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    30 July 2019, Volume 53 Issue 4 Previous Issue    Next Issue
    Research Report
    Synthesis, Characterization and Anticoagulant Activity of Corncob Xylan Sulfate
    Hongyu FAN,Min WEI,Jian ZHAO,Jianchun JIANG
    2019, 53 (4):  1-8.  doi: 10.3969/j.issn.1673-5854.2019.04.001
    Abstract ( 597 )   HTML ( 792 )   PDF (598KB) ( 829 )   Save

    A new corncob xylan sulfate(XS) was synthesized by sulfur trioxide-pyridine(SO3·Py) method with corncob xylan extracted by alkali method as raw material and LiCl as catalyst in aprotic solvent. The influences of solvent, temperature, reaction time and material ratio on the degree of substitution(DS) of XS were investigated and the optimal conditions were determined by orthogonal test. The structures and properties of sulfated polysaccharides were investigated by GPC, FT-IR, elemental analysis and 13C NMR spectroscopy. And the in vitro anticoagulant activity of XS was studied.The results indicated that the optimal conditions for sulfation were DMF as solvent, molar ratio of SO3·Py complex and hydroxyl unit of xylose 1.5:1, 55℃ and 3 h, and the degree of substitution of XS was 1.53 and the yield of XS was 78.2%. And the weight average molecular mass of the xylan sulfate product was 36 754 and the dispersion coefficient was 1.191. Structural characterization revealed that sulfate groups were successfully introduced into xylan. A preliminary study of vitro anticoagulant activity was conducted and the results showed that the xylan sulfate had anticoagulant activity, which could significantly prolong the APTT and TT. When the degree of substitution was 1.53 and the mass concentration was 20 mg/L, the APTT, PT and TT of XS were 36.37, 14.22 and 14.70 s, respectively, which were basically equivalent to the positive control heparin sodium.

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    Pyrolysis Characteristics and Kinetic Analysis of Phragmites australis Stalk
    Xu ZHANG,Jiao SUN,Ying FAN,Yongquan CAO,Wenyi CHEN
    2019, 53 (4):  9-18.  doi: 10.3969/j.issn.1673-5854.2019.04.002
    Abstract ( 736 )   HTML ( 31587 )   PDF (669KB) ( 1766 )   Save

    In order to make full use of the Phragmites australis as biomass energy, pyrolysis test for Phragmites australis stalk was performed at different heating rates. The kinetic parameters of Phragmites australis pyrolysis were calculated by Coats-Redfern(CR) method, Flynn-Wall-Ozawa(FWO) method and Kissinger-Akahira-Sunose(KAS) method. The results showed that the pyrolysis of Phragmites australis stalk could be divided into four stages, of which the stage of 190-400℃ was the main pyrolysis stage. At this stage, comparing the conversion rate(α)calculated from the three methods with the experimental data, it was found that the deviation between the calculated values of the Coats-Redfern method and the experimental data was larger when the temperature was more than 250℃. The conversion rates obtained by using Flynn-Wall-Ozawa method and Kissinger-Akahira-Sunose method were in good agreement with the experimental values at the whole pyrolysis stage. According to the master-plots method, the optimal reaction mechanism of pyrolysis was random nucleation and the reaction series was 2.It was found that the Kissinger-Akahira-Sunose method was more suitable for calculating the kinetic parameters of Phragmites australis stalk pyrolysis compared with the Flynn-Wall-Ozawa method. The apparent activation energy calculated by the Kissinger-Akahira-Sunose method increased first and then decreased with the increase of conversion rate. And the activation energy reached the maximum(286.9 kJ/mol) when the conversion rate was 50%.

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    Synthesis and Aggregation Behavior of Acrylicpimaric Acid Polyglycol Ester
    Yanzhi ZHAO,Juying ZHOU,Fangkai DU,Haitang XU,Jianfang LU,Xia ZHANG
    2019, 53 (4):  19-25.  doi: 10.3969/j.issn.1673-5854.2019.04.003
    Abstract ( 484 )   HTML ( 210 )   PDF (1370KB) ( 753 )   Save

