CARBOHYDRATE POLYMERS
·
2018
·
IF 5.158
Yanjun Tang,Xinqi Zhang,Ruonan Zhao,Daliang Guo,Junhua Zhang
Nanocrystalline cellulose (NCC) has shown great potential for reinforcing nanocomposite systems, particularly in biopolymer-based nanocomposites. In the present work, transparent and biodegradable chitosan (CH)/guar gum (GG)/NCC nanocomposite films were designed and prepared. The effect of NCC loadings on the rheological behavior of the as-prepared nanocomposite suspensions was investigated, the overall properties of the resultant nanocomposite films as a function of various amounts of NCC were determined, and the surface morphology of various nanocomposite films was characterized by scanning electron microscopy (SEM). Results indicated that the increased NCC loadings increased the shear viscosity of the nanocomposite suspensions. Moreover, as expected, the obtained CH/GG/NCC nanocomposite films were found to exhibit improved tensile strength and reduced air permeability in comparison to pure CH/GG films. This work supported the conclusion that NCC was effective in reinforcing the CH/GG composite films, which may be a promising material for food packaging applications.
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高影响因子
CELLULOSE
·
2018
·Vol. 25
·期 10
·5659-5668
·
IF 3.809
Wang Guozhen,Meng Yan,Zhou Jinping,Zhang Lina
Abstract
Herein, one-step conversion of cellulose dissolved in 1.75 mol L −1 NaOH/0.074 mol L −1 ZnO aqueous solution to organic acids was realized through a hydrothermal degradation without heterogeneous catalyst. The effects of solvent, the concentrations of NaOH and ZnO, O 2 pressure, temperature and the reaction time on the yield of organic acids were investigated and discussed. The components of the degraded products were characterized with total organic carbon and high performance liquid chromatography. The results indicated that cellulose was depolymerized successfully to organic acids. Formic acid as the predominant species with 80.0% yield was obtained at the optimal conditions (150°C, 2 h, 3.0 MPa O 2 ), which was much higher than those reported in literatures. The small amount of ZnO in the solvent played an important role not only to promote the cellulose dissolution, but also to accelerate its oxidative degradation. The main features of this one-step degradation of cellulose were the green solvent, pre-dissolution of catalyst, and high selectivity. This work opened up a new avenue for the conversion of cellulose to organic acids under mild conditions. Graphical abstract The oxidative degradation of cellulose dissolved in NaOH/ZnO aqueous solution into organic acids was conducted under pressed O 2 without heterogeneous catalyst. The yield of FA which was the main product reached up to 80.0%.
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ACS Sustainable Chemistry & Engineering
·
2018
·
IF 6.14
Wen Hu,Gang Chen,Yu Liu,Yingyao Liu,Bo Li,Zhiqiang Fang
A general and scalable strategy to achieve transparent and hazy cellulose films with excellent mechanical properties, especially folding endurance, remains an obstacle. Herein, we incorporate transparent carboxymethyl cellulose (CMC) into opaque but hazy paper of uniformly distributed lignocellulosic fiber network by a facile and scalable impregnation to fabricate transparent and hazy all-cellulose composite films with strong mechanical properties. The CMC serves as a matrix to enhance the transparency and smoothness, whereas the isotropic intertwined network of long and slender lignocellulosic fibers simultaneously acts as a reinforcing phase to improve the mechanical properties and a light scatting source to enhance the optical haze. Consequently, the resulting composite film combines a high transparency (up to 90%) and optical haze (up to 82%) at 550 nm with superior mechanical properties (140 MPa tensile strength, 8.5 MJ m–3 toughness, and 3342 folding times). Moreover, this composite film demonstrated ultrasmoothness (Rq: 0.9 nm) and improved flame retardant performance. Mechanically robust, transparent, and hazy composite films with ultrasmoothness and enhanced fire retardancy may extend their opportunities in flexible optoelectronics.
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FOOD HYDROCOLLOIDS
·
2018
·
IF 5.089
Fu Liu,Jie Zheng,Cai-Huan Huang,Chuan-He Tang,Shi-Yi Ou
The development of high internal phase emulsions (HIPEs) stabilized by food-grade particles (e.g., cellulose nanocrystals, CNCs) has attracted increasing interests in the food colloid field. This paper reports a type of oil-in-water HIPEs using protein (bovine serum albumin, BSA)-covered CNCs as effective stabilizers. The BSA-covered CNCs were simply obtained by mixing aqueous solutions of anionic CNCs with the cationic BSA at pH 3.0. Turbidity and absorption measurements proved the binding of BSA to CNCs. The strong interaction and aggregation of BSA-covered CNCs were verified by atomic force microscopy measurements. Interestingly, the 0.5% (w/v) CNCs covered with a low amount of BSA (0.01%–0.1%, w/v) as the emulsifying agent yielded very stable, gel-like HIPEs ( ϕ = 0.8). The stiffness and microstructure of the HIPEs can be modulated either by changing the surface protein coverage at a fixed CNC concentration or by changing the concentration of CNCs with a fixed surface protein coverage (e.g., 80%). The improvement of the stiffness was largely attributed to the enhanced droplet packing effect and interfacial bridging effect. These findings offer a promising opportunity to extend the applications of protein-modified CNCs in the food and pharmaceutical industries.
