Enhancement of Electrical Property of Thermally-Annealed Nano Carbon Based Polymer Composite By High Frequency Induction Heating
Authors: Tsuchiya Shuntaro , Yasuhara Toshiyuki 
Published: February 2020

It has been said that CNT and Graphene have especially excellent electrical, thermally and mechanical property. Also it has been expected as fillers for polymer composite instead of conventional carbon fiber. Recently large amount of research has been done about Nanocarbon, so we can get easily a lot of kind of Nanocarbon. There is not the universal standard for Nanocarbon materials especially CNT and Graphene. Therefore, it causes a large problem for prediction of property of composites that their qualities and size are not uniform because property and structure of CNTs are changed by production method. CNTs has different names and property depending on the number of layers such as Single-wall carbon nanotube (SWCNT) and Multi-wall carbon nanotube (MWCNT). So the purpose in this study is to clarify the effect of Nano carbon materials quality on the properties of polymer based Nanocarbon composite and to develop polymer matrix Nanocarbon composite which have excellent properties. We improve the quality by heating the Nanocarbon materials in the inert atmosphere by high frequency induction heating. Also we compared filler properties of Nanocarbon composite polymer. First, the sample of CNT and Graphite was set into a carbon crucible and heated in the inert atmosphere for 10 to 30 minutes by high frequency induction heating. Thereafter, the qualities of the annealed samples were analyzed by Raman spectroscopy. In Raman spectroscopy can analyze crystal integrity, diameter and other. In the Raman scattering spectrum of CNT appear characteristic waveforms. Specifically, it are appeared near 1590 cm⁻¹ called G band and near 1350 cm⁻¹ called D band. Since the G band is derived from the in-plane stretching motion of the 6-membered ring structure of carbon atoms in graphite and the D band is derived from its defect structure, the crystal integrity (G / D ratio) is determined by the ratio of the peaks of the G band and the D band . In general, the larger the G / D ratio is, the higher the crystalline perfection is. For example, when graphene is thermally annealed at 1500 ° C for 15 minutes, the Full Width at Half Maximum (FWHM) is larger than that of without thermally annealing. It showed that impurities in graphite were removed by thermal annealing. But, there was not large change in G/D ratio. Second, the shapes of samples were analyzed for example diameter and length by using a scanning electron microscope. In SEM observation, the shape and size of Nanocarbon was mainly observed. TEM mainly observed the diameter, size and layers of CNT. Next, the nanocarbon samples were mechanical mixing with the polymer. This matrix used polypropylene (PP).The mixer used was of an elliptical blade. The temperature was 200 to 250 ° C. for 30 to 60 minutes, and the rotation speed was 80 to 100 rpm. Finally, the volume resistivity of the prepared composite material was measured using a resistivity meter. In general, the volume resistivity of PP is about 10 ^ 16 to 10 ^ 17 Ωcm, and the boundary through which electricity passes is said to be 10 ^ 6 Ωcm. Also, we think that annealed high quality Nanocarbon property in comparison with no thermal annealed Nanocarbon. So, we will be able to improve property of Nanocarbon composite.