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Liu L.,Zhejiang Sci-Tech University | Liu L.,National Engineering Laboratory of Textile Fiber Materials and Processing Technology | Gao Z.Y.,Zhejiang Sci-Tech University | Su X.P.,Zhejiang Sci-Tech University | And 4 more authors.
ACS Sustainable Chemistry and Engineering | Year: 2015

A high efficiency and eco-friendly porous cellulose-based bioadsorbent was synthesized by grafting acrylic acid and acrylamide to remove anionic dye acid blue 93 (AB93) and cationic dye methylene blue (MB) from single and binary dye solutions. The effects of initial dye concentration, bioadsorbent dosage, contact time, solution pH value, temperature, ionic strength and surfactant content on the adsorption capacity of the bioadsorbent were investigated. The maximum adsorption capacities of the bioadsorbent for both AB93 and MB were 1372 mg g-1 at an initial concentration of 2500 mg L-1. The conditions-dependent adsorption characteristics of the bioadsorbent indicated a high efficiency of dyes removal. The appropriate isotherm model for the equilibrium process was the Freundlich, and the kinetic studies revealed that the adsorption of AB93 and MB followed the pseudo-second-order kinetic models. The adsorbent behaviors were dominated by the electrostatic interactions between the bioadsorbents and the dye molecules. Moreover, the recyclability experiments showed that the bioadsorbent could be reused for at least three cycles with stable adsorption capacity even in complex systems containing binary-dyes, salt, and surfactant. Thus, the cellulose-based bioadsorbent can be effectively used for the removal of dyes from industrial textile wastewater. © 2015 American Chemical Society. Source

Liu L.,Zhejiang Sci-Tech University | Liu L.,National Engineering Laboratory of Textile Fiber Materials and Processing Technology | Jiang L.,Zhejiang Sci-Tech University | Xu G.K.,Zhejiang Sci-Tech University | And 4 more authors.
Journal of Materials Chemistry B | Year: 2014

A major problem related to the fabrication of drug-loaded fibers by wet spinning is the significant loss of load when the drugs and spinning dopes are directly mixed together. We report a novel method to fabricate drug-loaded alginate fibers by spinning an aqueous mixture containing alginate and alginate nanocapsules incorporated with drugs. The alginate fibers exhibit spotty features of nanocapsules located close to the surface of the fibers. Adsorption experiments demonstrate the superabsorbent properties of the fibers, as well as the dependence of adsorption profiles on salt ionic strength. The adsorption processes of all the fibers are well-described by the pseudo-second-order kinetics model. Drug release tests show that the cumulative release amount increased with an increase in the proportion of nanocapsules present in the fiber. In addition, the burst release behaviors of the fibers incorporated with the nanocapsules were also diminished dramatically. This work suggests that adding nanocapsules containing drugs into the spinning dopes is a promising strategy to fabricate novel drug-loaded fibers for immediate drug delivery for wound dressing. © The Royal Society of Chemistry 2014. Source

Liao Q.,Zhejiang Sci-Tech University | Su X.,Zhejiang Sci-Tech University | Zhu W.,Zhejiang Sci-Tech University | Hua W.,Zhejiang Sci-Tech University | And 5 more authors.
RSC Advances | Year: 2016

In this paper, a facile and green method was presented to prepare flexible, ultralight, and hydrophobic cellulose aerogels (CA) on the chemical cross-linking of cellulose solution, lyophilization and subsequent hydrophobic modification with methyltrichlorosilane (MTCS) by a thermal chemical vapor deposition (CVD) process. The resultant cellulose aerogels had an interconnected and highly porous structure with a varied pore size owing to different starting solution concentrations. And also the cellulose aerogels were ultralight (as low as 0.027 g cm-3), but they exhibited improved mechanical properties with compress stress of 1.10-3.85 MPa. After silanization, the MTCS-modified cellulose aerogels showed durable hydrophobicity with an average water contact angle of 141°, even maintaining 131° after 5 days. Furthermore, the flexible and hydrophobic cellulose aerogels could rapidly collect oils and organic solvents both on the surface and bottom from water, and exhibited excellent adsorption performances (e.g. 59.32 g g-1 of pump oil) as well as good recyclability. Thus, such a flexible and hydrophobic cellulose aerogel is a very promising material for oil spill cleanup and industrial oily wastewater purification. © 2016 The Royal Society of Chemistry. Source

