Anthocyanin is a kind of flavonoid which mainly exists in plants. It has strong biological activities such as anti-cancer and anti-oxidation, and is widely used in the field of nutrition and health care. Most anthocyanins are extracted directly from plants by physical or chemical means, but the yield is low, and the extracted anthocyanins are mostly mixtures due to the restrictions of time, region and season. Biosynthesis of anthocyanins have attracted much attention by researchers worldwide in recent years. As the biosynthesis of anthocyanins can be controlled artificially and the purity of the obtained products is high, it has been widely studied. Anthocyanins cannot exist stably in the environment, and need to be modified by glycosylation, acylation and methylation to increase their stability. The modified anthocyanins can be synthesized by microorganisms and significant color changes can be seen in the medium. The biosynthesis and modification of anthocyanins were reviewed in this paper, and the preparation technology of anthocyanin synthesis from plants and microorganisms was briefly introduced, the factors affecting anthocyanin synthesis were analyzed, and finally the future research direction of anthocyanin was predicted.
Lignin is the most abundant renewable aromatic polymer in nature, which complex structure and compact connection with cellulose and hemicellulose through covalent bond and hydrogen bond make it difficult to be separated efficiently. Deep eutectic solvents (DES) is a novel kind of green ionic liquid, which has been successfully applied to lignin isolation due to its unique physical and chemical properties. The research progress of dissolution and extraction of lignin by deep eutectic solvents (DES) is reviewed in detail. From the point of view of the mechanism of dissolving lignin by DES, the effects of different factors(composition, proportion, pH value, functional groups of DES, water content of system, raw material, reaction time, temperature, catalyst, co-solvent, and so on) on lignin removal were emphatically expounded. Based on the research progress of DES in lignin extraction, the research progress and futuer application of lignin extraction were summarized and prospected.
The hydrophilic, ductile, thermoplastic and biodegradable properties of cellulose acetate (CA) were introduced, and the basic structure and market application of three kinds of cellulose acetate were summarized.It was pointed out that CA still had some disadvantages such as poor thermal stability at high temperature, low mechanical strength and easily being contaminated. The impacts of the physical modification and chemical modification on the properties of CA were also reassessed.It could conclude that the chemical reaction with polymer could change the structure or properties of CA.The fouling resistance, thermoplastic, selective and reuse of the CA were improved greatly, while the physical modification could improve the porosity and thermal stability of CA membrane, and the membrane mechanical strength, metal ion exclusion rate and the water flux were improved. The applications of CA in seawater desalination, adsorption of toxic substances in flue gas, preparation of biomedical membrane, drug delivery, tissue repair and regeneration, biosensor, outdoor protection and air purification were also summarized, and the market prospect and development trend of CA were prospected.
The consumption of wood adhesive in China is huge. However, the main wood adhesive based on formaldehyde is still prevalent. In recent years, environment friendly adhesives such as non-formaldehyde adhesives and biomass adhesives have developed rapidly. Herein, the recent research and application of wood adhesives including urea-formaldehyde resin adhesives, phenolic resin adhesives, melamine-formaldehyde resin adhesives, protein adhesives, lignin adhesives, starch adhesives, tannins adhesives, isocyanate adhesive, emulsion adhesives and pyrolysis biological oil adhesives were reviewed. The development trend and the research direction of wood adhesives were also prospected.
As a natural material with good biocompatibility and biodegradability, nano-cellulose has unique structure and excellent mechanical properties. It has been widely used in the construction of electrochemical energy storage system of lithium-ion batteries(LIBs), and has made significant progress. This thesis provided an overview of the preparation and modification methods of cellulose nanofibrils(CNF), cellulose nanocrystals(CNC) and bacterial cellulose(BC) in the context of the application of advanced energy storage devices LIBs and green materials nanocellulose, and reviewed the research progress on the application of nanocellulose in the field of LIBs. It was mainly divided into three aspects: first, nanocellulose-based flexible LIBs electrodes; second, carbon materials derived from nano cellulose as electrodes; third, nano cellulose derived battery separator. Finally, some problems in this field were analyzed, summarized and prospected.
