Filler Network Research Articles

Cavity formation in silica‐filled rubber compounds observed during deformation by ultra small‐angle x‐ray scattering

AbstractWhen silica‐filled rubber compounds are deformed, structural modifications in the material's bulk lead to irreversible damage, the most significant of which is cavitation appearing within the interfaces of interconnected polymer and filler networks. This work introduces a new method to analyze cavitation in industrial‐grade rubbers based on ultra small‐angle x‐ray scattering. This method employs a specially designed multi‐sample stretching device for high‐throughput measurements with statistical relevance. The proposed data reduction approach allows for early detection and quantification of cavitation while providing at the same time information on the hierarchical filler structures at length scales ranging from the primary particle size to large silica agglomerates over four orders of magnitude. To validate the method, the scattering of SSBR rubber compounds filled with highly dispersible silica at different ratios was measured under quasi‐static strain. The strain was applied in incremental steps up to a maximum achievable elongation or breakage of the sample. From the measurements performed in multiple repetitions, it was found that the minimum strain necessary for cavity formation and the size evolution of the cavities with increasing strain are comparable between these samples. The sample with the highest polymer content showed the lowest rate of cavity formation and higher durability of silica structures. The structural stability of the compounds was determined by the evolution of the filler hierarchical structures, obtained by fitting data across the available strain range.

Novel polystyrene‐based light diffusing materials: Introduction of magnesium hydroxide to enhance scattering range and thermal conductivity

AbstractIn high‐power lighting, large‐screen display, and other practical application scenarios, Light diffusing materials (LDMs) with favorable thermal conductivity are desired to assist in heat dissipation. In this paper, platy magnesium hydroxide (pMH) and mesoporous spherical magnesium hydroxide (sMH) were introduced as scattering particles for the first time to prepare polystyrene (PS)‐based LDMs. The limited refractive index mismatch allowed MH to be filled in large quantities with less sacrifice of light transmission performance. Owing to the complex surface morphology and large specific surface area, sMH possesses stronger scattering capability, and its combination addition with pMH could effectively increase scattering range. Meanwhile, an effective filler network was constructed with the combined use of pMH and sMH, and thus enhanced the thermal conductivity of the composites. Additionally, PS/pMH‐sMH composites exhibited higher thermal stability. This study expands the auxiliary thermal management capability of light diffusion materials and presents a new application possibility for MH as scattering particles.Highlights A new application possibility for Magnesium hydroxide as scattering particles. Light transmittance degradation of PS/MH at high filler loadings was mitigated by RI matching. Complex surface morphology endowed sMH with strong scattering capability. Optimal filling ratio of pMH to sMH was tested for better scattering performance. Extended scattering range, improved TC and thermal stability was achieved.

Diffusion Behavior of Organic Solvents in Graphene Oxide/Nano Silica Hybrid Natural Rubber Latex Nanocomposite: Experimental and Theoretical Approach

AbstractThis study explores the impact of a graphene oxide (GO)/nano silica (NS) hybrid (GO/NS) filler on the diffusion characteristics of natural rubber (NR) composites when exposed to toluene, xylene, and hexane solvents. The lowest solvent uptake is observed for NR GO/NS 3 (3 phr), which is attributed to forming a robust filler network within the composite. The calculation of crosslink density using the Flory‐Rehner equation reveals significantly higher values for NR GO/NS 3, indicating good crosslinking density in the presence of the hybrid filler. Furthermore, molecular mass between crosslinks (Mc) is calculated, demonstrating a favorable fit with the Affine model. The investigation extends to theoretical modeling, where the Korsemeyer–Peppas and Peppas–Sahlin models are employed to predict solvent uptake behavior. Strikingly, the experimental values exhibit a strong alignment with the Peppas–Sahlin model. This comprehensive analysis provides valuable insights into the diffusion behavior of graphene oxide/nano silica (GO/NS) hybrid‐reinforced natural rubber latex in organic solvents, highlighting potential applications in areas such as solvent‐resistant coatings, barrier materials for chemical storage, and enhanced performance in protective gloves and seals used in harsh chemical environments.

