scholarly journals Silane Treatment as an Effective Way of Improving the Reinforcing Activity of Carbon Nanofibers in Nitrile Rubber Composites

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3481
Author(s):  
Bolesław Szadkowski ◽  
Anna Marzec ◽  
Przemysław Rybiński
Keyword(s):  
Electrical Conductivity ◽  
Carbon Nanofibers ◽  
Ethanol Solution ◽  
Butadiene Rubber ◽  
Silane Treatment ◽  
Silane Coupling Agents ◽  
Sem Images ◽  
Silane Modification ◽  
Direct Incorporation

Two different silane treatment methods were used to improve the reinforcing activity of carbon nanofibers (CNF) in acrylonitrile-butadiene rubber (NBR) composites. The first method was chemical silanization with [3-(2-aminoethylamino)propyl]trimethoxysilane (APTS) in ethanol solution, preceded by oxidation of the CNF with H2SO4/HNO3. The second method was direct incorporation of silanes during preparation of the composites (in-situ silanization). Three different silane coupling agents were used: [3-(2-aminoethylamino)propyl]trimethoxysilane, (3-mercaptopropyl)trimethoxysilane (MPTS), and 3-ureidopropyltrimethoxysilane (UPTS). The NBR composites were prepared in an internal laboratory mixer, with increasing concentrations of pure or modified CNF. The crosslink density and flammability of the NBR-filled composites were analyzed, as well as their rheological and mechanical properties. The electrical conductivity of the composites was measured to assess the formation of CNF networks in the elastomer matrix. The morphology of the CNF was assessed by scanning electron microscopy (SEM). Both the dispersion of the CNF in the NBR matrix and the polymer-filler interactions were improved following silane modification, as shown in SEM images and by the Payne Effect. The composites were also found to have enhanced moduli, tensile strength, hardness, damping, and electrical conductivity. Chemical treatment proved to be more effective at improving the reinforcing effect of CNF in the elastomer matrix than in-situ silanization. The results of this study demonstrate the great potential of both in-situ and chemical silanization for the preparation of reinforced polymer composites filled with CNF.

REACTIONS OF SILICA–SILANE RUBBER AND PROPERTIES OF SILANE–SILICA/SOLUTION-POLYMERIZED STYRENE–BUTADIENE RUBBER COMPOSITE

2016 ◽  
Vol 89 (3) ◽  
pp. 526-539 ◽  
Author(s):  
Yan-Chun Tao ◽  
Bin Dong ◽  
Li-Qun Zhang ◽  
You-Ping Wu
Keyword(s):  
Temperature Effects ◽  
Rolling Resistance ◽  
Rubber Matrix ◽  
Styrene Butadiene Rubber ◽  
Cross Linking ◽  
Butadiene Rubber ◽  
Silane Coupling Agents ◽  
In Situ Modification ◽  
Styrene Butadiene

ABSTRACT Silane coupling agents can effectively improve the silica dispersion in rubber matrix and strengthen the interfacial interaction, and they have been widely used in tire treads to achieve low rolling resistance. 3-mercaptopropyl-ethoxy-bis(tridecyl-pentaethoxy-siloxane) (Si747) is a new coupling agent, and the temperature effects on the reactions between Si747 and silica and between Si747 and solution-polymerized styrene–butadiene rubber (SSBR) were investigated via Fourier transform infrared spectroscopy, thermogravimetric analysis, and solid-state 13C nuclear magnetic resonance in the present study. The results show that the Si747 grafting degree on the silica surface increases with increasing temperature, the cross-linking reaction between Si747 and SSBR can occur at 130 °C, and the reaction degree gradually increases with enhancing temperature. The silane–silica/SSBR composites were prepared at different in situ modification temperatures, and the temperature effects on the bound rubber content, filler dispersion, mechanical properties, and viscoelastic properties were investigated. It reveals that slightly pre-cross-linking between Si747 and SSBR lowers the tanδ at 60 °C of the SSBR/silane–silica composites, and in situ modification at 150 °C achieves a combination of low rolling resistance and high wet grip for silane–silica/SSBR composites.

scholarly journals The Analysis of Micro-Scale Deformation and Fracture of Carbonized Elastomer-Based Composites by In Situ SEM

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 587
Author(s):  
Eugene S. Statnik ◽  
Semen D. Ignatyev ◽  
Andrey A. Stepashkin ◽  
Alexey I. Salimon ◽  
Dilyus Chukov ◽  
...  
Keyword(s):  
Structural Engineering ◽  
Elastic Moduli ◽  
Carbon Composite ◽  
Image Correlation ◽  
Butadiene Rubber ◽  
Sem Images ◽  
Micro Electro Mechanical Systems ◽  
Strength Limit ◽  
Before And After

