INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2021
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IF 6.953
Nan Sun,Mingwei Di,Yang Liu
In this work, lignin-containing polyester polyol (LPES) was successfully synthesized by vacuum melting method with lignin instead of polyol, and then reacted with isocyanate and chain extender to obtain lignin-based polyurethane elastomer (LPUE). The effects of lignin as reactive raw material, chain extender, and filler on the structure, thermostability , mechanical performance, and self-healing properties of elastomers were systematically studied, respectively. The comprehensive mechanical properties of the obtained materials were significantly enhanced after the introduction of lignin, especially the maximum tensile strength increased to 26.6 MPa and elongation at break reached 408.6%, which were 1510.3% and 2130.5% higher than that of the original polyurethane elastomer (PUE). Results revealed that lignin in the hard segment had a significant effect on the thermal stability and mechanical properties of polyurethane elastomer, and lignin in the soft segment had an obvious impact on the healing properties. Due to the hydrogen bonding interaction of the polar groups in the molecular chain of lignin to form a microphase-ordered structure, LPUE with excellent mechanical properties can be obtained.
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Sustainable Chemistry and Pharmacy
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2021
·
IF 4.508
Liuqun Gu,Meifeng Wang,Hui Li,Kai Ni Teh,Yiqun Li,Ye Liu
A new type of modified lignin, lignin-p-Boc, was obtained through reaction with di- tert -butyl dicarbonate (Boc 2 O) in aqueous media catalyzed by 4-dimethylaminopyridine (DMAP). Boc modification occurred regardless of type of lignin, was tunable, and proceeded well in recovering lignin at high purity from sodium lignosulfonate (a common byproduct from pulping industry; lignin content: 60%). Lignin-p-BOC was demonstrated as a potential reactive filler in green plastic and as a potential crosslinker in design of bioresorbable composite polymeric implants. Furthermore, the effect of the modification on breakdown rate of alkali lignin by microbes was investigated, and results showed that the modification substantially decreases the breakdown rate. The tunable Boc modification process was designed via a system thinking, including availability of raw lignin, economical/green modification, potentiality of drop-in-change to current thermoplastic processing, modification impact on microbial degradability/disposed environment at the end of use life; hence the holistic consideration makes this alternative method for upgrade of technical lignins very practical for future industrial application. Via “ in-situ ” forming “easily breakable covalent bonds” with existing thermopolymers inside, Lignin-p-BOCs are also promising to play an important role as both excellent binders via “random match” and reductants in transforming linear plastic waste into circular plastics.
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ACS Sustainable Chemistry & Engineering
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2020
·
IF 7.632
Wenliang Wang,Zhenhao Ma,Xingjin Zhao,Shiwei Liu,Liping Cai,Sheldon Q. Shi,Yonghao Ni
Microwave absorbents play a vital role in governing the monomeric products from lignin during the microwave-assisted depolymerization (MAD) process. The influence of various microwave absorbents on the conversion efficiency and lignin monomeric products in a dynamic vapor flow reaction system was investigated. Results showed that the selected microwave absorbents could linearly and rapidly heat lignin from 200 to 500 °C within 8 min under a microwave power of 1000 W. The yields of liquid products, guaiacols, and phenols were increased linearly with the heating rate (°C/min). The high microwave absorptivity of absorbents promoted the formation of liquid products and phenolic compounds. To offer further support, the use of MoS2 with a very high microwave absorptivity (185.0 °C/min) showed very high yields of liquid products (34.1 wt %) and phenolics (32.1 wt %). This work provided an effective methodology to enhance the lignin conversion efficiency to monomeric products using microwave absorbents.
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ACS Sustainable Chemistry & Engineering
·
2020
·
IF 7.632
Chongbo Cheng,Pengfei Li,Wenbing Yu,Dekui Shen,Xiaoxiang Jiang,Sai Gu
Lignin containing numerous phenylpropane units is considered to be a renewable and abundant resource for the production of value-added aromatic chemicals. A series of nonprecious metal/bimetallic catalysts were prepared for the catalytic hydrogenolysis of organosolv poplar lignin (OPL) in ethanol/isopropanol solvent in this work. Effects of Ni/C, Cu/C, NiCu/C, and NiW/C catalysts on OPL depolymerization were investigated, where the NiCu/C catalyst was found to be optimal for the conversion of OPL to phenolic monomers at a yield of 63.4 wt % at 270 °C for 4 h without external H2. The synergistic effect of mixed solvent was remarkable during the catalytic hydrogenolysis process, leading to the increased yield of monomer products. The catalytic process of OPL conversion and possible reaction route of ethanol/isopropanol solvent were proposed with regard to the analysis of products and fresh/spent catalysts. The effects of reaction temperature, reaction time, catalyst recyclability, solvent recyclability, and feedstock adaptability were investigated in view of bio-oil and monomer yields. This work provides an economical and sustainable method for the efficient conversion of lignin to high-value chemicals.