Exploring the wear resistance of EPDM‐PAE/SWCNTs composites with a novel perspective of micro‐network structure

AbstractThe effect of single‐walled carbon nanotubes (SWCNTs) on the crosslinking network structure of Ethylene Propylene Diene Monomers (EPDM)—Polyamide elastomers (PAE) is investigated in detail using Hansen Solubility Parameter (HSP) theory. Rheological method and scanning electron microscopy (SEM) are used to investigate the effect of SWCNTs on the molecular chain movement and their interaction with the filler network of EPDM‐PAE. The DIN abrasion test is conducted to obtain the effect of SWCNTs on the wear characteristics of EPDM‐PAE/SWCNTs composites. The linear synergistic relationship between crosslinking density and wear volume indicates that the change in wear properties is contributed by the micro‐network structure. The addition of SWCNTs increases the chemical crosslinking density and improves the wear properties of EPDM‐PAE. However, the decrease in the physical crosslinking density leads to an increase in the degree of internal friction within the network structure, resulting in a decrease in the wear performance. Changes in wear resistance can be related to the micro‐network structure, which provides a novel approach to studying the wear characteristics of high‐performance elastomers. It is also an innovative work based on the network structure to guide the preparation of new wear‐resistant elastomeric materials.

Fraction-dependent filler network in silicone rubber: Unraveling abrupt enhancement in rheological properties via solvent extraction and DLS study

A pivotal nanofiller network will be constructed by the filler loading threshold inside the silicone rubber, leading to abrupt enhancement in the rheological properties of the composites. However, the contribution of the nanofiller network to the performance mutation is poorly understood due to lack of direct evidence to recognize the formation of filler networks. This work quantitatively investigated the filler aggregation network of solvent-extracted monodisperse silica-filled polydimethylsiloxane (PDMS) composites to interpret the rheological properties. The results indicated that, when filler loadings reach 60 phr, the size of the filler network reaches its maximum (1280.5 nm), significantly increasing the storage modulus (166 kPa) and Payne effect (163 kPa), due to the formation of a filler network confirmed by Dynamic Light Scattering (DLS) and scanning electron microscope (SEM) observation. The reduction in aggregate size observed with longer extraction times is because of the collapse of the nanofiller network, which occurs as the polymer chains are removed. The aggregates reappear in a monodisperse form as the extraction duration reaches 20 days. This confirms that filler aggregates of interconnected polymer chains can form a well-developed network structure that effectively supports and transfers stresses. This contributes to an in-depth understanding of the formation mechanism of nanofiller networks, aiding the advancement of high-performance polymer nanocomposites.

Constructing house-of-cards-like networks with BNNS confined in interlocking Al2O3 platelet skeletons for thermally conductive epoxy composites

The construction of 3D filler networks is an effective strategy to improve the thermal conductivity of epoxy resins, yet it is still severely limited by the disconnection of conduction channels. In this contribution, an original interlocking hybrid skeleton with continuous conduction channels was developed by assembling BNNS into an in situ-formed interlocking Al2O3 platelet skeleton using commercial polyurethane as a template, where large intergranular contact areas of Al2O3 platelets were established by sintering to greatly decrease the contact thermal resistance. Besides, the interlocking Al2O3 skeleton coupled with BNNS under hydrogen bonding endowed further improvement of its thermal conductivity. The optimized Al2O3/BNNS/EP composite displayed an excellent thermal conductivity of 5.01 W/mK at 15.3 vol% of Al2O3 and 11.4 vol% of BNNS loading, far higher than that of neat epoxy resin by 1904.0 %. Meanwhile, the interlocking hybrid skeleton provided the epoxy resin with low dielectric loss, satisfactory thermal stability and flame retardancy.

