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28 December 2023, Volume 43 Issue 6 Previous Issue    Next Issue

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Preparation, Characterization and Properties of Bamboo Nanocellulose Film Minzhao LI, Enqing ZHU, Jing YANG, Haiyan YANG, Dawei WANG, Zhengjun SHI 2023, 43 (6):  1-7.  doi: 10.3969/j.issn.0253-2417.2023.06.001 Abstract ( 165 )   HTML ( 21 )   PDF (3051KB) ( 235 )   Save To prepare renewable biomass-based membrane materials with excellent mechanical properties, high light transmittance, good water vapor and oxygen barrier properties, bamboo nanocellulose(B-CNF) was prepared from bleached sulfate bamboo pulp fibers(BP), and then the molecular structure of cellulose in bamboo fibers was modified by oxidation with sodium periodate to prepare bamboo nanocellulose membrane material using bamboo as matrix. When B-CNF was oxidized and treated with NaIO4 for 0.5, 1.5 and 3 h, the resulting oxidized bamboo nanocellulose was labeled as OB-CNF-0.5, OB-CNF-1.5 and OB-CNF-3, respectively, and the corresponding prepared membrane materials were labeled as OBF-0.5, OBF-1.5 and OBF-3. The membrane material prepared by B-CNF was named as BF. The membrane materials were characterized by Fourier transform infrared spectrometer(FT-IR), scanning electron microscope(SEM), and atomic force microscope(AFM) and other methods, and their mechanical properties, light transmission properties, water vapor and oxygen barrier properties were tested. The results showed that the oxidation of periodate could successfully introduce aldehyde groups in the long chain of cellulose molecules of bamboo fibers. As the oxidation time of periodate was extended to 3.0 h, the content of aldehyde groups in bamboo nanocellulose increased to 1.23 mmol/g. Compared with BF, with the extension of oxidation time, the bamboo nanocellulose-based membrane material would gradually develop a layered structure. The light transmission at the wavelength of 600 nm increased from 82.24% to 97.49%, the water vapor transmission(WVTR) decreased from 0.35 g·mm/(m2·h·kPa) to 0.13 g·mm/(m2·h·kPa), and the oxygen transmission(OTR) decreased from 4.37×10-3cm3/(m2·d·Pa) to 1.68×10-5cm3/(m2·d·Pa).The comprehensive performance of the membrane material OBF-1.5 was great, with tensile strength of 42.85 MPa, elongation at break of 8.88%, light transmission over 90% at 600 nm, water vapor transmission of 0.14 g·mm/(m2·h·kPa) and oxygen transmission of 1.68×10-5cm3/(m2·d·Pa) Figures and Tables | References | Related Articles | Metrics

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Synthesis, Characterization and Antimicrobial Activity of ω-Aminomethyl Longifolene Pingping LU, Yanqun HUANG, Yuehong GAN, Lanjie HUANG, Hai GE, Daozhan HUANG 2023, 43 (6):  8-16.  doi: 10.3969/j.issn.0253-2417.2023.06.002 Abstract ( 116 )   HTML ( 15 )   PDF (2590KB) ( 161 )   Save The target compound of ω-aminomethyl longifolene(5) was synthesized from ω-chloromethyl longifolene(3) by Gabriel synthesis via intermediate N-substituted phthalimide derivative(4). The structures of compounds 4 and 5 were confirmed by high resolution mass spectrum(HRMS), Fourier transform infrared(FT-IR), 1H nuclear magnetic resonance(1H NMR), 13C nuclear magnetic resonance(13C NMR) and single-crystal X-ray diffraction(SC-XRD). The absolute configuration of compound 5 was inferred from the crystal structure of the synthesized compound 4. In the hydrolysis reaction of compound 4, the yield of compound 5 could be improved and the separation and purification process could be simplified by adding sodium hydroxide and heating reflux hydrazinolysis conditions under solvent-free. The results of single-factor experiment showed that under the optimum hydrazine hydrolysis conditions of n(hydrazine hydrate): n(compound 4)=23:1, 5 g 10% sodium hydroxide solution, and 6 h reaction time at reaction temperature of 120 ℃, the yield and purity of compound 5 could be reached 94.1% and 99.98%, respectively. The results of antibacterial activity assay in vitro showed that compound 5 could significantly inhibit the growth of four bacteria(Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Klebsiella pneumoniae) and three fungi(Candida albicans, Candida tropicalis and Aspergillus niger). The minimum inhibitory concentrations(MIC) were 1.95, 1.95, 7.81, 3.91, 3.91, 1.95 and 15.63 mg/L, respectively. Among them, compound 5 showed stronger inhibitory activities against C. albicans and C. tropicalis than positive control ketoconazole. Figures and Tables | References | Related Articles | Metrics

