GREEN CHEMISTRY
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2013
·Vol. 16
·期 3
·1326-1335
·
IF 6.828
Benlian Lu,Airong Xu,Jianji Wang
As a kind of promising solvents, ionic liquids (ILs) have been used to dissolve cellulose and great progress has been made in recent years. However, the dissolution mechanism, especially the role of cations of ILs in the dissolution of cellulose, is still in debate. In this work, 13 kinds of ILs with a fixed anion [CH3COO]− but varied cationic backbones and alkyl chains have been prepared and characterized. The solubilities of cellulose in these ILs were measured at different temperatures. This allowed us to systematically study the effect of cationic structures on the cellulose dissolution at a given temperature. In order to investigate the dissolution mechanism, Kamlet–Taft parameters of these ILs in the temperature range from 25 to 65 °C and 13C NMR spectra of 1-benzyl-3-methylimidazolium acetate ([phC1mim][CH3COO]) + cellulose systems at 90 °C were also determined. It was found that acidic protons on the heterocyclic rings of the cations are essential for the dissolution of cellulose in the ILs, but the van der Waals interaction of cation with cellulose is not important. These protons may form C–H⋯O hydrogen bonds with hydroxyl and ether oxygen of cellulose to increase cellulose solubility. Cations of the ILs may also decrease cellulose solubility by strong interaction with anions or steric hindrance effect of large size group in their alkyl chains. These interactions together with strong O–H⋯O hydrogen bonds between the anion and hydroxyl protons of cellulose resulted in the disruption of the inter- and intra-molecular hydrogen bonds and thus effective dissolution of cellulose.
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Chemistry Central Journal
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2013
·Vol. 7
·期 1
·1-5
·
IF 1.312
Liu Run-Qiang,Bai Lian-yang,Zhang Yi-Jun,Zhang Yu-Ping
Background At present, the study on the homogeneous-phase derivatization of cellulose in ionic liquid is mainly focused on its acetylation. To the best of our knowledge, there has been no such report on the preparation of cellulose-tris(3,5-dimethylphenylcarbamate) (CDMPC) with ionic liquid 1-allyl-3-methyl-imidazolium chloride (AmimCl) so far.Results With ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl) as a reaction solvent, cellulose-tris(3,5-dimethylphenylcarbamate) (CDMPC) was synthesized by the reaction of 3,5-dimethylphenyl isocyanate and soluble microcrystalline cellulose in a homogeneous phase. The synthesized CDMPC was then coated onto the surfaces of aminopropyl silica gel to prepare a chiral stationary phase (CSP). The prepared CSP was successfully used in chiral separation of seven racemic pesticides by high performance liquid chromatography (HPLC). Good chiral separation was obtained using n-hexane and different modifiers as the mobile phases under the optimal percentage and column temperature, with the resolution of metalaxyl, diniconazole, flutriafol, paclobutrazol, hexaconazole, myclobutanil and hexythiazox of 1.73, 1.56, 1.26, 1.00, 1.18, 1.14 and 1.51, respectively. The experimental results suggested it was a good choice using a green solvent of AmimCl for cellulose functionalization.Conclusion CDMPC was successfully synthesized as the chiral selector by reacting 3, 5-dimethylphenyl isocyanate with dissolved microcrystalline cellulose in a green ionic liquid of AmimCl.
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PubMed
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POWDER TECHNOLOGY
·
2013
·
IF 2.024
Dewen He,Cancheng Bai,Chongwen Jiang,Tao Zhou
Titanium containing MCM-41 is synthesized hydrothermally in the presence of structure-directing agent cetyltrimethylammonium bromide (CTAB). Bi- and tri-metal Fe and Zn are impregnated in these materials to improve the acid catalytic sites as well. XRD , BET nitrogen adsorption isotherm, TEM and SEM analysis confirm the presence of mesopores in the composite. The local environment of titanium incorporated into the mesoporous silicate material is investigated by FT-IR and UV–Vis spectroscopy. These results indicate the presence of active centers within the composite material Ti, Fe and Zn. The new composite materials are preliminarily tested in the hydrolysis of cellulose . All the titanium MCM-41 materials improve the conversion of cellulose, providing higher catalytic activity in hydrolysis. There is maximum sugar and 5-HMF concentration resulted from hydrolysis of cellulose with Fe/Ti-MCM-41 catalyst.
