scholarly journals Thermoelastic properties nanocomposite chloroprene of rubber with montmorilonit

Author(s):  
S.M. Ponomarenko

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.

2014 ◽  
Vol 602-603 ◽  
pp. 290-295 ◽  
Author(s):  
Zbigniew Pędzich ◽  
Dariusz M. Bieliński ◽  
Rafał Anyszka ◽  
Radosław Lach ◽  
Magdalena Ziąbka

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.


Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2534
Author(s):  
Sriharish Malebennur Nagaraja ◽  
Sven Henning ◽  
Sybill Ilisch ◽  
Mario Beiner

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.


2020 ◽  
Vol 10 (20) ◽  
pp. 7244
Author(s):  
Sung Ho Song

As eco-friendly “green tires” are being developed in the tire industry, conventionally used carbon black is being replaced with silica in rubber compounds. Generally, as a lubricant and dispersing agent, processing aids containing zinc ions have been employed as additives. However, as zinc is a heavy metal, alternative eco-friendly processing aids are required to satisfy worldwide environmental concerns. Furthermore, non-toxic, degradable, and renewable processing aids are required to improve the mechanical properties of the rubber composites. In this study, we evaluated the effects of diverse silica-based processing aids containing hydrocarbon, benzene, and hydroxyl functional groups on the mechanical properties of rubber composites. Among them, rubber composites that used amphiphilic terpene phenol resin (TPR) with hydrophilic silica showed compatibility with the hydrophobic rubber matrix and were revealed to improve the mechanical and fatigue properties. Furthermore, owing to the enhanced dispersion of silica in the rubber matrix, the TPR/styrene butadiene rubber composites exhibited enhanced wet grip and rolling resistance. These results indicated that TPR had multifunctional effects at low levels and has the potential for use as a processing aid in silica-based rubber composites in tire engineering applications.


Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2665
Author(s):  
Yihang Li ◽  
Yuzhu Xiong ◽  
Qingpo Zhang

A rivet–inspired method of decorating aramid fiber (AF) with silica particles (SiO2) is proposed to produce SiO2@AF hybrid materials that have largely enhanced interfacial interaction with the rubber matrix. AF was firstly surface-modified with polyacrylic acid (PAA) to obtain PAA–AF, and SiO2 was silanized with 3-aminopropyltriethoxysilane to obtain APES–SiO2. Then, SiO2@AF was prepared by chemically bonding APES–SiO2 onto the surface of PAA–AF in the presence of dicyclohexylcarbodiimide (DCC) and 4-dimethylaminopyridine (DMAP). With the incorporation of SiO2@AF into the rubber matrix, SiO2@AF hybrid materials with high surface roughness can play a role as ‘rivets’ to immobilize large numbers of rubber chains on the surface. The tear strength and tensile strength of rubber composite that filling 4 phr SiO2@AF are dramatically increased by 97.8% and 89.3% compared to pure rubber, respectively. Furthermore, SiO2@AF has superiority in enhancing the cutting resistance of rubber composites, in contrast with unmodified AF and SiO2. SiO2@AF is suitable to be applied as a novel reinforcing filler in rubber composites for high performance.


2018 ◽  
Vol 38 ◽  
pp. 02022
Author(s):  
Dewei Zhang ◽  
Chuansheng Wang ◽  
Bo Shen ◽  
Shaoming Li ◽  
Huiguang Bian

In recent years, rubber composites reinforced by short fibers has been researched deeply, because of its good performances such as higher wear resistance, higher cut resistance and so on. Some research results indicated that if short fibers get orientation in rubber composites, the performances of rubber products could be promoted greatly. But how to make short fibers get orientation in rubber matrix during extrusion is still a real problem. And there are many parameters affect the short fibers orientation. So, in this paper, the effects of die structure including expansion-die and dam-expansion-die on extrusion flow field of short fiber and rubber composite material during extrusion process has been researched by Polyflow. And the FEA results about the pressure field, velocity field and the velocity vector of the rubber composites flow field indicate that, comparing with expansion-die and the dam-expansion-die, the latter one is better for the extrusion process of rubber composites and making short fibers get radial orientation in rubber matrix.