    Acrylpimaric acid was obtained with rosin and acrylic acid as raw materials and characterized by gas chromatography-mass spectrometry technology(GC-MS). Acrylicpimaric acid polyglycol ester was synthesized by steglich esterification method under mild conditions with acrylicpimaric acid and polyglycol(PEG 2000) as monomers. Structure and properties of the substance were studied by infrared, gel permeation chromatography(GPC), and thermogravimetric(TG). The average-number molecular weight of the substance was 4 700 with the polydispersity index of 1.2. The decomposition temperature of acrylicpimaric acid and polyglycol ester was 308-410℃. The critical micelle concentration(CMC) of acrylicpimaric acid polyglycol ester in water was 1 g/L by surface tension and steady-state fluorescence method. The aggregation behaviors of acrylicpimaric acid polyglycol ester in water were investigated by rayleigh light scattering(RLS), dynamic light scattering(DLS) and scanning electron microscopy(SEM) techniques. The results indicated that the stabilized micelle of 1 g/L acrylicpimaric acid polyglycol ester aggregated as the temperature was higher than the aggragation temperature(74℃) and the aggregation temperature decreased from 74℃ to 65℃ as the solution concentration increased from 1 g/L to 1.5 g/L. And as the temperature of acrylicpimaric acid polyglycol ester solution increased from 25℃ to 85℃, the average diameter of hydrate particle(Dh) increased from 295 nm to 1 056 nm.

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    Characteristics of Low Temperature Co-pyrolysis Products of Low-rank Coal and Corncob
    Ping KE,Xuanming HE,Jing LIU,Dongzheng FENG
    2019, 53 (4):  26-30.  doi: 10.3969/j.issn.1673-5854.2019.04.004
    Abstract ( 623 )   HTML ( 10247 )   PDF (1877KB) ( 920 )   Save

    Low temperature distillation equipment was used to study the low temperature co-pyrolysis of lignite and corncob under different proportions. The results showed that when the corncob content was 30%, the tar yield reached 11.70%, which was 53.75% higher than that of the lignite mono-pyrolysis. With the addition of corncob, the contents of CO, CH4 and H2 in pyrolysis gas gradually increased. The results of GC-MS showed that as adding 30% corncob, aliphatic content increased from 24% to 30.67%, the phenol content increased from 6.29% to 18.49%, heteroatom content decreased from 29.75% to 13.33%, which achieved a substantial pyrolysis of tar and high-quality tar generation. The SEM, BET and heat value analysis of pyrolysis char showed that the surface of co-pyrolysis char became more rough, and the pore structure was improved. The heat value of co-pyrolysis char was obviously higher than the lignite pyrolysis separately.

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    Effect of Partial Removal of Parenchyma Tissues of Neosinocalamus affinis on Pulping and Bleaching Properties of Chemimechanical Pulp
    Hualan ZHANG,Guigan FANG,Kuizhong SHEN,Yongjun DENG,Xiaoliang LI,Shanming HAN
    2019, 53 (4):  31-36.  doi: 10.3969/j.issn.1673-5854.2019.04.005
    Abstract ( 401 )   HTML ( 8946 )   PDF (511KB) ( 946 )   Save

    The microstructure of bamboo chips was destoried by screw extrusion and part of parenchyma tissues were removed by screening. The obtained bamboo chips were impregnated individually by using different chemical impregnation, i.e. alkaline peroxide(AP), caustic soda(AA) and alkaline sodium sulfite(AS) and followed with atmospheric high consistency refining operation, those different chemimechanical pulps(CMP) were bleached with multiple-stage alkaline peroxide bleaching sequence and the bleached chemimechanical pulps(BCMP) were compared their bleach abilities. Results showed that, the chemical compositions of bamboo chips by removing 11.4% parenchyma tissues were significant different from these of initial bamboo chips, for instance, ash content decreased by 38.6%, cellulose content increased by 4.71%. But screw extrusion didn't cause obvious damage to bamboo fiber. AP impregnation could significantly reduce the refining energyconsumption, which was 18% less than that of AA impregnation as the Canadian standard freeness was 300 mL, and improve the bonding strength of CMP. AA impregnation produced pulps with better bulk properties but poor strength, these properties of AS pulps located among AP and AA pulps; by suing the same H2O2 dosage of 8.0%, the optimal alkali dosages of AP, AS and AA impregnation 4.5%, 4.5% and 3.5%, the bleached pulp brightness of 56.8%(ISO) was achieved from AP impregnation process, but only 49.9%(ISO) obtained from AA process.

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    Preparation of Oxalic Acid Modified Bagasse Carbon and Its Adsorption Characteristics for Cr(Ⅵ)
    Xuemei LIU,Chuang MA,Jiaxi TAO
    2019, 53 (4):  37-44.  doi: 10.3969/j.issn.1673-5854.2019.04.006
    Abstract ( 615 )   HTML ( 17771 )   PDF (1059KB) ( 970 )   Save

