot water (LHW) pretreatment was used. The acid hydrolysis turned out to be a good method to verify the biomass potential for bioethanol production. After acid hydrolysis of raw and extracted biomass, high total sugars yields were obtained (between 626.2 to 808.5 mg/g raw or extracted biomass), while in the case of enzymatic hydrolysis the total sugars yields were very low (between 45.5 to 68.9 mg/g raw or extracted biomass). The LHW pretreatment greatly enhanced the enzymatic digestibility of the studied wood. The average glucose yield from enzymatic hydrolysis was up to 602.0 mg/g pretreated biomass and was higher than that from acid hydrolysis (the maximum yield was 566.9 mg/g extracted biomass). As a result of the LHW pretreatment, up to 91.3% of the hemicelluloses were removed from the solid fraction. From the obtained glucose and xylose results, it was concluded that Populus trichocarpa wood had a higher potential for bioethanol production than P. deltoides x maximowiczii wood. The presence of extractives (low molecular substances) in raw poplar wood (up to 2.8%) had a low impact on the yield from acid and enzymatic hydrolysis.

BioResources, 2012

Two hyperbranched polyglycerols (HBPGs) and one oligoglycerol containing bisphenol A in the core ... more Two hyperbranched polyglycerols (HBPGs) and one oligoglycerol containing bisphenol A in the core of the molecule were synthesized from glycerol carbonate and applied as polyols in 2-component polyurethane adhesive systems. It was shown that mechanical performance of the joints made in solid wood depended on the hydroxyl functionality of the polyglycerol as well as on the type of the isocyanate used as a crosslinker. The shear strengths of the best-performing joints exceeded that of the substrate. Eventually, it was proved that hyperbranched polyglycerols might be convenient glycerol-derived raw materials for polyurethane adhesives.

Wood Science and Technology, 2021

In this paper, the influence of physicochemical pretreatment methods on the chemical composition,... more In this paper, the influence of physicochemical pretreatment methods on the chemical composition, enzymatic hydrolysis efficiency and porosity of fast-growing Populus trichocarpa wood was compared. Among the pretreatment methods, the liquid hot water (LHW) and steam explosion (SE) were used, which were performed at three different temperatures (160 °C, 175 °C and 190 °C) and two residence times (15 min and 1 h). The chemical composition, enzymatic hydrolysis and porosity analysis were done for native wood and solid fraction obtained after LHW and SE pretreatments. The porosity analysis was performed by inverse size exclusion chromatography method. Additionally, inhibitors of hydrolysis and fermentation processes in the liquid and solid fractions obtained after pretreatments were examined. Based on the results, it was found that the tested pretreatments caused the greatest changes in the chemical content of hemicelluloses. It was found that after LHW and SE pretreatments up to 99.1% ...

BioResources, 2014

This study aimed to determine glucose and xylose content by acid hydrolysis of wood samples, both... more This study aimed to determine glucose and xylose content by acid hydrolysis of wood samples, both unmodified and thermally modified (modification time was 2, 6, 10 hours), using high performance liquid chromatography. Optimization of the hydrolysis process on the native ash wood samples showed that 3 h was the best time in the hydrolysis process. After that time, 58.8% of glucose and 20.8% of xylose were obtained. In turn, chromatographic analysis showed incomplete hydrolysis of ash wood samples, which were modified in a nitrogen atmosphere, especially at shorter times (2 and 6 h) of modification. With longer modification times (10 h), the hydrolysis of ash wood samples was completed. The above mentioned problem was caused mainly by the increase of cellulose crystallinity degree. The decrease of this parameter was observed only after 10 h of thermal modification, which would facilitate the process of acidic hydrolysis. Additionally, it was observed that the thermal modification of ash wood at 190 °C in a nitrogen atmosphere for 10 h caused a drastic decrease in the xylose content (from 20.8% to 8.0%) and only a slight decrease in the glucose content (from 58.8% to 54.9%).