Surface engineering of silica to control creep failure resistance of natural rubber-based composites for potential application in the suspension of rolling stock

Immobilization of polymer chains by silica on one side could increase the viscoelastic energy loss and on the other could postpone chain relaxations and temporarily conceal creep deformation. It is not yet clear how the formation of an interphase layer contributes to the change of creep resistance. Bifunctional silane, “Bis(triethoxysilylpropyl) disulfide” is employed to induce various degrees of covalent bonds at the rubber-silica interface, and also brings multiple degrees of immobilization. Interestingly, it was found that by controlling interfacial phenomena, the creep rate can be altered in a wide range of 4.35–1.65 (%/decade). It was mechanistically explained how the maximum creep resistance is observed for the sample having a medium level of surface treatment. The formation of a filler network indicated an essential role in increasing the high-temperature creep failure of systems having no favorable polymer-filler interaction.

Quantitative Study on Reinforcing Mechanism of Nanofiller Network in Silicone Elastomer Based on Fluorescence Labeling Technology

Although there have been many theoretical studies on the enhancement effect of nanofiller networks and their interaction with elastomer molecular chains on the mechanical properties of elastomers, its mechanism description is still not completely clear. One of the main obstacles is the lack of quantitative characterization techniques and corresponding theoretical models for the three-dimensional morphology of complex nanofiller networks. In this paper, the precipitated silica-filled silicone rubber was studied by fluorescence labeling combined with laser scanning confocal microscopy, and the real three-dimensional images of dispersion and aggregation structure of filled rubber systems were obtained. The microstructure evolution of nano-particle aggregates caused by the increase in the filler volume fraction was quantitatively described, and the reinforcement mechanism of elastomers with a distribution of aggregates and filler networks composed of nanoparticles was studied. Furthermore, a nano-composite reinforcement model based on volume fraction, particle shape, interaction, and filler dispersion has been proposed.

Synergistic enhancement of magic triangle properties of PC tread stocks modified by amine-capped trans-1,4-poly (butadiene-co-isoprene)

The development of high-performance “green tires” with synergistically improved “magic triangle” properties like lower rolling resistance, higher wet-skid resistance and higher abrasion resistance has always been a hot issue. In this work, an effective strategy for developing high-performance “green tires” with simultaneously improved “magic triangle” properties of solution-polymerized styrene-butadiene rubber (SSBR)/cis-1,4-polybutadiene rubber (BR) nanocomposites modified by amine-capped trans-1,4-poly(butadiene-co-isoprene) copolymers (F-TBIR) was proposed. A series of F-TBIR with 10–60 mol% amine-capped efficiency (CE) and 30-90 × 104 weight-average molecular weight (Mw) were synthesized by using heterogeneous TiCl4/MgCl2–Al(i-Bu)3 Ziegler-Natta catalyst with dicyclohexylamine (DCHA) as chain transfer agent (CTA). With the increase in CE of F-TBIR, the silica-filled SSBR/BR/F-TBIR compounds exhibited improved green strength, modulus at 100 % elongation and bound rubber, and their vulcanizates showed synergistically improved “magic triangle” properties like obviously reduced rolling resistance and abrasion loss, and increased wet-skid resistance. It was found that the incorporation of 10 phr F-TBIR3 with CE of 60 mol% and Mw of 32 × 104 resulted in highly expected properties of the SSBR/BR/F-TBIR3 nanocomposite. The contribution mechanism of F-TBIR3 was discussed based on the improvements of polymer network structures and filler network structures. This work is expected to provide an effective strategy to construct the desired network structures for high-performance rubber composites.

