Silicone Rubber Composites Research Articles

Microchannels-enabled Vertical Alignment of Hexagonal Boron Nitride in Silicone Rubber Composites to Achieve High Through-plane Thermal Conductivity

Hexagonal boron nitride (h-BN) with high vertical alignment in polymer composites is necessary to improve through-plane thermal conductivity (TC) for thermal management applications. However, how to achieve simple, efficient and precise control of h-BN vertical alignment in polymer composites remains a challenge. Herein, a novel concept of inducing vertical alignment of h-BN in silicone rubber (SR) composites via controlling flow patterns in specially designed microchannels was proposed. The extremely strong elongational and shear stresses provided by the narrow section of the microchannels induced h-BN to align perpendicular to the flow direction. In the subsequent channel, the weak shear stress manipulated h-BN to form a ladder structure in the SR composites, including the vertical core layer and horizontal skin layer. Such ladder structure not only improved the through-plane TC of SR composite but also prevented overheating in the face of local heat sources. Moreover, the obtained SR composites exhibit a through-plane TC of 5.08 W/mK at 34.3 vol % h-BN loading when the horizontal skin layer was removed, indicating excellent heat transfer efficiency for thermal management application. We believe that this work would strengthen both scientific and technological cognition of the filler alignment during polymer composites processing.

Construction of multi-functional silicone rubber/reduced graphene oxide/multi-walled carbon nanotube composites with segregated structure by surfactant-free Pickering emulsion method

Polymer composites with segregated structure (PC–S) have the advantages of low filler usage and excellent functionality. Emulsion blending combined with direct molding technology is the main method for the preparation of PC-S. However, due to the high fluidity of low-viscosity silicone rubber (SR), PC-S cannot be prepared by this technique. In addition, surfactants affect the heat resistance of the final SR composites (SRC). In order to solve the above problems, in this study, a Pickering emulsification combined with pre-crosslinking technology for SR was successfully developed by using graphene oxides (GO)/multi-walled carbon nanotubes (MWCNTs) hybrid fillers (GM) as emulsifiers, and SR/reduced GO (RGO)/MWCNTs composites with segregated structure (SSGM) were prepared. When RGO content is 4.5 wt%, MWCNTs content is 3.2 wt%, SSGM shows the highest electrical conductivity of 12.5 S/m, the highest electromagnetic interference shielding efficiency (EMI SE) of 41.4 dB, and an excellent flame retardant performance. The whole preparation process avoids the use of organic solvents and surfactants, which reduces the production cost of SSGM and the environmental pollution, and provides a feasible preparation route for the industrialized production of SSGM.

Improving the ablative properties of silicone rubber by adding aluminum foil/expanded perlite

In this study, aluminum foil (AF) and expanded perlite (EP) were used as the reinforcing fillers to improve the ablation properties of phenyl methyl vinyl silicone rubber composites. The expansion and caramelization of char layer enhanced the ablation and thermal insulation performance of silicone rubber-based composites. The improved bonding of char layer provided a good basis for enhancing ablative properties. The presence of EP increased the emissivity of the char layer which improved the heat radiation properties during ablation process, and it was advantageous to lower surface temperature and reduce thermal erosion. The graphitic degree of char layer was increased which improved high-temperature and oxidative resistance. SEM observations revealed that the surface and cross-section of the char layer were densified, as characterized by the pore size distribution analysis. The above results indicated that the ablation and anti-erosion resistance as well as thermal insulation behavior of silicone rubbers were significantly improved by implementing the expansion and caramelization strategy, which exhibit promising applications as flexible anti-ablation materials for thermal protection purposes.