Liu L.,Zhejiang Sci-Tech University | Liu L.,National Engineering Laboratory of Textile Fiber Materials and Processing Technology | Shou L.,Zhejiang Sci-Tech University | Yu H.,Zhejiang Sci-Tech University | And 3 more authors.
Journal of Macromolecular Science, Part B: Physics | Year: 2015

Medical devices, such as Foley catheters, which are commonly fabricated from silicone rubber, need to have excellent mechanical properties and physiological inertness. This study reports the development of a facile method to prepare silicone rubber with excellent long-term performance by controlling the vulcanization procedure parameters only. Mechanical, viscoelastic, and chemical properties of vulcanized silicone rubber were investigated. The corrosion resistance of vulcanized silicone rubber was assessed by exposure to artificial body urine for a period of up to 14 days. The mechanical properties of silicone rubber were changed via adjusting the vulcanization procedure parameters. The improved mechanical properties of silicone rubber are attributed to an increase in crosslink density resulting from the proposed vulcanization technology. After 14 days of immersion in urine, no significant changes in mechanical properties and internal structure were observed. This indicated that the as-prepared rubber samples had high tear resistance and physiological inertness. These long-term properties are important for their applications as semi-permanent implant materials, such as Foley catheter balloons in clinics. Our process of vulcanization of silicone rubber may have potential for fabrication of such medical devices. Copyright © 2015 Taylor & Francis Group, LLC. Source

Liu L.,Zhejiang Sci-Tech University | Liu L.,National Engineering Laboratory of Textile Fiber Materials and Processing Technology | Yang X.,Zhejiang Sci-Tech University | Yu H.,Zhejiang Sci-Tech University | And 4 more authors.
RSC Advances | Year: 2014

Inspired by the ordered β-sheet crystalline structure and molecular orientation of natural silkworm silk, biomimetic silk fibers with refined crystalline structure were creatively produced through incorporating cellulose nanocrystals (CNCs) into silk fibroin (SF) matrix to mimic the β-sheet crystallites in natural silk via wet-spinning assembly technology. The influence of CNCs and post-draw on the structural characteristics, and thermal and mechanical properties of regenerated cellulose nanocrystal/silk fibroin (CNC/SF) fibers were comparatively studied with those of degummed silk. The resultant CNC/SF fibers exhibited a uniform, circular shape as well as dense morphology. The CNCs were uniformly dispersed into SF matrix and aligned along the fiber axis, which were beneficial to the formation of more ordered structure through intermolecular hydrogen bonding interactions. The crystallinity and overall molecular orientation of CNC/SF fibers were increased with increases of draw ratio and CNC contents, although lower than those of degummed silk. DSC and TGA analysis revealed that thermal decomposition behavior of CNC/SF fibers presented different features depending on the CNC contents, whereas maximum decomposition temperature of CNC/SF fibers improved sharply at first and then decreased slightly with the increase of CNC contents. Moreover, the tan δ peak temperatures of SF were increased with the addition of CNC, indicating restrained SF molecular mobility in the vicinity of the CNC surface. These results indicated that the CNC could substantially enhance the mechanical properties of SF and this enhancement could be attributed to the strong hydrogen bonding interactions as well as CNC-induced crystallization and orientation. Meanwhile, Young's modulus, tensile strength and breaking strain of the CNC/SF fibers with 5 wt% CNC were significantly increased to 28.8 ± 2.6 GPa, 728.5 ± 36.4 MPa and 23.1 ± 1.6% respectively, higher than those of degummed silk. Thus it was demonstrated that biomimicking the natural silk crystalline structure using CNC as β-sheet crystallite is a promising strategy for production of artificial silk fiber with improved strength without compromising the toughness. © 2014 The Royal Society of Chemistry. Source

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