scholarly journals Study on the Preparation of Ionic Liquid Doped Chitosan/Cellulose-Based Electroactive Composites

2019 ◽  
Vol 20 (24) ◽  
pp. 6198
Author(s):  
Fang Wang ◽  
Chong Xie ◽  
Liying Qian ◽  
Beihai He ◽  
Junrong Li
Keyword(s):  
Ionic Liquid ◽  
Composite Film ◽  
Young’S Modulus ◽  
Water Retention ◽  
Young's Modulus ◽  
Cellulose Film ◽  
Electroactive Materials ◽  
Deformation Amplitude ◽  
Pure Cellulose ◽  
Cellulose Composite

Electro-actuated polymer (EAP) can change its shape or volume under the action of an external electric field and shows similar behavioral characteristics with those of biological muscles, and so it has good application prospects in aerospace, bionic robots, and other fields. The properties of cellulose-based electroactive materials are similar to ionic EAP materials, although they have higher Young’s modulus and lower energy consumption. However, cellulose-based electroactive materials have a more obvious deficiency—their actuation performance is often more significantly affected by ambient humidity due to the hygroscopicity caused by the strong hydrophilic structure of cellulose itself. Compared with cellulose, chitosan has good film-forming and water retention properties, and its compatibility with cellulose is very excellent. In this study, a chitosan/cellulose composite film doped with ionic liquid, 1-ethyl-3-methylimidazolium acetate ([EMIM]Ac), was prepared by co-dissolution and regeneration process using [EMIM]Ac as the solvent. After that, a conductive polymer, poly(3,4-ethylenedioxythiophene)/poly (styrene sulfonate) (PEDOT: PSS), was deposited on the surface of the resulted composite, and then a kind of cellulose-based electroactive composites were obtained. The results showed that the end bending deformation amplitude of the resulted material was increased by 2.3 times higher than that of the pure cellulose film under the same conditions, and the maximum deformation amplitude reached 7.3 mm. The tensile strength of the chitosan/cellulose composite film was 53.68% higher than that of the cellulose film, and the Young’s modulus was increased by 72.52%. Furthermore, in comparison with the pure cellulose film, the water retention of the composite film increased and the water absorption rate decreased obviously, which meant that the resistance of the material to changes in environmental humidity was greatly improved.

α-Cellulose-Based Films: Effect of Sodium Lignosulfonate (SLS) Incorporation on Physicochemical and Antibacterial Performance

2021 ◽  
Author(s):  
Xinyu Lu ◽  
Han Que ◽  
Haoquan Guo ◽  
Chenrong Ding ◽  
Xu Liu ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Tensile Strength ◽  
Hydrogen Bonds ◽  
Composite Film ◽  
Raw Materials ◽  
Mixed System ◽  
Cellulose Film ◽  
Sodium Lignosulfonate ◽  
Pure Cellulose ◽  
Antibacterial Performance

Abstract A homogeneous α-cellulose film was prepared by regeneration method from ZnCl2/CaCl2/cellulose mixed system and was further combined with sodium lignosulfonate (SLS) by crosslinking through interaction hydrogen bonds and “bridge linkages”. The physicochemical and antibacterial performance of films were all investigated and results showed that modified films exhibited stronger tensile strength, higher thermal stability, lower hydrophilic effect, better UV shielding as compared with those of pure cellulose film, and especially, better antibacterial ability derived from the presence of phenolic and sulfonate groups in SLS. This study proposed a simple and sustainable method for fabricating a multifunctional and environmentally friendly composite film by using two main lignocellulose resources as raw materials.

Graphene oxide and zinc oxide decorated chitosan nanocomposite biofilms for packaging applications

2020 ◽  
Vol 40 (2) ◽  
pp. 152-157 ◽  
Author(s):  
Pınar Terzioglu ◽  
Yasin Altin ◽  
Ayse Kalemtas ◽  
Ayse Celik Bedeloglu
Keyword(s):  
Tensile Strength ◽  
Zinc Oxide ◽  
Graphene Oxide ◽  
Composite Film ◽  
Young’S Modulus ◽  
Mechanical Performance ◽  
Young's Modulus ◽  
Chitosan Film ◽  
Oxide Composite ◽  
Wide Range

