Conductive Silicone Rubber Research Articles

Effect of silver plating time on the properties of conductive silicone rubber filled with silver-coated carbonyl nickel powder

This article investigates the effect of the silver plating time on the microwave shielding and mechanical properties of the conductive silicone rubber filled with silver-coated carbonyl nickel powder. The results show that the electromagnetic shielding effectiveness (SE) of the rubber with the silver-coated carbonyl nickel powder rises up to about twice that of the rubber with the carbonyl nickel powder and the elongation of the rubbers at break increases when the plating time reaches 40 min. The property improvement is related to the strengthening effects of the silver coating layer on the carbonyl nickel powder in the rubber. The silver coating layer builds a silver-silver conductive channel and a cooperative mechanism of the electromagnetic wave reflection and absorption. That is beneficial to increasing the SE of the rubber. In addition, the silver coating layer on the surface of the carbonyl nickel powder has a better combining ability with the rubber than the powder itself, which may play an important part in the increase of the elongation.

Effect of Powder Morphologies on the Property of Conductive Silicone Rubber Filled with Carbonyl Nickel Powder

Conductive silicone rubbers filled with the spherical, flaky, and chain-spherical carbonyl nickel powder were prepared. The effects of powder morphologies on their electromagnetic and mechanical properties were analyzed. The electromagnetic shielding effectiveness (SE) and tensile strength of the rubbers varies with their powder morphologies: the SE values increase from the spherical and the chain-spherical to the flaky morphology in the frequency range of 100–400 MHz. In the range of 500–1500 MHz, the SE rises from the spherical and the flaky to the chain-spherical morphologies. In addition, the tensile strength increases from the spherical and the flaky to the chain-spherical morphologies. These variations are related to the differences in the conductive network structure and the powder distribution in the rubber.

增塑剂对纯银导电硅橡胶物理机械性的影响

本文通过纯银导电橡胶配方中增塑剂添加量变化的实验，对丙二醇增塑剂对纯银导电硅橡胶中机械物理性能的影响进行了研究，研究结果表明适当添加比例的丙二醇增塑剂对导电硅橡胶的物理性能和加工性能都有一定程度的提升。 In this paper, the effect of the amount of plasticizer on the mechanical properties of pure silver conductive silicone rubber was studied through the experiment of the change of the amount of plasticizer in the formula of silver conductive rubber. The results show that adding appropriate proportion of propylene glycol plasticizer on physical properties of conductive silicone rubber and processing properties have a certain degree the promotion.

航空用高导电硅橡胶设计及性能研究

本文通过高导电硅橡胶配方中硅橡胶和导电填料的选型和测试的实验，对硫化合成后的玻璃镀银微珠导电橡胶和铝镀银导电橡胶进行一系列环境试验前后指标的对比研究，研究结果表明采用30度级且平均分子量120万的乙烯基硅橡胶和平均粒径40 µm的铝镀银或玻璃镀银填料制成的高导电硅橡胶具有优秀的电性能、力学性能和环境适应性能。 In this paper, through the selection and testing of silicone rubber and conductive filler in high conductive silicone rubber formulation, a comparative study of indexes before and after a series of environmental tests was conducted on the glass coated silver coated micro conductive rubber and aluminum silver plated conductive rubber. The results show that high conductive silicone rubber, made of the vinyl silicone rubber of 30 degree and the average molecular weight of 1 million 200 thousand and the aluminum silver or silver plated glass filler of the average particle size of 40 µm, has excellent electrical properties, mechanical properties and environment properties.

Electrically and thermally conductive underwater acoustically absorptive graphene/rubber nanocomposites for multifunctional applications.

Graphene is ideal filler in nanocomposites due to its unique mechanical, electrical and thermal properties. However, it is challenging to uniformly distribute the large fraction of graphene fillers into a polymer matrix because graphene is not easily functionalized. We report a novel method to introduce a large fraction of graphene into a styrene-butadiene rubber (SBR) matrix. The obtained graphene/rubber nanocomposites were mechanically enhanced, acoustically absorptive under water, and electrically and thermally conductive. The Young's modulus of the nanocomposites was enhanced by over 30 times over that for rubber. The electrical conductivity of nanocomposites was ≤219 S m-1 with 15% volume fraction of graphene content, and exhibited remarkable electromagnetic shielding efficiency of 45 dB at 8-12 GHz. The thermal conductivity of the nanocomposites was ≤2.922 W m-1 k-1, which was superior to the values of thermally conductive silicone rubber thermal interface materials. Moreover, the nanocomposites exhibited excellent underwater sound absorption (average absorption coefficient >0.8 at 6-30 kHz). Notably, the absorption performance of graphene/SBR nanocomposites increased with increasing water pressure. These multifunctional graphene/SBR nanocomposites have promising applications in electronics, thermal management and marine engineering.

