ENSACO® Conductive Carbon Black for polymer ... - Timcal Graphite

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22 Thermally conductive polymers NThe ability of a material to conduct heat is known as its thermal conductivity. Thermal conductivity itself is nothing else than transportation of thermal energy from high to low temperature regions. Thermal energy within a crystalline solid is conducted by electrons and/or discrete vibrational energy packets (phonons*). Each effect, phonons and movement of free electrons, contributes to the rate at which thermal energy moves. Generally, either free electrons or phonons predominate in the system. *Phonons In the crystalline structures of a solid material, atoms excited into higher vibrational frequency impart vibrations into adjacent atoms via atomic bonds. This coupling creates waves which travel through the lattice structure of a material. In solid materials these lattice waves, or phonons, travel at the velocity of sound. During thermal conduction it is these waves which aid in the transport of energy. www.timcal.com Typical applications for TIMREX® Graphite and Coke What is thermal conductivity? Scrap PC 40 12 Typical data of thermal conductivity of graphite powders pressed to density ≈ 2.2 g/cm 3 , 25°C Thermal conductivity of graphite N The thermal conductivity in graphite is generally dominated by phonons, and limited by the crystallite size. In addition, due to its particular structure, thermal conductivity is different in the different directions of the crystal. It is highly conducting along its layers (ab direction) and not so well perpendicular to the layers (c direction) because their is no bonding between the layers. The thermal conductivity of a perfect graphite crystal is ~3000 W/(m.K) in the ab direction and ~6 W/(m.K) in the c direction. NThe table below shows the thermal conductivities of TIMREX ® Graphite measured on pure graphite compacts (obtained by Hipped Samples; HIP 350 MPa, 1900°C). Thermally conductive plastics can replace most metals (i.e. aluminium and copper), ceramics, and conventional plastics in heat-sensitive applications. Thermal Conductivity W/(m.K) 20.00 15.00 10.00 5.00 Thermally conductive polymers Thermally conductive polymers are able to evenly distribute heat generated internally from a device and eliminate “hot spots.” Possible applications for thermally conductive plastics include heatsinks, heat exchangers, appliance temperature sensors and many other industrial applications. Also thermally conductive elastomers can be found in a wide variety of industrial applications such as gaskets, vibration dampening, interface materials, and heat sinks. NVirgin polymers can be considered thermal insulators having a thermal conductivity of approximately 0.2 W/(m.K). By adding TIMREX ® Graphite a final value up to 15-20 W/(m.K) can be achieved (as it is shown in the following graph in which different types of graphite powder were added to a PP matrix) which represents an increase of 75 to 100 times compared to the unfilled polymer. Thermal conductivity of graphite (in plane) - PP compounds BNB 90 KS grades 10% KS+BNB90 0.00 0 20 40 60 80 100 Loading (% wt)
Typical applications for TIMREX® Graphite and Coke Flame retardant polymers What is expandable graphite and how does it work as flame retardant? NExpandable graphite (EG) (or graphite salt) is a halogen-free material consisting of graphite and acid. The acid is intercalated between the graphene layers. EG is manufactured by the oxidation of natural graphite in a strong acid such as sulphuric or nitric acid. After the reaction the graphite is washed in order to remove traces of acid left on the surface (typically the final pH of our TIMREX ® Flare Grades range from 4 to 8). Expansion Volume (ml/g) 180.0 160.0 140.0 120.0 100.0 80.0 60.0 40.0 20.0 NWhen expandable graphite is exposed to heat, it can expand to several hundred times its original volume, and covers the entire burning surface of the substrate with a “worm” like structure of expanded graphite. NThe char, formed by the expanded graphite, acts as an insulating agent and dramatically reduces the heat release, mass loss, smoke generation, and toxic gas emission of the substrate. TIMREX® Flare 100 Expansion behaviour vs Temperature 0.0 0 100 200 300 400 500 600 700 Temperature (°C) Expansion behaviour of TIMREX ® Flare Grades The expansion volume of the graphite salt is a function of the temperature. The temperature, at which expansion begins, the so-called onset temperature, mainly depends on the type of acid (the graph shows the expansion behaviour vs temperature of TIMREX ® Flare 100). Particle size, carbon and acid content also affect the expansion. The bigger the particle size, the higher the expansion volume. The higher the carbon content or the acid contents the higher the expansion volume. Possible applications: PU foams; door & wall sealing; intumescent pipe wraps; rubber products; textiles, carpets and mats; coatings. Advantages: halogen free; environmental friendly; lower loading required compared to other mineral flame retardant materials; synergistic effect with other flame retardant materials. The information contained in this brochure is believed to be correct. However, no warranty is made, either expressed or implied regarding the accuracy or the results to be obtained from the use of such information. The user assumes all risk and liability for loss, damage or injury to property or others resulting from the use of the material. No statement is intended or should be construed as recommendation to infringe any existing patent. 23
Page 1 and 2: Graphite Carbon Black Carbon additi
Page 3 and 4: TIMREX ® Graphite and ENSACO ® Ca
Page 5 and 6: Introduction to TIMREX ® Graphite
Page 7 and 8: Typical effects on polymer compound
Page 9 and 10: Typical effects on polymer compound
Page 11 and 12: ENSACO ® Conductive Carbon Blacks
Page 13 and 14: ENSACO ® Conductive Carbon Blacks
Page 15 and 16: NBR conductive hose compound NBR NT
Page 17 and 18: Typical applications for ENSACO® C
Page 19 and 20: Incorporation of graphite powder in
Page 21: Influence of TIMREX ® Graphite and

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