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Effect of the Number of Activated Carbon Electrodes on the Desalination Performance of Capacitive Deionization Chang TAN, Bei LI, Shengchun HU, Ao WANG, Yanping ZHANG, Kang SUN 2023, 43 (6):  17-24.  doi: 10.3969/j.issn.0253-2417.2023.06.003 Abstract ( 101 )   HTML ( 3 )   PDF (867KB) ( 147 )   Save This study constructed capacitive deionization(CDI) systems with different numbers of stacked units, using activated carbon as electrode material without ion exchange membranes. The effects of the number of stacked units on freshwater productivity, salt adsorption capacity and energy efficiency of the CDI system were explored. The results show that CDI systems with 1, 2, and 4 pairs of electrodes achieve the total salt removal quantity of 10.11, 23.41, and 34.22 mg at the same flow rate, respectively. Furthermore, the average concentration reduction(ΔC) and the thermodynamic energy efficiency(ηTEE) of the CDI systems increase dramatically with the increase of the electrode units: ΔC increased from 2.16 mmol/L to 7.31 mmol/L, and ηTEE increased from 0.66% to 2.17%.In the CDI system with two pairs of electrodes, the charge efficiency and the salt adsorption capacity(QSAC) do not be affected by the flow rate, while the ΔC, energy consumption, and ηTEE of the system all significantly decrease with the increase of the flow rate. In addition, when simultaneously increasing the stacked units and flow rate with the same factor, the total salt removal quantity of the CDI system was 10.11, 22.25 and 32.89 mg at the stacked units of 1, 2, 4, respectively. All of these three systems achieve the average desalination concentration of about 2 mmol/L. Therefore, increasing the number of stacked units can effectively expand the scale of CDI system. Figures and Tables | References | Related Articles | Metrics

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Synthesis and Properties of Soybean Oil-based Flame Retardant Wood Coatings Fei ZHANG, Yue MA, Jia HUANG, Yun HU, Chengguo LIU, Yonghong ZHOU 2023, 43 (6):  25-32.  doi: 10.3969/j.issn.0253-2417.2023.06.004 Abstract ( 116 )   HTML ( 5 )   PDF (13176KB) ( 150 )   Save Hydrophobic nano-SiO2 modified bio-based UV curable resin was prepared using glycidyl methacrylate modified itaconic acid prepolymer(GI) and epoxy soybean oil(ESO) based synthetic product GIESO as raw materials and using tetrahydrofuran methacrylate(THFMA) as diluent. Then, 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO) as a phosphorus-containing flame retardant was introduced to prepare a UV-curable wood coatings with hydrophobic and flame retardant properties. The effects of SiO2 and DOPO on coating properties were studied by adjusting the relative contents of these two components in the resins. The research results showed that when the amount of SiO2 was 0.5%(calculated by the mass of GIESO/THFMA, which was also applied as below), the comprehensive performance of the coating GIESO/THFMA-Si0.5 was the best, with a water absorption rate of 0.49% and a contact angle of 108.2°. When the dosage of DOPO was 20%, a UV-curable wood coatings with high film coating, hydrophobic and flame retardant properties was prepared. The hardness of film was 6H, the adhesion was level 1, the flexibility was 4 mm, the contact angle was 103.7° and the limiting oxygen index(LOI) was up to 24.0%. Figures and Tables | References | Related Articles | Metrics