Bio-inspired Graphene-enhanced Thermally Conductive Elastic Silicone Rubber as Drag Reduction Material

This study presented a graphene platelet/silicone rubber (GPL/SR) composite as a drag reduction material, inspired by the boundary heating drag reduction mechanism of dolphin skin. Graphene was added as a thermally conductive filler at weight fractions of 0.17 wt%, 0.33 wt% and 0.67 wt% to pristine silicone rubber (PSR). Tests of the thermal conductivity and tensile properties showed that the thermal conductivity of all three GPL/SR materials of 0.17 wt%, 0.33 wt% and 0.67 wt% graphene were 20%, 40% and 50% higher than that of the PSR, respectively, and the elastic modulus of the 0.17 wt% GPL/SR materials was lowest. Droplet velocity testing, which can reflect the drag reduction mechanism of the heating boundary controlled by the GPL/SR composite, was performed between 0.33 wt% GPL/SR, which typically exhibits good mechanical properties and thermal conductivity performance, and the PSR. The results showed that on the 0.33 wt% GPL/SR, the droplet velocity was higher and the rolling angle was lower, implying that the GPL/SR composite had a drag-reducing function. In terms of the drag reduction mechanism, the heat conductivity performance of the GPL/SR accelerated the heat transfer between the GPL/SR composite surface and the droplet. The forces between the molecules decreased and the droplet dynamic viscosity was reduced. The drag of a sliding water droplet was proportional to the dynamic viscosity, which resulted in drag reduction. The application of GPL/SR material to the control fluid medium should have important value for fluid machinery.

열 열화한 열전도성 실리콘 고무의 전기특성

열 열화한 열전도성 실리콘 고무의 전기특성

Wearable textile input device with multimodal sensing for eyes-free mobile interaction during daily activities

As pervasive computing is widely available during daily activities, wearable input devices which promote an eyes-free interaction are needed for easy access and safety. We propose a textile wearable device which enables a multimodal sensing input for an eyes-free mobile interaction during daily activities. Although existing input devices possess multimodal sensing capabilities with a small form factor, they still suffer from deficiencies in compactness and softness due to the nature of embedded materials and components. For our prototype, we paint a conductive silicone rubber on a single layer of textile and stitch conductive threads. From a single layer of the textile, multimodal sensing (strain and pressure) values are extracted via voltage dividers. A regression analysis, multi-level thresholding and a temporal position tracking algorithm are applied to capture the different levels and modes of finger interactions to support the input taxonomy. We then demonstrate example applications with interaction design allowing users to control existing mobile, wearable, and digital devices. The evaluation results confirm that the prototype can achieve an accuracy of ≥80% for demonstrating all input types, ≥88% for locating the specific interaction areas for eyes-free interaction, and the robustness during daily activity related motions. Multitasking study reveals that our prototype promotes relatively fast response with low perceived workload comparing to existing eyes-free input.

Improving the electrical and electromagnetic shielding properties of conductive silicon rubber filled with Ni-coated carbon fibre by magnetic field

In this work, the effects of magnetic field induction on electrical and electromagnetic shielding properties of conductive silicon rubbers (CSRs) filled with Ni-coated carbon fibres (Ni/CFs) have been investigated. When the magnetic field intensity is above the threshold value of 0.10 T during the vulcanisation, it is beneficial to their electrical property that the volume resistivity decreases from 48.7 Ω·cm to 1.57 Ω·cm, owing to the orientation alignment of Ni/CFs in CSRs filled with Ni/CFs (40 phr). Moreover, with the aids of magnetic field induction, the prepared CSRs with lower amount of Ni-CF filler can receive better electromagnetic shielding of 65 dB in 500 MHz–3 GHz, which reduce cost effectively. This vulcanisation process shows promises for various applications in power transmission and transformation industries.