Effect of different silane coupling agent modified SiO2 on the properties of silicone rubber composites: Based on molecular dynamics

Silicone rubber composites doped with nanoparticles are widely used in the field of electrical and aerospace insulation. The silane coupling agent modified on the surface of the particles enhances the compatibility between the nanoparticles and the insulating material, thus further improving the mechanical, dielectric properties and thermal stability of the composites. On this basis, the silicone rubber composite system models of three silane coupling agents (KH550, KH560, KH570) modified SiO2 are established respectively. Through the analysis methods of interaction energy, free fraction volume, radial distribution function and pull-out simulation, the improving mechanism of three silane coupling agents modified SiO2 on material properties can be explored from the perspective of molecular simulation. The results show that the interaction energy between KH570/SiO2 and silicone rubber system is the largest regardless of temperatures (280K ~ 400K). At low temperature (280K), the free fraction volume of KH550 and KH560 modified SiO2 systems is lower than that of KH570 modified system, while at high temperature, the free fraction volume of KH570/SiO2 system is the lowest. The three silane coupling agents modified SiO2 all increase the Young's modulus and bulk modulus of silicone rubber composites, and reduced the relative dielectric constant of the composites. The silicone rubber composite system mixed with KH570/SiO2 has the largest adsorption capacity for water molecules and the most obvious effect to inhibit the diffusion of water molecule. The results of this work can provide reference for the design and performance optimization of modified SiO2/silicone rubber composites in hygrothermal environment.

Facile preparation of heptazine-covered Fe2O3 and its synergistic effect on the enhanced flame retardance of silicone rubber composite

The flammability of silicone rubber (SR) significantly limits its broad use in areas that require high flame retardancy. In this study, heptazine-covered Fe2O3, which exhibits effective flame retardancy, was prepared using simple ball milling and heat treatment, which are advantageous for large-scale production. The prepared filler was incorporated into SR. The addition of 7.02 wt% FM filler increased the thermal degradation onset temperature at 5 % weight loss from 492.5 °C for neat SR to 502.7 °C (FM 1:1 composite). Moreover, the peak heat release rate and peak smoke production rate of the FM 1:1 composite significantly decreased by 43.15 % and 68.42 %, respectively, indicating a significant enhancement in the fire safety and smoke suppression of the FM composites. The chemical, morphological, and electronic structures of the FM fillers, pyrolysis gas production, and char residue were thoroughly investigated to reveal the possible flame-retarding mechanisms of the SR composites.

Effect of silane coupling agent on mechanical properties, flame retardancy, and ceramifiable behavior of ceramifiable flame‐retardant silicone rubber composite

AbstractIn order to improve the dispersibility of inorganic fillers and enhance its ceramifiable flame‐retardant efficiency, the ceramifiable flame‐retardant silicone rubber composites were prepared using glass powder, zinc borate, ammonium polyphosphate, mica powder, platinum catalyst as ceramifiable flame‐retardant agent, and various silane coupling agents as interfacial modifier. The micromorphology, mechanical properties, flame retardancy, thermal stability, and combustion behavior of ceramifiable flame‐retardant silicone rubber composites, as well as the flexural strength of the corresponding ceramics generated after pyrolysis of the composites were examined. The results reveal that the inclusion of silane coupling agents improves the dispersibility of ceramifiable flame‐retardant agents substantially. The mechanical properties, flame retardancy, thermal stability, and combustion behavior of ceramifiable flame‐retardant silicone rubber composites are all improved. When compared to a composite without a silane coupling agent, the tensile strength of the composite can be improved by up to 1.9 times. Only 0.5phr silane coupling agent is required to raise the vertical combustion rating from V‐1 to V‐0, and the composite with 3 phr KH570 has a LOI value of 38.6. Meanwhile, the heat release rate of the composite is reduced to a certain extent, and the time to ignition and residue are dramatically enhanced after the addition of silane coupling agent in the cone calorimetry test. Moreover, flexural strength of the corresponding ceramics generated after pyrolysis of the composites rapidly increases with increasing silane coupling agent content, which can reach to 24.7 MPa with addition of 3 phr KH570.

Simulation-Directed Construction of Bamboo-Forest-Like Heat Conduction Networks to Enhance Silicon Rubber Composites' Heat Conduction Properties.