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Yield and Ingredient Analysis of Essential Oil in Different Povenances of Fokienia hodginsii Leaves Meixuan CHEN, Xia HUANG, Bingjun LI, Jundong RONG, Yushan ZHENG, Liguang CHEN 2023, 43 (6):  33-42.  doi: 10.3969/j.issn.0253-2417.2023.06.005 Abstract ( 101 )   HTML ( 8 )   PDF (744KB) ( 149 )   Save The essential oils of Fokienia hodginsii(Dunn) A. Henry et H. H. Thomas leaves from different provenances were studied. By reducing the influence of growth environment on leaf essential oil content and composition, the relationship between the essential oil and heredity of Fujian cypress from different provenances was better reflected, and provenances with more application value were screened out. The research object was taken from 14 F. hodginsii provenances of F. hodginsii provenance experimental forest in Fengtian state-owned forest farm of Anxi, Fujian Province. The essential oil from F. hodginsii leaves was extracted by ultrasonic assisted steam distillation. The components and GC content of the essential oil of F. hodginsii leaves were detected by GC-MS, and the differences in the yield and composition of the essential oil from different provenances of Fujian cypress leaf were analyzed. Through single factor test and orthogonal test design, the optimum extraction process of ultrasonic assisted steam distillation of F. hodginsii leaves was obtained under the conditions as follow: liquid-to-material ratio of 3.5:1(mL: g), extraction time of 8 h, ultrasonic treatment time of 30 min and ultrasonic power of 240 W. Under these conditions, the yield of essential oil was 0.252%. A total of 17 main components were detected in the essential oil of 14 provenances, accounting for 86%-92% of the total components. The GC content of the main components(components with content greater than 1%) was significantly different. Among them, α-pinene, 1-octen-3-ol, β-pinene, β-myrcene, D-limonene, β-caryophyllene, Z, Z, Z-1, 5, 9, 9-tetramethyl-1, 4, 7-cycloun-decatriene, β-cubebene, and γ-cadinene were the common major components. The GC content of α-pinene was about 50%. The essential oil composition and GC content of Chongqing Jiangjin provenance were significantly different from those of other provenances. The essential oil composition and GC content of most of the provenance leaves in Fujian Province had a strong correlation. Among three provenances in Guangxi, there was a strong correlation between the two provenances of Guilin Guanyang and Nanning Damingshan. The essential oil compositions of Shenzhen Nanling, Guangdong Province had a strong correlation with the provenance in Fujian Province, which showed that the essential oil composition and the GC content of F. hodginsii leaves with a closer seed source had a strong correlation. The comprehensive score of the main components of the essential oil of F. hodginsii leaves from different provenances was the highest in Guangxi Laibin Jinxiu, with low content of α-pinene, and the lowest comprehensive score was Fujian Putian Xianyou, with high α-pinene content. According to the provenance, GC content of the main components and the comprehensive score of the main components, Fujian Sanming Datian and Guangxi Guilin Guanyang were more suitable as excellent provenances for extracting the essential oil of F. hodginsii leaves, which could be used for early breeding varieties, so as to achieve better development and utilization of F. hodginsii. Figures and Tables | References | Related Articles | Metrics

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Physicochemical Characteristics and Antiglycation Capacity of Insoluble Dietary Fiber from Rhodomyrtus tomentosa Fruit Yejun DENG, Lixin HUANG, Caihong ZHANG, Pujun XIE 2023, 43 (6):  43-50.  doi: 10.3969/j.issn.0253-2417.2023.06.006 Abstract ( 112 )   HTML ( 1 )   PDF (2570KB) ( 144 )   Save The insoluble dietary fiber(IDF) in Rhodomyrtus tomentosa fruits was prepared by water method and enzymatic modification extraction, respectively. Scanning electron microscopy(SEM), Fourier transform infrared spectrometer(FT-IR), X-ray diffraction(XRD), and other methods were used to characterize their physicochemical characteristics. The inhibitory effects of R. tomentosa fruits IDF at each protein glycation stages as well as the adsorption capacity to advanced glycation end-products(AGE) were evaluated. The results indicate that the IDF prepared by water extraction method(WIDF) presented higher content of water, fat, protein and ash. The extraction yield of R. tomentosa fruits IDF by enzymatic modification extraction method(EIDF) was 67.43%, which was lower than that of water extraction method. The functional groups of IDF prepared by these two methods were similar, whereas the EIDF presented a lower comparative crystallinity at 29.32%. The rough surface, loose structure and holes were observed in EIDF. As the mass concentration of EIDF was 2 g/L, the contents of fructosamine and carbonyl compounds in glycation system were (1.98±0.25) mmol/L and (21.75±1.17) μmol/g, with fluorescence intensity of β-amyloid protein at (5.26±0.14)×106 and AGE inhibitory rate at (18.15±0.73)%, respectively, and the anti-glycation capacity of EIDF was better than that of WIDF. As the concentration of EIDF was 10 g/L, 33.28% of AGE could be adsorbed. Figures and Tables | References | Related Articles | Metrics

