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Table of Content

    30 March 2020, Volume 54 Issue 2 Previous Issue    Next Issue
    Research Report
    Flame Retardant Polyurethane Foam with Hydroxymethylated Sodium Sulfonate/Expanded Graphite/Aluminum Hypophosphite
    Cong LI,Wenjuan MA,Zhichen BA,Yizheng GU,Zhiming LIU
    2020, 54 (2):  1-5.  doi: 10.3969/j.issn.1673-5854.2020.02.001
    Abstract ( 310 )   HTML ( 1626 )   PDF (2756KB) ( 378 )   Save

    Sodium lignosulfonate was used to modify polyurethane foam and improve its flame retardant performance. First, hydroxymethylated sodium lignosulfonate(HSL) was obtained by methylation of sodium lignosulfonate. Then, some polyether polyol was replaced by hydroxymethylated sodium lignosulfonate and mixed with polymerized 4, 4'-diphenyl-methane-diisocyanate(MDI) to prepare hydroxymethylated sodium lignosulfonate modified polyurethane foam, and then added aluminum hypophosphite(AHP) and expanded graphite(EG) to further improve the flame retardancy of polyurethane foam. The limit oxygen index(LOI), thermogravimetry(TGA) and scanning electron microscopy(SEM) were used to test the samples. The flame-retardant properties of polyurethane foam samples were analyzed by limiting oxygen index test. The results showed that when the amount of hydroxymethylated sodium lignosulfonate instead of polyether polyols was 60% calculated by the percentage of HSL mass in the total mass of HSL and polyether polyol, the LOI index of polyurethane foam reached 21.6%, the maximum thermal degradation rate reduced by 1.53 %/min, the carbon residue increased by 15.04 percent points, and the number and area of foam pores decreased. When adding a mixture of flame retardants(mass ratio of expanded graphite and aluminum hypophosphite 3:1), the LOI index of polyurethane foam reached 26.3%, the maximum thermal degradation rate reduced by 1.52 %/min, the carbon residue increased by 23.52 percent points, and the number and area of foam pores decreased further. Therefore, a polyurethane foam with excellent flame retardancy is prepared in this experiment. It has broad application prospects in the field of architecture, transportation and food insulation.

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    Preparation and Properties of Bagasse Holocellulose Films and Membranes
    Hao YANG,Qi CHEN,Huimin ZHAO,Haojie GU,Jie YAN,Hailin LIN
    2020, 54 (2):  6-14.  doi: 10.3969/j.issn.1673-5854.2020.02.002
    Abstract ( 428 )   HTML ( 124997 )   PDF (6212KB) ( 502 )   Save

    The holocellulose film was manufactured from the holocellulose that was extracted from the bagasse with using ZnCl2 solution as solvent by using the phase inversion method. Then, the effect of holocellulose dosage(calculated by the mass of ZnCl2 solution, similarly hereinafter), dissolution time, gelation time and glycerin soaked mass fraction on the porosity, water flux of wet membrane and mechanical properties of dry film, were investigated. Sequentially, SEM, XRD, FT-IR and TG were applied to study the dissolution and film formation mechanism. The results showed that the holocellulose extracted from the bagasse could be used as raw material to prepare cellulose films. And when the holocellulose dosage was 5%, the gelation time was 3 d and the dissolution time was 1 h, the water flux of the obtained wet membrane reached the minimum of 17.2 L/(m·h), and the porosity was 83.3%. And the corresponding dry film obtained by plasticizing with 10% glycerol had the maximun tensile strength of 21.9 MPa and the elongation at break reached 22.2%.FT-IR and TG analysis showed that hemicellulose was not contained in the film made from holocellulose, and the hemicellulose may be hydrolyzed during dissolution or precipitated during film formation. SEM image showed that there are a large number of uniform holes inside the wet membrane, and the pores of the membrane shrank to form a dense structure.XRD results showed that the cellulose type Ⅰ to cellulose type Ⅱ after film formation, and the crystallinity decreased from 48.8% to 41.5%.