Highly vertically thermally conductive silicon rubber (SiR) composites are widely used as thermal interface materials (TIMs) for chip cooling. Herein, inspired by water transport and transpiration of Moso bamboo-forests extensively existing in south China, and guided by filler self-assembly simulation, bamboo-forest-like heat conduction networks, with bamboo-stems-like vertically aligned polydopamine-coated carbon fibers (VA-PCFs), and bamboo-leaves-like horizontally layered Al2O3(HL-Al2O3), are rationally designed and constructed. VA-PCF/HL-Al2O3/SiR composites demonstrated enhanced heat conduction properties, and their through-plane thermal conductivity and thermal diffusivity reached 6.47W(mK)-1 and 3.98mm2s-1 at 12vol% PCF and 4vol% Al2O3 loadings, which are 32% and 38% higher than those of VA-PCF (12vol%) /SiR composites, respectively. The heat conduction enhancement mechanisms of VA-PCF/HL-Al2O3 networks on their SiR composites are revealed by multiscale simulation: HL-Al2O3 bridges the separate VA-PCF heat flow channels, and transfers more heat to the matrix, thereby increasing the vertical heat flux in composites. Along with high volume resistivity, low compression modulus, and coefficient of thermal expansion, VA-PCF/HL-Al2O3/SiR composites demonstrate great application potential as TIMs, which is proven using multiphysics simulation. This work not only makes a meaningful attempt at simulation-driven biomimetic material structure design but also provides inspiration for the preparation of TIMs.

Novel fillers for wearable technology: Impact of titanium carbide and thinners on room temperature vulcanized silicone rubber composites

Wearable technology has emerged as a robust pathway to achieve smart functionalities in healthcare, sports, fitness, and beyond. This study investigates the mechanical and electromechanical properties of silicone rubber (SR) composites. The SR was reinforced with titanium carbide (TiC) and modified with varying (room-temperature vulcanized) RTV-thinner (silicone oil) concentrations. RTV-SR was utilized, which cures at room temperature to form a flexible, durable, and moldable rubber widely used for sealing, bonding, and making molds. The addition of TiC enhanced tensile strength from 0.5 MPa (control) to 0.59 MPa (5 phr of TiC), and tensile modulus from 0.41 MPa to 0.51 MPa. However, the thinner inclusion reduced tensile properties. For instance, the T10 sample (10 phr thinner) showed a tensile strength of 0.51 MPa and a tensile modulus of 0.29 MPa making the composites soft. Thinner addition also increased ductility, with fracture strains rising from 151 % (control) to 217 % (T10). Compressive strength followed a similar trend, with the control and 5 phr TiC samples exhibiting compressive strengths of 0.18 MPa and 0.17 MPa, respectively, which decreased to 0.12 MPa for the T20 sample. Under cyclic loading, TiC-filled samples showed consistent load patterns, while thinner addition resulted in increased energy dissipation and reduced stiffness. Electromechanical analysis revealed that TiC 5 phr samples exhibited stable piezoelectric responses, with voltage outputs increasing from ±0.1 mV at 15 % strain to ±1.0 mV at 40 % strain. The T5 samples demonstrated significant voltage improvements, generating ±2.5 mV at 15 % strain and ±5 mV at 40 % strain. Long-term cyclic tests confirmed the stability of T5 samples, maintaining voltage outputs of −1.5 mV to 1.5 mV over 50 minutes. Response time analysis indicated faster response times for TiC 5 phr samples, decreasing from 145 ms at 15 % strain to 102 ms at 40 % strain, while thinner addition led to longer response times. Real-time electromechanical tests under mechanical study showed that T5 samples achieved optimal performance with voltage peaks up to ±2.4 mV under thumb pressing. These findings highlight the trade-off between mechanical strength and flexibility, suggesting that an optimal balance of TiC and thinner enhances the properties of silicone rubber composites for applications in wearable technology and sensors.

