Pure Rubber Research Articles

Effects of emission and performance characteristics study of rubber seed biodiesel fueled DI diesel engine fumigated with methanol

In response to growing fuel costs, rising demand for fossil fuels, concerns over tailpipe emissions, and research into locally produced renewable and alternative fuels, researchers are exploring for fuels that may be produced from renewable sources that burn efficiently. This article explains how to evaluate a compression ignition engine's performance and emissions using rubber seed oil and methanol fumigation. The viscosity of rubber seed oil is lower. Rubber seed biodiesel was produced using the transesterification process, and the characteristics of pure and blended Rubber seed biodiesel were examined. The emissions of neat diesel fuel are compared to those of B20 rubber seed biodiesel and its methanol fumigation. It has been discovered that as load increases, braking power tends to increase as well. The methanol fumigation decreases when the fuel consumption unique to brakes is taken into account. The brake thermal efficiency is increased by 2.75 %. when the methanol fumigation and in the investigation for CO emissions, B20 is found to be increased at an increase in loads. Thus the same is found while it is done with the methanol fumigation. The incomplete combustion has produced the CO. it is found that there is a few amounts of HC is increased in all loads. There is a drop in the NOX at all the loads when it is under the methanol fumigation which is 12.5 % lesser than the NOX compared with neat diesel. In the CO2 emission there is a reduction in emission in the methanol fumigation up to 4 %.

Hydroxyl Boron Nitrid e/Natural Rubber Composites with Enhanced Mechanical and Thermal Conduction Properties: Implications for Heat Dissipative Tires or Conveyor Belts

For its significant technological interest, a systematic investigation on mechanical and thermal conduction properties of natural rubber reinforced by functionalized hexagonal boron nitride nanosheets is highly desirable. We herein first demonstrate a unique synthesis of hydroxyl-functionalized boron nitride nanosheets (OH-BNNSs) via a simple one-pot reduction reaction. This involves negative charging by treating BNNSs with lithium in liquid ammonia and subsequent bubbling of oxygen into dispersion of BNNS salts. Subsequently, a series of functionalized boron nitride nanosheets/natural rubber (NR) composites were fabricated by latex mixing and co-coagulation. Co-coagulating a stable aqueous suspension of OH-BNNSs with natural rubber latex afforded a weblike morphology consisting of platelet networks between the latex particles. Compared to pure rubber, the tensile strength and storage modulus at 25 °C for OH-BNNSs/NR (5 wt %) are increased by 466% and 1 order of magnitude, respectively. Benefiting from the unique structure, the composite at 5 wt % shows a 40% improvement in thermal conductivity relative to pure rubber. This latex-based method provides a facile and effective strategy to design and fabricate advanced functional BNNS-based polymeric nanocomposites with a segregated filler network morphology and considerable property enhancements in direct competition with graphene sheets. The composites could be potentially used in heat dissipative tires or conveyor belts.

Achieving enhanced electromagnetic shielding by novel flexible rubber based nanocomposite with the incorporation of nickel spinal ferrites and polyaniline

The chemical oxidative method was used for the polymerization of the polyaniline (PANI) using APS as an oxidant and formic acid as a dopant and co-precipitation method was used for the precipitation of nickel ferrites (NiFe). Polyaniline used to impart conductivity and nickel ferrites for magnetic permeability to achieve high EMI shielding. Seven different composites were made varying their composition and tested for various properties like morphology, DC conductivity, EMI shielding etc. In SEM analysis it was discovered that PANI and NiFe particles dispersed in NBR rubbers uniformly. DC conductivity was also rised to 286 S/cm from 10−7 S/cm. XRD and particle size analysis used to conform the successful fabrication of PANI and NiFe and their particle size respectively. DSC confirmed that the melting point dosned by the addition of PANI and NiFe in NBR rubber. EMI shielding of almost 52 dB was achieved while pure rubber provide only 1–2 dB.