Neuro-fuzzy estimation of passive robotic joint safe velocity with embedded sensors of conductive silicone rubber

Robotic operations need to be safe for unpredictable contacts. Joints with passive compliance with springs can be used for soft robotic contacts. However the joints cannot measure external collision forces. In this investigation was developed one passive compliant joint which have soft contacts with external objects and measurement capabilities. To ensure it, conductive silicone rubber was used as material for modeling of the compliant segments of the robotic joint. These compliant segments represent embedded sensors. The conductive silicone rubber is electrically conductive by deformations. The main task was to obtain elastic absorbers for the external collision forces. These absorbers can be used for measurement in the same time. In other words, the joint has an internal measurement system. Adaptive neuro fuzzy inference system (ANFIS) was used to estimate the safety level of the robotic joint by head injury criteria (HIC).

Impedance characteristics of surface pressure-sensitive carbon black/silicone rubber composites

The surface pressure-sensitive characteristics of carbon black/silicon rubber (CB/SR) composites with positive pressure coefficient of impedance (PPCI) effect were researched. The linearity is very good when the impedance’s logarithm changes with the applied load at optimal operating frequency (1KHz). The pressure sensor based on the flexible composites exhibit fast response when pressures are applied and canceled with a response time of 3s. The sensor appears a higher sensitivity in AC electrical field than that in DC electrical field. Dielectric polarization theory was used to explain the sensitive behavior of the pressure sensor. Internal structure diagrams of CB/SR composites were used to explain the positive pressure coefficient of resistive (PPCR) effect and negative pressure coefficient of capacitive (NPCC) effect. AC electric field is applicable for the flexible pressure sensor based on conductive silicon rubber composites.

Research on the Piezoresistive Properties of Conductive Silicone Rubber under Water Pressure

The conductive silicon rubber samples have been prepared in different filler ingredients, the platform is builded for testing the piezoresistive characteristics of conductive silicon rubber when the material is under water pressure and the test methods are designed, the body piezoresistive properties and surface piezoresistive properties under the water pressure within a certain range are studied respectively. The results show that, the sample of 6% acetylene black/2% nanoSiO2 blends exhibit the best piezoresistive performance when the samples are under water pressure, the piezoresistive properties of the material can be improved with the increase of the thickness of the materials (2mm-4mm), and the conductive silicon rubber used for the pressure-sensitive materials of piezoresistive gauge is feasible.

Cover Image, Volume 132, Issue 11

Journal of Applied Polymer ScienceVolume 132, Issue 11 Cover ImageFree Access Cover Image, Volume 132, Issue 11 First published: 15 December 2014 https://doi.org/10.1002/app.41788Citations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Abstract Ablation-resistant polymeric composites have been widely used in the aerospace industry. Cheng Zhou, Lin Yu,Wei Luo, Yang Chen, Huawei Zou, and Mei Liang examine the ablative performance of aluminum silicate ceramic fiber (ASF) and calcium carbonate (CaCO3) filled silicone rubber composites prepared through a two-roll mill. These composites were considered to obtain low thermally conductive silicone rubber and generate a firm and thermal insulating layer after burning. The results revealed that the addition of ASF and CaCO3 was crucial to the enhancement of the ablation resistance for the silicone rubber composites. The cover shows the oxyacetylene ablation process. (DOI: 10.1002/app.41619) Citing Literature Volume132, Issue11March 15, 2015 RelatedInformation

Improvement of thermal and electrical properties of Silicone–Ni composites using magnetic field

Thermally and electrically conductive silicone–rubber composites filled with nickel particles have been prepared for several filler concentrations and for three different spatial distributions using various magnetic field orientations. The alignment of metallic particles in the polymeric matrix was confirmed by SEM and optical observation of the microstructure of composites. The spatial distribution of the particles does not affect the specific heat behavior of composites; while higher heat and electric transport ability was reached for composites filled with alignment of particles along the main heat flux due to creation of 1D structure of Ni particles. This filler configuration allows enhancement of the thermal conductivity of about 100% compared to the transverse and random distribution of particles; and contributes also to reducing the percolation threshold from 25 to 2vol.% of nickel particles. Thus a great improvement of both thermal and electrical behavior is obtained by using a magnetic field for the preparation of silicone–nickel composite.