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Investigation on the Epoxidized Lignin for Reinforcing Melamine-Urea-Formaldehyde Co-condensation Resins Shishuai GAO, Yitong XIE, Xiulan CHEN, Chunpeng WANG, Fuxiang CHU, Daihui ZHANG 2023, 43 (6):  51-56.  doi: 10.3969/j.issn.0253-2417.2023.06.007 Abstract ( 84 )   HTML ( 1 )   PDF (1025KB) ( 143 )   Save Epoxidized lignin(EL) was prepared by epoxidation of epichlorohydrin with the hydroxyl and carboxyl groups in lignin molecules. EL was used as a formaldehyde-free cross-linking agent for melamine-urea-formaldehyde(MUF) co-condensation resins to improve the bonding strength of MUF resin, and the reaction between EL and free formaldehyde in the MUF resin decreased the formaldehyde emissions of resin. With the increase of ring-opening reaction temperature between lignin and epichlorohydrin, the epoxy group content of EL showed a trend of increasing and then decreasing, which was determined by the infrared spectroscopy and chemical titration methods. The EL epoxy index reached the highest value of 2.6 mol/kg at 100 ℃. Compared with the MUF resin without EL, the modulus of elasticity(5.94 MPa) of added 5% EL-100 MUF resin increased by 117% after curing, and shear strength(1.11 MPa) increased by 33.7% and the formaldehyde emission(0.206 mg/L) decreased by 27.0%. Figures and Tables | References | Related Articles | Metrics

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Comparative Study on Test Methods of Iodine Adsorption Value of Activated Carbon Based on the I2/KI Mass Ratio Li ZHANG, Songlin ZUO, Ziqing WANG 2023, 43 (6):  57-64.  doi: 10.3969/j.issn.0253-2417.2023.06.008 Abstract ( 86 )   HTML ( 2 )   PDF (958KB) ( 139 )   Save This study investigated the effects of two different I2/KI mass ratios on the iodine adsorption value of activated carbon prepared by seven common methods, with specific surface area ranging from 800 to 3 500 m2/g, including steam-activated coconut shell activated carbon(AC-11, AC-12, AC-13), phosphoric acid-activated powdered activated carbon(AC-21, AC-22), and KOH-activated petroleum coke high specific surface area activated carbon(AC-31, AC-32). The influence of specific surface area and pore structure of activated carbon on iodine adsorption value was analyzed. The results show that, activated carbons with a larger specific surface area, developed mesopore structure, and wide mesopore distribution, exhibited a more significant effect of the I2/KI mass ratio on the iodine adsorption value. The difference between the iodine adsorption value of the test sample AC-31 under m(I2): m(KI)=1:1.5 and that under m(I2): m(KI)=1:2 could reach 140 mg/g. For microporous activated carbon AC-13 with iodine adsorption value around 800 mg/g, the difference between the two testing methods was almost negligible, which suggested that the difference between the activated carbon iodine adsorption value obtained by the old and new versions of wood and coal activated carbons iodine adsorption value testing standards was very small. Under the condition of activated carbon iodine adsorption value test, the pore sizes of activated carbon that effectively adsorb iodine molecules were mainly between the range of 0.8-1.5 nm. For microporous activated carbon such as coconut shell activated carbon, the value of the specific surface area was not much difference from the iodine adsorption value, with a certain degree of equivalence. The essence of the I2/KI mass ratio influence was that the change of the ratio of the two determines the starling concentration of elementary iodine in the iodine stardard solution, which affected the iodine adsorption value of activated carbon. Figures and Tables | References | Related Articles | Metrics

