Preparation and characterization of silicone rubber/graphene nanosheets nanocomposites by in-situ loading of the coupling agent

2019 ◽  
Vol 53 (24) ◽  
pp. 3459-3468
Author(s):  
Elnaz Esmizadeh ◽  
Mostafa Arjmandpour ◽  
A Vahidifar ◽  
Ghasem Naderi ◽  
Charles Dubois
Keyword(s):  
Mechanical Properties ◽  
Silicone Rubber ◽  
Coupling Agent ◽  
Loss Modulus ◽  
Graphene Nanosheets ◽  
Low Frequency ◽  
Cure Kinetics ◽  
Relaxation Processes ◽  
Tensile Data

Inexpensive approach to fully disperse graphene nanosheet (GNS) in silicone rubber (SR) by the addition of (3-Aminopropyl) triethoxysilane (APTES) as the coupling agent is presented in this study. The effects of GNS loading and presence of APTES on the cure characteristics, dynamic-mechanical, rheological and mechanical properties of the resulting SR compounds were systematically studied by rheometry, DMTA and tensile testing, respectively. The obtained results were correlated with the microstructure of the samples investigated by SEM and TEM analyses. Vulcanization curves revealed that the GNS and the coupling agent had an accelerating effect on the cure kinetics of the SR compounds leading to a steady decrease in scorch time and optimum cure time along with a gradual increase in the effective torque value. Morphological results showed that the GNSs could disperse more homogeneously within SR matrix using a simple solution mixing approach by in-situ loading of APTES. DMTA results showed restricted relaxation processes in GNS-reinforced SR systems in comparison with the pure SR, with more pronounced effect for the system containing APTES owing to improved interactions between graphene and SR which prevented the molecular mobility of neighboring chains of SR matrix. The tensile data demonstrated about 20% rise of modulus in the GNS-filled rubber nanocomposites in the presence of APTES. Low-frequency rheological properties including the storage modulus (G′), the loss modulus (G″), and complex shear viscosity (η*) showed a significant increase of about 10-fold, 75% and 20%, respectively, with the incorporation of APTES and GNS. Thus it could be expected that APTES had a substantial potential to be applied in-situ as the coupling agent to fabricate SR/GNS nanocomposites with exfoliated GNS morphology and increased the rheological and mechanical properties.

Preparation and Characterization of In Situ Nanocomposites of Graphene Nanosheets/Polyurethane

2019 ◽  
Vol 814 ◽  
pp. 90-95 ◽  
Author(s):  
Guang Lei Lv ◽  
Yuan Yuan Li ◽  
Chen Fei ◽  
Zhi Hao Shan ◽  
Jing Gan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Tensile Strength ◽  
Graphene Nanosheets ◽  
Graphene Sheets ◽  
Microstructural Properties ◽  
Wear Performance ◽  
Polyurethane Composites

Graphene nanosheets/polyurethane (GNS/PU) was prepared in situ by polymerization technique for the manufacture of PU safety shoes soles. The graphene nanosheets/polyurethane composites were characterized for their mechanical properties, thermal conductivity and abrasion resistance, and comparison is made with those of the neat polyurethane. The microstructural properties of GNS/PU were characterized by SEM. The results show that with the increase of the amount of graphene within the range of weight-percentages analyzed, the tensile strength of the composites gradually increases. The tensile strength of the GNS/PU composites increased to 64.14 MPa with 2 wt% GNS, compared with 55.1 MPa for neat PU. When the graphene sheets reached 2 wt%, the abrasion volume reached 71 mm3. Compared with the pure PU, the wear performance of GNS/PU composites was significantly improved.

