Electrical conductivity and Raman imaging of double wall carbon nanotubes in a polymer matrix

Raman spectroscopy is used to access the dispersion state of DWNTs in a PEEK polymer matrix. The interaction of the outer tube with the matrix can be determined from the line shape of the Raman G band. This allows us to distinguish regions where the nanotubes are well dispersed and regions where the nanotubes are agglomerated. The percolation threshold of the electrical conductivity of the double wall carbon nanotubes (DWNTs)/PEEK nanocomposites is found to be at 0.2–0.3 wt.%. We find a maximum electrical conductivity of 3 x 10-2 S/cm at 2 wt.% loading. We detect nanotube weight concentrations as low as 0.16 wt.% by Raman spectroscopy using a yellow excitation wavelength. We compare the Raman images with transmission electron microscopy images and electrical conductivity measurements. A statistical method is used to find a quantitative measure of the DWNTs dispersion in the polymer matrix from the Raman images

Study of the effects of multi-walled carbon nanotubes on mechanical performance and thermal stability of polypropylene

Carbon nanotubes (CNTs) have been added to polypropylene (PP) matrix to improve the overall performance of composites. The mixing process has been carried out by melt compounding using a twin screw co-rotating extruder with different CNTs amounts in the 0.5-10 wt% from a concentrated PP-CNTs masterbatch (20 wt% CNTs). Results show a remarkable increase in tensile strength and elastic modulus while a decrease in elongation at break is detected. With regard to thermal behavior, a remarkable increase in thermal stability at high temperatures (decomposition process studied by thermogravimetric analysis) is obtained as the CNTs amount increases. In addition to this improvement, a noticeable increase in thermal stability at medium temperatures (degradation onset determined by differential scanning calorimetry, DSC) is also observed. In a similar way, other property related to thermal and mechanical performance, such as Vicat softening temperature (VST) is improved with CNTs content. The optimum balance between cost and properties seems to be in the 13 wt% range. POLYM. ENG. SCI., 52:733-740, 2011. (C) 2011 Society of Plastics EngineersContract grant sponsor: "Ministerio de Ciencia e Innovacion'' cofinanced by FEDER funds (European Union); contract grant number: IPT-310000-2010-37; contract grant sponsor: Conselleria d'Industria, Comerc i Turisme-IMPIVA cofinanced by FEDER funds (European Union); contract grant number: IMIDIC/2009/109.Pascual, J.; Peris, F.; Boronat Vitoria, T.; Fenollar Gimeno, OÁ.; Balart Gimeno, RA. (2012). Study of the effects of multi-walled carbon nanotubes on mechanical performance and thermal stability of polypropylene. Polymer Engineering and Science. 52(4):733-740. https://doi.org/10.1002/pen.22128S733740524Burris, D. L., Boesl, B., Bourne, G. R., & Sawyer, W. G. (2007). Polymeric Nanocomposites for Tribological Applications. Macromolecular Materials and Engineering, 292(4), 387-402. doi:10.1002/mame.200600416Kim, J. Y., Kim, D. K., & Kim, S. H. (2009). Thermal decomposition behavior of poly(ethylene 2,6-naphthalate)/silica nanocomposites. Polymer Composites, 30(12), 1779-1787. doi:10.1002/pc.20749Mahrholz, T., Stängle, J., & Sinapius, M. (2009). Quantitation of the reinforcement effect of silica nanoparticles in epoxy resins used in liquid composite moulding processes. Composites Part A: Applied Science and Manufacturing, 40(3), 235-243. doi:10.1016/j.compositesa.2008.11.008MARYNIAK, M., GUSKOS, N., TYPEK, J., PETRIDIS, D., SZYMCZYK, A., GUSKOS, A., … KWIATKOWSKA, M. (2009). Thermal characterization of polymer composites with nanocrystalline maghemite. Polimery, 54(07/08), 546-551. doi:10.14314/polimery.2009.546Mavinakuli, P., Wei, S., Wang, Q., Karki, A. B., Dhage, S., Wang, Z., … Guo, Z. (2010). Polypyrrole/Silicon Carbide Nanocomposites with Tunable Electrical