Foldable Conductive Cellulose Fiber Networks Modified by Graphene Nanoplatelet-Bio-Based Composites

Truly foldable flexible electronic components require a foldable substrate modified with a conducting material that can retain its electrical conductivity and mechanical integrity even after hard mechanical manipulations and multiple folding events. Here, such a material exploiting the combination of all-biodegradable components (substrate and the polymer matrix) and graphene nanoplatelets is designed and fabricated. A commercially available thermoplastic starch-based polymer (Mater-Bi) and graphene nanoplatelets are simultaneously dispersed in an organic solvent to formulate conductive inks. The inks are spray painted on pure cellulose sheets and hot-pressed into their fiber network after drying. The resultant nanostructured flexible composites display excellent isotropic electrical conductivity, reaching very low sheet resistance value ≈10 Ω sq−1, depending on the relative concentration between the biopolymer and the graphene nanoplatelets. Transmission electron microscopy results indicated that during hot-pressing, graphene nanoplatelets are physically embedded into the cellulose fibers, resulting in high electrical conductivity of the flexible composite. The paper-like flexible conductors can withstand many severe folding events, maintaining their mechanical and electrical properties and showing only a slight decrease of their electrical conductivity with respect to the unfolded counterparts. Unlike conductive paper technologies, the proposed paper-like flexible conductors demonstrate both sides isotropic conductivity due to pressure-induced impregnation

Ultrahigh Molecular Weight Polyethylene/Graphene Oxide Nanocomposites: Wear characterization and Biological Response to wear particles

In the field of total joint replacements, polymer nanocomposites are being investigated as alternatives to ultra high molecular weight polyethylene (UHMWPE) for acetabular cup bearings. The objective of the present study was to investigate the wear performance and biocompatibility of UHMWPE/graphene oxide (GO) nanocomposites. This study revealed that low concentrations of GO nanoparticles (0.5 wt%) do not significantly alter the wear performance of UHMWPE. In contrast, the addition of higher concentrations (2 wt%) led to a significant reduction in wear. In terms of biocompatibility, UHMWPE/GO wear particles did not show any adverse effects on L929 fibroblast and PBMNC viability at any of the concentrations tested over time. Moreover, the addition of GO to a UHMWPE matrix did not significantly affect the inflammatory response to wear particles. Further work is required to optimise the manufacturing processes to improve the mechanical properties of the nanocomposites and additional biocompatibility testing should be performed to understand the potential clinical application of these materials

Morphology, thermal, and electrical properties of polypropylene hybrid composites co-filled with multi-walled carbon nanotubes and graphene nanoplatelets