In situ tensile fracturing of multilayer graphene nanosheets for their in-plane mechanical properties

2019 ◽  
Vol 30 (47) ◽  
pp. 475708 ◽  
Author(s):  
Peifeng Li ◽  
Ke Cao ◽  
Chenchen Jiang ◽  
Shang Xu ◽  
Libo Gao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Graphene Nanosheets ◽  
Multilayer Graphene ◽  
Tensile Fracturing

scholarly journals Dynamics of Excitation and Inhibition in the Light-Adapted Limulus Eye in situ

1971 ◽  
Vol 58 (1) ◽  
pp. 1-19 ◽  
Author(s):  
Marguerite Biederman-Thorson ◽  
John Thorson
Keyword(s):  
Steady State ◽  
Lateral Inhibition ◽  
Low Frequency ◽  
Dynamic Responses ◽  
Relaxation Processes ◽  
Pass Filter ◽  
Generator Potential ◽  
Low Pass Filter ◽  
Low Pass

The dynamics of spike discharge in eccentric cell axons from the in situ lateral eye of Limulus, under small sinusoidal modulation of light to which the eye is adapted, are described over two decades of light intensity and nearly three decades of frequency. Steady-state lateral inhibition coefficients, derived from the very low-frequency response, average 0.04 at three interommatidial spacings. The gain vs. frequency of a singly illuminated ommatidium is described closely from 0.004 to 0.4 cps by the linear transfer function s0.25; this function also accounts approximately for the measured phase leads, the small signal adaptation following small step inputs, and for Pinter's (1966) earlier low-frequency generator potential data. We suggest that such dynamics could arise from a summation in the generator potential of distributed intensity-dependent relaxation processes along the dendrite and rhabdome. Analysis of the dynamic responses of an eccentric cell with and without simultaneously modulated illumination of particular neighbors indicates an effect equivalent to self-inhibition acting via a first-order low-pass filter with time constant 0.42 sec, and steady-state gain near 4.0. The corresponding filters for lateral inhibition required time constants from 0.35 to 1 sec and effective finite delay of 50–90 msec.

Rheology, morphology and mechanical properties of LLDPE/PS blends catalyzed by combined Lewis acids

e-Polymers ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
Yan-Long Liu ◽  
Li-Gang Yin ◽  
Zhuo Ke ◽  
Qiang Shi ◽  
Jing-Hua Yin
Keyword(s):  
Mechanical Properties ◽  
Storage Modulus ◽  
Lewis Acids ◽  
Low Frequency ◽  
Complex Viscosity ◽  
Reactive Blending ◽  
Izod Impact ◽  
Rheological Experiments ◽  
And Storage

AbstractThe rheological, morphological and mechanical properties of LLDPE/PS blends with a combined catalyst, Me3SiCl and InCl3·4H2O, were studied in this work. The higher complex viscosity and storage modulus at low frequency were ascribed to the presence of graft copolymers, which were in situ formed during the mixing process. From the rheological experiments, the complex viscosity and storage modulus of reactive blends were higher than the physical blends. The dispersion of LLDPE particles of reactive blending becomes finer than that of physical blends, consistent with the rheological results. As a result of increased compatibility between LLDPE/PS, the mechanical properties of reactive blends show much higher tensile and Izod impact strength than those of physical blends.

FABRICATION AND PROPERTIES OF SILICONE RUBBER/ZnO NANOCOMPOSITES VIA IN SITU SURFACE HYDROSILYLATION

2011 ◽  
Vol 18 (01n02) ◽  
pp. 33-38 ◽  
Author(s):  
ZHIJIE YUAN ◽  
WEIHUA ZHOU ◽  
TING HU ◽  
YIWANG CHEN ◽  
FAN LI ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Silicone Rubber ◽  
Zno Nanoparticles ◽  
Photoelectron Spectroscopy ◽  
Rubber Matrix ◽  
Thermal Stabilities ◽  
X Ray ◽  
Vinyl Silane

The silicone rubber (SR) nanocomposites have been successfully prepared via the in situ hydrosilylation reaction in the presence of pristine ZnO and vinyl silane modified ZnO ( SiVi@ ZnO ) nanoparticles. The structure of the pristine ZnO and SiVi @ ZnO nanoparticles were analyzed by the Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), respectively. The morphology, thermal stabilities, mechanical properties and thermal conductivity of the nanocomposites were also investigated. The results showed that the SiVi @ ZnO nanoparticles exhibit a better dispersion in the silicone rubber than the pristine ZnO nanoparticles. The corresponding silicone rubber/ SiVi @ ZnO (SR/ SiVi @ ZnO ) nanocomposites showed higher mechanical properties and thermal conductivity due to the better dispersion in silicone rubber matrix.