Thermal conductivity enhancement of epoxy by a 3D Si3N4 crystal rod/grain skeleton fabricating from photovoltaic silicon waste

Silicon nitride (Si3N4) is one of the preferred fillers for the preparation of high thermal conductivity polymer composites because of its intrinsic high thermal conductivity and good electrical insulation. To maximize the thermal conductivity enhancement effect of the fillers in the composites, it is necessary to pre-construct a three-dimensional (3D) thermally conductive filler network. Herein, surfactant foaming was applied to pre-construct a 3D Si-containing framework from photovoltaic silicon waste (PSW), which was subsequently transformed into a porous skeleton consisting of Si3N4 rods and grains by in-situ nitridation reaction sintering. And finally, thermal conductive Si3N4/epoxy (EP) composites were fabricated after infiltrating EP into the network skeleton. When the filler content of Si3N4 was 41.00 vol%, the obtained Si3N4/EP composite showed the highest thermal conductivity of 2.99 W·m-1·K-1, which was 13.95 times higher than that of pure EP. Tests on running CPU and heating table showed that the Si3N4/EP substrate had excellent heat dissipation performance compared to the pure EP substrate. The 3D continuous network formed by "bridging" between two different morphologies of Si3N4 microcrystals contributed to providing effective multi-directional heat transfer paths and thereby improving the thermal conductivity of the composites. Overall, the low cost of raw silicon source originating from industrial waste as well as the simple and practical construction of heat-conducting filler network demonstrate the promising application of the Si3N4/EP composites fabricated in our work.

Phase change thermal interface film with bicontinuous and textured filler network for efficient wearable heat dissipation

Wearable thermal management needs to simultaneously meet thermal conductivity, heat storage capacity, stability, flexibility, and economy, but these characteristics constrain each other in the development of phase change thermal interface materials (PhC-TIM). Therefore, relying on the economic bicontinuous structure for fillers’ orientation, a new type of bicontinuous phase change thermal interface material (BPTIM) was designed, which includes thermal storage phase composed of paraffin (PCMs) and flexible molecule styrene–butadiene–styrene (SBS), and thermal conductivity phase composed of adhesive polyurethane (PU) and thermal conductive medium boron nitride (h-BN). In the experiment, shear force generated by stirring and optimized two-phase volume ratio resulted in the stretching and compressing of the thermal conductive phase, promoting the orientation of h-BN and ultimately forming a textured thermal-conductive network in a high PCMs content bicontinuous structure. Moreover, the introduction of SBS had brought bending resistance and thermal stability. These characteristics enabled BPTIMs to significantly reduce the surface temperature of the wearable device by 23 °C. Overall, this design provides a certain reference for the widespread application of PhC-TIM in thermal management of wearable electronic products.

Enhanced abrasion resistance of NR/BR/TBIR composites through the synergistic reinforcement of carbon black and graphene oxide: Structural influence and mechanistic insights

AbstractCarbon black (CB) with different structural parameters together with graphene oxide were formed into uniformly dispersed filler network for enhancing the abrasion resistance of natural rubber/cis‐1,4‐polybutadiene rubber/trans‐1,4‐poly(isoprene‐butadiene) rubber blended composites. It showed that the CB structural parameters, such as specific surface area, surface activity and structural degree affected the formation of bound rubber. With the increase of bound rubber content, the homogeneity of filler network structure was improved and the filler‐rubber interaction was enhanced, resulting in a remarkable increase in the mechanical properties, thermal performance and abrasion resistance of the composites. Among the different types of CB, the composites filled with high‐structural‐degree CB of N134 had DIN wear volume as low as 76 mm3 and exhibited 19.5% higher abrasion resistance than N330. Wear surface observations and wear mechanism analyses showed that the increase in abrasion resistance was related to the improvement in tear resistance, hardness and thermal properties of the composites. Multiple linear regression analyses yielded that the structural degree in the structural parameters of CB had a significant correlation effect on the formation of bound rubber, and there was a strong linear relationship between the abrasion resistance of the composites and the content of bound rubber.Highlights Trans‐1,4‐poly(isoprene‐butadiene) rubber as compatibilizer for NR/BR blends. Synergistic enhancement of rubber using carbon black and graphene oxide. Carbon black with high structural degree promotes the formation of bound rubber. Described correlation between CB structural parameters and abrasion resistance of rubber.