Conductivity. The Journal of Physical Chemistry C, 114(9), 3874-3882. doi:10.1021/jp911766yRuan, W. H., Mai, Y. L., Wang, X. H., Rong, M. Z., & Zhang, M. Q. (2007). Effects of processing conditions on properties of nano-SiO2/polypropylene composites fabricated by pre-drawing technique. Composites Science and Technology, 67(13), 2747-2756. doi:10.1016/j.compscitech.2007.02.004Cheng, H. K. F., Sahoo, N. G., Pan, Y., Li, L., Chan, S. H., Zhao, J., & Chen, G. (2010). Complementary effects of multiwalled carbon nanotubes and conductive carbon black on polyamide 6. Journal of Polymer Science Part B: Polymer Physics, 48(11), 1203-1212. doi:10.1002/polb.22010Díez-Pascual, A. M., Naffakh, M., Gómez, M. A., Marco, C., Ellis, G., González-Domínguez, J. M., … Ashrafi, B. (2009). The influence of a compatibilizer on the thermal and dynamic mechanical properties of PEEK/carbon nanotube composites. Nanotechnology, 20(31), 315707. doi:10.1088/0957-4484/20/31/315707Guadagno, L., Naddeo, C., Raimondo, M., Gorrasi, G., & Vittoria, V. (2010). Effect of carbon nanotubes on the photo-oxidative durability of syndiotactic polypropylene. Polymer Degradation and Stability, 95(9), 1614-1626. doi:10.1016/j.polymdegradstab.2010.05.030Hubert, P., Ashrafi, B., Adhikari, K., Meredith, J., Vengallatore, S., Guan, J., & Simard, B. (2009). Synthesis and characterization of carbon nanotube-reinforced epoxy: Correlation between viscosity and elastic modulus. Composites Science and Technology, 69(14), 2274-2280. doi:10.1016/j.compscitech.2009.04.023O’Connor, I., Hayden, H., O’Connor, S., Coleman, J. N., & Gun’ko, Y. K. (2009). Polymer Reinforcement with Kevlar-Coated Carbon Nanotubes. The Journal of Physical Chemistry C, 113(47), 20184-20192. doi:10.1021/jp9046566Sahoo, N. G., Rana, S., Cho, J. W., Li, L., & Chan, S. H. (2010). Polymer nanocomposites based on functionalized carbon nanotubes. Progress in Polymer Science, 35(7), 837-867. doi:10.1016/j.progpolymsci.2010.03.002Wang, W.-Y., Luo, G.-H., Wei, F., & Luo, J. (2009). Electrical conductivity and thermal properties of acrylonitrile-butadiene-styrene filled with multiwall carbon nanotubes. Polymer Engineering & Science, 49(11), 2144-2149. doi:10.1002/pen.21454Ansari, M. N. M., Ismail, H., & Zein, S. H. S. (2008). Effect of Multi-walled Carbon Nanotubes on Mechanical Properties of Feldspar Filled Polypropylene Composites. Journal of Reinforced Plastics and Composites, 28(20), 2473-2485. doi:10.1177/0731684408092377Cheng, H. K. F., Sahoo, N. G., Khin, T. H., Li, L., Chan, S. H., Zhao, J., & Juay, Y. K. (2010). The Role of Functionalized Carbon Nanotubes in a PA6/LCP Blend. Journal of Nanoscience and Nanotechnology, 10(8), 5242-5251. doi:10.1166/jnn.2010.2415Giraldo, L. F., López, B. L., & Brostow, W. (2009). Effect of the type of carbon nanotubes on tribological properties of polyamide 6. Polymer Engineering & Science, 49(5), 896-902. doi:10.1002/pen.21386Grady, B. P., Arthur, D. J., & Ferguson, J. (2009). Single-walled carbon nanotube/ultrahigh-molecular-weight polyethylene composites with percolation at low nanotube contents. Polymer Engineering & Science, 49(12), 2440-2446. doi:10.1002/pen.21494Liu, S.-P., Hwang, S., Yeh, J.-M., & Pan, K.-W. (2010). Enhancement of surface and bulk mechanical properties of polycarbonate through the incorporation of raw MWNTs — Using the twin-screw extruder mixed technique. International Communications in Heat and Mass Transfer, 37(7), 809-814. doi:10.1016/j.icheatmasstransfer.2010.05.019Sengupta, R., Ganguly, A., Sabharwal, S., Chaki, T. K., & Bhowmick, A. K. (2007). MWCNT reinforced Polyamide-6,6 films: preparation, characterization and properties. Journal of Materials Science, 42(3), 923-934. doi:10.1007/s10853-006-0011-1Bangarusampath, D. S., Ruckdäschel, H., Altstädt, V., Sandler, J. K. W., Garray, D., & Shaffer, M. S. P. (2009). Rheology and properties of melt-processed poly(ether ether ketone)/multi-wall carbon nanotube composites. Polymer, 50(24), 5803-5811. doi:10.1016/j.polymer.2009.09.061Causin, V., Yang, B.