Investigation of charge dynamics in the corona‐aged silicone rubber alumina nanocomposite

AbstractThe effect of corona aging on the surface potential dynamics and charge trap characteristics of silicone rubber alumina nanocomposite are examined using surface potential decay measurement. The aging was carried out by exposing the specimens to corona stress generated by a high‐frequency AC multi needle‐plane electrode system. The results show that the addition of alumina filler increases the surface potential decay time and maximum trap energy. A reduction in trap depth is observed with the corona aging, and the addition of alumina filler limits the degradation and change in charge trap distribution. The results of an analysis of the space charge behavior of different nanocomposites and their comparison are presented. The space charge variation analysis was carried out under the applied electric field of 20 kV/mm at room temperature using the pulsed electro‐acoustic technique (PEA). Based on the results, the charge density, electric field, and charge trap distribution were deduced. It is concluded that the space charge concentration and enhancement in the electric field of the aged material increases with aging duration and it is maximum in the case of 60 min corona‐aged pure silicone rubber. Analysis of the recovery of the charge dynamics of the sample after corona discharges at the different time intervals shows that the recovery of trap distribution is faster for a virgin sample and slower for the sample with 5 wt% of alumina.

Carbon Nanotube-Based Intumescent Flame Retardants Achieve High-Efficiency Flame Retardancy and Simultaneously Avoid Mechanical Property Loss.

Intumescent flame retardants (IFR) are an excellent solution to the problem of easy combustion of polymers. Still, the negative effect of the addition of flame retardants is the decline of the mechanical properties of polymers. In this context, carbon nanotubes (CNTs) are modified with tannic acid (TA) and then wrapped on the surface of ammonium polyphosphate (APP) to construct a special intumescent flame retardant structure (CTAPP). The respective advantages of the three components in the structure are explained in detail, especially the role of CNTs with high thermal conductivity in the flame retardant system. Compared with pure natural rubber (NR), the peak heat release rate (PHRR), total heat release (THR), and total smoke production (TSP) of the composites proposed with special structural flame retardants are decreased by 68.4%, 64.3%, and 49.3%, respectively, while the limiting oxygen index (LOI) increased to 28.6%. The TA-modified CNTs wrapped on the surface of APP can effectively reduce the mechanical damage caused by the flame retardant to the polymer. To sum up, the flame retardant structure of TA-modified CNTs wrapped on APP can effectively enhance the flame retardant properties of the NR matrix and reduce the negative impact on mechanics caused by adding APP flame retardant.

Molecular dynamics simulation of the effect of the thermal and mechanical properties of addition liquid silicone rubber modified by carbon nanotubes with different radii

Abstract For microscopic analysis of the effect of doping with carbon nanotubes (CNTs) of different radii on the thermal and mechanical properties of addition liquid silicone rubber (ALSR) composites, models of pure silicone rubber and silicone rubber composites containing CNTs of different radii were constructed based on a molecular dynamics approach using vinyl-capped polydimethylsiloxane (VPDMS) as the base polymer and polyhydroxymethylsiloxane (PHMS) as the cross-linker. The thermal and mechanical properties and microstructures of the different models were analyzed and compared. It was found that the doping of CNTs could change the thermomechanical properties of the composites, and the doping of CNTs with small radius had a more positive effect on the material, the thermal conductivity, glass transition temperature, and mechanical properties of the composites are improved. Due to the doping of CNTs, the free volume percentage and the mean square displacement of the composites are reduced. It is noteworthy that during the modeling and optimization process, there are molecular chains that pass through the large radius CNTs, and the structural properties of the composite CNTs themselves play a more critical role in the enhancement effect of the thermodynamic properties of the composites compared to the binding energy and free volume.