Carbonized elastomer-based composites (CECs) possess a number of attractive features in terms of thermomechanical and electromechanical performance, durability in aggressive media and facile net-shape formability, but their relatively low ductility and strength limit their suitability for structural engineering applications. Prospective applications such as structural elements of micro-electro-mechanical systems MEMS can be envisaged since smaller principal dimensions reduce the susceptibility of components to residual stress accumulation during carbonization and to brittle fracture in general. We report the results of in situ in-SEM study of microdeformation and fracture behavior of CECs based on nitrile butadiene rubber (NBR) elastomeric matrices filled with carbon and silicon carbide. Nanostructured carbon composite materials were manufactured via compounding of elastomeric substance with carbon and SiC fillers using mixing rolling mill, vulcanization, and low-temperature carbonization. Double-edge notched tensile (DENT) specimens of vulcanized and carbonized elastomeric composites were subjected to in situ tensile testing in the chamber of the scanning electron microscope (SEM) Tescan Vega 3 using a Deben microtest 1 kN tensile stage. The series of acquired SEM images were analyzed by means of digital image correlation (DIC) using Ncorr open-source software to map the spatial distribution of strain. These maps were correlated with finite element modeling (FEM) simulations to refine the values of elastic moduli. Moreover, the elastic moduli were derived from unloading curve nanoindentation hardness measurements carried out using a NanoScan-4D tester and interpreted using the Oliver–Pharr method. Carbonization causes a significant increase of elastic moduli from 0.86 ± 0.07 GPa to 14.12 ± 1.20 GPa for the composite with graphite and carbon black fillers. Nanoindentation measurements yield somewhat lower values, namely, 0.25 ± 0.02 GPa and 9.83 ± 1.10 GPa before and after carbonization, respectively. The analysis of fractography images suggests that crack initiation, growth and propagation may occur both at the notch stress concentrator or relatively far from the notch. Possible causes of such response are discussed, namely, (1) residual stresses introduced by processing; (2) shape and size of fillers; and (3) the emanation and accumulation of gases in composites during carbonization.

Reinforcement of General-Purpose Grade Rubbers by Silica Generated In Situ

2000 ◽  
Vol 73 (3) ◽  
pp. 534-550 ◽  
Author(s):  
Shinzo Kohjiya ◽  
Yuko Ikeda
Keyword(s):  
Mechanical Properties ◽  
Sol Gel ◽  
General Purpose ◽  
Diameter Distribution ◽  
Styrene Butadiene Rubber ◽  
Coupling Agents ◽  
Butadiene Rubber ◽  
Silane Coupling Agents ◽  
Silane Coupling

Abstract The use of the sol—gel process on general-purpose grade rubbers is reviewed in the absence or presence of silane coupling agents. The sol—gel reactions of tetraethoxysilane (TEOS) in epoxidized natural rubber (ENR), styrene—butadiene rubber (SBR) or butadiene rubber (BR) vulcanizates produced silica generated in situ. This silica was found to be a good reinforcing agent by investigating tensile and dynamic mechanical properties and morphology observation by transmission electron microscopy (TEM). The amount of silica formed was limited by the degree of swelling of the rubber vulcanizate by TEOS which was the precursor of the silica. However, the dispersion of silica generated in situ was better than conventionally added silica due to its formation in place. Also, it was noted that the diameter distribution of in situ silica was monodispersed. Silane coupling agents, such as mercaptosilane, aminosilane, and bis(3-triethoxysilylpropyl) tetrasulfide, were compounded in the vulcanizates and their effects on silica generated in situ were evaluated. Their effects were significant. The dispersion of the silica in the rubbery matrix became better and the particle size became smaller and monodispersed, as observed by TEM, which improved mechanical properties. The superior properties of silica generated in situ have been studied further to elucidate the mechanism of reinforcement.

scholarly journals Thermoplastic Dynamic Vulcanizates with In Situ Synthesized Segmented Polyurethane Matrix

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1663 ◽  
Author(s):  
Andrea Kohári ◽  
István Zoltán Halász ◽  
Tamás Bárány
Keyword(s):  
Mechanical Properties ◽  
Butadiene Rubber ◽  
Scanning Calorimetry ◽  
Dynamic Vulcanization ◽  
Sem Images ◽  
Acrylonitrile Butadiene Rubber ◽  
Atomic Force ◽  
Rubber Particles ◽  
Rubber Phase