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Processing Optimization and Bacteriostasis of Cinnamomum camphora Leaves Essential Oil by Subcritical R134a Extraction Shan HU, Weiqu LIANG, Peiwu XIE, Huajian LUO, Huiming LIAN, Hao HUANG 2023, 43 (6):  65-73.  doi: 10.3969/j.issn.0253-2417.2023.06.009 Abstract ( 78 )   HTML ( 6 )   PDF (639KB) ( 130 )   Save In order to study the efficient extraction technology of camphor tree essential oil and broaden its application range, the subcritical extraction of essential oil from Cinnamomum camphora leaves was optimized by orthogonal design experiment with 1, 1, 1, 2-tetrafluoroethane(R134a) as extraction solvent. The differences in chemical compositions and antimicrobial activity of essential oil from C. camphora leaves extracted by subcritical R134a extraction and the traditional steam extraction were compared. The results showed that the optimal parameters for subcritical R134a extraction of essential oil from C. camphora leaves were as follows: the particle size of the raw material obtained by crushing with 2 mm aperture sieve, the solid-liquid ratio of 6:1(L: kg), the extraction temperature of 45 ℃, the extraction time of 40 min/times, and the extraction for 4 times. Under this condition, the extraction ratio of essential oil was(2.87±0.08)%. GC-MS analysis of the two leaves essential oils obtained from steam extraction and subcritical R134a extraction identified 39 and 35 compounds, with the relative total peak areas of 99.97% and 99.91%, respectively. The chemical components of the two leaves essential oils were mainly alcohols and hydrocarbons, and borneol was the main chemical component in the essential oils. The relative peak area of borneol in steam extraction essential oil(64.29%) was greater than that of subcritical R134a-extracted essential oil(58.09%). The two kinds of leaves essential oils from leaves had different degrees of antimicrobial effect on plant pathogens. The antimicrobial activity of leaves essential oil extracted by subcritical R134a extraction on pathogenic fungi was better than that of essential oil extracted by steam extraction. The two essential oils from leaves had the highest antimicrobial rate against Phytophthora capsici, which were 71.74% and 62.87%, respectively. Figures and Tables | References | Related Articles | Metrics

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Preparation and Properties of Fluorocarbon Coatings Modified by Hydroxyl Hydrogenated Rosin Derivative Wen QI, Yajing HU, Xingwei LI, Man QIN, Chun LU 2023, 43 (6):  74-80.  doi: 10.3969/j.issn.0253-2417.2023.06.010 Abstract ( 92 )   HTML ( 5 )   PDF (620KB) ( 141 )   Save To improve the low hardness and poor adhesion of fluorocarbon coatings, and expand their further application in the marine antifouling field, hydroxyl hydrogenated rosin derivative was synthesized by reacting renewable resource hydrogenated rosin with epichlorohydrin. The structure of the derivative was characterized using acid value, hydroxyl value determination, as well as GC-MS and FT-IR techniques. The obtained product was used to modify fluorocarbon coatings, and the influence for the addition amount of hydroxyl hydrogenated rosin derivative on the performance of the modified fluorocarbon coatings was studied. The results showed that hydroxyl hydrogenated rosin derivative was a mixture of 3-hydrogenated rosin acyloxy-2-hydroxypropyl chloride and 3-hydrogenated rosin acyloxy-1, 2-dihydroxy-propane. The acid value of derivative was 4.7 mg/g, and the hydroxyl value was 243.1 mg/g. With the increase of hydroxyl hydrogenated rosin derivative amount, the drying time, the pencil hardness and the adhesion strength of the modified fluorocarbon coatings increased, and the flexibility and impact resistance met the standard requirements. The coatings also exhibit good acid and alkali resistance(no abnormalities was found after it was immersed in acid and alkali solutions for 10 days). When the addition of the hydroxyl hydrogenated rosin derivative was 15%, the comprehensive performance of the coating was optimal, with drying time of 5.8 minutes, pencil hardness of 4H, coating adhesion strength of 15.5 MPa, and qualified results for 2 mm shaft bending and 50 cm impact test. Figures and Tables | References | Related Articles | Metrics

