scholarly journals Manifestation of Interactions of Nano-Silica in Silicone Rubber Investigated by Low-Frequency Dielectric Spectroscopy and Mechanical Tests

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 717 ◽  
Author(s):  
Chao Wu ◽  
Yanfeng Gao ◽  
Xidong Liang ◽  
Stanislaw M. Gubanski ◽  
Qian Wang ◽  
...  
Keyword(s):  
Silicone Rubber ◽  
Power Transmission ◽  
Mechanical Performance ◽  
Filler Content ◽  
Low Frequency ◽  
Mechanical Tests ◽  
Nano Silica ◽  
Rubber Composites ◽  
Rubber Composite ◽  
Surface Modified

Silicone rubber composites filled with nano-silica are currently widely used as high voltage insulating materials in power transmission and substation systems. We present a systematic study on the dielectric and mechanical performance of silicone rubber filled with surface modified and unmodified fumed nano-silica. The results indicate that the different interfaces between the silicone rubber and the two types of nano-silica introduce changes in their dielectric response when electrically stressed by a sinusoidal excitation in the frequency range of 10−4–1 Hz. The responses of pure silicone rubber and the composite filled with modified silica can be characterized by a paralleled combination of Maxwell-Wagner-Sillars interface polarization and DC conduction. In contrast, the silicone rubber composite with the unmodified nano-silica exhibits a quasi-DC (Q-DC) transport process. The mechanical properties of the composites (represented by their stress-strain characteristics) reveal an improvement in the mechanical strength with increasing filler content. Moreover, the strain level of the composite with a modified filler is improved.

Effects of Micro-Eggshells Filler on Tracking and Erosion Resistance of Silicone Rubber Composites

2020 ◽  
Vol 846 ◽  
pp. 37-41
Author(s):  
Pattarabordee Khaigunha ◽  
Tanakorn Wongwuttanasatian ◽  
Amnart Suksri
Keyword(s):  
Thermal Stability ◽  
Heat Resistance ◽  
Silicone Rubber ◽  
Erosion Resistance ◽  
Rubber Composites ◽  
Surface Tracking ◽  
Rubber Composite ◽  
The Matrix ◽  
Thermal Stability Of ◽  
Inclined Plane Test

This study investigates the effects of micron-sized eggshells filler on resistance to tracking and erosion of silicone rubber composite. Eggshells with particle size from 44 to 53 microns were filled into liquid room temperature vulcanizing (RTV) silicone rubber with 0, 5, 15, 25, and 30 part per hundred of rubber (phr). IEC-60587 inclined plane test (IPT) was employed to appraise the surface tracking resistance. Thermogravimetric analysis was conducted to evaluate its thermal stability. Experimental results revealed an improvement of tracking and erosion resistance due to an addition of eggshells particles. Furthermore, the thermal stability of the composites showed variation in the increasing amount of the filler. The filler indicated that higher thermal stability of eggshells influences the heat resistance of the matrix. An increase of the heat resistance resulted in the ability to slow down tracking growth and erosion in the discharge region.

Fatigue of Cord—Rubber Composites: II. Strain-Based Failure Criteria

1998 ◽  
Vol 71 (5) ◽  
pp. 866-888 ◽  
Author(s):  
B. L. Lee ◽  
B. H. Ku ◽  
D. S. Liu ◽  
P. K. Hippo
Keyword(s):  
Fatigue Life ◽  
Carbon Black ◽  
Composite Laminates ◽  
Stress Amplitude ◽  
Low Frequency ◽  
Cyclic Strain ◽  
Rubber Composites ◽  
Dynamic Creep ◽  
Rubber Composite ◽  
The Matrix