Lightweight and flame retardant silicone rubber foam prepared by supercritical nitrogen: The influence of flame retardants combined with ceramicizable fillers

Silicone rubber foam has wide application potential because of the lightweight and good mechanical flexibility. Herein, silicone rubber foam with ceramicizable flame retardant coating was prepared by talc, ammonium polyphosphate (APP) and carbon black (CB). The composite foam density was 0.12 g/cm3. Talc had significant melting and flame retardant effects on the ceramicization. The molten crystal structure condensed APP and CB together in turn, and finally formed ceramics with higher bending strength, which improved the flame retardant and ceramic properties. When 30 % talc, 10 % APP and 20 % CB in the coating, the peak heat release rate was 98.7 kW/m2, which was reduced by 300 % compared with the pure silicone rubber coating. After ablation, the compression strength was 900 % higher than that of pure silicone rubber coating because of the formation of ceramicizable coating. This work provides a promising strategy for the preparation of highly efficient flame retardant silicone rubber foam.

A robust and transparent nanosilica-filled silicone rubber coating with synergistically enhanced mechanical properties and barrier performance

Implantable electronic devices (IEDs) are widely used by human beings to achieve medical treatment and diagnosis nowadays. However, ideal encapsulation of IEDs is still far from perfect as full prevention of body fluid diffusion into the coating remains unsolved. Herein, we develop a high-performance composite coating for IED encapsulation by introducing SiO2 nanoparticles into silicone rubber, which synergistically enhances mechanical properties and improves barrier performance. By fabricating composite coatings with different nanosilica contents, 3% nanosilica is proved to be an optimal additive content with an excellent combination of improved fracture strength (from 2.5 MPa to 4.5 MPa), increased coating resistance (from 104 to 109 Ω cm2) and ideal coating uniformity. Mechanical and electrochemical characterizations subsequently confirm substantially enhanced mechanical properties and barrier performance of the composite coating, which effectively resist crack propagation and impede penetrations of water and chloride ions through the coating. Theoretical calculations further uncover that modified SiO2 particles with enriched methyl groups endow a strong bridging effect to interact with silicone rubber monomer, which, together with anti-agglomeration property of methyl groups, contributes to a pronounced improvement in mechanical performance of nanosilica-filled silicone rubber. Benefitting from the enhanced mechanical and barrier properties, the as-fabricated nanosilica-filled silicone rubber demonstrates superior protection for the encapsulated circuits with a significantly improved lifetime (709.1 h) compared to that of circuits coated by pure silicone rubber (472.8 h) and bare circuit boards (1 h), which offers great values for packaging material design in future IED encapsulation.

Durability and mechanical properties of rubber concrete incorporating basalt and polypropylene fibers: Experimental evaluation at elevated temperatures

Waste tires cause serious environmental problems, such as pollution, which can be reduced by mechanically grinding rubber tires into powder to obtain rubber particles. These components are then used in equal mass (20%) to replace fine aggregate to manufacture rubber concrete (RC), a new type of environmentally friendly building material. This study explored the performance of RC and different volume fractions (0.5%, 1.0% and 1.5%) basalt-polypropylene fiber-reinforced rubber concrete (BPRC) under elevated temperatures through a series of experiments on mass, relative dynamic elastic modulus, static compressive strength, and dynamic compressive strength. The experimental results showed that with increasing temperature, mass loss in RC and BPRC gradually increased, their relative dynamic elastic moduli slowly decreased. Their static compressive and dynamic compressive strengths reflected different degrees of loss, the strength loss temperature node of pure rubber concrete is earlier and the loss degree is more. The best performance was shown by the BPRC with 1% and 1.5% volume ratios of basalt and polypropylene fibers, respectively. Mixing basalt and polypropylene fibers into RC is beneficial to improvements in its performance after an increase in temperature.

Low-temperature resistance of fluorine rubber with modified Si-based nanoparticles