Flexible and anisotropically conductive film by assembly of silicone rubber and cobalt-coated glass fiber composites

In this study, we prepared electromagnetic cobalt-coated glass fiber (Co@GF) composites via an electroless plating method. Subsequently, a conductive sandwich flexible film consisting of Co@GF composites and liquid silicone rubber (RTV-2) was successfully formed using the tape casting method at room temperature. Based on the perfect coating and excellent electrical conductivity of the Co@GF composites, the resultant RTV-2/Co@GF/RTV-2 sandwich flexible film showed a low volume resistivity of 0.264 Ω·cm and could stretch to 100% (of 4.40 Ω·cm) without obvious fracture. When a magnetic field was applied during the curing process, the electromagnetic Co@GF composites were aligned automatically in the RTV-2 matrix because of their ferromagnetic nature. The as-prepared film exhibited anisotropy in its electrical performance. The volume resistivity parallel to the magnetic field direction is approximately two times lower than that in the perpendicular direction. The maximum difference in the volume resistivity (ρ∥ = 0.768 Ω·cm and ρ⊥ = 1.549 Ω·cm) was obtained at a magnetic field intensity of 800 mT. In addition, a magnetic field intensity of 100 mT helps improve the electrical conductivity of the as-obtained sandwich film. The anisotropic RTV-2/Co@GF/RTV-2 sandwich flexible film is considered a promising flexible electronic sensor, where discrepant inductive sensitivity is required in orthogonal directions.

Study on powdering properties of silicone rubber insulating material in a coastal area

Abstract Silicone rubber insulation materials are widely used in energy systems. The powdering of silicone rubber sheds is a newly discovered aging phenomenon in recent years, and there is no specific research. In this paper, the powder composition of the composite insulators in coastal areas was studied, and the powdering process of silicone rubber under a high humidity environment of salt fog was repeated in the laboratory. The results show that the powders can be divided into two types according to particle shape, element composition, and molecule groups: the inorganic filler and its dehydrated product and the small molecule siloxane after polymer aging fracture. The particle size of Type I of powder is 3∼8μm, and the particle size of Type II of small molecule siloxane is 0.3∼1.1μm. The surface hydrophobicity of the powdered sample in a salt-fog environment will deteriorate, and the static contact angle will decrease. However, the hydrophobicity will gradually recover after leaving the harsh environment. Powdering of composite insulator silicone rubber in coastal areas is a complex physical and chemical process caused by the combined action of electricity, heat, and moisture. During this, polymer molecular chains break, and fillers gradually precipitate, forming powders.

Thermally and electrically anisotropic silicone rubber composites with frequency-selective EMI shielding

The rapid development of highly integrated and multifunctional electronic devices urgently requires polymer composites with anisotropic thermal and electrical conductivities and electromagnetic interference (EMI) shielding. Herein, the precise control of high alignment and alternating distribution of graphite (Gt)-carbon nanotubes (CNTs) and hexagonal boron nitride (h-BN) via co-extrusion to fabricate alternating multilayered SR composites were reported. Such ordered hierarchical structures not only constructed efficient thermally and electrically conductive networks within the layer but also effectively segregated the electrical and thermal conduction path in the through-plane direction. Simultaneously, owing to the destructive interference of EM waves between the two Gt-CNTs layers, resulting in significant improvements in total shielding effectiveness along with obvious shielding peak shift with decreasing the thickness of the h-BN layer. The 4-layer SR composites exhibited anisotropic thermal and electrical conductivities and frequency-selective EMI Shielding. Specifically, the 4-layer SR composites exhibited in-plane thermal conductivity of 8.71 W/mK, breakdown voltage of 8.0 kV/mm and EMI shielding effectiveness of 31–43.2 dB, when the thickness ratio of the Gt-CNTs layer and the h-BN layer was 4:1. Furthermore, the ordered hierarchical structures of the SR composites could be directionally transformed through stacking-cutting to meet different heat dissipation and electrical conduction application scenarios. This research provides new insights into the simple preparation, rational design and multifunctional integration of polymer composites for advanced electronic devices.

