Despite the great potential of cellulose wood pulp and cellulose nanofibrils as reinforcing filler in thermoplastics,its use is limited due to its tendency to form agglomerates and due to its high hydrophilic characte...Despite the great potential of cellulose wood pulp and cellulose nanofibrils as reinforcing filler in thermoplastics,its use is limited due to its tendency to form agglomerates and due to its high hydrophilic character.Here we describe fiberboard composites with high contents of wood pulp or cellulose nanofibrils,and a resin of poly(styrene-methyl-methacrylate-acrylic acid)used as water-based emulsion.Cellulose wood pulp and cellulose nanofibrils were used directly in the form of water suspensions.The method is based on the flocculation of the polymer emulsion followed by agglomeration of a mixture of the polymer emulsion and cellulose suspension,leading to the co-precipitation of the composite material,which can be easily separated from the water phase.Composites with acrylic polymer/cellulose fibers in the proportions of 75:25,50:50 and 25:75 wt%were prepared.Composites were characterized by scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),thermogravimetric analysis(TGA),dynamic mechanical analysis(DMA)and water absorption tests.SEM analysis revealed a very good dispersion of the fibers without evidence of agglomeration,which led to superior mechanical properties.These results showed the effectiveness of the methodology and the potential of cellulose wood pulp and CNF as reinforcement fillers in fiberboard composites and any other high fiber-content materials.展开更多
Metal-free photocatalysts have attracted growing concern recently.Herein,the composites combining g-C_(3)N_(4)with wood pulp cellulose biochar(WPBC/g-C_(3)N_(4))were synthesized to effectively activate peroxymonosulfa...Metal-free photocatalysts have attracted growing concern recently.Herein,the composites combining g-C_(3)N_(4)with wood pulp cellulose biochar(WPBC/g-C_(3)N_(4))were synthesized to effectively activate peroxymonosulfate(PMS)under visible light for the degradation of diclofenac(DCF).The incorporation of WPBC endowed g-C_(3)N_(4)with enhanced visible light absorption,improved charge separation capability,reduced electrical conductivity,and increased photocatalytic and PMS activation capability.Based on quenching tests,electron paramagnetic resonance(EPR),electrochemical analysis and solvent exchange experiments,both radical and nonradical mechanisms were proposed.Radical species including·OH,h^(+),·O_(2)^(-)were identified to contribute to DCF degradation.The 1O2 and electron transfer were the dominant nonradical pathways for DCF degradation.Moreover,the common influencing factors were examined,and DCF concentration was the most influential factor based on principal component analysis.Generally,the composites exhibited good reusability during consecutive runs.Based on HPLC/MS analysis,four intermediates were detected and the possible DCF degradation pathway was proposed.This work provided a potential strategy based on metal-free WPBC/g-C_(3)N_(4)for the photocatalytic activation of PMS to effectively degrade emerging contaminants in wastewater.展开更多
SUMMARYThe purpose of this study was to evaluate basic density, chemical composition and fiber dimensions of ten Eucalyptus sp wood samples and verify the impact of this set of parameters and their combination on the ...SUMMARYThe purpose of this study was to evaluate basic density, chemical composition and fiber dimensions of ten Eucalyptus sp wood samples and verify the impact of this set of parameters and their combination on the Kraft pulping process yield and on bleached pulp quality. Ten eucalypt woods of different species, with basic densities varying from 365 to 544 kg/m3 and total wood carbohydrate contents varying from 70.0 to 74.5%, were transformed into kraft pulp of kappa number 17-18 and bleached to 90% ISO brightness by the sequence OD(PO)D. Wood basic density showed stronger correlations with fiber dimensions, pulping yield and pulp quality than did chemical composition. Lighter woods resulted in higher yields. However, wood specific consumption was lower for denser woods, even though these demanded more drastic pulping conditions to achieve a given kappa number. The pulp quality results suggest that lower density woods should be directed towards fabrication of refined paper (printing and writing grades) while the denser woods be directed to the sanitary papers segment (tissue grades).展开更多
Using 3-year-old culms of 8 provenances of Bambusa chungii from Guangdong, Guangxi and Hainan Provinces, the indexes of wood properties, such as fiber dimensions and chemical composition were investigated and analyzed...Using 3-year-old culms of 8 provenances of Bambusa chungii from Guangdong, Guangxi and Hainan Provinces, the indexes of wood properties, such as fiber dimensions and chemical composition were investigated and analyzed by the methods of Analysis of variance and correlation coefficient to reveal the geographic genetic variation situation. The results showed that there are significant differences be- tween fiber length, fibrin and 1% NaOH extraction contents of B. chungii from 8 provenances; moreover, the fiber length and fiber length/width ratio had a decreasing change pattern with geographic variation from the south to the north in altitude （from high to low in ele- vation）. The heritabilities for fibrin, fiber length, 1% NaOH extractive, lignin and fiber length/width ratio were 0.7, 0.84, 0.54, 0.38 and 0.13, respectively. A significant negative correlation was found between 1% NaOH extraction, benzo-alcohol extraction contents and bamboo culm yield, whereas there was a significant positive correlation between fibrin contents and bamboo wood yield. Besides, a close correlation was detected between fiber dimensions indices and bamboo growth or bamboo wood yield. Finally, three provenances with high qualities and culm yield, i.e. Huaiji, Xinyi and Guilin, were selected as superior sources based on principal component analysis.展开更多
文摘Despite the great potential of cellulose wood pulp and cellulose nanofibrils as reinforcing filler in thermoplastics,its use is limited due to its tendency to form agglomerates and due to its high hydrophilic character.Here we describe fiberboard composites with high contents of wood pulp or cellulose nanofibrils,and a resin of poly(styrene-methyl-methacrylate-acrylic acid)used as water-based emulsion.Cellulose wood pulp and cellulose nanofibrils were used directly in the form of water suspensions.The method is based on the flocculation of the polymer emulsion followed by agglomeration of a mixture of the polymer emulsion and cellulose suspension,leading to the co-precipitation of the composite material,which can be easily separated from the water phase.Composites with acrylic polymer/cellulose fibers in the proportions of 75:25,50:50 and 25:75 wt%were prepared.Composites were characterized by scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),thermogravimetric analysis(TGA),dynamic mechanical analysis(DMA)and water absorption tests.SEM analysis revealed a very good dispersion of the fibers without evidence of agglomeration,which led to superior mechanical properties.These results showed the effectiveness of the methodology and the potential of cellulose wood pulp and CNF as reinforcement fillers in fiberboard composites and any other high fiber-content materials.