Fluorine rubber contains fluorine atoms with strong electronegativity, which endow it with novel properties, such as oil resistance, heat resistance, chemical resistance, but also lead to poor low temperature resistance. Si-based nanoparticles are used as the new active crosslinking point of fluorine rubber, which can break the original regular structure to improve the low-temperature resistance and ensuring the mechanical properties of fluorine rubber. The relative optimal silane coupling agent is selected according to the relative concentration and the interaction energy of the molecular interface in different models. The optimal silane coupling agent can avoid the agglomeration of Si-based nanoparticles in fluorine rubber and form flexible bridge between inorganic Si-based nanoparticles and fluorine rubber long chains. It is discovered that the mechanical and low-temperature properties of the modified Si-based nanoparticles/fluorine rubber (FKM-M Si) was optimal compared with pure fluorine rubber (P-FKM) and unmodified Si-based nanoparticles/fluorine rubber (FKM-UM Si). The brittleness temperature (T b ) is reduced from -18.0 °C to -29.0 °C, allowing for a wider range of applications for FKM-M Si. This study provided a potential for the application of fluorine rubber composites in harsh low-temperature environment. • The silicon nanoparticles have larger Si–O–Si bond angles, high orientation freedom and good flexibility. • Improving the dispersion of silicon nanoparticles in fluorine rubber by chemical modification. • Unique nanocomposite structure is the key point of the low temperature resistance.

Mussel inspired modification of nanodiamonds for thermally conductive, and electrically insulating rubber composites

An innovative bioinspired method is presented for the preparation of surface-modified nanodiamonds (ND) particles by poly(dopamine) (PDA). The process was aimed at improving the thermal conductivity and maintaining the insulating capability of silicone rubber (SiR). ND was successfully and effectively modified by dopamine in different hours, which was confirmed by HR-TEM, TGA, FTIR, and XRD. The poly(dopamine) coating on ND particles improved its interfacial interaction with silicon rubber and promoted the uniform dispersion of fillers, resulting in the ND-18/SiR composite that acquired a higher thermal conductivity (0.295 W/(m·K)) at the loading of 6 wt%, 81 % higher than that of pure silicone rubber (0.163 W/(m·K)). In addition, the composite materials still displayed an excellent insulating property with a resistance of ≈10 11 Ω·cm, which was a big advantage for thermal management. • The agglomeration problem of ND nanoparticles was reduced by using dopamine. • ND-X particles exhibit excellent dispersibility and compatibility with SiR. • ND-X particles enhance thermal conductivity and maintain electrical insulation of nanocomposites.

Tensile performance and viscoelastic properties of rubber nanocomposites filled with silica nanoparticles: A molecular dynamics simulation study

Understanding the relationship between the macro-properties and microstructure of rubber and rubber nanocomposites (RNCs) is crucial for the design and optimization of relevant rubber composite products. Herein, we explore the mechanical and viscoelastic properties of rubber and RNCs filled with silica nanoparticles by using atomistic molecular dynamics simulation. It is found that increasing cross-linking density can greatly enhance the tensile performance of pure rubber, and reduce the permanent deformation and hysteresis loss. The addition of silica nanoparticles causes significant changes in the static distribution, movement, and bond orientation, and the Tg of RNCs increases by more than 6% when the volume fraction of NPs reaches 10%. At fixed volume fraction of NPs, decreasing the NP size can further enhance the mechanical properties of RNCs, and the maximum tensile stress can increase by 50%. In addition, cross-linking in the RNCs can improve the viscoelastic properties, and more highly crosslinked RNCs present larger storage modulus and loss modulus, and smaller loss angle. This work gives an in-depth understanding of the effect of microstructure on the mechanical properties of RNCs.

Dual-Aligned carbon nanofiber scaffolds as heat conduction path to enhance thermal conductivity of polymer composites

To improve the thermal conductivity of thermal interface materials (TIM), we constructed a dual-aligned scaffold, i.e., both aligned carbon nanofiber (CNFs) in the microscopic structures and directional microporous channels, serving as the heat conduction paths of TIMs. The dual-aligned scaffold was firstly fabricated by combining magnetic alignment and conventional freeze-casting, and the composites of the dual-aligned scaffold and silicone rubber (D-AS/SR) were then obtained by immersing the dual-aligned scaffold into the silicone rubber with vacuum assistance. Through this method, not only the high axial thermal conductivity of CNFs can be fully utilized, but also a long-range continuous and parallel structure can be fabricated as the heat conduction paths of TIMs. The results show that the thermal conductivity of the D-AS/SR composites reached 4.66 W/(m·K) at 7.73 vol% CNFs, which is 1.5 times higher than that of the composites constructed by conventional freezing casting and 25 times higher than that of pure silicone rubber. Additionally, the compressive strength of the D-AS/SR composites was greatly improved, whereas the electrical insulation of the composites was significantly reduced, which limited the use of D-AS/SR composites in conditions requiring good electrical insulation.