Abstract Fatigue failure mechanisms under low-frequency loading and their dependence on the strain properties were assessed for the rubber matrix composite of bias aircraft tire carcass reinforced by nylon cords as well as two model rubber composites reinforced by steel wire cables. Under cyclic tension at constant stress amplitude, these angle-plied, cord—rubber composite laminates exhibited localized damage in the form of cord—matrix debonding, matrix cracking, and delamination. The process of fatigue damage accumulation in the cord—rubber composite laminate was accompanied by a steady increase of cyclic strain (dynamic creep) and moderate temperature changes. The fatigue life was found to be linearly proportional to the inverse of the dynamic creep rate, i.e., the time required to increase cyclic strain by a unit amount. Regardless of the associated level of stress amplitude or fatigue life, the gross failure under low-frequency loading occurred when the total strain accumulation, i.e., cumulative creep strain, reached the static failure strain. The use of higher stress amplitude resulted in a decrease of fatigue life by simply shortening the time to reach the critical level of strain for gross failure. This observation indicates that the damage initiation and eventual structural failure of angle-plied, cord—rubber composite laminates are “ strain-controlled” processes. These critical strain properties appear to be controlled by the process of interfacial failure between the cord and matrix. Under static tension, the strain levels for cord—matrix debonding and gross failure of composite laminates showed no significant dependence on the level of carbon black loading of the matrix compound, despite the fact that carbon black loading strongly affected the modulus, strength and strain properties of the matrix. Also the number of debonding sites around the cut ends of cords increased at almost the same rate as the static strain increased regardless of the variation of matrix properties.

Assessment of mechanical strength of nano silica concrete (NSC) subjected to elevated temperatures

2019 ◽  
Vol 10 (1) ◽  
pp. 90-109 ◽  
Author(s):  
Hala Mohamed Elkady ◽  
Ahmed M. Yasien ◽  
Mohamed S. Elfeky ◽  
Mohamed E. Serag
Keyword(s):  
Elevated Temperature ◽  
Bond Strength ◽  
Elevated Temperatures ◽  
Mechanical Performance ◽  
Mechanical Tests ◽  
Nano Silica ◽  
Content Type ◽  
Post Exposure ◽  
Concrete Mix ◽  
Bond Strengths

Purpose This paper aims to inspect the effect of indirect elevated temperature on the mechanical performance of nano silica concrete (NSC). The effect on both compressive and bond strengths is studied. Pre- and post-exposure to elevated temperature ranges of 200 to 600°C is examined. A range covered by three percentages of 1.5, 3 and 4.5 per cent nano silica (NS) in concrete mixes is tested. Design/methodology/approach Pre-exposure mechanical tests (normal conditions – room temperature), using 3 per cent NS in the concrete mix, led to the highest increase in both compressive and bond strengths (43 per cent and 38.5 per cent, respectively), compared to the control mix without NS (based on 28-day results). It is worth noticing that adding NS to the concrete mixes does not have a significant effect on improving early-age strength. Besides, permeability tests are performed on NSC with different NS ratios. NS improved the concrete permeability for all tested percentages of NS. The maximum reduction is accompanied by the maximum percentage used (4.5 per cent NS in the NSC mix), reducing permeability to half the value of the concrete mix without NS. As for post-exposure to elevated-temperature mechanical tests, NSC with 1.5 per cent NS exhibited the lowest loss in strength owing to indirect heat exposure of 600°C; the residual compressive and bond strengths are 73 per cent and 35 per cent, respectively. Findings The dispersion technique of NS has a key role in NSC-distinguished mechanical performance with NSC having lower NS percentages. NS significantly improved bond strength. NS has a remarkable effect on elevated temperature endurance. The bond strength of NSC exposed to elevated temperatures suffered faster deterioration than compressive strength of the exposed NSC. Research limitations/implications A special scale factor needs to be investigated for the NSC. Originality/value Although a lot of effort is placed in evaluating the benefits of using nano materials in structural concrete, this paper presents one of the first outcomes of the thermal effects on concrete mixes with NS as a partial cement replacement.