The cellulose dissolution capability and dissolution mechanism of current novel solvent systems, including aqueous solvent systems (NaOH aqueous solution, alkali/urea and NaOH/thiourea aqueous solution, quaternary ammonium/phosphine aqueous solution, and molten inorganic salt hydrates) and organic solvent systems (LiCl/N, N-dimethylacetamide, ionic liquids and deep eutectic solvents) were reviewed. Sequentially, the advantages and disadvantages of various solvents were discussed, which could provided a reference for the future development and utilization of green cellulose solvents.
The inherent properties of kapok fiber were summarized, such as light weight, high degree of hollowness up to 80%-90%, and super-hydrophobic surface, etc. Meanwhile, physical and chemical modification methods which could be widely used to improve the application characteristics of kapok fiber were introduced. The recent research progress focused on the application of kapok fiber and/or its modified treatment as eco-friendly oil-absorbing material, lithium-sulfur battery anode material and supercapacitor electrode material as well as the development of kapok fiber/polyester composite for sound absorbing material was presented. Based on the comprehensive research status of kapok fiber at home and abroad, the current challenges and future prospects on kapok fiber exploitation with respect to expanding new uses and high value-added utilization were highlighted.
Enzymatic hydrolysis residue of xylan was autohydrolyzed, and the autohydrolysate was then fractionated by two-step ethanol precipitation. The obtained three kinds of xylan fractions with varied degree of polymerization (Dp) were evaluated through in vitro proliferation by Bifidobacterium adolescentis. The autohydrolysis was carried out at 180℃ for 40 min to obtain autohydrolysate mainly contained xylooligosaccharides (XOS) with Dp of 2-6. The content of XOS was 57.36% of the xylan in the autohydrolysate, and the yield of XOS was 26.54% of the xylan in the feedstock. Two-step ethanol precipitation could fractionate the xylan in the autohydrolysate into sample S1, S2 and S3, with the range of Dp of 24-122, 7-19 and 1-6, respectively. Low Dp of sample S3 contained mainly XOS which was 95.91% and exhibited significant prebiotic activity. After 36 h incubation, the cell concentration was 0.25 g/L, 4.72 times of the initial, with the sugar residue of 43.48%, and with the concentration of short-chain fatty acids of 1.96 g/L.
In this paper, the principle, preparation and influencing factors of bamboo-based supercapacitor materials are mainly introduced, as well as the research progress in the structural design and technical studies. Comparing to the single activated bamboo-carbon, bamboo-based carbon composites, taking bamboo-carbon as the template for the growth/fitting of pseudo-capacitance materials, are emphatically discussed. The redox reaction at the interface between the pseudo-capacitance material and the electrolyte results in the additional pseudo-capacitance, significantly improving the electrical performance of bamboo-based carbon materials and then extending the area of its applications. Finally, the perspective of the abundant bamboo resources in the field of supercapacitors is prospected, basing on the summary of current research progress and facing problems.
Lignocellulosic resource, derived from agricultural and forestry residues in China, is an abundant, cheap and renewable feedstock from which can be bioconverted to bio-based chemicals such as fumaric acid. Production of bio-based chemicals from lignocellulose owes important social, environmental and economic benefits. Fumaric acid, an important platform chemical, has been widely used in the areas of materials, food, medicine, chemical engineering, etc. Rhizopus oryzae, is used as the main producer of fumaric acid and requires a little nutrients for growth.This review discussed production of fumaric acid from lignocellulose by Rhizopus oryzae, focusing on metabolic pathway of glucose and xylose, lignocellulosic feedstocks, fermentation strategies, co-production of multiple products. The emerging technologies and methods will improve large-scale production of fumaric acid from lignocellulose by Rhizopus oryzae.