The aim of this paper was the detailed investigation of the properties of one-shot bulk polymerized thermoplastic polyurethanes (TPUs) produced with different processing temperatures and the properties of thermoplastic dynamic vulcanizates (TDVs) made by utilizing such in situ synthetized TPUs as their matrix polymer. We combined TPUs and conventional crosslinked rubbers in order to create TDVs by dynamic vulcanization in an internal mixer. The rubber phase was based on three different rubber types: acrylonitrile butadiene rubber (NBR), carboxylated acrylonitrile butadiene rubber (XNBR), and epoxidized natural rubber (ENR). Our goal was to investigate the effect of different processing conditions and material combinations on the properties of the resulting TDVs with the opportunity of improving the interfacial connection between the two phases by chemically bonding the crosslinked rubber phase to the TPU matrix. Therefore, the matrix TPU was synthesized in situ during compounding from diisocyanate, diol, and polyol in parallel with the dynamic vulcanization of the rubber mixture. The mechanical properties were examined by tensile and dynamical mechanical analysis (DMTA) tests. The morphology of the resulting TDVs was studied by atomic force microscopy (AFM) and scanning electron microscopy (SEM) and the thermal properties by differential scanning calorimetry (DSC). Based on these results, the initial temperature of 125 °C is the most suitable for the production of TDVs. Based on the atomic force micrographs, it can be assumed that phase separation occurred in the TPU matrix and we managed to evenly distribute the rubber phase in the TDVs. However, based on the SEM images, these dispersed rubber particles tended to agglomerate and form a quasi-continuous secondary phase where rubber particles were held together by secondary forces (dipole–dipole and hydrogen bonding) and can be broken up reversibly by heat and/or shear. In terms of mechanical properties, the TDVs we produced are on a par with commercially available TDVs with similar hardness.

scholarly journals Improved Electrical Conductivity of Carbon/Polyvinyl Alcohol Electrospun Nanofibers

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Nader Shehata ◽  
Nabil Madi ◽  
Mariam Al-Maadeed ◽  
Ibrahim Hassounah ◽  
Abdullah Ashraf
Keyword(s):  
Electrical Conductivity ◽  
Polyvinyl Alcohol ◽  
Mass Loss ◽  
Carbon Nanofibers ◽  
Mechanical Characteristics ◽  
Gas Adsorption ◽  
Electrospun Nanofibers ◽  
Electrospinning Process ◽  
Sem Images ◽  
Deposition Techniques

Carbon nanofibers (CNFs) gained much interest in the last few years due to their promising electrical, chemical, and mechanical characteristics. This paper investigates a new nanocomposite composed of carbon nanofibers hosted by PVA and both are integrated in one electrospun nanofibers web. This technique shows a simple and cheap way to offer a host for CNFs using traditional deposition techniques. The results show that electrical conductivity of the formed nanofibers has been improved up to 1.63 × 10−4 S/cm for CNFs of weight 2%. The peak temperature of mass loss through TGA measurements has been reduced by 2.3%. SEM images show the homogeneity of the formed PVA and carbon nanofibers in one web, with stretched CNFs after the electrospinning process. The formed nanocomposite can be used in wide variety of applications including nanoelectronics and gas adsorption.

In-situ Modification of Graphene Oxide by Insoluble Sulfur and Application for Nitrile Butadiene Rubber

2020 ◽  
Vol 35 (2) ◽  
pp. 221-228
Author(s):  
S.-B. Chen ◽  
T.-X. Li ◽  
S.-H. Wan ◽  
X. Huang ◽  
S.-W. Cai ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Butadiene Rubber ◽  
Nitrile Butadiene Rubber ◽  
In Situ Modification

scholarly journals A new method for preparing excellent electrical conductivity carbon nanofibers from coal extraction residual

2021 ◽  
pp. 100109
Author(s):  
Wenyang Lu ◽  
Tongtong Wang ◽  
Xin He ◽  
Kaidi Sun ◽  
Zaixing Huang ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Carbon Nanofibers ◽  
New Method ◽  
Coal Extraction

Electrical conductivity and hydrophobicity of graphene oxide-modified carbon nanofibers

2021 ◽  
pp. 138551
Author(s):  
He-Dong Huang ◽  
Zeyu Guo ◽  
Peng-yan Yang ◽  
Peng Chen ◽  
Jie Wu
Keyword(s):  
Electrical Conductivity ◽  
Graphene Oxide ◽  
Carbon Nanofibers

Chemically reduced graphene oxide-coated knitted fabric imparted conductivity and outstanding hydrophobicity

2021 ◽  
pp. 004051752199547
Author(s):  
Min Hou ◽  
Xinghua Hong ◽  
Yanjun Tang ◽  
Zimin Jin ◽  
Chengyan Zhu ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Chemical Reduction ◽  
Knitted Fabric ◽  
Mesh Structure ◽  
Reduced Graphene ◽  
Chemically Reduced Graphene Oxide ◽  
Modified Hummers Method

Functionalized knitted fabric, as a kind of flexible, wearable, and waterproof material capable of conductivity, sensitivity and outstanding hydrophobicity, is valuable for multi-field applications. Herein, the reduced graphene oxide (RGO)-coated knitted fabric (polyester/spandex blended) is prepared, which involves the use of graphite oxide (GO) by modified Hummers method and in-situ chemical reduction with hydrazine hydrate. The treated fabric exhibits a high electrical conductivity (202.09 S/cm) and an outstanding hydrophobicity (140°). The outstanding hydrophobicity is associated with the morphology of the fabric and fiber with reference to pseudo-infiltration. These properties can withstand repeated bending and washing without serious deterioration, maintaining good electrical conductivity (35.70 S/cm) and contact angle (119.39°) after eight standard washing cycles. The material, which has RGO architecture and continuous loop mesh structure, can find wide use in smart garment applications.

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