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CARBOHYDRATE POLYMERS
·
2018
·
IF 5.158
Fengcai Lin,Ruting Zheng,Jianwen Chen,Wenmin Su,Biying Dong,Chensheng Lin,Biao Huang,Beili Lu
A combination of conductive polymer with natural biomass is an ideal alternative to the classical conductive materials. In this study, PPy/SA/TOMFC composite hydrogels were fabricated by incorporation of TEMPO-oxidized microfibrillated cellulose (TOMFC) into the alginate-based matrix along with the in situ polymerization of pyrrole monomer. It was found that the mechanical and conductive properties of the composite hydrogels were associated with the concentration of TOMFC, which facilitated the formation of more compact 3D network structures and the growing of PPy conductive network. The mechanical properties of the synthesized hydrogels were significantly enhanced by incorporation of higher amount of TOMFC. In addition, with the introduction of 5.0 wt% TOMFC, the electrical conductivity of composite hydrogels could be ten times higher than that of PPy/SA hydrogels. Moreover, the obtained PPy/SA/TOMFC hydrogels exhibited tunable swelling properties and good biocompatibility, making them promising candidates for the use as biomaterial.
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高影响因子
CELLULOSE
·
2018
·Vol. 25
·期 6
·3189-3196
·
IF 3.809
Lv Pengfei,Zhou Huimin,Zhao Min,Li Dawei,Lu Keyu,Wang Di,Huang Jieyu,Cai Yibing,Lucia Lucian Amerigo,Wei Qufu
A simple, rapid method for developing conductive, ultrafine, and high aspect ratio silver nanowires (AgNWs) is reported. Transparent and flexible nanocomposites were fashioned from bacterial cellulose (BC) and AgNWs in a very straightforward and direct manner without the addition of materials or the need for specific facilities. The as-prepared BC/AgNWs composite thin films were able to demonstrate acceptable transparency (near 80% at 550 nm), high flexibility, good mechanical strength (18.95 MPa) and stable conductivity (7.46 Ω sq −1 ) under various bending states.
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CELLULOSE
·
2019
·Vol. 26
·期 9
·5621-5633
·
IF 3.917
Zhang Shengli,Kai Chengcheng,Liu Bofang,Zhang Silue,Wei Wei,Xu Xiaoling,Zhou Zuowan
Abstract Polyethylenimine (PEI), a type of water-soluble chain polymer containing a great number of primary, secondary and tertiary amine groups in the molecule, was used as an N-halamine precursor. It was grafted onto dialdehyde cellulose membrane (DCM) followed by chlorination to prepare a novel N-halamine antibacterial cellulose membrane (Cl–PEI–DCM). The appropriate conditions affecting the aldehyde content of DCM and the active chlorine (Cl + ) content of Cl–PEI–DCM were systematically studied at oxidation, grafting and chlorination stages, respectively. The structure and properties of the samples were investigated by SEM, ATR–FTIR, XRD, XPS, light transmittance measurements and tensile tests. The stability and rechargeability of the Cl–PEI–DCM were evaluated, and its antibacterial activity was tested against S. aureus and E. coli . Results showed that the Cl + content of the chlorinated samples was strongly dependent on the aldehyde content of DCM and PEI concentration. Under the optimum testing condition, the Cl + content of the Cl–PEI–DCM reached 1.30 wt%. The hydroxyl groups on the cellulose membrane were changed to aldehyde groups and the successful introduction of PEI and N–Cl bond were confirmed. The 1.30 wt% Cl–PEI–DCM exhibited high antibacterial activity against both S. aureus and E. coli , which can completely inactivate two bacterial pathogens within 5 min even after 15 days of storage. Moreover, the Cl–PEI–DCM membrane displayed good stability, rechargeability, transparency and high mechanical strength. These results demonstrated that the Cl–PEI–DCM can be considered as a visualized wound dressing material or antibacterial shoe insole. Graphical abstract
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CARBOHYDRATE POLYMERS
·
2018
·
IF 5.158
Zhenzhen Liu,Mingjie Chen,Yanzhu Guo,Xing Wang,Li Zhang,Jinghui Zhou,Haiming Li,Qingshan Shi
Cationic amphiphilic cellulose copolymers were prepared through grafting hydrophobic poly (p-dioxanone) (PPDO) chains onto hydrophilic quaternized cellulose derivatives (QC) via ring-opening polymerization (ROP) reaction, which was performed in 1-butyl-3-methylimidazolium chloride (BmimCl) and using 4-dimethylaminopyridine (DMAP) or 1,8-diazabicyclo (5.4.0) undec-7-ene (DBU) as catalyst. Their chemical structures and physical properties were confirmed by FT-IR, 1 H-, 13 C-, 2D HSQC-NMR, X-ray diffraction (XRD), and thermal stability (TGA) techniques, while self-assembly behavior was characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM) and fluorescence techniques. Both of the sizes and critical micelle concentration (CMC) values of micelles were decreased with increasing grafting contents of PPDO in the copolymers, which were in the ranges of 110–246 nm and 64–253 μg/mL, respectively. The ζ-potentials of micelles were cationic andranged from 39.1 mV to 45.4 mV. The highest encapsulation efficiencyof paclitaxel (PTX) into the micelles was 61.8% and 92.0% of loaded PTX was continuously released from micelles in phosphate buffered saline medium for 36 h.