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RSC Advances
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2013
·Vol. 3
·期 35
·15058-15064
·
IF 2.562
Kezheng Gao,Ziqiang Shao,Xi Wang,Yunhua Zhang,Wenjun Wang,Feijun Wang
In recent years, much effort has been dedicated to achieve environmentally friendly, low cost, and excellent performance energy storage devices. In this work, cellulose nanofibers (CNFs)/multi-walled carbon nanotubes (MWCNTs) hybrid aerogels are prepared from CNFs/MWCNTs hydrogels by supercritical CO2 drying using CNFs as an effective, environmentally friendly, and steady dispersant of MWCNTs. All-solid-state flexible supercapacitors are fabricated using CNFs/MWCNTs hybrid aerogel film as the electrode material and charge collector. One-dimensional CNFs can effectively prevent the aggregation of MWCNTs, significantly enhance the re-wettability, and improve the utilization efficiency of the mesopores. Therefore, CNFs/MWCNTs hybrid aerogel film-based all-solid-state flexible supercapacitors exhibit excellent electrochemical properties: the specific capacitance is about 178 F g−1. The flexible supercapacitors also exhibit excellent cyclic stability. Our work provides a novel method using low cost, and environmentally friendly CNFs to realize the full potential of the MWCNTs in an assembled bulk form. Taking its low cost and environmentally friendliness, CNFs/MWCNTs hybrid aerogel has great potential as the electrode material for all-solid-state flexible supercapacitors.
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COLLOID AND POLYMER SCIENCE
·
2015
·Vol. 294
·期 1
·135-143
·
IF 1.865
Guo Yanzhu,Zhang Li,Li Haiming,Han Ying,Zhou Jinghui,Wang Xiaohui
A series of α-tocopherol succinate-conjugated hydroxyethyl cellulose (HEC-TOS) polymers were synthesized in this study. The weight percentages of TOS in HEC-TOS were varied from 15 to 36 % by adjusting the weight ratios of TOS to HEC from 1:4 to 5:2. The HEC-TOS polymers exhibited typical properties of amphiphilic polymers and were able to self-assemble into spherical nanomicelle in aqueous solution as revealed by TEM. The micelle sizes and critical micelle concentrations (CMC) of HEC-TOS conjugates were correlated with their molecular structures and were in the range of 24.5–115.1 nm and 16–99 μg/ml, respectively. Paclitaxel (PTX) was encapsulated into the core of HEC-TOS micelle by sonication-dialysis method. The highest loading concentration of PTX in micelle was 315 mg/ml, which was about 50 times higher than that in water (6 mg/l). The in vitro study showed that PTX was continuously released from PTX-loaded micelle in phosphate buffered saline (PBS) medium for 108 h.
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JOURNAL OF APPLIED POLYMER SCIENCE
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2015
·Vol. 132
·期 25
·
IF 1.768
Xiaoqin Chen,Bojian Hu,Xiaodong Xing,Zuliang Liu,Yan Zuo,Qian Xiang
In this article, we present a simple method for synthesizing antibacterial cellulose fibers that were modified with a cationic polymer and immobilized silver chloride (AgCl) particles. Relatively simple techniques of graft polymerization and onsite precipitation were used to fabricate the composites. Scanning electron microscopy images, Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, and energy-dispersive X-ray spectroscopy confirmed the immobilization of the AgCl particles. The observed inhibition zone of the immobilized AgCl particle composites indicated that the biocidal silver ions were released from the composites in aqueous solution. Compared with cationic-polymer-grafted cellulose fibers or AgCl alone, the cationic polymer/AgCl composites showed excellent antibacterial activity against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus . © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 42092.
