JOURNAL OF CARBOHYDRATE CHEMISTRY
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2014
·
IF 1.183
Hongxia Liu,Xiaojian Li,Shiqi Wang,Shaojun Huang,Chun Wei,Jian Lv
Microcrystalline cellulose extracted from sisal fibers (SFMCC) and octa-aminopropyl polyhedral oligomeric silsesquioxane (POSS-NH2) were used to fabricate POSS/SFMCC hybrids through a simple cross-linking process with epichlorohydrin as the cross-linking agent. The chemical structure and morphology of hybrids are characterized with FTIR spectra, X-ray diffraction, and SEM. The results present that POSS-NH2 has been grafted onto the surface of SFMCC. The thermal property of hybrids has been improved with a 19°C higher maximum thermal decomposition temperature than SFMCC, as measured by TGA and DSC. The residual mass of hybrids and SFMCC were 15.6 wt% and 4.4wt% at 700°C, respectively.
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高影响因子
CARBOHYDRATE POLYMERS
·
2014
·
IF 3.916
Qingyuan Niu,Kezheng Gao,Wenhui Wu
A cellulose nanofibril film is modified by chemical assembly of boronate-terminated conjugated polymer chains at its specific sites, C-6 carboxyl groups. The modified cellulose nanofibril film is used as a fluorescent sensor for nitroaromatic vapor. Thanks to the specific reactive sites, numerous loose cavities or pathways located in the film sensor's out-layer have been formed, and the fraction of easily accessible cavities of the novel fluorescent film sensor is up to 0.97, which could benefit the penetration and diffusion of analyte vapor. Therefore, the novel fluorescent film sensor exhibits high sensitivity toward nitroaromatic vapor with a fast response. The fluorescence quenching efficiency of the chemical-assembly film sensor is about 3 times larger than that of the spin-cast film sensor using the same conjugated polymer for 600 s exposure to DNT vapor. In addition, the novel fluorescent film sensor shows good reversibility.
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PubMed
高影响因子
CARBOHYDRATE POLYMERS
·
2014
·
IF 3.916
Dong Tian,Yangyang Han,Canhui Lu,Xinxing Zhang,Guiping Yuan
In this paper, we demonstrated that acidic ionic liquids (ILs) can be used as “quasi-homogeneous” catalysts for the efficient acetylation of cellulose. Unlike existing techniques that use large amount of ILs as solvent to dissolve and acetylate cellulose, a small amount of acidic ILs was used as catalyst in this study to overcome the low efficiency associated with relatively high viscosity and costs of ILs during homogeneous acetylation. Fully substituted cellulose acetate with a conversion of 88.8% was obtained by using only 9 mol% IL 1-vinyl-3-(3-sulfopropyl) imidazolium hydrogen sulfate as catalyst, which is much higher than that of common commercialized solid acid catalysts. The degree of substitution and solubility of the obtained cellulose acetate can be facilely controlled by varying the concentration of ILs and reaction time. The dual function of swelling and catalyzing of acidic ILs for the acetylation of cellulose is responsible for the excellent catalytic performance.
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PubMed
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MATERIALS RESEARCH INNOVATIONS
·
2014
·
IF 0.473
H. Yagoub,S. Ma,S. Yang,J. Xu
Cellulose nanocrystals (CNC) with 3–4 nm in diameter and 100–300 nm long were obtained by sulphuric acid hydrolysis from cellulose pulp. CNC were deposited by layer-by-layer (LBL) assembly with cationic polyelectrolyte, poly(allylamine hydrochloride) (PAH) and poly(diallyldimethylammonium chloride) (PDDA), to prepare thin films. PDDA is a fully charged polyelectrolyte while PAH is partially charged and its charge density is dependent on pH value. We compared the LBL assembly behaviour of CNC with weak and strong polyelectrolyte.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2014
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IF 3.84
Xueqin Wang,Yan Li,Xiaoqi Li,Jianyong Yu,Salem S. Al-Deyab,Bin Ding
Determination of environmental contaminants such as trace formaldehyde mostly relies on bulky and costly analytical equipment. However, a particular demand for portable, rapid, and sensitive method that can be used in resource-limited settings has received paramount concern. Towards this need, we are presenting here a rational design of colorimetric sensor strips using electrospun cellulose nanofibrous membrane-immobilized pararosaniline. Based on the specific reaction between formaldehyde and pararosaniline, the strips could undergo a distinct color transition from light pink to purple, specifically in the presence of trace-level formaldehyde over other possible interferential volatile organic compounds. Benefiting from the large specific surface area and high porosity of nanofibrous membranes, the strips achieved ultralow naked eye detection limit of 0.06 mg m −3 (below the regulatory level of 0.1 mg m −3 ), wide linear range from 0.12 to 6 mg m −3 , and short response time (15 min) in the absence of advanced instrumentation. Additionally, the sensing responses were visualized quantitatively by HSI coordinates which are presented with lightness and chromatic values and analyzed by a principal component analysis method. Furthermore, the strips exhibited remarkably improved analytical performance compared to commercial filter paper-based ones. With its cost-effective design and portability, this sensitive and specific colorimetric strips could potentially be used for providing air contamination information.