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    In Vitro Antibacterial Activity of Extract from Platycarya strobilacea Sieb.et Zucc.
    Man XU,Yongmei WANG,Liangliang ZHANG,Xinyu HU
    2020, 54 (2):  15-20.  doi: 10.3969/j.issn.1673-5854.2020.02.003
    Abstract ( 279 )   HTML ( 141 )   PDF (532KB) ( 306 )   Save

    The antibacterial activity of the extract from Platycarya strobilacea(PSE) was measured in vitro against nine bacteria including Aeromonas hydrophila, Aeromonas sobria, Aeromonas caviae, Aeromonas veronii, Edwardsiella tarda, Vibrio parahaemolyticus, Yersinia pestis, Escherichia coli and Staphylococcus aureus. The results showed that PSE had inhibitory effects on 9 kinds of bacteria, and the minimum inhibitory concentration was 4.50 g/L. For each type of bacteria, the bacteriostatic effect was enhanced with the increase of PSE concentration, in which the strongest antibacterial activity was against E. coli with the IC50 of 0.035 g/L, followed by Staphylococcus aureus with the IC50 of 0.053 g/L. The results of imported toxicity test on mice showed that the LD50 values of PSE to male and female mice were 5 010 and 7 940 mg/kg weight, which indicated that the PSE was actually non-toxic.

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    Fly Ash from Biomass Power Plant to Prepare Biochar
    Guangbing LIANG,Yanhong LI,Changyu ZI,Yuanqin ZHANG,Zhaoxia PENG,Yulin ZHAO,Wenbo ZHAO
    2020, 54 (2):  21-26.  doi: 10.3969/j.issn.1673-5854.2020.02.004
    Abstract ( 448 )   HTML ( 592 )   PDF (2752KB) ( 445 )   Save

    Biochar could be produced from biomass power plants fly ash after acidic leaching and demineralization. Biomass fly ash and biochar were characterized by X-ray diffraction(XRD), Fourier infrared spectroscopy(FT-IR), scanning electron microscope(SEM), X-ray energy dispersive spectrometer(EDS) and N2 adsorption/desorption. The results indicated that the biochar mass was 13.7% of the mass of fly ash and the aromatic degree of biochar was 28.4%. Moreover, the content of aliphatic carbon was high and the oxygen functional groups were abundant. Meanwhile, the specific surface area, total pore volume and mean pore diameter of biochar were 128.98 m2/g, 0.08 m2/g and 3.4 nm, respectively. The obtained biochar coated with hydroxide radicals has the potential for practical production and application, due to its loose and rough surface, abundant pore structure and high surface reactive.

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    Characteristics of Fast Pyrolysis of Chestnut Shell Based on PY-GC/MS Technology
    Ping HUANG,Liangliang JIA,Jian LI,Dongbing LI
    2020, 54 (2):  27-32.  doi: 10.3969/j.issn.1673-5854.2020.02.005
    Abstract ( 271 )   HTML ( 94 )   PDF (395KB) ( 343 )   Save

    In order to investigate the fast pyrolysis characteristics of chestnut shells, single-stage and two-stage fast pyrolysis were carried out by pyrolysis-gas chromatography/mass spectrometry(Py-GC/MS), and the pyrolysis products were qualitatively and quantitatively analyzed. The results showed that during single-stage fast pyrolysis the total number of product species and yield increased with the pyrolysis temperature. In the two-stage fast pyrolysis, the temperature of the first stage had little effect on the total product yield, but a higher temperature gave more product species. The main components of the pyrolysis products were nitrogenous, sugars or acids, of which D-allose and acetic acid were the highest. With the single-stage fast pyrolysis temperature of 500 ℃ the content of D-allose could go up to 17%. For the two-stage pyrolysis, when the first-step and second-step temperatures were 450 ℃ and 600 ℃, respectively, the content of acetic acid could go up to 15.9%.

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    Research on Mechanical Blowing Rice Straw Polyurethane Foam
    Dongfang YUAN,Yucang ZHANG
    2020, 54 (2):  33-39.  doi: 10.3969/j.issn.1673-5854.2020.02.006
    Abstract ( 346 )   HTML ( 176 )   PDF (1174KB) ( 339 )   Save

    Rice straw was smashed into powder with the particle size of 250-590 μm. Catalytic liquefaction tecnology under atomosphere pressure and heating was used to liquify the straw powder. Subsequently, polyurethane rigid foam(PURF) was produced by physical foaming method of liquified rice straw as material and PAPI with pentamethyl diethylenetriamine(PC5) and N, N-dimethyl cyclohexlemine(PC8) as co-catalyst and n-pentane as physical blowing agent. And the water-blown polyurethane foam was prepared as compare. The optimal conditions for PURF production was mass ratio of PC5 and PC8 4:5, foam stabilizer dosage 4%, and blowing agent n-pentane dosage 15%, the tensile strength and compressive strength of the obtained PURF were 347 kPa and 181 kPa. The FT-IR and scanning electron microscope(SEM) were used to compare two kinds of PURF. And the results showed that compared with the water-blown polyurethane foam, the obtained PURF had lower isocyanate concentration, lower open porosity and more superior mechanical properties.