Numerical Simulation for Mechanical Behavior of Carbon Black Filled Rubber Composites Based on Cubic Representative Volume Element

2014 ◽  
Vol 627 ◽  
pp. 285-288
Author(s):  
Qing Li ◽  
Xiao Xiang Yang
Keyword(s):  
Carbon Black ◽  
Representative Volume Element ◽  
Filler Content ◽  
Numerical Models ◽  
Volume Element ◽  
Experimental Results ◽  
Rubber Composites ◽  
Strain Behavior ◽  
Filled Rubber ◽  
Rubber Composite

Based on the connection between macroscopic and microscopic characteristics of carbon black filled rubber composites, Representative Volume Element (RVE) containing one single particle has been proposed, and three dimensional cubic RVE has been established to study and analyze the macroscopic mechanical properties of the carbon black filled rubber composites by the micromechanical finite element method. The research shows that the stiffness of the composite is increased with the increase of the volume fraction of carbon black filler particles. By comparison, it is shown that the results of the predictions on the stress-strain behavior of the rubber composite made with the cubic RVE numerical models containing one spherical particle are in good agreement with the experimental results for seven and fifteen percent carbon black filler content, but there is some discrepancy between them for twenty-five percent carbon black filler content. The results of the predictions on the stress-strain behavior of the rubber composite made with the cubic RVE numerical models containing one cubical particle are higher than the experimental results, and the higher the carbon black filler content, the greater is the discrepancy between them.

Study on Short Basalt Fiber Reinforced Silicone Rubber Composites

2013 ◽  
Vol 800 ◽  
pp. 383-386 ◽  
Author(s):  
Wei Li Wu ◽  
Jin Yue Cai
Keyword(s):  
Mechanical Properties ◽  
Composite Materials ◽  
Silicone Rubber ◽  
Basalt Fiber ◽  
Rubber Composites ◽  
Excellent Performance ◽  
Elongation At Break ◽  
Rubber Composite ◽  
Insulating Properties ◽  
Ozone Resistance

Silicone rubber has excellent performance, such as cold resistance, heat resistance, ozone resistance, thermal properties and insulating properties and so on. However, silicone rubber is in the state of semi-liquids and it is very soft, so the mechanical properties of silicone rubber are very poor. In order to improve its availability of silicone rubber, short basalt fiber / silicone rubber composite materials were prepared by using short basalt fiber as reinforcement, and its mechanical properties and compatibility were studied. The best formulation of short basalt fiber / silicone rubber composite materials were determined by testing Shore A hardness, tensile strength and elongation at break, and the morphology structure and compatibility of short basalt fiber / silicone rubber composite materials were discussed by scanning electron microscope and infrared spectrum, prepare excellent performance of silicone rubber composite materials.

Enhancing the Piezoresistance Senstivity and Repeatability of Carbon Nanotube/Silicone Nanocomposites

2014 ◽  
Vol 590 ◽  
pp. 207-210
Author(s):  
Xiao Xiang Zhang ◽  
Long Ba
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Composite Materials ◽  
Carbon Black ◽  
Silicone Rubber ◽  
Smart Materials ◽  
Biomedical Engineering ◽  
Rubber Composites ◽  
Rubber Composite ◽  
Percolation Network

The nanocomposites of carbon nanotube/polymer have been studied to explore their piezoresistance properties, which can be used as smart materials in the fields like biomedical engineering, robotic engineering, and advanced instrumentation. The differences in piezoresistance behavior of the previous studies were explained by the less uniformity of carbon nanotubes. To clarify the resistance versus deformation relations for carbon nanotube/silicone rubber composite materials, we have fabricated composite materials with various nanotube and carbon black contents. The measurements show that the resistance versus deformation sensitive range is depends on both the content of nanotube and carbon black, while the tiny variation of content of the carbon black affects largely the total piezoresistance sensitivity and repeatability. The experiment shows that adequate amount of carbon balck mixed with carbon nanotube can improve the piezoresistance repeatability. The deformation induced variation of the conducting percolation network shall be the dominating mechanism for the piezoresistance behavior of carbon nanotube/silicone rubber composites.

scholarly journals Surface Modification of Staple Carbon Fiber by Dopamine to Reinforce Natural Latex Composite

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 988
Author(s):  
Xiaolong Tian ◽  
Shuang Han ◽  
Qianxiao Zhuang ◽  
Huiguang Bian ◽  
Shaoming Li ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
High Performance ◽  
Dynamic Mechanical Properties ◽  
Rubber Matrix ◽  
National Defense ◽  
Rubber Composites ◽  
Rubber Composite ◽  
Thermal And Electrical Properties ◽  
Surface Modified ◽  
Poor Adhesion