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Structural Characteristics and Antioxidant Activity of Polysaccharide from Morinda citrifolia fruit in vitro Qingfen WANG, Xinyu AO, Shusen GONG, Lang LIU, Mei DAO, Tian WU 2023, 43 (6):  81-88.  doi: 10.3969/j.issn.0253-2417.2023.06.011 Abstract ( 94 )   HTML ( 7 )   PDF (856KB) ( 136 )   Save To clarify the structural characteristics and antioxidant properties of the polysaccharides from Morinda citrifolia L. fruit, the crude polysaccharides from M. citrifolia fruit were extracted and purified by hot water leaching method. The structural characterization of purified polysaccharides was analyzed by infrared spectroscopy, nuclear magnetic resonance and gas chromatography mass spectrometry analysis. The ability of crude and purified polysaccharides to scavenge ABTS free radicals(·ABTS+), DPPH radicals(DPPH·), superoxide negative radicals(O2-·) and hydroxyl radicals(·OH) was measured by UV spectrophotometer, and the reducing power of polysaccharides was determined by the potassium ferricyanide reduction method. The results showed that the extraction rates of crude polysaccharide and purified polysaccharide were 9.48% and 0.35%, respectively, and the purified polysaccharide was mainly consisted of β-type glycosides, as well as a small amount of α-type glycosides, and contained uronic acids, which was an acidic sugar. Purified polysaccharides were polysaccharides with 1→4 linked pyranose glucose and non-reducing terminal pyranose as the main connection mode, and contained a branching structure. Both crude polysaccharide and purified polysaccharide could scavenge free radicals, where the scavenging ability of ·ABTS+ was the best, with the maximum scavenging rate reaching 100%, followed by DPPH· and ·OH, and the scavenging ability of O2-· was weaker. The scavenging ability of crude polysaccharides to free radicals was stronger than that of purified polysaccharides, and the scavenging capacity of crude polysaccharides for ·ABTS+ and DPPH· was comparable to that of the positive control Vc. Both crude polysaccharides and purified polysaccharides had reducing power, and showed a quantitative-effect relationship, and crude polysaccharides had stronger reducing power than that of purified polysaccharides. Figures and Tables | References | Related Articles | Metrics

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Preparation, Characterization and Performance Analysis of Melamine-Urea- Glyoxal Co-condensed Resin Xin JIANG, Delong WANG, Jinwen WANG, Guanben DU, Shuduan DENG 2023, 43 (6):  89-97.  doi: 10.3969/j.issn.0253-2417.2023.06.012 Abstract ( 90 )   HTML ( 6 )   PDF (2344KB) ( 131 )   Save This paper used non-volatile glyoxal(G) to replace formaldehyde to react with melamine(M) and urea(U) to prepare melamine-urea-glyoxal(MUG) co-condensed resins, at room temperature with the molar ratio of the raw material of U and G was 0.30:1.0, and with the dosage of M was 13.86, 17.64, 21.42 and 25.20 g, respectively. The basic properties, curing properties and bonding properties of the MUG resins were determined and analyzed. The structure of the resin was characterized by Fourier transform infrared spectroscopy(FT-IR), mass spectrometry(MS) and nuclear magnetic resonance carbon spectroscopy(13C NMR). The results showed that the solid content and viscosity of MUG resins were greatly affected by the molar ratio of raw materials, which increased with the increase of M content. The MUG resin mainly contained N—H, O—H, C═O, C—O, C═N and other functional groups, and the main infrared absorption peaks of MUG resin with different molar ratios of raw materials did not change significantly. The possible reaction mechanism was deduced according to the molecular fragments, proving the co-polycondensation reaction M, U and G in the system. When the amount of melamine added was 21.42 g, the curing temperature of the resin was lower and the storage modulus was higher. For the plywood fabricated by the as prepared resin, the dry bonding strength, wet strength cold water for 24 h and with hot water for 3 h were 2.51, 1.29 and 0.85 MPa, respectively. Figures and Tables | References | Related Articles | Metrics