Fabrication of highly thermally conductive and irradiation resistant UHMWPE-based composites for nuclear shielding applications

With the advancement of nuclear energy, the safety of both humans and the surrounding environment necessitates the adoption of effective nuclear radiation shielding materials. Polymer-based shielding materials have garnered attention due to their lightweightness and ease of moldability. However, they normally possess low thermal conductivity (λ) and easy deformation at high temperatures, which potentially cause catastrophic disasters during service if they are mechanically failed due to heat accumulation. To address the above concerns, highly thermally conductive and irradiation resistant ultra-high molecular weight polyethylene (UHMWPE)-based composites were fabricated. Planar fillers such as boron nitride (BN) and graphite (Gt) along with lead (Pb) powders were employed to construct a densely packed filler network for improving the λ and mechanical properties of UHMWPE-based composites. The λ was increased from 3.81 to 6.20 W/mK when 20 wt% Pb (2.88 vol%) was added to BN30/Gt20 (i.e., UHMWPE composite with 30 wt% BN and 20 wt% Gt), representing an increase of 62.73 %. Moreover, the λ of Pb80 was increased from 0.87 to 3.29 W/mK by merely adding 5 wt% (9.99 vol%) Gt, representing a remarkable increase of 278.16 %. GEANT4 simulation results indicated that BN30/Gt20/Pb20 exhibited excellent neutron shielding performance. Samples which were irradiated using 60Co γ-rays at a total dosage of 1.15×105 Gy exhibited enhanced mechanical performance, which indicated excellent irradiation resistance of UHMWPE-based composites. Therefore, a facile method was proposed to prepare multi-functional UHMWPE-based composites that demonstrate promising application in nuclear sectors.

Enhanced Gas Barrier and Mechanical Properties of Styrene-Butadiene Rubber Composites by Incorporating Electrostatic Self-Assembled Graphene Oxide @ Layered Double Hydroxide Hybrids.

Rubber composites with a high gas barrier and mechanical properties have received considerable attention due to their potential applications. Constructing complex filler networks in a rubber matrix is an effective strategy to simultaneously enhance the gas barrier and mechanical properties. In this work, graphene oxide layered double hydroxide (GO@LDHs) hybrids were obtained by the electrostatic self-assembly method. A unique interspersed and isolated structure was formed in GO@LDHs hybrids due to the chemical interactions between the functional groups on GO sheets and the metal cations on LDH layers. Subsequently, the GO@LDHs hybrids were incorporated into a styrene-butadiene rubber (SBR) matrix using a green latex compounding method. The results showed that the GO@LDHs hybrids were uniformly embedded in the SBR matrix, constructing an overlapped filler network and forming physical bonding points that reduced the free volume of the composites. The electrostatic interactions between GO@LDHs hybrids facilitated energy dissipation during stretching, thereby improving the mechanical performance of the rubber composites. More importantly, the N2 gas permeability and fracture toughness of GO@LDHs/SBR composites decreased by 52.2% and increased by 845%, respectively, compared to those of a pure SBR matrix. The construction of GO@LDHs hybrids offers new insights for designing rubber composites with a high gas barrier and mechanical properties.