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JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
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2020
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IF 3.905
Qingguo Zhou,Zhongyang Luo,Guoxiang Li,Simin Li
Lignin pyrolysis is a promising method for the sustainable production of phenolic compounds from biomass. However, detailed knowledge about the radicals involved in this process and their influence during the coking is missing. Herein, we report on the pyrolysis of guaiacol, a lignin monomer at 600 °C under inert and hydrogen gas conditions. During the pyrolysis process, the formed radicals were detected by two improved electron paramagnetic resonance spectroscopy methods. Successfully observed o-phenyl semiquinone radical anion, cyclopentadienyl radical, methyl radical, hydroxyl radical, methoxy radical, phenyl radical, phenoxy radical, etc. during the pyrolysis of guaiacol, as well as the changes of related radicals in different pyrolysis stages. It was found that o-semiquinone radical anions and cyclopentadienyl radicals were the key free radicals in the generation of coke and tar during the pyrolysis process. And through hydrogenation pyrolysis experiments, it was verified that the relative content of o-semiquinone radical and the solid coke were reduced with a hydrogen supply source. Our results showed that by controlling the key free radicals in the coking process, the formation of coke can be suppressed and the conversion efficiency can be improved.
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MATERIALS LETTERS
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2020
·
IF 3.204
Yan Zhao,Minyue Wen,Chunhu He,Changlang Liu,Zongru Li,Yin Liu
The lignin residue produced by straw fermentation or straw acid hydrolysis is used as a carbon source to synthesize graphene. After adding tetrahydrofuran as a modifier and Fe(NO 3 ) 3 as a catalyst to lignin for pretreatment, the resulting product was heat treated at 900℃ for 3 h. The prepared graphene was characterized by XRD, Raman, HRTEM, and the electrochemical properties of the prepared graphene also were tested. The results of this study open up a new way for the efficient preparation of graphene based on renewable resources lignin. The prepared lignin-based graphene was used for electrochemical testing and found to be a good electrode material for super capacitors.
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ELECTROCHIMICA ACTA
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2020
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IF 6.215
Meilian Cao,Wanli Cheng,Xiaohui Ni,Yi Hu,Guangping Han
The lignin-based multi-channels carbon nanofibers (MCNFs) @ SnO 2 nanocomposites with various microstructures are synthesized via co-electrospinning by regarding Poly (vinyl pyrrolidone) (PVP)–SnCl 2 ·2H 2 O as shell materials and lignin-Poly (methyl methacrylate) (PMMA) at different mass ratios as core materials, followed by heat treatment and acid treatment. The experimental results show that when the mass ration of lignin to PMMA in the core region is 5:5, the obtained nanocomposites possess hierarchical internal channels, porous surface, and high specific surface area. This optimized nanocomposite as supercapacitor electrode shows high specific capacitance of 406 F g −1 at current density of 0.5 A g −1 . In addition, the electrode exhibits unexceptionable cycling stability with only 5% capacitance decay over 10 000 cycles at 10 A g −1 . Furthermore, the symmetric supercapacitor using the optimized nanocomposites as electrodes possesses remarkable power and energy densities. The superior electrochemical performance of nanocomposites is benefited from the hierarchical structures of MCNFs, faradaic pseudocapacitance of SnO 2 , and pore-forming effect of SnCl 2 ·2H 2 O. The unique hierarchical nanocomposites show great potential in future development of lignin-based low-cost, non-toxic and eco-friendly carbon materials for high-performance energy storage devices.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2020
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IF 5.162
Zhengyi Zhang,Jiaoman Li,Yan Zhang,Zhenfu Jin
Lignin, which is crosslinked by ether and carbon‑carbon linkages, is a highly branched polymer consisting of phenyl propane units. And owing to the abundant phenolic hydroxyl groups and its structural heterogeneous characteristics, lignosulfonate, considered as a renewable aromatic macropolymer, can be used as co-curing agent in EP thermoset systems. In this study, kinetics of lignosulfonate (LS) and partially depolymerized lignosulfonate (DLS) as co-curing agents for applications to EP thermoset were discussed with the differential scanning calorimetry (DSC) measurement. The activation energy ( E a ) and dynamic modeling of curing reaction were obtained by the methods of non-isothermal kinetic analysis reported by Kissinger and Ozawa. The glass transition temperature ( T g ) was determined by DSC and mechanical properties of epoxy resins were carried out using the Universal Testing Machine. The LS dropped the exothermic peak temperature and E a of curing reaction of EP thermoset. Those of DLS were more active than the higher molecular weight lignosulfonate. The EP thermoset cured with DLS (EP-DLS) exhibited much higher reactivity, and the curing reaction could be occurred at lower temperature. The T g of EP-DLS has risen by 10 °C compared with the case without lignosulfonate. The tensile strength , elongation at break and impact strength of EP-DLS rose by 28.7%, 52.5% and 53.5%, respectively, than those of the epoxy resin cured with LS (EP-LS).Molecular weight of lignosulfonate could be an important factor of the curing reaction of EP thermoset. The high performance EP thermoset could be obtained by partially depolymerized lignin as co-curing agents.
