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Yu H.,Beijing Forestry University | Yu H.,MOE Key Laboratory of Wooden Material Science and Application | Li X.,Beijing Forestry University | Zhang W.,Nanjing Institute for the Comprehensive Utilization of Wild Plant | And 4 more authors.
Cellulose | Year: 2015

Furfural residues (FRs) is an industrial waste material with an enormous potential for bio-ethanol production. In this study, FRs were pretreated with green liquor (GL) combined with hydrogen peroxide (GL–H2O2) or ethanol (GL-ethanol). The wettability and electrostatic contributions of untreated and pretreated FRs was investigated as well as that of isolated lignin cellulolytic enzyme lignin (CEL) and cellulose. The results showed that the hydrophilicity of FRs was increased after GL–H2O2 and GL-ethanol pretreatment. Lignin is the key factor that affects the hydrophilicity of substrate. The cellulase binding for lignin was reduced due to the increase of hydrophilicity of lignin, resulting in the improvement of enzymatic hydrolysis. The electrostatic contributions was also an important factor that influenced the cellulase binding of lignin. After pretreatments, the negative charge of lignin was decreased. Accordingly, the cellulase binding capacity was reduced. This effect was more significant after the GL-ethanol pretreatment. Thus, the glucose yield of the substrate obtained from the GL-ethanol pretreatment (86.1 %) was larger than that from the GL–H2O2 pretreatment (82.2 %). Unlike the CEL, GL–H2O2 pretreatment increased the negative charge of cellulose. And the increase of negative charge improved the affinity of cellulose to cellulase via electrostatic attraction. The XPS analyses indicated that the carbonyl groups from lignin play an important role in decreasing the hydrophobicity of the substrates. © 2015, Springer Science+Business Media Dordrecht. Source


Wang K.,MOE Key Laboratory of Wooden Material Science and Application | Dong Y.,MOE Key Laboratory of Wooden Material Science and Application | Yan Y.,MOE Key Laboratory of Wooden Material Science and Application | Zhang S.,MOE Key Laboratory of Wooden Material Science and Application | Li J.,MOE Key Laboratory of Wooden Material Science and Application
Polymer Composites | Year: 2016

Wood polymer composites (WPCs) were prepared in this study by grafting polystyrene onto poplar wood cell walls through free-radical copolymerization methods. Methacryloyl chloride was first employed to cause swelling and react with the hydroxyl groups on the wood cell walls. Styrene monomers were then copolymerized with the methacryl groups in situ. The resultant WPCs were observed by Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The physical and mechanical properties of the composites, including dimensional stability, water uptake, dynamic hydrophilicity, surface hardness, and thermal stability, were also evaluated. Results suggest that methacryl groups and styrene were successfully copolymerized, and that the resultant copolymer was grafted onto the wood matrix through the reaction of methacryl groups and hydroxyl groups on wood components. Graft copolymerization not only significantly improved the interfacial compatibility between the polymer and wood substance, but also provided the wood with higher dimensional stability, better hydrophobic properties, and enhanced surface hardness. © 2016 Society of Plastics Engineers. Source


Wang W.,MOE Key Laboratory of Wooden Material Science and Application | Peng Y.,MOE Key Laboratory of Wooden Material Science and Application | Chen H.,MOE Key Laboratory of Wooden Material Science and Application | Gao Q.,MOE Key Laboratory of Wooden Material Science and Application | And 2 more authors.
Polymer Composites | Year: 2015

In order to improve the hydrophilicity of ammonium polyphosphate (APP), as well as its compatibility with composite matrix, in this research, beta-cyclodextrin (β-CD) was cross-linked by polydiphenylmethane diisocyanate (PMDI) and used as clothing to prepare microencapsulated APP (MCAPP) via polymerization in situ. Then, APP and MCAPP were mixed with wood-flour and polypropylene to manufacture wood-flour/polypropylene composites (WPCs) by hot pressing. Both APP and MCAPP were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), water solubility tests, and water contact angle (WCA) tests. Limiting oxygen index (LOI) and cone calorimetry tests were used to investigate the flame retardancy of WPCs. Moreover, laser Raman spectroscopy and real-time FTIR (RT-FTIR) were used to explore the flame retardant mechanism. Results indicated that APP was successfully coated by the cross-linked β-CD. MCAPP showed lower water solubility and better surface hydrophobicity, and WPC/MCAPP performed better flame retardnacy and mechanical properties. © 2015 Society of Plastics Engineers. Source

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