Improvement of shoulder peak effect in graphene/silicone rubber strain sensors by nanosilica

Conducting polymer composites (CPCs) typically exhibit shoulder peak phenomena in their resistive response signals, which greatly limits their practical application as strain sensors in the field of vibration damping. In this paper, nanosilica (SiO2) nanoparticles were incorporated into graphene (GR)/methyl vinyl silicone rubber (VMQ) composites to obtain the optimum content of SiO2 to eliminate the shoulder peak phenomenon. The results showed that the shoulder peak phenomenon of the resistance response signal of the composites disappeared after the addition of 30 % SiO2, which explained the mechanism of eliminating the shoulder peak phenomenon. Meanwhile, the tensile strength and Young's modulus of the composites were improved, and excellent resistance-strain response properties were obtained, including a wide sensing range (＞200 %), high sensitivity (GF = 839.02), fast response time (37 ms), and good durability and stability (9000 cycles at 50 % strain). It shows that the strain sensor has great potential for health monitoring in the field of vibration damping.

Superhydrophobic Tensile Designability of Silicone Rubber Composites.

Silicone rubber has broad applications in the field of industrial engineering due to its stable physical and chemical properties. However, the superhydrophobic properties, of silicone rubber, especially large deformation superhydrophobic properties, were not satisfactory for many harsh application environments and complex engineering structures. Here, we report the preparation of superhydrophobic tensile designable silicone rubber composites by a mixed deposition process that included powder deposition and smoke deposition. The infrared test showed that the deposited powder from silicone rubber combustion was mainly composed of SiO2 and short chain siloxane. The mixed deposited surface with a rich micro-nanostructure, which was the key to the formation of superhydrophobic properties. The water contact angle (WCA) and sliding angle (SA) of coating surface could reach 157.6° and 5° ± 1°, respectively, and the tensile designability of superhydrophobic surface is closely related to the prestretched process. In addition, bounce tests, high temperature tests, and solvent resistance tests showed the application potential of modified silicone rubber composites in the field of engineering.

Synergistic effect of multifunctional POSS and carbon nanotubes on mechanical properties and thermal stability of silicone rubber composites

AbstractThe over‐loading of heat‐resistant fillers in silicone rubber creates a contradiction between heat resistance and mechanical properties, thus greatly limiting the durability of silicone rubber products in cutting‐edge applications and complex scenarios. To address this issue, silicone rubber was filled with octavinyl polyhedral oligomeric silsesquioxane (POSS) and carbon nanotubes (CNT) and crosslinked with 2,5‐dimethyl‐2,5‐di(tert‐butylperoxy)hexane (DBPMH) in an attempt to obtain composites with excellent mechanical properties and great thermal stability. Optical microscopy and X‐ray diffraction analyses revealed the size of POSS crystals decreased and the characteristic peaks disappeared after the peroxide crosslinked the polymer at elevated temperature. Specifically, silicone rubber composite filled with 0.1 phr POSS and 1.0 phr CNT exhibited a tensile strength of 10.2 MPa and elongation at a break of 450%. Further, the strength and elongation could be kept after thermo‐oxidative aging at 250°C for 32 h. Thermogravimetric analysis results demonstrate that the addition of POSS and CNT into silicone rubber exhibits a synergistic effect, markedly improving the thermal stability of the material. This method provides a valuable reference for manufacturing silicone rubber products that possess both excellent mechanical properties and high thermal stability under extreme working conditions.Highlights A novel silicone rubber composite with excellent mechanical properties and thermal stability was prepared. A small amount of octavinyl polyhedral oligomeric silsesquioxane (POSS) and carbon nanotubes exhibited a synergistic effect to improve thermal stability. The dependence of the morphological evolution of POSS crystals in SR on the 2,5‐dimethyl‐2,5‐di(tert‐butylperoxy)hexane and temperature was studied.

Review of Recent Progress on Silicone Rubber Composites for Multifunctional Sensor Systems.