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    Review Comment
    Research Progress of Lignin Chemical Degradation and Its Applications in Polymer Materials
    Qian YANG,Guifeng LIU,Guomin WU,Zhenwu KONG
    2020, 54 (2):  40-50.  doi: 10.3969/j.issn.1673-5854.2020.02.007
    Abstract ( 516 )   HTML ( 90216 )   PDF (639KB) ( 456 )   Save

    As a kind of abundant renewable phenolic structure polymer, lignin could replace traditional fossil resources to be used in synthetizing polymer materials. Especially, its rigid aromatic macromolecular structure could give materials good thermal stability and mechanical performance. However, the complex chemical composition and molecular structure, lower reactivity of lignin limited its application. Chemical degradation had advantages of high efficiency, high selectivity and could be used widely. Compared to lignin, oligomers derived from lignin chemical degradation had more reactive functional groups, higher reactivity and better solubility, which would be beneficial to expanding the high value-added applications of lignin in the field of polymer materials. The current research progress on the chemical degradation of lignin and its products applications in polymer materials were mainly reviewed.

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    Mechanism and Research Progress of Acid Synthesis During Sludge Anaerobic Fermentation
    Dongna LI,Xiaojun MA
    2020, 54 (2):  51-60.  doi: 10.3969/j.issn.1673-5854.2020.02.008
    Abstract ( 558 )   HTML ( 86253 )   PDF (592KB) ( 484 )   Save

    In order to achieve the reduction and recycling, anaerobic digestion of sludge is the most widely used treatment method in the world. Volatile fatty acids(VFAs), an important product in acidification stage, could be used to remove nitrogen and phosphorous from wastewater as carbon sources, and to synthesize valuable products, such as bioplastics polyhydroxyalkanoates(PHAs). Metabolic mechanism and microbial mechanism of acidogenesis process during sludge anaerobic fermentation were introduced. The research results of anaerobic fermentation of sludge in recent years were reviewed systematically. The effects of substrate species, pretreatment technology, pH value and fermentative temperature on the acid production by anaerobic fermentation of sludge and its research progress were discussed. Temperature and pH value obtained more attention and it was summarized and compared the acid production by sludge fermentation under different substrate types, temperature, acid and alkaline conditions could affect the production and type distribution, while sludge pretreatment technology tended to increase the production of acid, but had little effect on the type distribution. The application of anaerobic fermentation in the synthesis of PHAs, bioenergy, nitrogen and phosphorus removal from sewage was also introduced. Finally, due to the different organic compoments of the substrate, the acidification efficiency would be different. Meanwhile, controlling the substrate type, pH value and temperature would not only affect the acid production, but also affect the acid production type. Therefore, the research directions of further study were given as the reasons for differences in acidification efficiency of different substrates, directional fermentation of sludge to produce acid, and achieving the regulation of various acids proportions in total VFAs.

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    Progress in High Value-added Utilization of Silicon Resource from Biomass Ash
    Zhaoxia PENG,Yanhong LI,Yiqin CHEN,Guangbing LIANG,Yong HUANG,Changyu ZI
    2020, 54 (2):  61-66.  doi: 10.3969/j.issn.1673-5854.2020.02.009
    Abstract ( 336 )   HTML ( 169 )   PDF (1633KB) ( 430 )   Save

    Biomass ash contains amorphous silicon with chemical activity, which can be used to synthesize high value-added products. The composition and structure of biomass ash were summarized. In terms of synthesizing gels from biomass ash, the research progress in synthesizing xerogels, aerogels, and hydrogels at home and abroad in recent years was summarized. This article reviewed the research progress in the preparation of anode materials and catalyst materials for lithium ion batteries using silicon resources in biomass ash in recent years. By the application analysis of silicon resources of biomass ash, it was presented that the silicon resource in biomass ash was hopeful to be the low cost precursor of producing high value-added silicon based materials, and the development direction of resource utilization of biomass ash in industry was provided.

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