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The Adsorption Properties of Silica-based Tannin Composites for Formaldehyde Aichen ZHAO, Hui ZHOU, Mengdi FANG, Lei LI, Yu LIU 2023, 43 (6):  98-106.  doi: 10.3969/j.issn.0253-2417.2023.06.013 Abstract ( 87 )   HTML ( 7 )   PDF (3635KB) ( 144 )   Save Based on the issue of formaldehyde pollution in indoor air environment, silica-based tannin composite material(DMSNs-tannin) was prepared using forest by-product tannic acid as the adsorption source, dendritic mesoporous silica nanoparticles(DMSNs) as the matrix, and amino modified silica(DMSNs-NH2) as the intermediate. When the addition amount of tannic acid was 0.3, 0.4, and 0.5 g, the prepared composite materials were DMSNs-0.3, DMSNs-0.4, and DMSNs-0.5, respectively. The structure was characterized by SEM, TEM, nitrogen adsorption/desorption isotherms, FT-IR, and TG analysis. The effect of different tannin loading amounts on its formaldehyde adsorption performance was investigated, and the adsorption kinetics was explored. The research results indicated that the composite material had rich pore structure and high thermal stability. Compared with DMSNs-NH2, DMSNs-tannin had better formaldehyde adsorption performance. The DMSNs-0.5 had the highest loading capacity of tannic acid, reaching 23.60%, with a loading efficiency of 47.33%, and a formaldehyde adsorption rate of 86.19% after 6 hours adsorption. The special mesoporous structure of DMSNs provided channels for the diffusion of formaldehyde. Their adsorption process was in accordance with the quasi second-order kinetic model, indicating that their adsorption of formaldehyde was mainly chemical adsorption, which was related to adsorption sites, demonstrating a composite adsorption process of adsorption on the surface of composite materials and diffusion within particles. Figures and Tables | References | Related Articles | Metrics

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Preparation of Tung Oil-modified Amine and Its Application Performance in Epoxy Anti-corrosion Coatings Na YAO, Xiaohua YANG, Jianling XIA, Mei LI, Yan ZHANG 2023, 43 (6):  107-112.  doi: 10.3969/j.issn.0253-2417.2023.06.014 Abstract ( 90 )   HTML ( 3 )   PDF (502KB) ( 171 )   Save In order to improve the flexibility, corrosion resistance, water resistance and low temperature curing ability of polyamine curing agent, a new type of tung oil-modified amine(TPH) curing agent was synthesized from tung oil through transesterification, Friedel-Crafts substitution, Mannich base condensation and amidation. The physicochemical indicators were characterized. The effect of the addition amount of monofunctional(benzyl glycidyl ether) and difunctional(1, 4-butanediol diglycidyl ether) reactive diluent on the coating properties, and the mechanical properties and anti-corrosion properties of the coating were tested, which were compared with the properties of the cardanol phenalkamine(PCD) cured paint film. The results showed that when the amount of diluent in the anti-corrosion coating was 10%, the tack-free and hard drying time of TPH paint film surface was 40 and 90 min, respectively. Its impact toughness was 80 cm, flexibility was 1 mm, pencil hardness was 5H, and impact resistance was ≥40 cm. Heat resistance(150 ℃±3 ℃, 4 h) showed slightly foaming paint film without falling off, the heat and humidity resistance was 1 000 h under the temperature of 47 ℃±1 ℃, and the relative humidity of 96%±2%, and salt spray resistance showed no rust, no bubbles, and no discoloration(1 500 h). The hardness of aviation kerosene (168 h) was up to 4H, and 4109 engine lubricant(121 ℃±3 ℃, 24 h) and 15# hydraulic oil(66 ℃±3 ℃, 24 h) all showed non-foaming and non-falling off. Compared with PCD film, TPH film had excellent impact flexibility, pencil hardness, high and low temperature resistance and solvent resistance. Figures and Tables | References | Related Articles | Metrics