The latest progress (the year 2021-2024) on multifunctional sensors based on silicone rubber is reported. These multifunctional sensors are useful for real-time monitoring through relative resistance, relative current change, and relative capacitance types. The present review contains a brief overview and literature survey on the sensors and their multifunctionalities. This contains an introduction to the different functionalities of these sensors. Following the introduction, the survey on the types of filler or rubber and their fabrication are briefly described. The coming section deals with the fabrication methodology of these composites where the sensors are integrated. The special focus on mechanical and electro-mechanical properties is discussed. Electro-mechanical properties with a special focus on response time, linearity, and gauge factor are reported. The next section of this review reports the filler dispersion and its role in influencing the properties and applications of these sensors. Finally, various types of sensors are briefly reported. These sensors are useful for monitoring human body motions, breathing activity, environment or breathing humidity, organic gas sensing, and, finally, smart textiles. Ultimately, the study summarizes the key takeaway from this review article. These conclusions are focused on the merits and demerits of the sensors and are followed by their future prospects.

Review on functionalized CNTs reinforced silicone rubber composites for potential wearable applications

AbstractWearable technology refers to the devices that are integrated with textiles, or implanted in the body or plants for smart monitoring. Hence, this wearable technology has attracted tremendous attention from researchers globally due to its smart functions to be useful for mankind. The key target of this review is to examine the potential of rubber composite materials for such wearable devices. The rubber composites reviewed explore silicone rubber as a rubber matrix (SR). Another objective includes the use of multi‐walled carbon nanotubes (MWCNTs) in pristine and functionalization forms explored as reinforcing fillers. Moreover, prospects of CNT including their structure, properties, and types are explored both in pristine and functionalized state are reviewed. Following this, the mechanical, and electrical, properties of such composites are reviewed. The reported results show that the reinforcing properties are strongly improved by adding functional groups to CNT in rubber composite. These improvements in reinforcing properties are assisted by the functional groups like carboxyl (OH), carbonyl (CO), epoxy, and alkoxy (CO) on the surface of filler are useful. They assist in improving the filler‐rubber compatibility thereby improving filler dispersion and thus finally mechanical and electrical properties. Following this, such improved properties are explored for specific real‐time wearable technologies. This real‐time monitoring includes nursing plant pulse growth monitoring, health monitoring, and humidity sensors. The review further proposes that the functionalized CNTs can be useful for obtaining robust real‐time strain‐sensing monitoring. Moreover, it assists in obtaining sharp response time, strain sensitivity, and good stretchability. Finally, the prospects and challenges are explored discussing the real‐time monitoring of these sensors.Highlights Configurations for nursing plant growth and other monitoring parameters are reviewed. The properties of pristine and functionalized carbon nanotubes reinforced silicone rubber for wearable technology were reviewed. The mechanical, and electrical aspects of functionalized carbon nanotubes were comparatively reviewed. Applications such as wearable strain sensors, humidity sensors, and wearable plant pulse monitoring sensors were reported.

Enhancing radiation resistance of silicone rubber through the addition of polydopamine-modified cerium dioxide

With the widespread use of nuclear science and technology, slowing down the aging of polymers in a radiation environment has become a matter of great concern. In this work, cerium dioxide (CeO2) and CeO2 encapsulated with dopamine (PDA@CeO2) were selected as special fillers to prepare the silicone rubber (SR) composites, and their radiation resistance were investigated by comparing the mechanical properties and thermal performance before and after irradiation. The interfacial bridge formed by PDA results in a greater elongation at break for PDA@CeO2/SR5.0 (770.0 ± 33.6 %) than for CeO2/SR (686.0 ± 15.0 %). After irradiation with γ-rays, the retention of elongation at break of both CeO2/SR0.1 and PDA@CeO2/SR0.1 were larger than SR. Furthermore, PDA@CeO2/SR0.1 showed an impressive retention of 90.5 ± 2.7 % of the tensile strength retention after exposure to an absorbed dose of 200 kGy. The disparity in crosslink density prior to and following irradiation indicated that both CeO2 and PDA@CeO2 were efficacious in reducing radiation crosslinking within the SR. An electron paramagnetic resonance spectrometer and an ultraviolet lamp (UV-EPR) were used to observe in real time the free radical scavenging ability of CeO2 and PDA@CeO2 inside the SR. These results indicated that CeO2 and PDA@CeO2 was expected to prevent further chain reactions in silicone rubber by scavenging free radicals generated in SR, thus improving the radiation resistance of SR.