Mechanical behavior of entangled metallic wire mesh–silicone rubber interpenetrating phase composites under quasistatic compression

Interpenetrating phase composites (IPCs) with porous metal materials as the matrix and polymer materials as the reinforcement, which have a broad application prospect, have both the high strength of metal materials and the high energy absorption capacity of polymer materials. Entangled metallic wire materials are a new type of porous material with damping characteristics, which is an excellent choice for use as the matrix of IPCs. In the present work, a novel entangled metallic wire material–silicone rubber IPC is developed through the vacuum infiltration method with the entangled wire material as the matrix and silicone rubber as the reinforcing element. The mechanical properties (loss factor and tangent modulus) of the as-synthesized composites are characterized through compression tests. More specifically, the effects of key experimental parameters (strain) and material properties (matrix density, wire diameter, and anisotropy) on the mechanical properties of the composites are analyzed in detail. It is found that with the introduction of interfacial friction, the loss factor of the composites becomes higher than those of the pure entangled metallic wire material and silicone rubber; in particular, the tangent modulus is significantly enhanced. The complex structural characteristics of the proposed composite enable the loss factor and tangent modulus to exhibit a nonlinear relationship with the density over a range of displacement values. Moreover, the smaller the wire diameter is, the greater the loss factor of the composites is, while the tangent modulus exhibits the opposite trend. The unique wire contact form and preparation process endow the composites with nonlinear properties in the molding direction as well as pronounced anisotropy characteristics. HIGHLIGHT A novel interpenetrating phase composite is proposed. The composite quasistatic curve is nonlinear with excellent mechanical properties. The improved energy consumption properties are due to the interfacial friction. The increase in wire density greatly improves the elastic modulus of the composite. The composite is anisotropic with a better bearing capacity in the molding direction.

Manipulating the mechanical properties of cis-polyisoprene nanocomposites via molecular dynamics simulation

Attributed to the reinforcing effect of the NPs, filled natural rubber (NR) exhibits more excellent mechanical properties compared to pure natural rubber and has been attracting considerable scientific and technological attention. However, only a few studies have shown a systematical understanding of the structure-mechanics relation of filled natural rubber. Herein, a common strategy used to study the effects of the critical structural factors on strain-induced crystallization (SIC) and mechanical properties at the molecular level is to adopt molecular dynamic simulation (MD). Increasing the cross-linkage of the polymer matrix improves the entanglement degree, and the mechanical properties are reinforced by the high orientation of the polymer chains due to the high entanglement degree and the dissipation of energy due to the unentangling. Surprisingly, we find that the stress-strain behaviour of filled natural rubber is significantly manipulated by nanoparticle (NP) content, size and strength of interfacial interaction, evidenced by the increase of the chain orientation, SIC, and energy dissipated by NPs and polymer matrix, compared with the case of pure natural rubber. The underlying mechanism is the adsorption of the polymer by NPs, which leads to the orientation and crystallization of the polymer chains induced by NPs during the deformation process and energy dissipation through the slip of NPs and polymer chains. In general, this work demonstrates a detailed molecular-level structure-mechanics relation of filled natural rubber and provides some rational guidelines for experimentally designing and fabricating high-performance elastomer nanocomposites.

Thermo-plastic material durability resistivity evaluation through experimental and analytical tactics

Thermoplastic vulcanizates (TPV) / brandonite (BR) blends were created with completely different ratios of N-339(HAF): N-660(SRF) atomic number 6 fillers. The mechanical characteristics of pure rubber mix and persons loaded with different percentages of carbon black were examined. The 80TPV:20BR mix had the highest values for durability and elongation at break. The calculated changes in the mechanical characteristics of mixes were correlative to the morphology as detected by SEM. The electrical resistance of rubber mixes changed during compression.