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The Yield Improvement of Three-state Products from Biomass Pyrolysis Based on Machine Learning Zhi YI, Ling JI, Mingyue LI, Husheng CHEN, Yunchang XIAO 2023, 43 (6):  113-122.  doi: 10.3969/j.issn.0253-2417.2023.06.015 Abstract ( 109 )   HTML ( 7 )   PDF (1243KB) ( 149 )   Save By mining the experimental data in the literatures of fast pyrolysis of lignocellulosic biomass in a bubbling fluidized bed and establishing a random forest(RF) regression model, the yield of bio-oil, biochar, and gas via biomass pyrolysis was predicted based on biomass feedstock characteristics and pyrolysis conditions. Fifteen feature variables were sorted out from five key factors influencing the distribution of biomass pyrolysis products, and seven models were obtained by combining the input variables. All models showed good prediction performance for the three-state products from biomass pyrolysis, with a regression coefficient(R2) greater than 0.9. Model 6 had the fewest input variables and the highest accuracy, with R2 values of 0.942 8, 0.956 1, and 0.939 1 for the yield predictions of biochar, bio-oil, and biomass pyrolysis gas, and the root mean square errors(RMSE) were 2.679 1, 2.939 5, and 3.108 3, respectively. Contribution analysis of the models revealed that pyrolysis conditions(Ⅴ) were the most important factors affecting the pyrolysis products yield, with contributions degree of 0.332 7, 0.220 4, and 0.214 7 for biochar, bio-oil, and gas yield predictions, respectively. Partial dependence plots(PDP) combined with the distribution boxplots analysis of each feature variable showed that pyrolysis temperature(HT), lignin mass fraction(Lig), and particle size(PS) were the main factors affecting biochar yield. Bio-oil and biomass pyrolysis gas yields were determined by HT, cellulose mass fraction(Cel), hemicellulose mass fraction(Hem), feed rate(FR), and gas flow rate(GFR), which were less affected by Lig and PS. The bio-oil yield could be improved by selecting biomass feedstock with high-quality fractions of cellulose and hemicellulose and increasing gas flow rate appropriately. In addition, the regression models of extreme gradient boosting(XGBoost), support vector machine(SVM), and artificial neural network(ANN) were established, which were compared with the RF regression model. The RF model showed the highest accuracy and good generalization ability for predicting the yield of the three-state products. The research findings promoted a comprehensive understanding of the biomass pyrolysis process and provided theoretical guidance for the control of the of the three-state products yield in biomass fast pyrolysis. Figures and Tables | References | Related Articles | Metrics

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Optimization of Extraction Process and Antibacterial Activity Evaluation on the Antibacterial Active Components from Enteromorpha clathrata Zhongtang ZHANG, Tianle CHEN, Yaxuan BAI, Saikun PAN 2023, 43 (6):  123-129.  doi: 10.3969/j.issn.0253-2417.2023.06.016 Abstract ( 78 )   HTML ( 6 )   PDF (558KB) ( 142 )   Save On the basis of conducting antibacterial experiments on the water extract and ethanol extract of Enteromorpha clathrata, the ethanol extraction process was optimized through single factor experiments and response surface analysis. The main components in the ethanol extract were conventionally qualitatively analyzed, and the antibacterial effects of different solvent extracts were further studied. Finally, the ethyl acetate extract was analyzed using GC-MS. The results showed that the ethanol extract of E. clathrata had better antibacterial effect and better inhibitory effect on Staphylococcus aureus than that of the water extract. The optimal process conditions obtained by response surface analysis were as follows: ethanol volume fraction of 92%, liquid material ratio of 30:1, extraction temperature of 83 ℃, extraction time of 4 h. Under this condition, the diameter of the inhibitory zone of ethanol extract against S. aureus was (1.152±0.015) cm. Conventional qualitative analysis found that the ethanol extract of E. clathrata contains organic acids, sterols, and terpenoids, but did not contain alkaloids, anthraquinone, phenols, saponins, flavonoids and other components. The ethyl acetate extract had the best bacteriostatic effect (the inhibition zone diameter was 2.82 cm), followed by dichloromethane and petroleum ether extracts (the inhibition diameters were 1.68 and 1.06 cm, respectively), and n-butanol and water extracts had no bacteriostatic effect. GC-MS analysis showed that the ethyl acetate extract contained 12 volatile components, mainly acid compounds and aromatic compounds. Figures and Tables | References | Related Articles | Metrics

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Research Progress on the Application of Deep Eutectic Solvent in Lignocellulose Pretreatment Shuheng ZHAO, Zhuojie LI, Jianjun HU, Sen YAO, Wei WANG 2023, 43 (6):  130-138.  doi: 10.3969/j.issn.0253-2417.2023.06.017 Abstract ( 105 )   HTML ( 1 )   PDF (1182KB) ( 156 )   Save Deep eutectic solvent(DES) was a new type of green solvent, which was simple preparation, low cost, non-toxic, biodegradable, recyclable, etc, and had broad prospects in the application of lignocellulose pretreatment. In this paper, the composition, classification, preparation methods and physicochemical properties of DES were summarized. Subsequently, the research and application of DES in the field of biomass pretreatment were reviews. The mechanistic of DES pretreatment and separation of lignocellulose were concluded. The application progress of DES selectively separating lignocellulose was mainly introduced in order to provide theoretical reference for large-scale application of DES in pretreatment of lignocellulosic biomass. Figures and Tables | References | Related Articles | Metrics