-X., Marega, C., Goh, S. H., & Marigo, A. (2009). Nucleation, structure and lamellar morphology of isotactic polypropylene filled with polypropylene-grafted multiwalled carbon nanotubes. European Polymer Journal, 45(8), 2155-2163. doi:10.1016/j.eurpolymj.2009.05.026Bikiaris, D., Vassiliou, A., Chrissafis, K., Paraskevopoulos, K. M., Jannakoudakis, A., & Docoslis, A. (2008). Effect of acid treated multi-walled carbon nanotubes on the mechanical, permeability, thermal properties and thermo-oxidative stability of isotactic polypropylene. Polymer Degradation and Stability, 93(5), 952-967. doi:10.1016/j.polymdegradstab.2008.01.033Fang, Z., Song, P., Tong, L., & Guo, Z. (2008). Thermal degradation and flame retardancy of polypropylene/C60 nanocomposites. Thermochimica Acta, 473(1-2), 106-108. doi:10.1016/j.tca.2008.04.019Kovalchuk, A. A., Shevchenko, V. G., Shchegolikhin, A. N., Nedorezova, P. M., Klyamkina, A. N., & Aladyshev, A. M. (2008). Isotactic and syndiotactic polypropylene/multi-wall carbon nanotube composites: synthesis and properties. Journal of Materials Science, 43(22), 7132-7140. doi:10.1007/s10853-008-3029-8Rakhimkulov, A. D., Lomakin, S. M., Dubnikova, I. L., Shchegolikhin, A. N., Davidov, E. Y., & Kozlowski, R. (2010). The effect of multi-walled carbon nanotubes addition on the thermo-oxidative decomposition and flammability of PP/MWCNT nanocomposites. Journal of Materials Science, 45(3), 633-640. doi:10.1007/s10853-009-3977-7Sahoo, N. G., Thet, N. T., Tan, Q. H., Li, L., Chan, S. H., Zhao, J., & Yu, S. (2009). Effect of Carbon Nanotubes and Processing Methods on the Properties of Carbon Nanotube/Polypropylene Composites. Journal of Nanoscience and Nanotechnology, 9(10), 5910-5919. doi:10.1166/jnn.2009.1236Prashantha, K., Soulestin, J., Lacrampe, M. F., Claes, M., Dupin, G., & Krawczak, P. (2008). Multi-walled carbon nanotube filled polypropylene nanocomposites based on masterbatch route: Improvement of dispersion and mechanical properties through PP-g-MA addition. Express Polymer Letters, 2(10), 735-745. doi:10.3144/expresspolymlett.2008.87Radhakrishnan, V. K., Davis, E. W., & Davis, V. A. (2010). Influence of initial mixing methods on melt-extruded single-walled carbon nanotube-polypropylene nanocomposites. Polymer Engineering & Science, 50(9), 1831-1842. doi:10.1002/pen.21696Fu, S., Song, P., Yang, H., Jin, Y., Lu, F., Ye, J., & Wu, Q. (2010). Effects of carbon nanotubes and its functionalization on the thermal and flammability properties of polypropylene/wood flour composites. Journal of Materials Science, 45(13), 3520-3528. doi:10.1007/s10853-010-4394-7Koval’chuk, A. A., Shevchenko, V. G., Shchegolikhin, A. N., Nedorezova, P. M., Klyamkina, A. N., & Aladyshev, A. M. (2008). Effect of Carbon Nanotube Functionalization on the Structural and Mechanical Properties of Polypropylene/MWCNT Composites. Macromolecules, 41(20), 7536-7542. doi:10.1021/ma801599qMiller, S. G., Bauer, J. L., Maryanski, M. J., Heimann, P. J., Barlow, J. P., Gosau, J.-M., & Allred, R. E. (2010). Characterization of epoxy functionalized graphite nanoparticles and the physical properties of epoxy matrix nanocomposites. Composites Science and Technology, 70(7), 1120-1125. doi:10.1016/j.compscitech.2010.02.023Cadek, M., Coleman, J. N., Barron, V., Hedicke, K., & Blau, W. J. (2002). Morphological and mechanical properties of carbon-nanotube-reinforced semicrystalline and amorphous polymer composites. Applied Physics Letters, 81(27), 5123-5125. doi:10.1063/1.1533118Qian, D., Dickey, E. C., Andrews, R., & Rantell, T. (2000). Load transfer and deformation mechanisms in carbon nanotube-polystyrene composites. Applied Physics Letters, 76(20), 2868-2870. doi:10.1063/1.126500Chen, G.-X., Kim, H.-S., Park, B. H., & Yoon, J.-S. (2006). Multi-walled carbon nanotubes reinforced nylon 6 composites. Polymer, 47(13), 4760-4767. doi:10.1016/j.polymer.2006.04.02