Morphology and properties of carbon black‐filled thermoplastic vulcanizate (TPV) composites based on hydrogenated acrylonitrile butadiene rubber and thermoplastic polyester elastomer

AbstractThe unique morphology of thermoplastic vulcanizates (TPVs) reveals a significant correlation between the microstructure and performance, and the development of high‐performance TPV composites for specialized applications has become a current research priority. This study is devoted to developing heat‐ and oil‐resistant TPV composites filled with carbon black (CB) based on hydrogenated acrylonitrile butadiene rubber (HNBR) and thermoplastic polyester elastomer (TPEE) following the masterbatch procedure of dynamic vulcanization. Herein, it focuses on the effects of CB content on the morphology, filler network structure, and properties of the TPV/CB composites. As observed by morphological studies, CB nanoparticles are interconnected and aggregated to form a dual network structure of rubber and CB particles in the composite. With the increasing CB content, it's demonstrated that dual networks have enhanced and shifted to rigid. Consequently, the hardness, thermal stability, and oil resistance of TPV/CB composites are improved, with a 104% elevation in the stress at 300% strain. The flowability in the molten state, toughness (the elongation at break decreased from 690% to 310%), and elasticity deteriorated by oversized (0.5 ~ 1.2 μm) CB agglomerates and rigid rubber particles. This study gives new insight into the microstructure‐properties relationship of TPVs, offering theoretical guidance for fabricating HNBR‐based TPV composites.

Revealing the nanoscale reinforcing mechanism: How topological structure of carbon black clusters influence the mechanics of rubber

The mechanical reinforcement of rubber by carbon black (CB) depends strongly on its the size and topography of CB clusters. However, the underlying mechanisms remain largely unexplored. This study uses atomic force microscopy (AFM) to probe interfacial properties at the nanoscale to elucidate the influence of the CB topological structure on macroscopic mechanical properties. A substantial amount of high-modulus bound rubber is found inside the CB aggregates, particularly in highly branched ones. This phenomenon plays a critical role in reinforcement, as corroborated by quantitative AFM nanomechanics, chain segment motion results and theoretical calculations. A quantitative analysis of the filler network reveals that the branched chain structure effectively reduces the packing spacing and improves the stress transfer efficiency.

Electromechanical response of multilayer graphene sheet/polypropylene nanocomposites and its relationship with the graphene sheet physicochemical properties

Abstract The mechanical, electrical, and piezoresistive responses of multilayer graphene sheet (GS)/polypropylene (PP) nanocomposites are investigated using four GSs of distinctive physicochemical properties. It is found that the morphology of the interconnected network of GS agglomerates at the mesoscale governs the mechanical, electrical, and electro-mechanical (piezoresistive) properties of the PP nanocomposites. The morphology of the mesoscale network of electroconductive fillers governs the effective properties of the nanocomposite. This network morphology strongly depends on the GS lateral size, dispersion, agglomeration, and, to a lesser extent, the specific surface area of the GSs. Within the range of lateral sizes investigated herein (1 - 21 m), larger GSs yields nanocomposites with higher electrical conductivity. On the other hand, GSs of moderate lateral size (~ 6.5 m) and specific surface area of ~ 141 m2/g render GS/PP nanocomposites with a more dispersed and more sparsely interconnected network. This better dispersed network with agglomerates of smaller dimensions is concomitant with improved stiffness and strength, and higher gauge factors (~ 18.2) for this GS/PP nanocomposites. Excellent capabilities for detection of human motion were proved for these nanocomposites.

Hysteresis-Free Temperature Sensing with Printable Electronic Skins Made of Liquid Polyisoprene/CNTs.

