Ceramizable Composites for Fire Resistant Applications

2014 ◽  
Vol 602-603 ◽  
pp. 290-295 ◽  
Author(s):  
Zbigniew Pędzich ◽  
Dariusz M. Bieliński ◽  
Rafał Anyszka ◽  
Radosław Lach ◽  
Magdalena Ziąbka
Keyword(s):  
Silicone Rubber ◽  
Electrical Circuit ◽  
Silica Matrix ◽  
Inorganic Materials ◽  
Rubber Matrix ◽  
Metal Core ◽  
Rubber Composites ◽  
Filled Elastomer ◽  
Ceramic Fillers ◽  
Electrical Cables

The paper concerns composite materials made of silicone rubber matrix and ceramic fillers used as flame resistant coverings for electrical cables. Under fire, such materials must be able to form, relatively quickly, compact and stiff protecting coating, strong enough to maintain integrity of electrical circuit, even up to melting temperature of metal core. The residue of fired silicone rubber or silica filled elastomer exhibit a form of white powder. There is no evidence of solidification of silica particles, even after heating at 1100°C. However, the addition of some ceramic phases results in reaction with silica matrix (starting at about 900°C) producing a liquid phase, what facilitates particle binding. At lower firing temperatures (600°C) the problem of binding between the product of pyrolysis (silica) and filler is also present, what results in formation of fragile surface shield. The problem can be overcome by the addition of certain inorganic materials to the silicone rubber matrix. The paper discusses their influence on ability of silicone rubber composites, additionally containing glassy phase, wollastonite, mica, aluminium hydroxide, montmorillonite or calcined caoline, to ceramization.

Fused Silica Filled Silicone Rubber Composites for Flexible Electronic Applications

2015 ◽  
Vol 830-831 ◽  
pp. 537-540 ◽  
Author(s):  
L.K. Namitha ◽  
M.T. Sebastian
Keyword(s):  
Silicone Rubber ◽  
Moisture Absorption ◽  
Volume Fraction ◽  
Coefficient Of Thermal Expansion ◽  
Filler Loading ◽  
Fused Silica ◽  
Rubber Matrix ◽  
Rubber Composites ◽  
Filling Fraction ◽  
Filler Volume Fraction

Silicone rubber composites filled with fused silica were prepared through sigma mixing followed by hot pressing. Filling fraction of fused silica in the silicone rubber matrix was varied from 0-0.51 volume fraction (Vf) and its effects on dielectric properties at different frequencies, thermal properties and moisture absorption were investigated. The results indicate that with the increase of filler volume fraction the relative permittivity increases and dielectric loss decreases. The coefficient of thermal expansion decreased and the moisture absorption increased marginallyas the filler loading increased.

scholarly journals Silicone Rubber Composites Reinforced by Carbon Nanofillers and Their Hybrids for Various Applications: A Review

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2322
Author(s):  
Vineet Kumar ◽  
Md Najib Alam ◽  
Amutheesan Manikkavel ◽  
Minseok Song ◽  
Dong-Joo Lee ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electrical Properties ◽  
Silicone Rubber ◽  
Carbon Nanomaterials ◽  
Research Area ◽  
Rubber Matrix ◽  
Strain Sensing ◽  
Rubber Composites ◽  
Wide Range ◽  
Carbon Nanofillers

