Graphene-Rubber Composites

Transcription

1 Rev: Ver Graphene-Rubber Composites Product Features Rubber material is one of the most important and widely deployed materials. It is utilized in high- tech products, military defense and household supplies. Rubber by itself has low strength, low modulus, poor wear resistance and poor fatigue resistance. As such, most of the rubber need filler reinforcement. Graphene has excellent mechanical, thermal, electrical and gas and liquid barrier properties. Introducing this wondrous material in rubber materials would enhance its performance. AMG accumulated years of research experience to provide a variety of tailored solutions to industries. Our value-add and know-how are centered on: 1) Functionalizing graphene to enhance compatibilization with a myriad of rubber matrices for optimal dispersion. 2) Methods for designing innovative composite materials, high volume production, and environmentally benign composite materials. Applications of graphene/rubber composites can be used in diverse and broad segments, e.g. enhanced tire performance; over-current protection; protection of overheating of electronic components, switches, sensors, sealing devices; and electromagnetic shielding or absorbing materials. Technical specifications Enhance thermal conductivity Graphene has an intrinsically high thermal conductivity (5300 W / (m K)). Rubber is on the opposite spectrum as an insulator. It is natural to create a thermally conductive rubber composite by leveraging the property of graphene. This class of material fits nicely for thermal management in electronics or micro-electronics in industries. One critical barrier to effective macro-conductivity is the graphene/rubber interface. To affect fast heat transport, it is necessary to reduce the interfacial phononic loss by enhancing the graphene-rubber interfacial compatibility. The grafted-graphene (ggraphene) has been shown to disperse more evenly in rubber matrices. This, in turn, favors the formation of conductive network, which can effectively reduce the phonon scattering of the graphenerubber interface and further improve the thermal conductivity of the composites.

2 Rev: Enhance Lightweighting Graphene has high specific surface area and conductivity. In flexible electronic devices, graphenefilled rubber composites have high conductivity and thus lower thresholds to produce lightweight, highly conductive rubber composites. Surface modification or functionalization can effectively increase the dispersibility of the graphene derivatized filler and strengthen the graphene-rubber interface. As shown in the following figure, graphene (without functionalization) is not uniformly dispersed in rubber. Flocculated morphology (left) does not provide excellent material properties. By using special modification and dispersion technology, graphene is evenly dispersed in rubber matrix as seen in transparent and small flocculated sizes (right). Once graphene is uniformly distributed in matrix, product performance will increase substantially. Note: The left and right figures use the same weight ratio of graphene material. Gas barrier properties Rubber is an important sealant material. It can be found in car inner tubes, outdoor seals, aviation and spacecraft seals. These applications require high gas barrier performance. Graphene is a twodimensional nanosheet. Overlapping of these nanosheet increases the tortuous path for gas diffusion. The decreased in diffusivity, effectively, increases the gas barrier of the composite. Mechanical strength and wear resistance Graphene filled rubber composites are shown to increase mechanical strength, wear resistance and reduce rolling resistance concomitantly. This improves service life and overall durability. Graphene is the new wondrous filler for tire design.

3 Rev: Ver Bead Ring Graphene / Rubber Composites Tread Rubber Nylon Fabric Bead Wire Inner Liner Thermal conductivity Graphene enhances thermal distribution, dissipating localized hot spots when braking. Rolling resistance Graphene reduces rolling resistance and decreases fuel consumption. Antistatic Graphene is a good anti-static material for tires. It decreases static build-up and minimizes potential fire hazards. Wet grip Graphene tires offer higher wet grip performance and improves safety. Mechanical strength The strength of graphene reinforces rubber and thus improves wearbility. Air leakage Graphene has good air barrier properties and reduces the chance of air leakage in tires, i.e. lowers consumer maintenance. Thermal conductivity Compared with the same amount of carbon black, graphene can improve the thermal conductivity of synthetic rubber (SBR rubber) by three times. Thermal Conductivity Temperature Difference Thermal Conductivity (W/mK) Amount of Graphene (phr) N006-P dt (oc) Amount of Graphene (phr) N006-P

4 Tire mechanical strength Enhance mechanical strength of tires Reduce the loading of carbon black Increase tensile strength and elongation Maintain good elasticity of rubber Increase the hardness level Elongation % Elongation 10% Tensile Strength (MPa) Tensile Strength 9% phr N006P + 45phr CB phr N006P + 45phr CB Reduces rolling resistance /increases wet grip Add 10 phr graphene to the rubber material; rolling resistance will decrease 12%. The fuel consumption will be reduced. Add 10 phr of graphene to the rubber material; wet grip increases 14% according to the Tanδ value at 0 C. Tanδ (60oC) Rolling Resistance 12% Tanδ (0oC) Wet Grip Traction 14% phr CB+10phr Graphene phr CB+10phr Graphene

5 Rev: Ver Anti-static and air interdiction Anti-static The graphene/rubber composites can decrease rubber surface resistance to 10 3 ~10 5 Ω/sq. Graphene conductive tires effectively dissipate static electricity, prevent fires or explosion, especially for transporting flammable goods, special vehicles with electronic equipment, military (police) vehicles and other special needs vehicles. General-use vehicles apply as well. No Graphene Graphene 0.3 wt% 48% Air Penetration 26% 74% Air Leakage Adding 0.3 wt. % of graphene, the rubber composite can effectively reduce the air permeability by 48%, and improve airtight-ness. Application Electronic packaging Graphene improves the thermal conductivity of rubber while increasing the conductivity of the composite material. In other applications, such as electronic packaging, rubber products need to be insulative. Adding graphene can effectively tune the degree of thermal and electrical conductivity simultaneously.

6 Rev: Absorbing material and electromagnetic shielding The application of graphene proffers high microwave absorbance and lightweighting of materials. At AMG, we measured the dielectric constant and magnetic permeability of graphene / rubber composites via a waveguide method. The results showed that the composite material has high reflection loss (> 10 db) in a frequency range between 7. 5 to 12 GHz and reaches a maximum value (~ 60 db) at 10 GHz. The graphene/rubber nanocomposites demonstrate to be a very effective lightweight, microwave absorbing material and can be deployed in spacecrafts, aircrafts and microelectronics. Sensor Because graphene can change the conductivity of materials upon strain, it is piezoresistive. This property can be utilized for sensors, e.g. pressure sensitive sensors, magnetic sensors and solvent sensors. A recent demonstration of graphene blended in silica-silicone rubber showed excellent pressure-sensitive properties. All information and properties are obtained from the tests that Angstron believes to be accurate. However, these values are presented for comparison purposes and do not represent a guarantee by the manufacturer. The customer should carry out their own tests of suitablity for particular applications. Please contact our techinical service department for further information regarding Angstron s products.