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APPLIED SURFACE SCIENCE
·
2015
·
IF 2.711
Xiangyu Wang,Pei Wang,Jun Ma,Huiling Liu,Ping Ning
Nano zero-valent iron (NZVI) was innovatively and successfully modified by using hydroxyethyl cellulose (HEC) and hydroxypropylmethyl cellulose (HPMC) as dispersants. The systematic characterization observations (including XRD, SEM and TEM) illustrate that, compared with bare nano zero-valent iron particles (BNZVI), the particle sizes of hydroxyethyl cellulose modified (ENZVI) and hydroxypropylmethyl cellulose modified (PNZVI) were decreased, while the dispersity and antioxidizability of ENZVI and PNZVI particles were increased. The discoloration efficiencies of ENZVI, PNZVI, and BNZVI were compared by using dyes (including orange II, methyl orange, methyl blue, and methylene blue) as target pollutant. The results show that both the discoloration efficiency and reaction rate of ENZVI and PNZVI are higher than that of BNZVI. In addition, effects of dispersant content, dye type, pH value, initial dye concentration, iron dosage, and reaction temperature on discoloration efficiencies were studied. The results show that discoloration efficiency was decreased by increasing initial pH value and dye concentration, and it was increased with the increase the iron dosage and reaction temperature. Under optimized NZVI addition of 0.7 g L −1 , the discoloration efficiencies of ENZVI and PNZVI were increased to 96.33% and 98.62%, respectively. And the possible discoloration pathway and dispersant modification mechanism of NZVI were discussed. This study suggests hydroxyethyl cellulose and hydroxypropylmethyl cellulose dispersed NZVI can be utilized as a promising modified nano-material for degradation of dye wastewater.
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POLYMER BULLETIN
·
2016
·Vol. 73
·期 7
·2073-2085
·
IF 1.371
Zhang Xuzhen,Ma Piming,Zhang Yong
Cellulose nanocrystal (CNC) was extracted from microcrystalline cellulose (MCC) and then surface modified by acetic anhydride to obtain acetylated CNC (ACNC). ACNC that has lower polarity than CNC was mixed with poly(butylene adipate- co -terephthalate) (PBAT) through melt blending to obtain composites. ACNC was uniformly dispersed in PBAT matrix as evidenced by scanning electron microscopy observation. Thermogravimetric analysis indicates the thermal stability of PBAT could be improved by the addition of either CNC or ACNC. In the rheological tests and dynamic mechanical analysis, PBAT/ACNC composites showed higher melt elasticity, complex viscosity, storage modulus and glass transition temperature than PBAT/CNC composites, indicating a stronger interfacial adhesion between ACNC and PBAT. As a result of the uniform dispersion of ACNC and strong interfacial adhesion between ACNC and PBAT, mechanical properties of PBAT/ACNC composites improve obviously. Good mechanical properties, high initial decomposition temperature and high glass transition temperature of PBAT/ACNC composites could contribute to the practical commercial utilization of PBAT.
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CARBOHYDRATE POLYMERS
·
2015
·
IF 4.074
Wei Yan,Chang Chen,Ling Wang,Dan Zhang,Ai-Jun Li,Zheng Yao,Li-Yi Shi
The emphasis of science and technology shifts toward environmentally friendly and sustainable resources and processes. Herein, we report a facile, one-pot and green synthesis of biomaterial-supported gold nanoparticles (AuNPs) with superior catalytic activity. Cellulose nanocrystal (CNC)-supported AuNPs were prepared by heating the aqueous mixture of HAuCl 4 , CNCs and polyethylene glycol, avoiding toxic chemicals, extreme condition and complicated procedure. The resultant CNC-supported AuNPs exhibited catalytic activities for the reduction of 4-nitrophenol by sodium borohydride. The maximum apparent rate constant reached 1.47 × 10 −2 s −1 , and the turnover frequency reached 641 h −1 . The superior catalytic performance can be ascribed to the large amount of highly dispersed AuNPs with few nanometers in size which are loaded on CNCs. About 90% of the AuNPs are smaller than 10 nm, and nearly 60% of the AuNPs are smaller than 5 nm. The synthesis is eco-friendly, facile and low-cost, thus has great potential for industrial and medical applications.