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ADVANCES IN POLYMER TECHNOLOGY
·
2014
·Vol. 34
·期 2
·
IF 2.147
Jian Lv,Deming Zeng,Chun Wei
In this paper, sisal fiber cellulose microcrystal (SFCM) was prepared by the sulfate pulping method, and sisal fiber cellulose microcrystal/unsaturated polyester (SFCM/UP) in situ resin was polymerized. Furthermore, the SFCM/UP composite was prepared by rolling and molding techniques. Effects of SFCM content on mechanical and wear properties of the UP composites were studied. Structure and properties of the in situ SFCM/UP resin and its composites were characterized by using Fourier transform infrared, polarized optical microscopy, thermogravimetric analysis, scanning electron microscopy, and other methods. The results showed that the addition of SFCM by in situ polymerization significantly improves the thermal stability of UP: The decomposition temperature ( T d5 ) of SFCM/UP in situ resin, at thermal weight loss of 5%, is increased by 16°C compared to that of the pure UP resin. On a condition that the SFCM content was 2%, the impact strength, flexural strength, and flexural modulus of SFCM/UP composites are higher than those of UP composites by 41.08%, 52.52%, and 32.31%, respectively. Moreover, the addition of SFCM significantly enhances the wear properties of unsaturated polyester composite at 200°C; the volume wear rate of SFCM/UP composite is lower than that of UP composites by 64%, indicating SFCM could significantly strengthen and toughen UP composites.
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JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL
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2013
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IF 3.187
Yueling Cao,Junwei Wang,Maoqing Kang,Yulei Zhu
Ni–WO 3 /SBA-15 catalysts were prepared by an impregnation way and applied to the hydrogenolysis of cellulose in aqueous solution. The effect of nickel and WO 3 loading, catalysts reduction temperature and time on cellulose conversion were investigated. Up to 70.7% ethylene glycol yield was obtained over 3%Ni–15%WO 3 /SBA-15 catalysts. Several physicochemical methods such as XRD, Raman spectroscopy, NH 3 -TPD, H 2 -TPR and XPS were used to determine the character of catalysts. Based on these studies, it was found that there was a strong electronic interaction between NiO and WO 3 , which not only promoted the reduction of WO 3 , but restrained the reduction of NiO. Together with the experimental results, it can be concluded that the WO 3− X , which may be the active species for the selective cleavage of C C bond, was formed after catalysts pretreatment process. Additionally, a possible catalytic mechanism was proposed.
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GREEN CHEMISTRY
·
2013
·Vol. 16
·期 4
·1854-1864
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IF 6.828
Juan Yu,Yupeng Liu,Xiaohuan Liu,Chunpeng Wang,Jifu Wang,Fuxiang Chu,Chuanbing Tang
A class of sustainable and renewable cellulose–rosin copolymers were prepared by immobilizing rosin-derived polymer chains on the backbone of ethyl cellulose (EC) by “grafting from” atom transfer radical polymerization (ATRP). Four different rosin based polymers derived from dehydroabietic acid (DA), one of the major resin acids in natural rosin, were attached to 2-bromoisobutyryl-functionalized EC. Meanwhile, DA-grafted EC was prepared by the simple esterification reaction between DA and EC. Kinetic studies showed that the polymerization of all monomers was controlled. These grafted copolymers adopt a worm-like or rod-like structure in tetrahydrofuran, verified by light scattering experiments. These copolymers have a tunable glass transition temperature and higher thermal stability in contrast to EC. Surface morphology by AFM analysis indicated good film-forming property when rosin polymers were grafted from EC. Additionally, the introduction of DA and rosin polymers remarkably enhanced the hydrophobicity of EC. The static contact angles of all these modified copolymers are above 90°. XPS analysis revealed that the surface of these rosin-modified EC copolymers was dominated by a hydrocarbon-rich rosin moiety. The UV absorption of modified EC composites is indicative of their potential application in UV-absorbent coating materials.