scholarly journals Reactive Compatibilization of Polyamide 6/Olefin Block Copolymer Blends: Phase Morphology, Rheological Behavior, Thermal Behavior, and Mechanical Properties

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1146 ◽  
Author(s):  
Xintu Lin ◽  
Yuejun Liu ◽  
Xi Chen ◽  
Yincai Wu ◽  
Lingna Cui ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Block Copolymer ◽  
Impact Strength ◽  
Thermal Behavior ◽  
Rheological Behavior ◽  
Loss Modulus ◽  
Low Frequency ◽  
Polyamide 6 ◽  
Particle Dispersion ◽  
Experimental Conditions

In this study, the morphology, rheological behavior, thermal behavior, and mechanical properties of a polyamide 6 (PA6) and olefin block copolymer (OBC) blend compatibilized with maleic anhydride-grafted polyethylene-octene copolymer (POE-g-MAH) were investigated. The morphological observations showed that the addition of POE-g-MAH enhanced the OBC particle dispersion in the PA6 matrix, suggesting a better interfacial compatibility between the pure PA6 and OBC. The results of the Fourier transform infrared (FTIR) spectroscopy analysis and the Molau test confirmed the compatibilization reactions between POE-g-MAH and PA6. The rheological test revealed that the melt viscosity, storage modulus (G’), and loss modulus (G”) of the compatibilized PA6/OBC blends at low frequency were increased with the increasing POE-g-MAH content. The thermal analysis indicated that the addition of OBC had little effect on the crystallization behavior of PA6, while the incorporation of POE-g-MAH at high content (7 wt%) in the PA6/OBC blend restricted the crystallization of PA6. In addition, the compatibilized blends exhibited a significant enhancement in impact strength compared to the uncompatibilized PA6/OBC blend, in which the highest value of impact strength obtained at a POE-g-MAH content of 7 wt% was about 194% higher than that of pure PA6 under our experimental conditions.

Fabrication of bionanocomposites reinforced with hemp nanocellulose and evaluation of their mechanical, thermal and dynamic mechanical properties

2021 ◽  
pp. 146442072110046
Author(s):  
SS Rana ◽  
MK Gupta
Keyword(s):  
Mechanical Properties ◽  
In Situ Polymerization ◽  
Loss Modulus ◽  
Dynamic Mechanical Properties ◽  
X Ray Diffraction ◽  
Dynamic Mechanical ◽  
Hemp Fibres ◽  
Polymerization Method

The present study aims to fabricate the epoxy-based bionanocomposites reinforced with hemp nanocellulose and the evaluation of their mechanical, thermal and dynamic mechanical properties. Nanocellulose from hemp fibres was isolated via the chemo-mechanical method and its bionanocomposites were prepared using the in situ polymerization method. Although many researchers have reported studies on the preparation and characterization of bionanocomposites however, studies on the mechanical, thermal, and dynamic mechanical properties of epoxy-based bionanocomposites reinforced with hemp nanocellulose are still unreported. The mechanical properties (i.e. tensile, flexural, hardness, and impact) and dynamic mechanical properties (i.e. glass transition temperature, damping behaviour, storage, and loss modulus) of the developed bionanocomposites were investigated. Further, the crystalline behaviour and thermal stability were also studied using the X-ray diffraction and thermogravimetric analysis techniques, respectively. The results revealed that an addition of nanocellulose considerably improved the mechanical, thermal, and viscoelastic properties of the bionanocomposites. As much as 52.17%, 48.17%, 89.08%, and 15.67% improvements in the tensile strength, flexural strength, impact strength, and hardness, respectively, for the 2 wt.% nanocellulose composites were found over the epoxy matrix.

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