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PubMed
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CELLULOSE
·
2014
·Vol. 21
·期 5
·3361-3369
·
IF 3.033
Lou Hongming,Lai Huanran,Wu Shun,Li Xiuli,Yang Dongjie,Qiu Xueqing,Huang Jinhao,Yi Conghua
The effects of long-chain fatty alcohols (LFAs) on the enzymatic hydrolysis of crystalline cellulose by two commercial Trichoderma reesei cellulase cocktails (CTec2 and Celluclast 1.5L) were studied. It was found that n -butanol inhibited the enzymatic hydrolysis, but n -octanol, n -decanol and n -dodecanol had strong enhancement on enzymatic hydrolysis of crystalline cellulose in the buffer pH range from 4.0 to 6.0. LFAs can increase the hydrolysis efficiency of crystalline cellulose from 37 to 57 % at Celluclast 1.5L loading of ten filter paper units (FPU)/g glucan. LFAs have similar enhancement on the enzymatic hydrolysis of crystalline cellulose mixed with lignin or xylan. The enhancement of LFAs increased with the decrease of the crystallinity index. LFAs not only enhanced the high-solid enzymatic hydrolysis of lignocellulose, but also improved the rheological properties of high-solid lignocellulosic slurries by decreasing the yield stress and complex viscosity. Meanwhile, LFAs can improve the enzymatic hydrolysis of cellobiose to glucose, especially at low cellulase loading.
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COMPOSITES PART A-APPLIED SCIENCE AND MANUFACTURING
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2017
·
IF 4.075
Yongkang Bai,Xin Chen
Herein, a fast water responsive shape memory polymer composites based on hydroxyethyl cellulose (HEC) has been fabricated by crosslinking with graphene oxide (GO) and citric acid (CA). The swelling behavior, mechanical properties, micro-topography, thermal stability, as well as water and moisture induced shape memory performance of this composite were all fully investigated to demonstrate its functions. After crosslinking with GO and CA, the composite exhibited excellent mechanical properties with tensile strength over 100 MPa, which was nearly 4 times higher than pure HEC. Moreover, the pre-deformed composite was able to fully recover to its original shape in aqueous environment, which not only quickly happened in water (14 s), but also occurred in wet air with relative humidity about 70 within only 5 min. With such outstanding properties, we envisage that this composite could play a significant role in developing new generations of water responsive sensors, actuators and biomedical devices.
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CARBOHYDRATE POLYMERS
·
2017
·
IF 4.811
Zehong Chen,Xinwen Peng,Xiaoting Zhang,Shuangshuang Jing,Linxin Zhong,Runcang Sun
Producing hierarchical porous N-doped carbon from renewable biomass is an essential and sustainable way for future electrochemical energy storage. Herein we cost-efficiently synthesized N-doped porous carbon from renewable cellulose by using urea as a low-cost N source, without any activation process. The as-prepared N-doped porous carbon (N-doped PC) had a hierarchical porous structure with abundant macropores, mesopores and micropores. The doping N resulted in more disordered structure, and the doping N content in N-doped PC could be easily tunable (0.68–7.64%). The doping N functionalities could significantly improve the supercapacitance of porous carbon, and even a little amount of doping N (e.g. 0.68%) could remarkably improve the supercapacitance. The as-prepared N-doped PC with a specific surface area of 471.7 m 2 g −1 exhibited a high specific capacitance of 193 F g −1 and a better rate capability, as well as an outstanding cycling stability with a capacitance retention of 107% after 5000 cycles. Moreover, the N-doped porous carbon had a high energy density of 17.1 W h kg −1 at a power density of 400 W kg −1 .
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