2015 ◽  
Vol 1109 ◽  
pp. 195-199 ◽  
Author(s):  
Abd Aziz Azira ◽  
Dayang Habibah Abangismawi I. Hassim ◽  
D. Verasamy ◽  
Abu Bakar Suriani ◽  
M. Rusop

In order to achieve improvements in the performance of rubber materials, the development of carbon nanotube (CNT)-reinforced rubber composites was attempted. The CNT/epoxidised natural rubber (ENR) nanocomposite was prepared through latex technology. Physical and mechanical properties of the CNT/ENR nanocomposites were characterized in contrast to the carbon black (CB)/ENR composite. The dispersion of the CNTs in the rubber matrix and interfacial bonding between them were rather good; monitored transmission electron microscopy and scanning electron microscopy. The mechanical properties of the CNT-reinforced ENR showed a considerable increase compared to the neat ENR and traditional CB/ENR composite. The storage modulus of the CNT/ENR nanocomposites greatly exceeds that of neat ENR and CB/ENR composites and a maximum conductivity of about 1 S m-1 can be achieved. The approach presented can be adapted to other CNT/polymer latex systems.


2011 ◽  
Vol 137 ◽  
pp. 1-6
Author(s):  
Qing Li ◽  
Xiao Xiang Yang

In this paper, the micromechanical finite element method based on Representative Volume Element has been applied to study and analyze the macro mechanical properties of the carbon black filled rubber composites by using two-dimensional plane stress simulations and three-dimensional axisymmetric simulations under uniaxial compression respectively. The dependence of the macroscopic stress-strain behavior and the effective elastic modulus of the composites, on particle shape, particle area/volume fraction and particle stiffness has been investigated and discussed. Additionally, the simulation results of the two-dimensional plane stress model and the three-dimensional axisymmetric model are evaluated and compared with the experimental data, which shows that the two-dimensional plane stress simulations generate poor predictions on the mechanical behavior of the carbon black particle reinforced rubber composites, while the three-dimensional axisymmetric simulations appear to give a better prediction.


2011 ◽  
Vol 221 ◽  
pp. 466-471 ◽  
Author(s):  
Jun Ping Song ◽  
Yan He ◽  
Lian Xiang Ma

Graphitized carbon black 40b2 and acetylene black were filled separately in natural rubber matrix for preparing vulcanized rubber. The thermal conductivity of both kinds of composites was studied considering filler loading and temperature. SEM and TEM were applied to observe morphology of the filler and composites. The experimental results show that thermal conductivity of acetylene black/rubber composites is much better than that of graphitized carbon black 40b2/rubber composites, which is opposite to the electric conduction properties. As filler loading increased, the difference increased, and when the filler loading is up to 40phr, the thermal conductivity value of acetylene black/rubber composite is 53% larger than the other one. TEM shows that acetylene black has more botryoidal structure, larger carbon black aggregates in size, and much looser surface than 40b2.Moreover, for acetylene black, particles contact by surface mainly, and for 40b2, particles contact by point mainly. SEM shows that the distribution of carbon black 40b2 in rubber matrix is much better than acetylene black. The better thermal conductivity for acetylene black is attributed to the higher structure, nonuniform distribution in rubber matrix and surface contact between particles.


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Suzana Samaržija-Jovanović ◽  
Vojislav Jovanović ◽  
Gordana Marković ◽  
Ivana Zeković ◽  
Milena Marinović-Cincović

Opalized white tuff (OWT) with 40 μm average particle size and 39.3 m2/g specific surface area has been introduced into polyisoprene rubber (NR). Their reinforcing effects were evaluated by comparisons with those from precipitated silica (PSi). The cure characteristic, apparent activation energy of cross-link (Eac) and reversion (Ear), and mechanical properties of a variety of composites based on these rubbers were studied. This was done using vulcanization techniques, mechanical testing, and scanning electron microscopy (SEM). The results showed that OWT can greatly improve the vulcanizing process by shortening the time of optimum cure (tc90) and the scorch time (ts2) of cross-linked rubber composites, which improves production efficiency and operational security. The rubber composites filled with 50 phr of OWT were found to have good mechanical and elastomeric properties. The tensile strengths of the NR/OWT composites are close to those of NR/PSi composites, but the tear strength and modulus are not as good as the corresponding properties of those containing precipitated silica. Morphology results revealed that the OWT is poorly dispersed in the rubber matrix. According to that, the lower interactions between OWT and polyisoprene rubber macromolecules are obtained, but similar mechanical properties of NR/OWT (100/50) rubber composites compared with NR/PSi (100/50) rubber composites are resulted.


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