Without fillers, rubber types such as silicone rubber exhibit poor mechanical, thermal, and electrical properties. Carbon black (CB) is traditionally used as a filler in the rubber matrix to improve its properties, but a high content (nearly 60 per hundred parts of rubber (phr)) is required. However, this high content of CB often alters the viscoelastic properties of the rubber composite. Thus, nowadays, nanofillers such as graphene (GE) and carbon nanotubes (CNTs) are used, which provide significant improvements to the properties of composites at as low as 2–3 phr. Nanofillers are classified as those fillers consisting of at least one dimension below 100 nanometers (nm). In the present review paper, nanofillers based on carbon nanomaterials such as GE, CNT, and CB are explored in terms of how they improve the properties of rubber composites. These nanofillers can significantly improve the properties of silicone rubber (SR) nanocomposites and have been useful for a wide range of applications, such as strain sensing. Therefore, carbon-nanofiller-reinforced SRs are reviewed here, along with advancements in this research area. The microstructures, defect densities, and crystal structures of different carbon nanofillers for SR nanocomposites are characterized, and their processing and dispersion are described. The dispersion of the rubber composites was reported through atomic force microscopy (AFM), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The effect of these nanofillers on the mechanical (compressive modulus, tensile strength, fracture strain, Young’s modulus, glass transition), thermal (thermal conductivity), and electrical properties (electrical conductivity) of SR nanocomposites is also discussed. Finally, the application of the improved SR nanocomposites as strain sensors according to their filler structure and concentration is discussed. This detailed review clearly shows the dependency of SR nanocomposite properties on the characteristics of the carbon nanofillers.

scholarly journals Thermoelastic properties nanocomposite chloroprene of rubber with montmorilonit

2021 ◽  
pp. 17-22
Author(s):  
S.M. Ponomarenko
Keyword(s):  
Mechanical Energy ◽  
Rubber Matrix ◽  
Thermoelastic Properties ◽  
Rubber Composites ◽  
Main Method ◽  
Mechanical Hysteresis ◽  
Filler Particles ◽  
Ceramic Fillers ◽  
Reinforcement Factor ◽  
Interplanar Space

The problem that arises during the operation of tires is cyclic deformation, in which there is a conversion of mechanical energy into heat. However, due to the low thermal conductivity of rubber, repeated cyclic loads of products based on them lead to heating, which is due to the phenomenon of mechanical hysteresis. The consequence is a deterioration of their performance over time and, as a consequence, a reduction in service life. The main method for increasing the interfacial interaction for ceramic fillers is to ensure the penetration of rubber molecules into the interplanar space (gallery) formed by the filler particles (intercalation), and the subsequent distribution of these nanoplates (exfoliation) to a thickness of several nanometers throughout the field. The aim of this work is to study the thermoelastic properties of rubbers made on the basis of nanosized mineral filler montmorillonite, which may indicate a way to solve the problem of their durability. It was investigate the influence of modified nanosize montmorilonit on thermoelastic properties of rubber composites on it basis. It is rotined that thermoelastic properties described a model, which takes into account holdings of local increase of tension for a rubber matrix and destruction of spatial net of nanoparticles with the increase of strein, which results in exotherms which show up as a result of friction between the filler particles. Quantitative analysis of the thermoelastic properties of rubber nanocomposites provides additional confirmation of the concept of the reinforcement factor, which depends on the deformation, and determines the thermoelastic properties of nanocomposites for the whole range of relative elongations.

scholarly journals Effect of POSS Particles and Synergism Action of POSS and Poly-(Melamine Phosphate) on the Thermal Properties and Flame Retardance of Silicone Rubber Composites

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1298 ◽  
Author(s):  
Przemysław Rybiński ◽  
Bartłomiej Syrek ◽  
Dariusz Bradło ◽  
Witold Żukowski
Keyword(s):  
Thermal Properties ◽  
Flame Retardant ◽  
Silicone Rubber ◽  
Degradation Mechanism ◽  
Rubber Matrix ◽  
Flame Retardance ◽  
Test Results ◽  
Rubber Composites ◽  
X Ray ◽  
Melamine Phosphate

This article presents flame retardant compounds for silicone rubber (SR) in the form of polyhedral oligomeric silsequioxanes (POSS), containing both isobutyl groups and amino-propyl (AM-POSS) or chloro-propyl group (HA-POSS) or vinyl groups (OL-POSS). Silsequioxanes were incorporated into the silicone rubber matrix in a quantity of 3 and 6 parts by wt by the method of reactive stirring with the use of a laboratory mixing mill. Based on the analyses performed by TG (Thermogravimetry) FTIR (Fourier Transform Infrared Spectroscopy), conical calorimeter, and SEM-EDX (Scanning Electron Microscopy and Energy Dispersive X-ray Spectroscopy) methods, the thermal degradation mechanism of non-cross-linked and cross-linked silicone rubber has been elucidated. The effects of POSS, and POSS in a synergic system with melamine polyphosphate (MPP), on the thermal properties and flammability of silicone rubber composites were presented. Based on the test results obtained, a mechanism of flame retardant action POSS and POSS-MPP has been proposed. It has been shown that POSS, especially with MPP, considerably increases the thermal stability and decreases the flammability of the SR rubber composites under investigation.