    Using bagasse(OB) as raw material, carbon bagasse carbon(CB) was obtained by carbonization at high temperature in air atmosphere, and then oxalic acid modified bagasse carbon(COB) was prepared by oxalic acid modification. The three kinds of samples were characterized by SEM, FT-IR and nitrogen adsorption-desorption isotherms, and the adsorption effect of Cr(Ⅵ) in simulated wastewater was simulated. The characterization results showed that the specific surface area was COB>CB>OB, the specific surface area of COB was 240.67 m2/g, the total pore volume was 0.138 cm3/g, and the average pore diameter was 2.30 nm. The pore structures of CB and COB were more than that of OB. The types and quantities of developed and oxygen-containing functional groups of CB and COB were significantly increased, and the adsorption capacities of CB and COB were improved. The results of adsorption experiments showed that the adsorption capacities of Cr(Ⅵ) were COB>CB>OB. Under the conditions of pH value 1, dosage of COB 0.6 g, adsorption time 100 min, adsorption temperature 25℃ and Cr(Ⅵ) mass concentration 50 mg/L, the removal rate of Cr(Ⅵ) by COB was 99.1%. The adsorption thermodynamics and kinetics results showed that the Langmuir isotherm adsorption model could better reflect the adsorption process, and the adsorption process followed the pseudo-second-order kinetics model, indicating that the adsorption process of Cr(Ⅵ) by bagasse carbon was mainly monolayer adsorption of chemisorption.

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    Antimicrobial Activities of p-Menth-3-en-1-amine and Its Schiff Base Derivatives
    Shouji ZHU,Xiaoshu WANG,Shichao XU,Zhendong ZHAO
    2019, 53 (4):  45-49.  doi: 10.3969/j.issn.1673-5854.2019.04.007
    Abstract ( 517 )   HTML ( 94 )   PDF (415KB) ( 859 )   Save

    The antimicrobial activities of p-menth-3-en-1-amine(1) and its Schiff base derivatives(2a-2l) against Staphylococcus aureus(gram-positive bacteria), Klebsiella pneumonia(gram-negative bacterium) and Candida albicans (fungus) were measured by using the microbroth dilution method. Then, the structure-activity relationship was established. The results showed that some products had certain antibacterial activities against these pathogenic bacteria. Compound 1 had the strongest antimicrobial activity against Staphylococcus aureus and the minimal inhibitory concentration(MIC) was 56.25 mg/L. Compound 2h and 2i had the strongest antimicrobial activity against Klebsiella pneumonia and the MICs were 112.5 mg/L. Compounds 2l had the strongest antimicrobial activities against Candida albicans and the MIC was 28.125 mg/L. The structure-activity relationship indicated that the antimicrobial activity would be stronger when the chlorine or bromine atom was introduced into the Schiff base derivatives; the antimicrobial activities of Schiff base derivatives containing a pyridine ring were higher than those of the Schiff base derivatives containing a furan, pyrrole or thiophene.

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    Review Comment
    Progress on Modification of Natural Plant Fiber for Composites
    Hongliang MA,Jian CHEN,Zhenwu KONG
    2019, 53 (4):  50-58.  doi: 10.3969/j.issn.1673-5854.2019.04.008
    Abstract ( 860 )   HTML ( 48637 )   PDF (3230KB) ( 1109 )   Save

    Natural plant fibers have unique structure and properties, and there are still many problems in compounding with resin matrix. Modification of natural plant fibers has important effect on improving their reactivity, interfacial compatibility with matrix resins and comprehensive properties of composites. Based on the analysis of the composition, structure and performance of natural plant fiber raw materials, some natural fiber pretreatment methods, such as steam-explosion pretreatment, thermal pretreatment, high energy radiation pretreatment, alkali pretreatment, peroxide pretreatment and combined pretreatment, were introduced, as well as some surface modification methods such as esterification modification, graft copolymerization and coupling agent modification. The research progress of natural fiber modification methods in composites and the effects of natural fiber modification on the properties of composites were summarized in order to provide ideas and references for the research of natural fibers reinforced composites.

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    Current Situation and Countermeasures of Hydroprocessing Biofuels Development in Large Petrochemical Corporation
    Xiangxing SHI,Hongchuan SONG,Ying HUANG,Kemei ZHOU
    2019, 53 (4):  59-66.  doi: 10.3969/j.issn.1673-5854.2019.04.009
    Abstract ( 670 )   HTML ( 630150 )   PDF (659KB) ( 1101 )   Save

    The background and significance of the hydroprocessing biofuels(green diesel and jet biofuel), current representative process route, performance advantage and its application at home and abroad were expounded. In combination with the stranded demonstration project of large refineries in the past ten years, the related reasons of project grounding were analyzed in depth from cost composition, price fixing to raw material supplying for the first time. On the actual situation of China, the advices as to how to utilize existing resource, innovate operation mode, establish a stable feedstock supplying chain(Jatropha curcas oil & waste cooking oil) and reduce production costs to make rapid development of hydroprocessing biofuels were provided at last.

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