Morphological, Physical, and Mechanical Properties of Sugar-Palm (Arenga pinnata (Wurmb) Merr.)-Reinforced Silicone Rubber Biocomposites.

The development of environmentally benign silicone composites from sugar palm fibre and silicone rubber was carried out in this study. The mechanical, physical, and morphological properties of the composites with sugar palm (SP) filler contents ranging from 0% to 16% by weight (wt%) were investigated. Based on the uniaxial tensile tests, it was found that the increment in filler content led to higher stiffness. Via dynamic mechanical analysis (DMA), the viscoelastic properties of the silicone biocomposite showed that the storage modulus and loss modulus increased with the increment in filler content. The physical properties also revealed that the density and moisture absorption rate increased as the filler content increased. Inversely, the swelling effect of the highest filler content (16 wt%) revealed that its swelling ratio possessed the lowest rate as compared to the lower filler addition and pure silicone rubber. The morphological analysis via scanning electron microscopy (SEM) showed that the sugar palm filler was evenly dispersed and no agglomeration could be seen. Thus, it can be concluded that the addition of sugar palm filler enhanced the stiffness property of silicone rubber. These new findings could contribute positively to the employment of natural fibres as reinforcements for greener biocomposite materials.

Dynamic behaviour of pipe protected by rubber–soil mixtures

As reuse materials, waste tyres mixed with soils are valuable materials to be used for many purposes in geotechnical projects that may be subjected to dynamic loads. The aim of this study is to assess the efficacy of using waste tyres in buried pipe protection. To achieve this purpose, a series of laboratory model tests were carried out to investigate the dynamic responses of pipe buried in pure soil and rubber soil mixtures with volume content of 10%, 20% and 30% rubber particles. Test results such as earth pressure and strain of buried pipe are discussed in this study. The results indicate that inclusion of 20–30% rubber particles in the mixtures leads to a change in earth pressure increment distribution, and these mixtures lead to obvious reductions in earth pressure increments. For the mixtures with 20–30% rubber particles, the pipe had lower strain under the dynamic loading. Compared with pure soil, the mixtures with 20–30% rubber particles exhibited better performance with regard to the responses of the pipe–soil system. Hence, the research undertaken in this paper provides a viable approach to protect buried pipes subjected to dynamic loading.

Fabrication, characterization and properties of silane functionalized graphene oxide/silicone rubber nanocomposites

AbstractIn this work, octadecyl trichlorosilane (ODTS) was used to modify the surface of graphene oxide. Further, varied concentrations of silane‐modified graphene oxide were used to make silicone rubber nanocomposite. The mechanical, thermal, and tribological properties of the composite were studied. The results showed that a small amount of silane‐modified graphene oxide significantly increased the mechanical and tribological performances. Under dry sliding, silane‐modified graphene oxide to the silicone matrix significantly reduced wear and friction properties. Nanocomposites have a lower wear rate than neat silicone rubber; their friction coefficient is almost 36% less than pure silicone rubber: the higher the load and temperature conditions, the more significant the difference in friction and properties. Wear mechanisms were revealed by scanning electron micrographs of the worn surface. The transfer film formation on the counter surface and acceptable wear debris improved the nanocomposites friction and wear resistance characteristics.

Study of nylon textile-reinforced natural rubber composite

This study focuses on the production of nylon-reinforced natural rubber composites. In general, technical textiles serve as reinforcement and strength materials for a wide range of applications in rubber/textile composites. The adhesion between rubber and nylon is the most important factor affecting the assembly process and the strength of the finished product. The results showed that natural rubber reinforced with nylon textiles can be efficiently prepared by splicing a single layer of nylon fabric between two layers of rubber. The nylon textile-reinforced natural rubber composite was characterized by tensile testing machines and rubber curing characteristics, etc. The main result showed that the mechanical properties of rubber/nylon composites were higher than those of pure rubber. From the experimental results, it was found that nylon fabric can strengthen the natural rubber composite material for use with car tires.