무전해 니켈도금에 의한 도전성 실리콘고무 시트의 제조

무전해 니켈도금에 의한 도전성 실리콘고무 시트의 제조

열전도성 실리콘 고무의 전압-전류 특성

열전도성 실리콘 고무의 전압-전류 특성

Effect of Electrical Conductivity and Physical Performance about Vulcanization System in Conductive Silicon Rubber

Vulcanization methods of conductive silicon rubber are described in this paper. Several common vulcanization agents are also be introduced. The conductivity and mechanical properties of the conductive silicon rubber composite materials are effected by vulcanization systems. The influence degree is introduced by respectively using different vulcanization method, vulcanizing time and vulcanizing temperature. The research progress of vulcanization system of conductive polymer composites is elaborated.

Effect of shape and size of nickel‐coated particles fillers on conductivity of silicone rubber‐based composites

Electrically conductive polymer composites have been widely used in recent years. The resistivity of the composites is influenced by several factors. The conductive silicone rubbers (CSRs) were prepared by adding the nickel‐coated graphite (Ni‐G) and/or nickel‐coated carbon fiber (Ni‐CF) into liquid silicon rubbers which were then subjected to the vulcanization. The effect of particle shape and size on the electrical conductivity of CSR was investigated; the results indicate that Ni‐CF filled CSR have lower percolation threshold than Ni‐G filled CSR. Compared to the filled particles with larger size, a higher amount of smaller particles are needed to form the same conductive pathway in CSR. Thus, there are more contact points in conductive pathway, which increase the total contact resistance. The volume resistivity of CSR can be significantly reduced by the doping of Ni‐CF particles, while the effect begins to wear off under high doping content. The fiber‐like Ni‐CF has a good “bridging” function for the formation of conductive pathway in CSR, which is greatly enhanced by increasing the length to diameter (l/d) ratio of Ni‐CF particles. Therefore, doping of the particles that have low percolation threshold can reduce the resistivity of the composites. POLYM. COMPOS., 36:1371–1377, 2015. © 2014 Society of Plastics Engineers

The Improvement of Modified Filler on the Anti-Aging Properties of Conductive Silicone Rubber

As we know that ceria (CeO2), alumina (Al2O3), aluminum (Al) and iron oxide (Fe2O3) can improve the anti-aging properties of the rubber, mixed these materials with carbon black and filling conductive silicone rubber, some samples have been prepared. Have described the anti-aging method of the silicone rubber and discussed the test method of the changes in properties after aging. Have tested the changes of mechanical properties and electrical conductivity before and after the air aging test of the conductive silicone rubber which with or without addition of modified material. Have discussed the reasons why modified materials can improve the anti-aging performance of the conductive silicon rubber. The results show that with the addition of these types of nanomaterials the stability of mechanical and electrical properties of the conductive silicone rubber can be improved before or after aging treatment.

Liquid silicone rubber (LSR)-based dry bioelectrodes: The effect of surface micropillar structuring and silver coating on contact impedance

Bioelectrode–skin contact impedances need to be minimized to enable high quality recordings of biopotentials. Low contact impedances can be achieved with large, effective bioelectrode–skin contact areas. In this study, novel dry microstructured electrodes based on electrically conductive liquid silicone rubber (LSR) were developed and characterized with electrical impedance spectroscopy (EIS) measurements. Two different micropillar structures with inter-pillar distances of 20μm and 100μm, respectively, were compared with smooth LSR electrodes, as such or coated with silver (Ag). A gelatin gel based skin model was used in EIS measurements to overcome the problems associated with real skin measurements. Both microstructurings were found to significantly decrease the contact impedance modulus. In addition, the Ag coating caused highly significant (p<0.01) decrease in impedance modulus for each surface topography, e.g. for smooth electrodes the impedance drop was roughly from 140±30kΩ to 50±10kΩ at 1Hz. The Ag coating combined with microstructuring expectedly revealed the most superior electrical characteristics as the contact impedance declined even as low as 10±2kΩ at 1Hz. Instead, no statistically significant differences in impedance values were detected between the two microstructurings in the uncoated or Ag-coated electrodes. However, more sparse microstructuring (100) seemed to offer lower variation, i.e. more reproducible results. In conclusion, present microstructured electrodes that do not pierce any layer of skin but improve the contact to skin might be a good alternative to conventional wet electrodes.