"This is the peer reviewed version of the following article: Wegrzyn, M., Galindo, B., Benedito, A., & Gimenez, E. (2015). Morphology, thermal, and electrical properties of polypropylene hybrid composites co‐filled with multi‐walled carbon nanotubes and graphene nanoplatelets. Journal of Applied Polymer Science, 132(46)., which has been published in final form at https://doi.org/10.1002/app.42793. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving."[EN] In this study, nanocomposites of polypropylene (PP) with various loadings of multi-wall carbon nanotubes (MWCNT) and graphene nanoplatelets (GnP) were formed by masterbatch dilution/mixing approach from individual masterbatches PP-MWCNT and PP-GnP. Melt mixing on a twin-screw extruder at two different processing temperatures was followed by characterization of morphology by transmitted-light microscopy including the statistical analysis of agglomeration behavior. The influence of processing temperature and weight fractions of both nanofillers on the dispersion quality is reported. Thermal properties of the nanocomposites investigated by DSC and TGA show sensitivity to the nanofillers weight fraction ratio and to processing conditions. Electrical conductivity is observed to increase up to an order of magnitude with the concentration of each nanofiller increasing from 0.5 wt % to 1.0 wt %. This is related with a decrease of electrical conductivity observed for unequal concentration of both nanofillers. This particular behavior shows the increase of electrical properties for higher MWCNT loadings and the increase of thermo-mechanical properties for higher GnP loadings. (c) 2015 Wiley Periodicals, Inc.This study is funded by the European Community's Seventh Framework Program (FP7-PEOPLE-ITN-2008) within the CONTACT project Marie Curie Fellowship under grant number 238363.Wegrzyn, M.; Galindo-Galiana, B.; Benedito, A.; Giménez Torres, E. (2015). Morphology, thermal, and electrical properties of polypropylene hybrid composites co-filled with multi-walled carbon nanotubes and graphene nanoplatelets. Journal of Applied Polymer Science. 132(46). https://doi.org/10.1002/app.42793S13246Yang, L., Liu, F., Xia, H., Qian, X., Shen, K., & Zhang, J. (2011). Improving the electrical conductivity of a carbon nanotube/polypropylene composite by vibration during injection-moulding. Carbon, 49(10), 3274-3283. doi:10.1016/j.carbon.2011.03.054Singh, I. V., Tanaka, M., & Endo, M. (2007). Effect of interface on the thermal conductivity of carbon nanotube composites. International Journal of Thermal Sciences, 46(9), 842-847. doi:10.1016/j.ijthermalsci.2006.11.003Kuan, H.-C., Ma, C.-C. M., Chang, W.-P., Yuen, S.-M., Wu, H.-H., & Lee, T.-M. (2005). Synthesis, thermal, mechanical and rheological properties of multiwall carbon nanotube/waterborne polyurethane nanocomposite. Composites Science and Technology, 65(11-12), 1703-1710. doi:10.1016/j.compscitech.2005.02.017Arasteh, R., Omidi, M., Rousta, A. H. A., & Kazerooni, H. (2011). A Study on Effect of Waviness on Mechanical Properties of Multi-Walled Carbon Nanotube/Epoxy Composites Using Modified Halpin–Tsai Theory. Journal of Macromolecular Science, Part B, 50(12), 2464-2480. doi:10.1080/00222348.2011.579868Cai, D., Jin, J., Yusoh, K., Rafiq, R., & Song, M. (2012). High performance polyurethane/functionalized graphene nanocomposites with improved mechanical and thermal properties. Composites Science and Technology, 72(6), 702-707. doi:10.1016/j.compscitech.2012.01.020Yan, D., Zhang, H.-B., Jia, Y., Hu, J., Qi, X.-Y., Zhang, Z., & Yu, Z.-Z. (2012). Improved Electrical Conductivity of Polyamide 12/Graphene Nanocomposites with Maleated Polyethylene-Octene Rubber Prepared by Melt Compounding. ACS Applied Materials & Interfaces, 4(9), 4740-4745. doi:10.1021/am301119bHaslam, M. D., & Raeymaekers, B. (2013). A composite index to quantify dispersion of carbon nanotubes in polymer-based composite materials. Composites Part B: Engineering, 55, 16-21. doi:10.1016/j.compositesb.2013.05.038Kuilla, T., Bhadra, S., Yao, D., Kim, N. H., Bose, S., & Lee, J. H. (2010). Recent advances in graphene based polymer composites. Progress in Polymer Science, 35(11), 1350-1375. doi:10.1016/j.progpolymsci.2010.07.005Pötschke, P., Dudkin, S. M., & Alig, I. (2003). Dielectric spectroscopy on melt processed polycarbonate—multiwalled carbon nanotube composites. Polymer, 44(17), 5023-5030. doi:10.1016/s0032-3861(03)00451-8Stankovich, S., Dikin, D. A., Dommett, G. H. B., Kohlhaas, K. M., Zimney, E. J., Stach, E. A., … Ruoff, R. S. (2006). Graphene-based composite materials. Nature, 442(7100), 282-286. doi:10.1038/nature04969Sathyanarayana, S., Olowojoba, G., Weiss, P., Caglar, B., Pataki, B., Mikonsaari, I., … Henning, F. (2012). Compounding of