Developing an electronic skin (e-skin) is becoming popular due to its capability to mimic human skin's ability to detect various stimuli. Mostly, such skins are tactile-based sensors. However, the exploration of nontactile-based sensing capability in the e-skin is still in a nascent stage. Herein, we report an approach toward developing electrical hysteresis- and cross-interference-free nontactile e-skin using liquid polyisoprene with an ultralow concentration of multiwalled carbon nanotubes (ϕ = 0.006 volume fraction) by leveraging the stencil printing technique. The impact of cross-linking the samples was studied. Uncross-linked samples demonstrated higher electrical conductivity than the cross-linked samples. A coarse-grained phenomenological model with molecular dynamics simulation was utilized to investigate filler network formation and percolation that dictate the conductivity of uncross-linked and cross-linked samples. Simulation studies supported the fidelity of the experimental findings. The uncross-linked e-skin demonstrated a higher temperature sensitivity (-1.103%/°C) than the cross-linked e-skin (-0.320%/°C) in the thermal conduction mode. Despite the superior sensitivity of the uncross-linked e-skin, the cross-linked systems demonstrated superior cyclic stability (35 thermal cycles), ensuring reliable sensor readings over extended usage. Judicious choice of encapsulant warranted the cross-linked e-skin sensor to nullify the impact of moisture on signal output, thereby providing cross-interference-free results. The optimized e-skin sample retained a similar thermal sensitivity even when used in the nontactile mode. From the application purview, the utility of the developed sensor was tested successfully for nontactile sensing of human body temperature. Additionally, the sensor was utilized to determine the respiratory profile by integrating the developed sensor into a wearable mask. This study advances nontactile e-skin-based sensing technology and opens new avenues for creating wearable and IoT devices for healthcare and human-machine interactions.

Construction of tree-ring mimetic 3D networks in polyvinyl alcohol/boron nitride composites for enhanced thermal management and mechanical properties

Constructing a three-dimensional (3D) filler network in polymer thermal interface materials (TIMs) is crucial for enhancing thermal conductivity and mechanical properties. However, the discontinuous and loose network of fillers are one of the main reasons hindering the joint improvement of thermal conductivity and mechanical properties. The construction of a regular and dense 3D continuous filler network remains a significant challenge. In this study, an innovative bidirectional freezing technique was designed to create a polyvinyl alcohol (PVA)/boron nitride (BN) composite with a tree-ring-like 3D network. This technique promotes the formation of 3D network consisting of long-range lamellar BN layers with a tree-ring-like structure by controlling the nucleation and growth of ice crystals along the bidirectional temperature gradient induced by a polytetrafluoroethylene (PTFE) cone. The resulting PVA/BN composite exhibits high thermal conductivity (6.25 W/m·K) due to the lower interfacial thermal resistance between fillers (1.271 × 10−7 K m2/W), and an enhanced tensile strength of 41.71 MPa, which is attributed to the regular and dense BN network. This study presents a feasible strategy for constructing a 3D continuous network structure in polymer-based TIMs, paving the way for advancements in thermal management solutions.

Modulation of Mechanical Properties of Silica-Filled Silicone Rubber by Cross-Linked Network Structure.

Associating molecular structure and mechanical properties is important for silicone rubber design. Although silicone rubbers are widely used due to their odourless, non-toxic, and high- and low-temperature resistance advantages, their application and development are still limited by their poor mechanical properties. The mechanical properties of silicone rubbers can be regulated by designing the cross-link density and cross-linking structure, and altering the molar contents of vinyl in the side groups of methyl vinyl silicone rubber (MVQ) leads to different cross-linking structures and cross-linking densities in the vulcanized rubber. Therefore, this study investigated the differences in molecular parameters and molecular chain structures of unprocessed MVQ rubbers with different vinyl contents. The results showed that MVQ rubbers with high vinyl contents were branched polymers, better facilitating the cross-linking reaction than MVQ rubbers with low vinyl contents. In addition, silicone rubbers with different vinyl contents were co-cross-linked to introduce an inhomogeneous cross-linked network in the silicone rubber to improve its mechanical properties. The cross-linked network properties were analysed by the Flory-Rehner model and Mooney-Rivlin plots, and it was found that the long chains in the sparsely cross-linked domains of the network favoured high elongation at break and the short chains in the densely cross-linked domains contributed to high modulus, which could satisfy the functions of reinforcing and toughening the rubber materials at the same time. It was also found by analysing the filler network and aggregate morphology that the inhomogeneous cross-linked network led to an improvement in the dispersion of silica in the rubber and a significant improvement in the mechanical properties of silicone rubber.