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ENERGY & FUELS
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2021
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IF 3.605
Kun-Lang Lu,Xian-Yong Wei,Guang-Hui Liu,Wei-Wei Yan,Fan Yin,Fa-Zhan Mao,Feng-Hua Wei,Zhi-Min Zong,Hong-Cun Bai
Benzyloxybenzene (BOB) and oxybis(methylene)dibenzene (OBMDB) were used as lignin-related model compounds (LRMCs). Three protic solvents (PSs), i.e., methanol, ethanol (E), and isopropanol, and two aprotic solvents (ASs), i.e., ethyl acetate and n-hexane, were selected to evaluate their effects on the catalytic hydroconversion (CHC) of the LRMCs over MoO3. Under the same conditions, the PSs are more effective for the CHC of LRMCs than the ASs. Under the optimal conditions in E, both BOB and OBMDB are completely converted and the total product yields are 200 and 198.1 mol %, respectively. MoO3 undergoes the surface modification, such as carburization and oxygen vacancy (OV) formation, during the reaction, which is crucial for the CHC of the LRMCs. The OV formation is determined by the self-transformation degree of PSs and the dispersity of ASs to MoO3 through the analyses of solvent-related environmental variables. In addition, solvents affect the CHC of LRMCs by controlling the adsorption performance of MoO3.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2019
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IF 3.375
Haixu Wang,Weifeng Liu,Zhikai Tu,Jinhao Huang,Xueqing Qiu
In this work, half the mass of carbon black (CB) was replaced by lignin for preparation of high-performance nitrile rubber/poly(vinyl chloride) composites via constructing interfacial Zn2+-based coordination bonds. It was demonstrated that lignin played a significant role as a natural ligand to form the Zn2+-based coordination interactions in the interphase between lignin and a rubber matrix. The tensile strength and Young’s modulus of the composites were significantly enhanced by the Zn2+-based coordination bonds owing to the dynamic fracture of coordination bonds. The thermo-oxidative aging resistance of the composites was improved by lignin and could be conveniently regulated by the content of ZnCl2 and sulfur. The high-temperature oil resistance of the composites also benefited from the partial substitution of CB by lignin and incorporation of the metal coordination bonds. This work opens a facile method for the potential application of green lignin in rubber–plastic composites through a conventional rubber compounding process.
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Nanomaterials
·
2019
·Vol. 9
·期 2
·188
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IF 4.034
Yu Zhou,Yanming Han,Gaiyun Li,Sheng Yang,Fuquan Xiong,Fuxiang Chu
Due to their exceptional absorption capacity, biodegradability, and non-toxicity, nanoparticles (NPs) from lignin have emerged as vehicles for inorganic particles and drug molecules. However, the method for preparing targeted lignin particles is still complex and lacks sufficient research. Herein, a succinct strategy was proposed for the preparation of targeted lignin-based drug delivery NPs to load Doxorubicin Hydrochloride (DOX). The lignin hollow NPs (LHNPs) were used as a platform for the preparation of targeted delivery material by incorporating magnetic NPs and folic acid (FA) via layer-by-layer self-assembling. The results showed that the surface of LHNPs was covered uniformly by Fe3O4NPs and grafted with folic acid. The folic-magnetic-functionalized lignin hollow NPs (FA-MLHNPs) could respond to magnetic field and folic acid receptors. In addition, the targeting performance of the FA-MLHNPs increased the cellular uptake of NPs in the case of HeLa cells. This research not only supported the modified NPs platform as a highly efficient nano-delivery method but also provided a facile approach to utilize renewable lignin biomaterials.Keywords:lignin;nanoparticles;targeted materials;drug delivery
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SCIENCE OF THE TOTAL ENVIRONMENT
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2019
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IF 5.589
Yi Meng,Chengxiang Li,Xueqian Liu,Jie Lu,Yi Cheng,Ling-Ping Xiao,Haisong Wang
A low-cost and well-separated approach is introduced for adsorption pollutants in water. Chemical modified lignin is prepared with diethylenetriamine to enhance the reaction activities, then used to prepare lignin derivate magnetic hydrogel microspheres (LDMHMs) via blending with Fe 3 O 4 . The LDMHMs are successful prepared by the determination of FT-IR data, and the morphology shown from SEM imagine indicates the LDMHMs are in nanosized. The prepared LDMHMs are used as adsorbents for organic dyes, such as methylene blue (MB), methyl orange (MO) and malachite green (MG), the plateaus data are 43 mg/g, 39 mg/g and 155 mg/g, respectively. For inorganic pollutions, such as Pb 2+ , Hg 2+ and Ni 2+ , the plateaus data are 33 mg/g, 55 mg/g and 23 mg/g, respectively. The adsorption data of unmodified lignin are 2.6 mg/g (Pb 2+ ), 3.3 mg/g (Hg 2+ ), 2.1 mg/g (Ni 2+ ), 8 mg/g (MB), 10 mg/g (MG) and 2 mg/g (MO) in the same condition. The adsorbents are recycled by magnetic separation, regenerating from acid condition and reused for multiple cycles. The regeneration ratios are all above 90%, indicating a highly reusability and further reducing the cost of the treatment.
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