MWCNTs with PS in a Twin-Screw Extruder with Varying Process Parameters: Morphology, Interfacial Behavior, Thermal Stability, Rheology, and Volume Resistivity. Macromolecular Materials and Engineering, 298(1), 89-105. doi:10.1002/mame.201200018Vega, J. F., Martínez-Salazar, J., Trujillo, M., Arnal, M. L., Müller, A. J., Bredeau, S., & Dubois, P. (2009). Rheology, Processing, Tensile Properties, and Crystallization of Polyethylene/Carbon Nanotube Nanocomposites. Macromolecules, 42(13), 4719-4727. doi:10.1021/ma900645fAlig, I., Lellinger, D., Dudkin, S. M., & Pötschke, P. (2007). Conductivity spectroscopy on melt processed polypropylene–multiwalled carbon nanotube composites: Recovery after shear and crystallization. Polymer, 48(4), 1020-1029. doi:10.1016/j.polymer.2006.12.035Chaharmahali, M., Hamzeh, Y., Ebrahimi, G., Ashori, A., & Ghasemi, I. (2013). Effects of nano-graphene on the physico-mechanical properties of bagasse/polypropylene composites. Polymer Bulletin, 71(2), 337-349. doi:10.1007/s00289-013-1064-3Hill, D. E., Lin, Y., Rao, A. M., Allard, L. F., & Sun, Y.-P. (2002). Functionalization of Carbon Nanotubes with Polystyrene. Macromolecules, 35(25), 9466-9471. doi:10.1021/ma020855rYu, Y.-H., Lin, Y.-Y., Lin, C.-H., Chan, C.-C., & Huang, Y.-C. (2014). High-performance polystyrene/graphene-based nanocomposites with excellent anti-corrosion properties. Polym. Chem., 5(2), 535-550. doi:10.1039/c3py00825hZhang, S., Yin, S., Rong, C., Huo, P., Jiang, Z., & Wang, G. (2013). Synergistic effects of functionalized graphene and functionalized multi-walled carbon nanotubes on the electrical and mechanical properties of poly(ether sulfone) composites. European Polymer Journal, 49(10), 3125-3134. doi:10.1016/j.eurpolymj.2013.07.011Huang, G., Wang, S., Song, P., Wu, C., Chen, S., & Wang, X. (2014). Combination effect of carbon nanotubes with graphene on intumescent flame-retardant polypropylene nanocomposites. Composites Part A: Applied Science and Manufacturing, 59, 18-25. doi:10.1016/j.compositesa.2013.12.010Chatterjee, S., Nafezarefi, F., Tai, N. H., Schlagenhauf, L., Nüesch, F. A., & Chu, B. T. T. (2012). Size and synergy effects of nanofiller hybrids including graphene nanoplatelets and carbon nanotubes in mechanical properties of epoxy composites. Carbon, 50(15), 5380-5386. doi:10.1016/j.carbon.2012.07.021Im, H., & Kim, J. (2012). Thermal conductivity of a graphene oxide–carbon nanotube hybrid/epoxy composite. Carbon, 50(15), 5429-5440. doi:10.1016/j.carbon.2012.07.029Jiang, X., & Drzal, L. T. (2011). Improving electrical conductivity and mechanical properties of high density polyethylene through incorporation of paraffin wax coated exfoliated graphene nanoplatelets and multi-wall carbon nano-tubes. Composites Part A: Applied Science and Manufacturing, 42(11), 1840-1849. doi:10.1016/j.compositesa.2011.08.011Hwang, S.-H., Park, H. W., Park, Y.-B., Um, M.-K., Byun, J.-H., & Kwon, S. (2013). Electromechanical strain sensing using polycarbonate-impregnated carbon nanotube–graphene nanoplatelet hybrid composite sheets. Composites Science and Technology, 89, 1-9. doi:10.1016/j.compscitech.2013.09.005Chatterjee, S., Nüesch, F. A., & Chu, B. T. T. (2013). Crystalline and tensile properties of carbon nanotube and graphene reinforced polyamide 12 fibers. Chemical Physics Letters, 557, 92-96. doi:10.1016/j.cplett.2012.11.091Lahiri, D., Hec, F., Thiesse, M., Durygin, A., Zhang, C., & Agarwal, A. (2014). Nanotribological behavior of graphene nanoplatelet reinforced ultra high molecular weight polyethylene composites. Tribology International, 70, 165-169. doi:10.1016/j.triboint.2013.10.012Pavlidou, S., & Papaspyrides, C. D. (2008). A review on polymer–layered silicate nanocomposites. Progress in Polymer Science, 33(12), 1119-1198. doi:10.1016/j.progpolymsci.2008.07.008Wegrzyn, M., Juan, S., Benedito, A., & Giménez, E. (2013). The influence of injection molding parameters on electrical properties of PC/ABS-MWCNT nanocomposites. Journal of Applied Polymer Science, 130(3), 2152-2158. doi:10.1002/app.39412Pegel , S. Villmow , T. Pötschke , P. In Polymer-Carbon Nanotube Composites: Preparation, Properties and Applications McNally , T. Pötschke , P. Woodhead Publishing Cambridge 2011Zhang, R., Moon, K., Lin, W., & Wong, C. P. (2010). Preparation of highly conductive polymer nanocomposites by low temperature sintering of silver nanoparticles. Journal of Materials Chemistry, 20(10), 2018. doi:10.1039/b921072eGrossiord, N., Kivit, P. J. J., Loos, J., Meuldijk, J., Kyrylyuk, A. V., van der Schoot, P., & Koning, C. E. (2008). On the influence of the processing conditions on the performance of electrically conductive carbon nanotube/polymer nanocomposites. Polymer, 49(12), 2866-2872. doi:10.1016/j.polymer.2008.04.03

