Pyrolysis properties of lignin separated from four different kinds of wood （fir, larch, poplar, and eucalyptus） compared with commercial lignin were investigated using a thermogravimetric analyzer coupled to a...Pyrolysis properties of lignin separated from four different kinds of wood （fir, larch, poplar, and eucalyptus） compared with commercial lignin were investigated using a thermogravimetric analyzer coupled to a Fourier-transform infrared spectrometer（TG-FTIR）. Kinetic parameters of lignin thermal cracking reaction, such as activation energy and pre-exponential factor, were calculated using a three-dimensional diffusion model. The carbon residue rate and activation energy of softwood lignin were higher than those of hardwood lignin, showing that the decomposition of the former is relatively more dif？cult than that of the latter during pyrolysis. The distinct characteristic peaks of small-molecule gases and oxygenated chemicals such as ethers, phenols, acids, aldehydes, and alcohols were observed near the maximum weight loss rate by analyzing the 3D IR spectrum of the gas phase products. The formation routes of the main gaseous products were discussed, and the following order of releasing amounts was noted： CO2〉CH4〉H2O〉CO. It is believed that these results will provide valuable information for the thermo-chemical conversion process of lignin from the point of view of feedstock.展开更多
Bamboo is a typical biological material widely growing in nature with excellent physical and mechanical properties.It is lightweight with high strength and toughness.The naturally optimized bamboo structure,which has ...Bamboo is a typical biological material widely growing in nature with excellent physical and mechanical properties.It is lightweight with high strength and toughness.The naturally optimized bamboo structure,which has inspired global material scientists and engineers for decades,is significantly important for the bionic design of novel structural materials with ultra-light,ultra-strong,or ultra-tough and comprehensive properties.Typical literature on innovative composite materials and structural members inspired by bamboo are reviewed in this paper,and the research progress and prospects in this field are expounded in three parts.First,the structural characteristics of the bamboo wall layer along the thickness and height directions are described in terms of chemical composition,gradient structure,pore structure,and hollow structure with variable cross-section.Second,this paper summarizes the research progress on new composite materials and structural components by applying bamboo’s structural features from the perspective of sustainability,designability,and customization.Finally,given the limitations of current research,the biomimetic scientific research on bamboo’s structural characteristics is prospected from the interpretation of bamboo structure,new bamboo-like materials,and structural design optimization perspectives,providing a reference for future research on biomimetic aspects of biomass.展开更多
Wood packaging waste with a high recycling value is one of the main components of packaging waste.However,most research has been focused on natural wood,and less is known about the recycling of wood-based panel waste ...Wood packaging waste with a high recycling value is one of the main components of packaging waste.However,most research has been focused on natural wood,and less is known about the recycling of wood-based panel waste commonly used in packaging.This paper examined the pyrolysis of common urea-formaldehyde(UF)resin particleboard,including the decomposition characteristics of its nitrogen-containing adhesives,the product types,and how they are generated.The samples and pyrolysis products were analyzed by infrared spectroscopy.The results showed that the UF resin was the main contributor to the release of ammonia(NH3)and hydrogen cyanide(HCN).At low temperatures,more NH3 was released than the HCN,and at high temperatures,the reverse was true.A high heating rate promoted the release of the NH_(3) and HCN.The UF resin and wood in the particleboard interacted and caused the release of the NH3 and HCN.These results provide a reference for further study of the thermochemical regeneration of wood-based packaging waste.展开更多
文摘Pyrolysis properties of lignin separated from four different kinds of wood （fir, larch, poplar, and eucalyptus） compared with commercial lignin were investigated using a thermogravimetric analyzer coupled to a Fourier-transform infrared spectrometer（TG-FTIR）. Kinetic parameters of lignin thermal cracking reaction, such as activation energy and pre-exponential factor, were calculated using a three-dimensional diffusion model. The carbon residue rate and activation energy of softwood lignin were higher than those of hardwood lignin, showing that the decomposition of the former is relatively more dif？cult than that of the latter during pyrolysis. The distinct characteristic peaks of small-molecule gases and oxygenated chemicals such as ethers, phenols, acids, aldehydes, and alcohols were observed near the maximum weight loss rate by analyzing the 3D IR spectrum of the gas phase products. The formation routes of the main gaseous products were discussed, and the following order of releasing amounts was noted： CO2〉CH4〉H2O〉CO. It is believed that these results will provide valuable information for the thermo-chemical conversion process of lignin from the point of view of feedstock.
文摘Bamboo is a typical biological material widely growing in nature with excellent physical and mechanical properties.It is lightweight with high strength and toughness.The naturally optimized bamboo structure,which has inspired global material scientists and engineers for decades,is significantly important for the bionic design of novel structural materials with ultra-light,ultra-strong,or ultra-tough and comprehensive properties.Typical literature on innovative composite materials and structural members inspired by bamboo are reviewed in this paper,and the research progress and prospects in this field are expounded in three parts.First,the structural characteristics of the bamboo wall layer along the thickness and height directions are described in terms of chemical composition,gradient structure,pore structure,and hollow structure with variable cross-section.Second,this paper summarizes the research progress on new composite materials and structural components by applying bamboo’s structural features from the perspective of sustainability,designability,and customization.Finally,given the limitations of current research,the biomimetic scientific research on bamboo’s structural characteristics is prospected from the interpretation of bamboo structure,new bamboo-like materials,and structural design optimization perspectives,providing a reference for future research on biomimetic aspects of biomass.
文摘Wood packaging waste with a high recycling value is one of the main components of packaging waste.However,most research has been focused on natural wood,and less is known about the recycling of wood-based panel waste commonly used in packaging.This paper examined the pyrolysis of common urea-formaldehyde(UF)resin particleboard,including the decomposition characteristics of its nitrogen-containing adhesives,the product types,and how they are generated.The samples and pyrolysis products were analyzed by infrared spectroscopy.The results showed that the UF resin was the main contributor to the release of ammonia(NH3)and hydrogen cyanide(HCN).At low temperatures,more NH3 was released than the HCN,and at high temperatures,the reverse was true.A high heating rate promoted the release of the NH_(3) and HCN.The UF resin and wood in the particleboard interacted and caused the release of the NH3 and HCN.These results provide a reference for further study of the thermochemical regeneration of wood-based packaging waste.
