Cellulose Nanocrystals Mechanical Reinforcement in Composite Hydrogels with Multiple Cross-Links: Correlations between Dissipation Properties and Deformation Mechanisms

2014 ◽  
Vol 47 (12) ◽  
pp. 4077-4086 ◽  
Author(s):  
Jun Yang ◽  
Chun-Rui Han ◽  
Xue-Ming Zhang ◽  
Feng Xu ◽  
Run-Cang Sun
Keyword(s):  
Cellulose Nanocrystals ◽  
Deformation Mechanisms ◽  
Mechanical Reinforcement ◽  
Composite Hydrogels ◽  
Multiple Cross ◽  
Cross Links

scholarly journals The Preparation of a Highly Stretchable Cellulose Nanowhisker Nanocomposite Hydrogel

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Jiufang Duan ◽  
Jianxin Jiang ◽  
Jianzhang Li ◽  
Liujun Liu ◽  
Yiqiang Li ◽  
...  
Keyword(s):  
Room Temperature ◽  
Nanocomposite Hydrogel ◽  
Cellulose Nanowhiskers ◽  
Composite Hydrogels ◽  
Ammonium Peroxydisulfate ◽  
Cellulose Nanowhisker ◽  
Stearyl Methacrylate ◽  
Highly Stretchable ◽  
Cross Links ◽  
Scanning Electron

Molecules that associate to form cross-links by hydrophobic association are designed and synthesised. Hydrogels, based on cellulose nanowhiskers (CNWs), acrylamide (AM), and stearyl methacrylate (C18), were synthesised by micellar copolymerisation, using ammonium peroxydisulfate as an initiator. CNWs composite hydrogels were characterised by Fourier transform infrared spectroscopy (FTIR) and their morphologies were investigated by scanning electron microscope (SEM). The system shows the original extensibility up to about 2500%: the tensile strength and compressive strength have maximum values of 1.338 MPa and 2.835 MPa, respectively. Besides excellent mechanical properties, CNWs composite hydrogels also have the ability to self-heal and remould: this is mainly attributed to the dissociation and reassociation of the associated micelles. In contrast to conventional cellulose hydrogels, these systems, when broken or cut, can be simply repaired by bringing together fractured surfaces to self-heal at room temperature.

Synergistic Reinforcement of Composite Hydrogels with Nanofiber Mixtures of Cellulose Nanocrystals and Chitin Nanofibers

2020 ◽  
Author(s):  
Cameron W. Irvin ◽  
Chinmay C. Satam ◽  
Jianshan Liao ◽  
Paul S. Russo ◽  
Victor Breedveld ◽  
...  
Keyword(s):  
Cellulose Nanocrystals ◽  
Composite Hydrogels ◽  
Chitin Nanofibers

Preparation and Viscoelastic Properties of Waterborne Polyurethane/Cellulose Nanocrystals Composites

2013 ◽  
Vol 771 ◽  
pp. 105-108 ◽  
Author(s):  
Qun Zhao ◽  
Ke Lu Yan
Keyword(s):  
Cellulose Nanocrystals ◽  
Viscoelastic Properties ◽  
Loss Modulus ◽  
Casting Process ◽  
Waterborne Polyurethane ◽  
Mechanical Analysis ◽  
Nanocomposite Films ◽  
Ultrasonic Dispersion ◽  
Mechanical Reinforcement ◽  
Power Law Equation

The objective of this work is to study the viscoelastic properties by which nanofillers produce mechanical reinforcement in polymers using dynamic mechanical analysis (DMA). To this purpose, waterborne polyurethane (WBPU) and cellulose nanocrystals (CNCs) composites films with various filler contents were prepared by ultrasonic dispersion followed by emulsion casting process. In frequency sweep tests, the storage modulus and loss modulus were recorded and modeled by the Power Law equation. CNCs precipitation significantly increased the steady state viscous properties of cellulose nanocoposite films but decreased the dynamic viscoelastic properties and frequency sensitivity of nanocomposite films.

scholarly journals Thermoreversible Gelation with Two-Component Mixed Cross-Link Junctions of Variable Multiplicity in Ternary Polymer Solutions

Gels ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 89
Author(s):  
Fumihiko Tanaka
Keyword(s):  
Functional Groups ◽  
Polymer Solutions ◽  
Sol Gel ◽  
Polymer Networks ◽  
Water Soluble ◽  
Cross Link ◽  
Variable Multiplicity ◽  
Multiple Cross ◽  
Thermoreversible Gelation ◽  
Cross Links

Theoretical scheme is developed to study thermoreversible gelation interfering with liquid–liquid phase separation in mixtures of reactive f-functional molecules R{Af} and g-functional ones R{Bg} dissolved in a common solvent. Formed polymer networks are assumed to include multiple cross-link junctions containing arbitrary numbers k1 and k2 of functional groups A and B of each species. Sol-gel transition lines and spinodal lines are drawn on the ternary phase plane for some important models of multiple cross-link junctions with specified microscopic structure. It is shown that, if the cross-link structure satisfies a certain simple condition, there appears a special molar ratio of the two functional groups at which gelation takes place with a lowest concentration of the solute molecules, as has been often observed in the experiments. This optimal gelation concentration depends on f and g (functionality) of the solute molecules and the numbers k1 and k2 (multiplicity) of the functional groups in a cross-link junction. For cross-links which allow variable multiplicity, special attention is paid on the perfectly immiscible cross-links leading to interpenetrating polymer networks, and also on perfectly miscible cross-links leading to reentrant sol-gel-sol transition. Results are compared with recent observations on ion-binding polymer solutions, polymer solutions forming recognizable biomolecular complexes, polymer/surfactant mixtures, hydrogen-bonding polymers, and hydrophobically-modified amphiphilic water-soluble polymers.

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