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Tang Y.,Zhejiang Sci-Tech University | Tang Y.,University of New Brunswick | Yang S.,Zhejiang Sci-Tech University | Zhang N.,Shanghai Tonnor Material Science Co. | Zhang J.,Zhejiang Sci-Tech University
Cellulose | Year: 2014

Nanocrystalline cellulose (NCC) was extracted from microcrystalline cellulose via low-intensity ultrasonic-assisted sulfuric acid hydrolysis process. NCC samples were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), particle size distribution (PSD) analysis, Fourier-transformed infrared spectra (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and rheological measurement. It was found that NCC yield reached 40.4 % under the optimum process of low-intensity ultrasonic-assisted sulfuric acid hydrolysis, while it was only 33.0 % in the absence of ultrasonic treatment. Furthermore, the results showed that the two NCC samples obtained from ultrasonic-assisted hydrolysis and conventional hydrolysis were very similar in morphology, both exhibiting rod-like structures with widths and lengths of 10-20 and 50-150 nm, respectively. XRD result revealed that the NCC sample from ultrasonic-assisted hydrolysis contained a small amount of cellulose II and possessed a Segal Crystallinity Index of 90.38 % and a crystallite size of 58.99 Å, higher than those of the NCC sample from conventional hydrolysis. Moreover, PSD analysis demonstrated that the former exhibited a smaller value in average particle size than the latter. In addition, rheological measurements showed that the NCC suspensions from the ultrasonic-assisted process exhibited a lower viscosity over the range of shear rate from 0.1 to 100 s-1 in comparison with that prepared in the absence of ultrasonic treatment. © 2013 Springer Science+Business Media Dordrecht. Source

Pei Q.Q.,Zhejiang Sci-Tech University | Tang Y.J.,Zhejiang Sci-Tech University | Zhang J.H.,Zhejiang Sci-Tech University | Zhu X.M.,Zhejiang Sci-Tech University | And 2 more authors.
Digest Journal of Nanomaterials and Biostructures | Year: 2014

Nanoparticle pigments hold great promisefor paper coating application targeting to improve the physical and optical properties of coated paper. In our previous work, the incorporation of TiO2and CaCO3nanoparticleswas found to exert an importantand significanteffecton the rheological behavior of paper coatings.The objective of the currentworkwas to investigate the influenceofadding TiO2and CaCO3nanoparticles into conventional paper coatings on the properties and surface structureof coated paper. Results revealed that the addition of TiO2and CaCO3nanoparticles had a significantly positive effect on the overall properties of coated paper.The surface strength, opacity and smoothness of coated paper basically increased with the increased addition of nanoparticle pigments. It appearedthat the optimum addition level of nanoparticle pigments was 12%with respect to the paper properties. SEM images provide further evidence that the addition of nanoparticle pigments conferred a relativelyregular surface structure to the coated paper. This work might be a solid step forward towards the development of advanced paper coatings and high-value added coated paper. © 2014 National Institute of Science Communication and Information Resources (NISCAIR). All rights reserved. Source

Zhou D.,Zhejiang Sci-Tech University | Tang Y.,Zhejiang Sci-Tech University | Zhang N.,Shanghai Tonnor Material Science Co. | Zhang J.,Zhejiang Sci-Tech University | Liu D.,Zhejiang Sci-Tech University
Digest Journal of Nanomaterials and Biostructures | Year: 2014

Due to the low-cost, earth-abundant availability and eco-friendly characteristics, cellulose derivatives (CDs) are being increasingly used as co-binders in the production of pigment coatings. In the present work, a comparative study on the effect of nanocrystalline cellulose (NCC) and sodium carboxymethyl cellulose (CMC) on the colloidal stability and rheological properties of pigment coatings was carried out. The sedimentation stability assessment results indicated that NCC replacing CMC significantly improved the colloidal stability of pigment coatings. In the presence of NCC, the resulting coatings showed no indication of sedimentation within a 48-hour storage period. Moreover, the rheological measurements revealed that all pigment coatings exhibited a strong shear-thinning behavior as the shear rate varied from 0 to 100 s-1. When further increasing the shear rate, the pigment coatings containing NCC tended to experience a shear-thickening behavior. More importantly, NCC was found to impart lower viscosity to pigment coatings in comparison with CMC. The presence of NCC resulted in a marked decrease in average particle size of coatings, implying that NCC might act as an efficient dispersion agent in pigment coatings. In addition, it was observed that the incorporation of NCC in pigment coatings offered a relatively uniform coating layer and was effective in enhancing the hydrophobicility of coated paper. Source

Tang Y.,Zhejiang Sci-Tech University | Shen X.,Zhejiang Sci-Tech University | Zhang J.,Zhejiang Sci-Tech University | Guo D.,Zhejiang Sci-Tech University | And 2 more authors.
Carbohydrate Polymers | Year: 2015

Due to its amazing physicochemical properties and high environmental compatibility, cellulose nano-crystals (CNC) hold great promise for serving as a strategic platform for sustainable development. Now, there has been growing interest in the development of processes using waste or residual biomass as CNC source for addressing economic and environmental concerns. In the present work, a combined process involving phosphoric acid hydrolysis, enzymatic hydrolysis and sonication was proposed aiming to efficiently exact CNC from low-cost old corrugated container (OCC) pulp fiber. The effect of enzymatic hydrolysis on the yield and microstructure of resulting CNC was highlighted. Results showed that the enzymatic hydrolysis was effective in enhancing CNC yield after phosphoric acid hydrolysis. CNC was obtained with a yield of 23.98 wt% via the combined process with phosphoric acid concentration of 60 wt%, cellulase dosage of 2 mL (84 EGU) per 2 g fiber and sonication intensity of 200 W. Moreover, the presence of enzymatic hydrolysis imparted the obtained CNC with improved dispersion, increased crystallinity and thermal stability. © 2015 Elsevier Ltd. Source

Hu X.L.,Zhejiang Sci-Tech University | Tang Y.J.,Zhejiang Sci-Tech University | Tang Y.J.,University of Science and Technology of China | Yang Z.Y.,Zhejiang Sci-Tech University | And 5 more authors.
Digest Journal of Nanomaterials and Biostructures | Year: 2015

Organic-inorganic nanocomposites, embodying enhanced properties, e.g., mechanical and thermal properties by combining the advantage of both organic and inorganic moieties, showed great promise in various application areas, such as coatings, cosmetics, catalysis, solar cell, and biology. In the present work, styrene-acrylic emulsion was successfully prepared by in-situ polymerization in the presence of CaCO3 nanoparticles. The obtained styrene-acrylic/CaCO3 nanoparticle composite emulsion was structurally characterized by TEM, FT-IR and TGA. Results showed that the styrene-acrylic/CaCO3 nanoparticle composite emulsion was composed by large amounts of core-shell latex particles, in which CaCO3 nanoparticles and polymer were employed as core and shell structure, respectively. Moreover, the thermal stability of styrene-acrylic emulsion was greatly improved as a function of the incorporated CaCO3 nanoparticles. Additionally, related properties, i.e., membrane forming ability, water resistance, ion stability, mechanical stability and storage ability of nanocomposite emulsion in the presence/absence of CaCO3 nanoparticles were also evaluated. © 2015, Inst Materials Physics. All rights reserved. Source

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