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CARBOHYDRATE POLYMERS
·
2019
·
IF 6.044
Ya Cheng,Xiuyan Ren,Guanghui Gao,Lijie Duan
The gel-based sensor was extensively investigated due to the flexible and extensible properties. Here, a flexible, excellent mechanical (fracture energy of 5238 kJ/m 3 ) and anti-freezing ionic conductive carboxymethyl cellulose-based organohydrogel sensor was prepared via Fe 3+ cross-linked sodium carboxymethyl cellulose (CMC) as the first network and covalently cross-linked polyacrylamide as the second network in the co-solvents of water and ethylene glycol. Owing to the clipping transportation of Fe 3+ in the water channels, the gel sensor had good sensitivity (GF = 1.4, 0˜30% strain) and fast strain-responsiveness (0.98 s) to monitor the subtle motions of human body. The CMC-based organohydrogel with high strain-sensitivity exhibited more potential applications of next-generation bioelectronic materials and devices.
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高影响因子
RSC Advances
·
2017
·Vol. 7
·期 65
·41070-41076
·
IF 3.108
Xin-ling Fu,Ming Zeng,Jian-bo Zhou,Chao Xu
A novel strategy for synthesizing silicalite-1 membrane by hydrothermal synthesis without organic template after coating the support with a mixture of modified cellulose and seeds was successfully proposed. The membrane possesses high ideal separation factors of H2 over various gases which is larger than the corresponding Knudsen diffusion coefficients. The selectivity of AcOH from AcOH/H2O mixtures can reach to 65 and stable for 180 h. The characterization results by XRD and SEM showed that the excellent performance can be attributed to both modified cellulose and the synthesis without organic template. Modified cellulose attracted more silicalite-1 nutrients to the support and assisted the synthesis of more compact silicalite-1 zeolite membrane. Calcination after synthesis was avoided, thus avoiding macrostructure defects appearing during the process of calcination.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2012
·
IF 3.898
Zhan Zhou,Qianming Wang
Here two novel terbium silica xerogels (H a and H b ) were assembled into cellulose hydrogels and two transparent films with narrow emission were successfully fabricated as fluorescent probes . We have found that the nitrite addition entailed efficient quenching effects of the photoluminescence intensity, contrasting the stable emissions upon exposure to other comparative ions (SO 4 2− , CO 3 2− , ClO 3 − , NO 3 − , AcO − , OH − , F − , Cl − , Br − , I − , K + , Na + , Fe 2+ , Mn 2+ , Pd 2+ , Cd 2+ , Co 2+ , Cu 2+ and Fe 3+ ). The recognition process may be ascribed to the coordination interaction between terbium ions and NO 2 − . Linear functions for spectroscopic titrations were obtained in both hydrogel-based films and the new soft sensors exhibit a dynamic range for determination of nitrite from 1 × 10 −5 to 1 × 10 −4 M.
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CARBOHYDRATE POLYMERS
·
2012
·
IF 3.628
Haiping Li,Wanguo Hou,Xiuzhi Li
The electrostatic and hydrogen bonding interactions between xanthan gum (XG) and semisynthetic cationic cellulose (JR400) in aqueous solution are investigated via stability map, FT-IR spectra, thermogravimetric analysis, potentiometric measurement and rheological method. The stability map shows three regions, a stable region with XG as the major component, a flocculated region and another stable region with JR400 as the major component. The stability of mixing system depends on both the concentration fraction of JR400 ( f JR ) and the overlapping concentrations of these two polymers. In the region near the stoichiometric f JR , the mixture shows stoichiometric flocculation, which is independent of the total polymer concentration. However, in the regions away from the stoichiometric f JR , the mixtures are stable when the concentration of major polymer component is higher than its overlapping concentration. In stable regions, the electrostatic and hydrogen bonding interactions can enhance the viscosity of mixing system at appropriate f JR values.
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高影响因子
危险品化学品经营许可证（带存储）