基金China Postdoctoral Science Foundation(Grant No.2019 M661856)Qing Lan Project of Jiangsu Province(Grant No.2020)+2 种基金Natural Science Foundation of Jiangsu Province,China(Grant No.BK20201385)National Key Research and Development Project(Grant No.2017YFC0505803)National Natural Science Foundation of China(NSFC)(Grant No.41977354).
文摘Metal-free photocatalysts have attracted growing concern recently.Herein,the composites combining g-C_(3)N_(4)with wood pulp cellulose biochar(WPBC/g-C_(3)N_(4))were synthesized to effectively activate peroxymonosulfate(PMS)under visible light for the degradation of diclofenac(DCF).The incorporation of WPBC endowed g-C_(3)N_(4)with enhanced visible light absorption,improved charge separation capability,reduced electrical conductivity,and increased photocatalytic and PMS activation capability.Based on quenching tests,electron paramagnetic resonance(EPR),electrochemical analysis and solvent exchange experiments,both radical and nonradical mechanisms were proposed.Radical species including·OH,h^(+),·O_(2)^(-)were identified to contribute to DCF degradation.The 1O2 and electron transfer were the dominant nonradical pathways for DCF degradation.Moreover,the common influencing factors were examined,and DCF concentration was the most influential factor based on principal component analysis.Generally,the composites exhibited good reusability during consecutive runs.Based on HPLC/MS analysis,four intermediates were detected and the possible DCF degradation pathway was proposed.This work provided a potential strategy based on metal-free WPBC/g-C_(3)N_(4)for the photocatalytic activation of PMS to effectively degrade emerging contaminants in wastewater.
文摘SUMMARYThe purpose of this study was to evaluate basic density, chemical composition and fiber dimensions of ten Eucalyptus sp wood samples and verify the impact of this set of parameters and their combination on the Kraft pulping process yield and on bleached pulp quality. Ten eucalypt woods of different species, with basic densities varying from 365 to 544 kg/m3 and total wood carbohydrate contents varying from 70.0 to 74.5%, were transformed into kraft pulp of kappa number 17-18 and bleached to 90% ISO brightness by the sequence OD(PO)D. Wood basic density showed stronger correlations with fiber dimensions, pulping yield and pulp quality than did chemical composition. Lighter woods resulted in higher yields. However, wood specific consumption was lower for denser woods, even though these demanded more drastic pulping conditions to achieve a given kappa number. The pulp quality results suggest that lower density woods should be directed towards fabrication of refined paper (printing and writing grades) while the denser woods be directed to the sanitary papers segment (tissue grades).
文摘Using 3-year-old culms of 8 provenances of Bambusa chungii from Guangdong, Guangxi and Hainan Provinces, the indexes of wood properties, such as fiber dimensions and chemical composition were investigated and analyzed by the methods of Analysis of variance and correlation coefficient to reveal the geographic genetic variation situation. The results showed that there are significant differences be- tween fiber length, fibrin and 1% NaOH extraction contents of B. chungii from 8 provenances; moreover, the fiber length and fiber length/width ratio had a decreasing change pattern with geographic variation from the south to the north in altitude （from high to low in ele- vation）. The heritabilities for fibrin, fiber length, 1% NaOH extractive, lignin and fiber length/width ratio were 0.7, 0.84, 0.54, 0.38 and 0.13, respectively. A significant negative correlation was found between 1% NaOH extraction, benzo-alcohol extraction contents and bamboo culm yield, whereas there was a significant positive correlation between fibrin contents and bamboo wood yield. Besides, a close correlation was detected between fiber dimensions indices and bamboo growth or bamboo wood yield. Finally, three provenances with high qualities and culm yield, i.e. Huaiji, Xinyi and Guilin, were selected as superior sources based on principal component analysis.