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APPLIED CATALYSIS A-GENERAL
·
2015
·
IF 3.942
Gang Xu,Aiqin Wang,Jifeng Pang,Mingyuan Zheng,Jianzhong Yin,Tao Zhang
Cellulose is the most abundant biomass in nature, and its catalytic conversion to commodity chemical ethylene glycol represents an important advance towards sustainable chemistry. In previous work, we have shown that tungstic acid plays a key role in selective C–C cleavage to form glycolaldehyde and then ethylene glycol. To further enhance the efficiency of tungstic acid, a series of additives were investigated in this work. Among various acid additives, H 2 SO 4 stands out as the most remarkable additive; ethylene glycol yield was enhanced from 32.6% to 52.6% at a H 2 SO 4 /H 2 WO 4 molar ratio of 0.03 and a H 2 WO 4 /cellulose weight ratio of 0.05, that is, an extremely dilute acid concentration. Weakly acidic sulfates (e.g., CuSO 4 and FeSO 4 ) have also been demonstrated to be highly efficient additives to improve the catalytic efficiency of tungstic acid, through promoting the hydrolysis of cellulose.
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RSC Advances
·
2015
·Vol. 5
·期 18
·13878-13885
·
IF 3.84
Dong Yang,Xinwen Peng,Linxin Zhong,Xuefei Cao,Wei Chen,Sha Wang,Chuanfu Liu,Runcang Sun
Cellulose nanocrystals (CNCs) pre-grafted with polymerizable groups have been used as nano crosslinking joints and nano reinforcements to synthesize highly-elastic hydrogels. However, the polymerizable CNCs usually have dispersion problems during hydrogel fabrication because of the hydrophobicity of the grafted polymerizable groups. In this study, TEMPO oxidation was successfully utilized to overcome this problem by introducing more hydrophilic groups on the CNCs surface, facilitating their homogeneous distribution in aqueous solution and hydrogels. Furthermore, AC and UC gels crosslinked by CNCs that were pre-grafted with acryloyl chloride (AC) and 10-undecylenoyl chloride (UC) on their surfaces were fabricated for finding out a more effective way to synthesize stronger nanocomposite hydrogels. The results showed that UC gels showed both higher tensile strength and higher elongation than the corresponding AC gels. It was shown that UC gels, which had longer grafted carbon chain lengths on CNC surfaces, possessed a better energy dissipation capacity under stretching than AC gels. The water swelling ratios of UC gels (13.0–36.7 g g−1) were also much higher than those of the corresponding AC gels (11.2–21.0 g g−1) as a result of larger spaces to hold water in the hydrogel network. This work gives an insight into the influence of carbon chain length on the properties of CNC crosslinked nanocomposite hydrogels, and provides an effective way to fabricate nanocomposite hydrogels with higher mechanical strength.
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CELLULOSE
·
2017
·Vol. 24
·期 4
·1889-1899
·
IF 3.417
Xu Qi,Wei Chengzhuo,Fan Lingling,Peng Shuo,Xu Weilin,Xu Jie
The bacterial cellulose (BC)/Al 2 O 3 nanofibrous composite membrane as a lithium-ion battery separator has been successfully prepared by coating Al 2 O 3 on the BC nanofibers through a simple in situ thermal decomposition of Al(NO 3 ) 3 · 9H 2 O. Thermal treatment tests show that the BC/Al 2 O 3 composite membrane is thermally stable at a high temperature of 200 °C while great shrinkage is observed for the commercial PP-PE-PP membrane. Moreover, the BC/Al 2 O 3 membrane is evaluated to have large porosity and excellent electrolyte uptake, consequently giving rise to larger ionic conductivity, lower interfacial resistance as well as better electrochemical stability. The half lithium-ion battery assembled with the BC/Al 2 O 3 separator demonstrates large discharge capacity and good cycling performance, suggesting that the BC/Al 2 O 3 membrane can be used as a lithium-ion battery separator.
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高影响因子
IRANIAN POLYMER JOURNAL
·
2015
·Vol. 24
·期 9
·747-758
·
IF 1.806
Gao Xin,Chen Keli,Zhang Heng,Yan Xuejing
A rapid microwave-assisted cationic synthesis of cellulosic polymer by grafting glycidyl trimethyl ammonium chloride (GTMAC) onto parenchyma cellulose (PC) from bagasse pith under low-power condition is reported. The effects of the microwave power, exposure time, GTMAC charge, water content, and aqueous-organic solvents by volume ratio were evaluated by determining cationization parameters such as yield, degree of substitution (DS), zeta potential, and charge density. The experimental results showed that the water-soluble and -insoluble fractions of cationic parenchyma cellulose (CPC) were obtained and their optimal DS were determined to be 0.72 and 0.63 at the microwave power of 100 W for 20 min, respectively. Surface cationization of PC resulted in an increase in zeta potential and charge density over the unmodified cellulose. In comparison with the original PC, the intrinsic viscosity of the cationic products decreased significantly. The presence of GTMAC on the surface of PC was confirmed by Fourier transform infrared spectroscopy. The crystallinity and surface structure of original cellulose and CPCs were also analyzed through X-ray diffraction and scanning electron microscopy, respectively. This work provided an efficient and economical feasibility to produce a cationic biopolymer from cellulose.
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