AbstractRecently, due to sustainable development and environmental protection policies, there is increasing interest in the development of new biodegradable polymer-based multifunctional composites. Chitosan is one of the most remarkable and preferred biopolymers, which is environmentally friendly as well as renewable, biocompatible, and inexpensive. Though it has a wide range of potential applications, the major limitation of chitosan – the problem of poor mechanical performance – needs to be solved. In this work, graphene oxide was first produced and then used to manufacture a chitosan/graphene oxide/zinc oxide composite film through a casting method. The properties of the chitosan film and the chitosan/graphene oxide/zinc oxide composite film were investigated using Fourier transform infrared spectroscopy, mechanical, thermal gravimetric, and ultraviolet (UV)-visible spectroscopy analyses. The results showed that the incorporation of graphene oxide and zinc oxide into the chitosan matrix resulted in enhanced mechanical properties and thermal stability of chitosan biocomposite films. The graphene oxide- and zinc oxide-reinforced chitosan film showed 2527 MPa and 55.72 MPa of Young’s modulus and tensile strength, respectively, while neat chitosan showed only 1549 MPa and 37.91 MPa of Young’s modulus and tensile strength, respectively. Conversely, the addition of graphene oxide decreased the transmittance, notably in the UV region.

scholarly journals Influence of Mixed Imide Composition and Thermal Annealing on Ionic Liquid Uptake and Conductivity of Polyimide-Poly(ethylene glycol) Segmented Block Copolymer Membranes

Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7450
Author(s):  
Gokcen A. Ciftcioglu ◽  
Curtis W. Frank
Keyword(s):  
Mechanical Properties ◽  
Ionic Liquid ◽  
Block Copolymer ◽  
Ethylene Glycol ◽  
Young’S Modulus ◽  
Thermal Annealing ◽  
Young's Modulus ◽  
Poly Ethylene Glycol ◽  
Poly Ethylene ◽  
The Impact

Understanding the impact of different bridging groups in the two-step polymerization of poly(ethylene glycol) (PEG)-incorporated polyimide (PI) materials is significant. It is known that the proton exchange membranes (PEMs) used in industry today can experience performance degradation under rising temperature conditions. Many efforts have been devoted to overcoming this problem by improving the physical and mechanical properties that extend the hygrothermal life of a PEM. This work examines the effect of oxygenated and fluorinated bridging anhydrides in the production of PI-PEG PEMs. It is shown that the dianhydride identity and the amount incorporated in the synthesis influences the properties of the segmented block copolymer (SBC) membranes, such as increased ionic liquid uptake (ILU), enhanced conductivity and higher Young’s modulus favoring stiffness comparable to Nafion 115, an industrial standard. Investigations on the ionic conductivity of PI-PEG membranes were carried out to determine how thermal annealing would affect the material’s performance as an ion-exchange membrane. By applying a thermal annealing process at 60 °C for one hour, the conductivities of synthesized segmented block copolymer membranes values were increased. The effect of thermal annealing on the mechanical properties was also shown for the undoped SBC via measuring the change in the Young’s modulus. These higher ILU abilities and mechanical behavior changes are thought to arise from the interaction between PEG molecules and ethylammonium nitrate (EAN) ionic liquid (IL). In addition, higher interconnected routes provide a better ion-transfer environment within the membrane. It was found that the conductivity was increased by a factor of ten for undoped and a factor of two to seven for IL-doped membranes after thermal annealing.

scholarly journals Transparent Cellulose-Based Films Prepared from Used Disposable Paper Cups via an Ionic Liquid

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4209
Author(s):  
Zhen Xu ◽  
Qiwen Zhou ◽  
Lixiang Wang ◽  
Guangmei Xia ◽  
Xingxiang Ji ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Daily Life ◽  
Low Cost ◽  
Packaging Materials ◽  
Good Mechanical Property ◽  
Cellulose Film ◽  
Green Process ◽  
Pure Cellulose ◽  
The Difference ◽  
Paper Cups

Paper cups are widely employed in daily life with many advantages, but most of the used paper cups are incinerated or landfilled, due to the great challenge of separating the thin inner polyethylene (PE) coating, causing the waste of energy and the pollution of our environment. Therefore, recycling and converting the used paper cups into high-value materials is meaningful and important. In this work, transparent cellulose-based films were successfully prepared from the used paper cups via 1-allyl-3-methylimidazolium chloride ionic liquid after simple pretreatment. Additionally, the difference in properties and structures of cellulose-based films regenerated in different coagulation baths (water or ethanol) was also explored. It was found that the cellulose-based film possessed good thermal property and displayed better hydrophobicity than the traditional pure cellulose film. Moreover, they also demonstrated good mechanical property and the tensile strength of cellulose-based film regenerated in water can reach 31.5 Mpa, higher than those of cellulose-based film regenerated in ethanol (25.5 Mpa) and non-degradable polyethylene film (9–12 MPa), indicating their great potential as the packaging materials. Consequently, valorization of the low cost used paper cups and preparation of high-valve cellulose-based films were realized simultaneously by a facile and green process.