A cellulose-based highly conductive film (RGO/CNF/RGO(RCR)) was prepared using graphene oxide (GO) and cellulose nanofiber (CNF). Graphene oxide@polypyrrole (GO@PPy) active material was deposited on both sides of the film, then an integrated flexible film with conductive anisotropy and good flexibility was acquired. Furthermore, the liquid electrolyte was infiltrated into the composite film, and the copper foil was used as the current collector to prepare the integrated sandwich structure supercapacitor(SC). The morphology and surface elements of the film were analyzed by scanning electronic microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Afterwards, the electrochemical performance of integrated capacitor was compared with stacked capacitor and gel capacitor. The results showed that PPy was wrapped on the surface of GO and deposited on the surface of RCR film in the form of GO@PPy, and a pseudo-capacitive layer of about 400 nm was formed. When the scanning rate was 5 mV/s, the area specific capacitances of integrated, stacked and gel capacitor reached the maximum, which were 28.5, 28.1 and 33.8 mF/cm2, respectively. When the scanning rate increased to 200 mV/s, the area specific capacitances decreased to 4.6, 3.2 and 1.1 mF/cm2, respectively. It could be seen that the integrated capacitor has higher stability. The tight and seamless connection of the integrated capacitor could effectively avoid the relative displacement and shedding between the adjacent components, and effectively reduce the resistance of electron/ion transfer. At the same time, the integrated capacitor also showed better flexibility, and its electrical performance remained stable after bending test. When the current density was 0.2 mA/cm2, the area and volume specific capacitance of the integrated capacitor could reach 64.8 mF/cm2 and 31.0 F/cm3, respectively, showing excellent electrochemical performance. The preparation of the integrated supercapacitor provides a new method for development of wearable electronic devices.
A novel soybean protein/polyacrylamide (SPI/PAAm) composite hydrogel was synthesized, in which soybean protein (SPI) and acrylamide (AAm) were used as raw materials, ammonium persulfate (APS) was used as the initiator, N, N'-methylenebisacrylamide (MBAA) was used as the covalent crosslinker, CaCl2 was used as the ionic crosslinker and N, N, N', N'-tetramethylethylenediamine (TEMED) was used as the accelerator. The structure and mechanical properties of the obtained hydrogels were analyzed, and the mechanical mechanism was then investigated. The results suggest that the obtained hydrogel had a double-network structure, including ionically-crosslinked soybean protein network and covalently-crosslinked polyacrylamide network. For the double-network hydrogel, the ionically-crosslinked network dispersed the applied stress and dissipated the energy, and the covalently-crosslinked network contributed to the shape retention. The synergistic effect resulting fromdouble networks endowed the hydrogel with high elasticity, high compressibility and fatigue resistance.The morphology analysis revealed that the obtained hydrogel showed a uniform cell structure, and the soybean protein was uniformly distributed within the hydrogel. The mechanical analysis indicated that the obtained hydrogel exhibited high compression-resilience property and elasticity, which could rapidly recover to its original shape upon 80% compressive strain without structural collapse or damage during 10 successive uniaxial compression cycles. More encouragingly, the obtained hydrogel possessed outstanding toughness and fatigue resistance, which could remain shape intact after undergoing 100 compression cycles at 20%, 50% and 80% strain, respectively.After 100 compression cycles at 20%, 50% and 80% strain, the corresponding stress remaining rates were 90%, 95% and 104%, the corresponding plastic deformation rates were 3.1%, 5.9%and 8.4%, and all the energy loss coefficients were below 0.3.
A class of bio-based hybrid membranes named EC-g-MPA-ESO were prepared by the esterification reaction between the epoxidized soybean oil (ESO) and the ethyl cellulose-rosin-based polymer (EC-g-MPA), synthesized by grafting rosin derivative maleopimaric acid (MPA) onto the ethyl cellulose (EC) backbone via esterification reaction. The chemical structure of EC-g-MPA was characterized by FT-IR, 1H NMR, and UV-Vis spectrophotometer, by which have confirmed the successful preparation of EC-g-MPA. Then, TGA, DSC, UV-Vis spectrophotometer, and tensile test were applied to investigate the thermal stability, curing properties, UV absorption properties, and mechanical properties of bio-based hybrid membrane EC-g-MPA-ESO with different ESO content. The results showed that the bio-based hybrid membrane exhibited UV absorption property. Compared with EC and EC-g-MPA, EC-g-MPA-ESO exhibited low glass transition temperature and excellent toughness. Mechanical test showed that when ESO content was 20% (based on the mass of EC-g-MPA), the blend film shows the best mechanical properties, and tensile strength reaches the maximum value of 12.07 MPa. Cyclic tensile test confirmed that the elastic restitution coefficient of EC-g-MPA-ESO increased with the increase of elongation. As the elongation reached 80%, the elastic restitution coefficient reached 54.6%, indicating that EC-g-MPA-ESO had good elastomer behavior and could be used as a thermoplastic elastomer. The hybrid membrane consists of cellulose matrix and rosin functional groups, and could find potential application in UV absorption and degradable plastic film.