Enhancement of the Electric-Force Response of Carbon Black/Silicone Rubber Composites by Silane Coupling Agents.

Flexible strain sensors have a wide range of applications in the field of health monitoring of seismic isolation bearings. However, the nonmonotonic response with shoulder peaks limits their application in practical engineering. Here we eliminate the shoulder peak phenomenon during the resistive-strain response by adjusting the dispersion of conductive nanofillers. In this paper, carbon black (CB)/methyl vinyl silicone rubber (VMQ) composites were modified by adding a silane coupling agent (KH550). The results show that the addition of KH550 eliminates the shoulder peak phenomenon in the resistive response signal of the composites. The reason for the disappearance of the shoulder peak phenomenon was explained, and at the same time, the mechanical properties of the composites were enhanced, the percolation threshold was reduced, and they had excellent strain-sensing properties. It also exhibited excellent stability and repeatability during 18,000 cycles of loading-unloading. The resistance-strain response mechanism was explained by the tunneling effect theoretical model analysis. It was shown that the sensor has a promising application in the health monitoring of seismic isolation bearings.

Shock attenuation of silicone rubber composites with shear thickening fluid

This study investigated the enhancement of shock attenuation in silicone rubber (SR) matrix composites through the incorporation of shear thickening fluid (STF) microdroplets. A series of SR-STF composites with various STF mass fractions (0 to 50 wt. %) were fabricated using an efficient emulsification method. The primary focus was on assessing the shock attenuation capabilities of SR-STF through laser-induced shock experiments. The results indicate a significant improvement in shock wave attenuation in the composites due to the addition of STF microdroplets. Notably, the SR-STF composite containing 30 wt. % STF exhibited a maximum 60 % reduction in shock pressure attenuation compared to SR of the same thickness. This enhancement is attributed to multiple mechanisms, including viscosity-induced dissipation, the initiation and propagation of cracks within both the SR matrix and the STF microdroplets, and interface-induced effects like interface separation, shock wave reflection and scattering, along with the thickening behavior of STF. An intriguing observation was the interplay of these mechanisms at different STF concentrations, leading to the identification of an optimal STF content for maximizing the shock attenuation. This research's findings highlight the crucial role of STF microdroplets in shock wave attenuation and offer a strategic approach for developing SR matrix composites with enhanced shock attenuation capacities.

Effect of Titanium Dioxide on Cure Characteristics and Physico Mechanical Properties of High-Temperature Vulcanizing Silicone Rubber Composites

Silicone rubber (SiR), a vital elastomer, is extensively used in producing various engineering and general products, owing to its distinctive properties. Despite the remarkable properties, SiR-based products require anti-microbial agents such as titanium dioxide, TiO2 to negate black mold issues. Still, adding this agent alters the composites' processability and physical and mechanical properties. This study examined the impact of adding different TiO2 content as fillers on silicone rubber composites' processability, physical properties, and mechanical properties. Raw materials of 20-hardness high-temperature-vulcanization (HTV) SiR- reinforced with various TiO2 contents at 0.0, 0.3, 0.6 and 1.2 wt% were prepared using a two-roll mill. The results indicated SiR composites reinforced with 0.3 wt% TiO2 exhibited the best performance with a tensile strength of 1.49 MPa, elongation at break of 340.87%, modulus 100% of 0.664 MPa, modulus 300% of 0.822 MPa, and modulus 500% of 0.954 MPa. This performance can be attributed to the efficient crosslink density and the effective interactions between the TiO2 and silicone rubber particles at this concentration. Structural and morphological analyses further corroborated the results. Consequently, it can be inferred that silicone rubber reinforced with 0.3 wt% titanium dioxide holds the potential for formulating silicone rubber compounds that necessitate anti-microbial properties.