Fast route to obtain Al2O3-based nanocomposites employing graphene oxide: Synthesis and Sintering

A fast approach based on microwave technology was employed for the sintering of novel composites of alumina and using graphene oxide (GO) as susceptor. The thermal stability and structure of GO materials produced by chemical oxidation of graphite were characterized. The morphology, structure and mechanical properties of the composites sintered by microwave approach were reported to the counterparts sintered by conventional method. The results indicated the formation of an interconnecting graphene network promoted the electrical conductivity in the composite having only 2 wt.% GO. Hardness and elastic modulus decreased significantly in samples sintered by conventional method due to lower values of density while microwave technology allowed to achieve a positive effect on the densification and showed a smaller grain size when compared to the one achieved by conventional heating. (C) 2014 Elsevier Ltd. All rights reserved.Financial support from European Commission (project no. NMP3-SL-2010-246073), Universidad Politecnica de Valencia (project SP20120677) and Ministerio de Economia y Competitividad - MINECO (project TEC2012-37532-C02-01, co-funded by ERDF (European Regional Development Funds) is gratefully acknowledged. A.B. acknowledges the Spanish Ministry of Science and Innovation (contract JCI-2011-10498). A.P. acknowledges support from Romanian Authority for Scientific Research - UEFISCDI (project no. PN-II-RU-PD-2012-3-0124).Benavente Martínez, R.; Pruna, AI.; Borrell Tomás, MA.; Salvador Moya, MD.; Pullini, D.; Penaranda-Foix, FL.; Busquets Mataix, DJ. (2015). Fast route to obtain Al2O3-based nanocomposites employing graphene oxide: Synthesis and Sintering. Materials Research Bulletin. 64:245-251. https://doi.org/10.1016/j.materresbull.2014.12.075S2452516

Interphases in Graphene Polymer-based Nanocomposites: Achievements and Challenges

Graphene constitutes a two dimensional sp² hybridized carbon material with outstanding electrical and mechanical properties. To date, novel methods for producing large quantities of graphene and its derivatives (doped or functionalized graphenes, nanoribbons and nanoplatelets) are emerging, and research dedicated to the fabrication of polymer nanocomposites using graphenes has started. In this Research News, we summarize the synthesis and properties of graphene and its derivatives, and provide an overview of the latest research dedicated to the fabrication of polymer composites for different applications, including mechanical, electrical, optical and thermal. Some of the recently fabricated composites exhibit outstanding properties, however, it is vital to understand the chemistry and physics of the interphases established between the polymer and the graphene surfaces. The challenges in the fabrication of super robust and highly conducting composites using graphenes are also discussed. It is believed that graphene-based polymer composites will result in commercial products if their interphases and reactivity are carefully controlled.Authors wish to thank Ministerio de Ciencia e Innovación (SPAIN) for financial support under grant MAT2010-17091. MT and SMVD acknowledge support from the Research Center for Exotic NanoCarbon Project, Japan regional Innovation Strategy Program by the Excellence, JST

Virtual testing of advanced composites, cellular materials and biomaterials: A review

This paper documents the emergence of virtual testing frameworks for prediction of the constitutive responses of engineering materials. A detailed study is presented, of the philosophy underpinning virtual testing schemes: highlighting the structure, challenges and opportunities posed by a virtual testing strategy compared with traditional laboratory experiments. The virtual testing process has been discussed from atomistic to macrostructural length scales of analyses. Several implementations of virtual testing frameworks for diverse categories of materials are also presented, with particular emphasis on composites, cellular materials and biomaterials (collectively described as heterogeneous systems, in this context). The robustness of virtual frameworks for prediction of the constitutive behaviour of these materials is discussed. The paper also considers the current thinking on developing virtual laboratories in relation to availability of computational resources as well as the development of multi-scale material model algorithms. In conclusion, the paper highlights the challenges facing developments of future virtual testing frameworks. This review represents a comprehensive documentation of the state of knowledge on virtual testing from microscale to macroscale length scales for heterogeneous materials across constitutive responses from elastic to damage regimes

Photocatalytic Degradation of Organic Pollutants in Water Using Graphene Oxide Composite

Developing sustainable and less-expensive technique is always challenging task in water treatment process. This chapter explores the recent development of photocatalysis technique in organic pollutant removal from the water. Particularly, advantages of graphene oxide in promoting the catalytic performance of semiconductor, metal nanoparticle and polymer based photocatalyst materials. Owing to high internal surface area and rapid electron conducting property of graphene oxide fostering as backbone scaffold for effective hetero-photocatalyst loading, and rapid photo-charge separation enables effective degradation of pollutant. This chapter summaries the recent development of graphene oxide composite (metal oxide, metal nanoparticle, metal chalcogenides, and polymers) in semiconductor photocatalysis process towards environmental remediation application