scholarly journals Experimental Investigation on the Effect of Graphene Oxide Additive on the Steady-State and Dynamic Shear Properties of PDMS-Based Magnetorheological Elastomer

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1777
Author(s):  
Minzi Liu ◽  
Mei Zhang ◽  
Jiangtao Zhang ◽  
Yanliang Qiao ◽  
Pengcheng Zhai

Isotropic polydimethylsiloxane (PDMS)-based magnetorheological elastomers (MREs) filled with various contents of graphene oxide (GO) additive were fabricated by the solution blending-casting method in this work. The morphologies of the produced MREs were characterized, and the results indicate that the uniform distribution of GO sheets and carbonyl iron particles (CIPs) becomes difficult with the increase of GO content. The steady-state and dynamic shear properties of the MREs under different magnetic field strengths were evaluated using parallel plate rheometer. It was found that the physical stiffness effect of GO sheets leads to the increase of the zero-field shear modulus with increasing GO content under both the steady-state and dynamic shear loads. The chemical crosslinking density of PDMS matrix decreases with the GO content due to the strong physical crosslinking between GO and the PDMS matrix. Thus, the MREs filled with higher GO content exhibit more fluid-like behavior. Under the dynamic shear load, the absolute MR effect increases with the GO content due to the increased flexibility of the PDMS matrix and the dynamic self-stiffening effect occurring in the physical crosslinking interfaces around GO sheets. The highest relative MR effect was achieved by the MREs filled with 0.1 wt.% GO sheets. Then, the relative MR effect decreases with the further increase of GO content due to the improved zero-field modulus and the increased agglomerations of GO and CIPs. This study shows that the addition of GO sheets is a possible way to prepare new MREs with high MR effect, while simultaneously possessing high zero-field stiffness and load bearing capability.

MRS Advances ◽  
2019 ◽  
Vol 4 (15) ◽  
pp. 879-887
Author(s):  
Rebecca Isseroff ◽  
Jerry Reyes ◽  
Roshan Reddy ◽  
Nicholas Williams ◽  
Miriam Rafailovich

ABSTRACTA significant drawback of enzyme use in industrial applications is its lack of stability. Graphene oxide (GO) has previously been investigated for enzyme immobilization and enhancement of enzymatic catalysis. Microbial transglutaminase (MTG) is an enzyme that is used to modify food proteins, increase durability of textiles, and crosslink hydrogels for drug delivery. We tested the effects of adding GO and partially reduced GO (pRGO) to water solutions of gelatin and then crosslinking it with MTG, measuring both the resulting gelatin modulus and then the time it took for the onset of gelation. We found that the presence of pRGO in a gelatin-MTG-water mixture (when using 0.75 g MTG in 10 ml of gelatin solution) significantly increases the modulus by 60% more than the control. Using this same concentration of MTG, we measured the onset of gelation time and found that pRGO in gelatin solution reduces the onset of gelation time by nearly 50% while inducing a very large increase in viscosity by three orders of magnitude, whereas the addition of GO increases the onset of gelation time by 33% and decreases the viscosity of the gel by more than one order of magnitude. The very large enhancement by pRGO of the viscosity may be due to pRGO’s electron withdrawing ability and/or may also be due to adsorption of gelatin to the pRGO platelets which effectively increases the crosslinking density through non-enzymatic processes assisting the enzymatic activity.


1981 ◽  
Vol 34 (3) ◽  
pp. 223 ◽  
Author(s):  
RE Robson

The combined effect of interaction of electrons with walls, neutral molecules and an electrostatic field is considered through analytic solution of Boltzmann's equation. In the first instance, we discuss a half-range decomposition in velocity space, corresponding to electrons moving to and from the walls, which is valid for all types of electron-molecule interactions. The half-range equations are solved in the steady state for zero field and the constant mean free path model, and it is shown that the familiar full-range 'two-term' approximation equations are adequate in this case, as far as estimating bulk properties of the electrons is concerned. For the nonzero field, again in the steady state, the full-range equations are solved for the constant collision frequency model.


Author(s):  
Wen-Bin Shangguan ◽  
Yumin Wei ◽  
Subhash Rakheja ◽  
Xu Zhao ◽  
Jun-wei Rong ◽  
...  

The natural frequency is the key performance parameters of a rubber materials damper, and it is determined by the static and dynamic shear properties of the rubber materials (rubber ring) and the moment of inertia of the inertia ring. The rubber ring is usually in compression state, and its static and dynamic shear properties are dependent on its sizes, compression ratio and chemical ingredients. A special fixture is designed and used for measuring static and dynamic shear performance of a rubber ring under different compression ratios in the study. To characterize the shear static and dynamic performances of rubbers, three constructive models (Kelvin-Voigt, the Maxwell and the fractional derivative constitutive model) are presented and the method for obtaining the model parameters in the fractional derivative constructive models are developed using the measured dynamic performance of a rubber shear specimen. The natural frequency of a rubber materials damper is calculated using the fractional derivative to characterize the rubber ring of the damper, and the calculated frequencies are compared with the measurements.


1995 ◽  
Vol 34 (6) ◽  
pp. 586-600 ◽  
Author(s):  
Carlos Tiu ◽  
Tony Moussa ◽  
Pierre J. Carreau

2007 ◽  
Vol 40 (7) ◽  
pp. 1477-1483 ◽  
Author(s):  
Eiji Tanaka ◽  
Toshihiro Inubushi ◽  
Koji Takahashi ◽  
Maya Shirakura ◽  
Ryota Sano ◽  
...  

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