scholarly journals Common Origin of Filler Network Related Contributions to Reinforcement and Dissipation in Rubber Composites

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2534
Author(s):  
Sriharish Malebennur Nagaraja ◽  
Sven Henning ◽  
Sybill Ilisch ◽  
Mario Beiner
Keyword(s):  
Network Topology ◽  
Filler Content ◽  
Matrix Composition ◽  
Rubber Matrix ◽  
Butadiene Rubber ◽  
Rubber Composites ◽  
Different Temperatures ◽  
Filler Network ◽  
General Perspective ◽  
Rubber Filler

A comparative study focusing on the visco–elastic properties of two series of carbon black filled composites with natural rubber (NR) and its blends with butadiene rubber (NR-BR) as matrices is reported. Strain sweeps at different temperatures are performed. Filler network-related contributions to reinforcement (ΔG′) are quantified by the classical Kraus equation while a modified Kraus equation is used to quantify different contributions to dissipation (ΔGD″, ΔGF″). Results indicate that the filler network is visco-elastic in nature and that it is causing a major part of the composite dissipation at small and intermediate strain amplitudes. The temperature dependence of filler network-related reinforcement and dissipation contributions is found to depend significantly on the rubber matrix composition. We propose that this is due to differences in the chemical composition of the glassy rubber bridges connecting filler particles since the filler network topology is seemingly not significantly influenced by the rubber matrix for a given filler content. The underlying physical picture explains effects in both dissipation and reinforcement. It predicts that these glassy rubber bridges will soften sequentially at temperatures much higher than the bulk Tg of the corresponding rubber. This is hypothetically due to rubber–filler interactions at interfaces resulting in an increased packing density in the glassy rubber related to the reduction of free volume. From a general perspective, this study provides deeper insights towards the molecular origin of reinforcement and dissipation in rubber composites.

Modelling and experimental characterisation of a compressional adaptive magnetorheological elastomer isolator

2021 ◽  
pp. 107754632110253
Author(s):  
Emiliano Rustighi ◽  
Diego F Ledezma-Ramirez ◽  
Pablo E Tapia-Gonzalez ◽  
Neil Ferguson ◽  
Azrul Zakaria
Keyword(s):  
Magnetic Field ◽  
Silicone Rubber ◽  
Magnetic Interaction ◽  
Iron Particle ◽  
Material Model ◽  
Rubber Matrix ◽  
Magnetorheological Elastomer ◽  
Volume Percentage ◽  
Shock Absorbers ◽  
Percent Concentration

This article proposes a simple physical-based model to describe and predict the performance of axially compressed magnetorheological elastomer cylinders used as vibration and shock absorbers. The model describes the magnetorheological elastomer macroscopic stiffness changes because of an externally applied magnetic field from a microscopic composite cell of silicone rubber and carbonyl iron particle. Despite neglecting the material hyperelasticity, anisotropy and adjacent magnetic interaction, the model describes effectively the effect of the magnetic field on the macroscopic modulus of elasticity. The changes in the mechanical properties with the induced magnetic field are measured on samples of different particle concentration based on volume percentage, that is, 10 and 30 percent concentration of iron particles in a silicone rubber matrix. The manufacturing process of the samples is detailed, as well as the experimental validation of the effective stiffness change under a magnetic field in terms of transmissibility and mobility testing. However, the prediction seems to be limited by the linear elastic material model. Predictions and measurements are compared, showing that the model is capable of predicting the tunability of the dynamic/shock absorber and that the proposed devices have a possible application in the reduction of mechanical vibrations.

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