The degradtion of condensed tannin to tannin oligomers or monomers with low molecular weight is of great significance for improving their bioavailability and realizing high value-added utilization. This article comprehensively summarizes the research progress of condensed tannins in the fields of microbial degradation (fungal, bacterial), chemical degradation (acid degradation, alkaline degradation, precious metal catalytic degradation and biological enzymolysis), resin catalytic degradation, etc. The problems and solutions are summarized, and the future development direction is prospected.
With the depletion of petroleum resources and the increasingly serious white pollution, the preparation of bio-based poly(ethylene 2, 5-furandicarboxylate)(PEF) from lignocellulosic resources has become one of the research hotspots in the fields of biorefinery and green chemical industry. Compared with petroleum-based plastics, such as poly(ethylene terephthalate)(PET) and polycarbonate(PC), PEF not only has excellent thermal properties and mechanical strength, but also has more obvious advantages in gas barrier properties, which is considered as a perfect substitute for PET. However, PEF also has some drawbacks, including low elongation at break, dark color, difficult degradation and slow deep crystallization speed. Therefore, it is necessary to modify PEF before practical application. In this paper, the research progresses of PEF modification, including copolymerization, blending and other modification methods were reviewed. The effects of different diols or diacid modified monomers, catalyst types, reaction modes, additives on the properties of PEF were summarized, and the developing trend and application prospects of modified PEF were discussed.
The anacardic acid based epoxy resin type-Ⅰ(EACA-Ⅰ) was synthesized by the reaction of anacardic acid(ACA) obtained from cashew nut shell liquid(CNSL) and epichlorohydrin. Then, the side chain oxidation of EACA-Ⅰ was carried out to form the anacardic acid based epoxy resin type-Ⅱ(EACA-Ⅱ). The chemical structure of the epoxy resins was characterized by HPLC, FT-IR and NMR. The epoxy values of EACA-Ⅰ and EACA-Ⅱ were 3.7 mmol/g and 6.0 mmol/g, and the viscosities at 25 ℃ were 80 and 300 mPa·s, respectively. The characterization of curing reaction and heat resistance of the cured products obtained from the reaction of epoxy resins with tetrahydromethyl-1, 3-isobenzofurandione(MeHHPA) and isophorondiamine(IPDA) were investigated by DSC and TGA, respectively. The results showed that the heat release of the curing process of the anacardic acid based epoxy resins with MeHHPA was moderate. However, the heat release of the curing process of anacardic acid based epoxy resin with IPDA was intense; the cured products obtained from the reaction of the anacardic acid based epoxy resins with MeHHPA showed good thermal stability with the initial temperature of degradation more than 371.6 ℃ and the peak temperature of weight loss at 417.5 ℃.
Desirable pine resources are the basis for the sustainable, high value-added and fine chemical utilization of pine oleoresin. According to the chemical composition and structural characteristics of pine oleoresin, combined with the analysis of the current situation of pine oleoresin resources as well as their deep processing and utilization industries, the demand for individuation pine resources is discussed from the perspective of fine utilization. By the perspectives of production, processing, utilization and benefits, intensive high-quality pine oleoresin resources are needed, which have strong oleoresin exudation, long-lasting resinosis, good quality, and easy processability. And by the perspective of deep processing and utilization, individuation oleoresin resources are needed further, which have higher quality, more useful, more balanced or more outstanding specific components. To research and breed individuation pine resources such as pimaric-type rosin, isopimaric-type rosin, mercusic-type rosin, α-pinene-type turpentine, β-pinene-type turpentine, 3-carene-type turpentine, β-phellandrene-type turpentine and longifolene-type heavy turpentine, are scientifically important and applicably valuable for the fine chemical utilization, high value-added deep processing of rosin and turpentine. It is recommended to focus on the main oleoresin-tapping pine species such as P. massoniana, P. kesiya var. langbianensis, P. elliottii, P. elliottii×P. caribaea, P. latteri Mason, etc., and carry out more integrative and interdisciplinary researches on oleoresin chemistry, fine chemicals, genomics, metabolomics, genetic breeding, resource cultivation, and chemical engineering of forest products.