Mechanical properties of FeAlSi powders prepared by mechanical alloying from different initial feedstock materials

2019 ◽  
Vol 107 (2) ◽  
pp. 207 ◽  
Author(s):  
Jaroslav Čech ◽  
Petr Haušild ◽  
Miroslav Karlík ◽  
Veronika Kadlecová ◽  
Jiří Čapek ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Alloying ◽  
Young’S Modulus ◽  
Milling Time ◽  
Young's Modulus ◽  
Element Model ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powder Particles ◽  
Complete Homogenization

FeAl20Si20 (wt.%) powders prepared by mechanical alloying from different initial feedstock materials (Fe, Al, Si, FeAl27) were investigated in this study. Scanning electron microscopy, X-ray diffraction and nanoindentation techniques were used to analyze microstructure, phase composition and mechanical properties (hardness and Young’s modulus). Finite element model was developed to account for the decrease in measured values of mechanical properties of powder particles with increasing penetration depth caused by surrounding soft resin used for embedding powder particles. Progressive homogenization of the powders’ microstructure and an increase of hardness and Young’s modulus with milling time were observed and the time for complete homogenization was estimated.

Degradation of Rocks, Through Cracking Caused by Differential Thermal Expansion, in Relation to Nuclear Waste Repositories

1981 ◽  
Vol 6 ◽  
Author(s):  
J.R. Mclaren ◽  
R.W. Davidge ◽  
I. Titchell ◽  
K. Sincock ◽  
A. Bromley
Keyword(s):  
Thermal Expansion ◽  
Grain Boundary ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Crack Density ◽  
Granitic Rocks ◽  
Multiphase Materials ◽  
Thermal Expansion Behaviour ◽  
Waste Repositories ◽  
Expansion Behaviour

ABSTRACTHeating to temperatures up to 500°C, gives a reduction in Young's modulus and increase in permeability of granitic rocks and it is likely that a major reason is grain boundary cracking. The cracking of grain boundary facets in polycrystalline multiphase materials showing anisotropic thermal expansion behaviour is controlled by several microstructural factors in addition to the intrinsic thermal and elastic properties. Of specific interest are the relative orientations of the two grains meeting at the facet, and the size of the facet; these factors thus introduce two statistical aspects to the problem and these are introduced to give quantitative data on crack density versus temperature. The theory is compared with experimental measurements of Young's modulus and permeability for various rocks as a function of temperature. There is good qualitative agreement, and the additional (mainly microstructural) data required for a quantitative comparison are defined.

Is it necessary to calculate Young’s modulus in AFM nanoindentation experiments regarding biological samples?

2020 ◽  
Vol 12 ◽  
Author(s):  
S.V. Kontomaris ◽  
A. Malamou ◽  
A. Stylianou
Keyword(s):  
Young’S Modulus ◽  
Biological Samples ◽  
Young's Modulus ◽  
Reference Sample ◽  
Nonlinear Behavior ◽  
Accurate Method ◽  
Accurate Solution ◽  
Hertz Model ◽  
Work Done

Background: The determination of the mechanical properties of biological samples using Atomic Force Microscopy (AFM) at the nanoscale is usually performed using basic models arising from the contact mechanics theory. In particular, the Hertz model is the most frequently used theoretical tool for data processing. However, the Hertz model requires several assumptions such as homogeneous and isotropic samples and indenters with perfectly spherical or conical shapes. As it is widely known, none of these requirements are 100 % fulfilled for the case of indentation experiments at the nanoscale. As a result, significant errors arise in the Young’s modulus calculation. At the same time, an analytical model that could account complexities of soft biomaterials, such as nonlinear behavior, anisotropy, and heterogeneity, may be far-reaching. In addition, this hypothetical model would be ‘too difficult’ to be applied in real clinical activities since it would require very heavy workload and highly specialized personnel. Objective: In this paper a simple solution is provided to the aforementioned dead-end. A new approach is introduced in order to provide a simple and accurate method for the mechanical characterization at the nanoscale. Method: The ratio of the work done by the indenter on the sample of interest to the work done by the indenter on a reference sample is introduced as a new physical quantity that does not require homogeneous, isotropic samples or perfect indenters. Results: The proposed approach, not only provides an accurate solution from a physical perspective but also a simpler solution which does not require activities such as the determination of the cantilever’s spring constant and the dimensions of the AFM tip. Conclusion: The proposed, by this opinion paper, solution aims to provide a significant opportunity to overcome the existing limitations provided by Hertzian mechanics and apply AFM techniques in real clinical activities.

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