Carbon fiber significantly enhances the mechanical, thermal and electrical properties of rubber composites, which are widely used in aerospace, military, national defense and other cutting-edge fields. The preparation of a high-performance carbon fiber rubber composite has been a research hotspot, because the surface of carbon fiber is smooth, reactive inert and has a poor adhesion with rubber. In this paper, a high-performance rubber composite is prepared by mixing dopamine-modified staple carbon fiber with natural latex, and the mechanisms of modified carbon fiber-reinforced natural latex composite are explored. The experimental results show that the surface-modified staple carbon fiber forms uniform and widely covered polydopamine coatings, which significantly improve the interface adhesion between the carbon fiber and the rubber matrix. Meanwhile, when the concentration of dopamine is 1.5 g/L and the staple carbon fiber is modified for 6h, the carbon fiber rubber composite shows excellent conductivity, thermal conductivity, and dynamic mechanical properties, and its tensile strength is 10.6% higher than that of the unmodified sample.

Preparation and Characterization of Graphene/RTV Silicone Rubber Composites

2013 ◽  
Vol 652-654 ◽  
pp. 11-14 ◽  
Author(s):  
Jian Dong ◽  
Peng Hui Wang ◽  
Dao Bao Sun ◽  
Yu Liang Xu ◽  
Ke Peng Li
Keyword(s):  
Silicone Rubber ◽  
Graphene Nanosheets ◽  
Continuous Phase ◽  
Rubber Composites ◽  
Parallel Sample ◽  
Sem Study ◽  
Rubber Composite ◽  
Dsc Curves ◽  
Rtv Silicone Rubber

In this article we report the preparation of a graphene/room temperature vulcanized (RTV) silicone rubber composite. Both the morphology and the properties of the composite were investigated in detail. SEM study shows that the composite has a microphase-separated structure. PDMS is the continuous phase, and the randomly distributed graphene nanosheets and a few aggregates are the dispersed phase. However, DSC curves of the composites have only one glass transition temperature (Tg). With the increases of the graphene content, Tg increases and Tm decreases. Mechanical properties tests show that the addition of graphene has a significant reinforcement effect on silicone rubber. The tensile strength is 0.37MPa with graphene mass fraction at 1.0%, which increases 76% compared with that of pure silicone rubber parallel sample.

scholarly journals Surface Recovery Investigation of Silicone Rubber Composites for Outdoor Electrical Insulation under Accelerated Temperature and Humidity

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3024
Author(s):  
M. Hassan Raza ◽  
Abraiz Khattak ◽  
Asghar Ali ◽  
Safi Ullah Butt ◽  
Bilal Iqbal ◽  
...  
Keyword(s):  
High Temperature ◽  
Silicone Rubber ◽  
Room Temperature ◽  
Nano Silica ◽  
Rubber Composites ◽  
Temperature And Humidity ◽  
Before And After ◽  
Overall Performance ◽  
Alumina Trihydrate ◽  
Better Than

Degradation of silicon rubber due to heat and humidity affect its performance in outdoor applications. To analyze the effects of high temperature and humidity on room temperature vulcanized (RTV) silicone rubber (SiR) and its composites, this study was performed. Five different sample compositions including neat silicone rubber (nSiR), microcomposites (15 wt% silica(SMC 15% SiO2) and 15 wt% ATH(SMC 15% ATH), nanocomposite (2.5 wt% silica(SNC 2.5% SiO2) and hybrid composite (10 wt% micro alumina trihydrate with 2 wt% nano silica(SMNC 10% ATH 2% SiO2) were prepared and subjected to 70 ˚C temperature and 80% relative humidity in an environmental chamber for 120 h. Contact angle, optical microscopy and Fourier transform infrared (FTIR) spectroscopy were employed to analyze the recovery properties before and after applying stresses. Different trends of degradation and recovery were observed for different concentrations of composites. Addition of fillers improved the overall performance of composites and SMC 15% ATH composite performed better than other composites. For high temperature and humidity, the ATH-based microcomposite was recommended over silica due to its superior thermal retardation properties of ATH. It has been proved that ATH filler is able to withstand high temperature and humidity.

Sign in / Sign up

Export Citation Format

Share Document