The lignin-based phenolic resin was synthesized by condensation reaction of phenol and formaldehyde, in which part of phenol was replaced with alkaline cornstalk lignin. To evaluate the effect of foaming agents on the structure property of the carbon foams, n-hexane, n-pentane and activated carbon loaded n-hexane were chosen as the foaming agents, and the prepared carbon foams were signed as CF-H, CF-P, and CF-ACH, respectively. The results indicated that the lignin-based phenolic foams prepared by different foaming agents exhibited excellent thermal stability, evidenced by the higher residual carbon recovery rate of 47.95% after thermal decomposition at 800 ℃. All of the prepared carbon foams belonged to amorphous carbon, in which non-graphitized carbonaceous structure was detected. The pore shape of CF-H, CF-P, and CF-ACH was spherical or ellipsoid with the pore size distribution of 20-300 μm, and their apparent densities ranged from 0.15 to 0.55 g/cm3. Compared with the normal carbon foams, the prepared lignin-based carbon foams had considerable compressive strength and the maximum compressive strength reached 13.13 MPa. In addition, the specific surface areas of CF-P, CF-ACH, and CF-H were 471.22 m2/g, 186.72 m2/g, and 42.08 m2/g, respectively. The pore opening rates of the carbon foams were all above 64%, and the area percentages of micropore were above 77%.
The ethanol extract of the leaves of Castanopsis fleuryi was isolated by Sephadex LH-20, MCI gel CHP 20P, Toyopearl HW-40F, Chromatorex C18 column chromatography and simi-preparative HPLC purification techniques to obtain ten compounds. Their structures were elucidated by spectroscopic data and comparison with literatures as:gallic acid(1), ethyl gallate(2), dehydrodigallic acid(3), gentisic acid 5-O-β-D-glucoside(4), cretanin(5), apigenin(6), kaempferol-7-O-β-D-glucoside(7), astilbin(8), aromadendrin7-O-β-glucopyranoside(9), amarusine A(10). All compounds were isolated from this plant for the first time.
pH-sensitive micelles BUDA-pentanolamine-(mPEG-NH2) (BPAU) were synthesized with traditional pH-sensitive micelle materials 5-amino-1-pentanol (pentanolamine), 1, 4-butanediol diacrylate (BUDA) and amino group functionalization methoxypolyethylene glycol (mPEG-NH2) as raw materials by self-assembly. Then, with trieneurushiol phenol borate derivative (URU-NH2) as the hydrophobic unit and galactose (Gal) as the recognition unit, the pH-sensitive BPAU-NH2-Gal nanomicelle was synthesized. And then, Paclitaxel (PTX) was used as the test drug, and nano-drug loaded micelles (PTX@BPAU-NH2-Gal) were prepared by dialysis. By nuclear magnetic (NMR), gel chromatography (GPC), surface/interfacial tension, Zeta potential analysis, micelle structure, average relative molecular mass (Mw) and critical micelle concentration (CMC), Zeta potential were characterized. The morphology of drug-loaded micelles was characterized by TEM, and the particle size was determined by DLS.High-performance liquid chromatography (HPLC) was used to determine the encapsulation efficiency and drug loading quantity of PTX. Dynamic membrane dialysis was used to investigate the release and uptake characteristics of drug-loaded micelles at different pH values in vitro. The results showed that BPAU-NH2-Gal was synthesized successfully, and the Mw value of micelle BPAU-NH2-Gal was about 15 550, dispersion index (PDI) was 1.49, the CMC value was about 90.29 mg/L, and the Zeta potential value was 29.69 mV. The drug-loaded micelle PTX@BPAU-NH2-Gal had an irregular elliptical structure with the average particle size about 195 nm; the encapsulation rate of paclitaxel was 92.51%, the drug load quantity was 31.76%.When the pH value was 4.5, the release rate was significantly higher than that in the environment with pH value of 6.8 and 7.4, and the micelle release had obvious pH responsiveness property.When the pH value of the buffer solution was 4.5, 6.8, and 7.4, the cumulative release rate of paclitaxel from the drug-loaded micelle within 90 h were 50.00%, 34.26% and 9.00%, respectively, which showed low toxicity to LO2 and high activity against HepG2.