... Romano, Carlo Naddeo, Luigi Vertuccio, Khalid Lafdi, and Liberata Guadagno ..... Kim Y.A., Kamio S., Tajiri T., Hayashi T., Song S. M., Endo M., Terrones M., ...
Thermal investigation of tetrafunctional epoxy resin filled with different carbonaceous nanostructures Vittorio Romano, Carlo Naddeo, Luigi Vertuccio, Khalid Lafdi, and Liberata Guadagno Citation: AIP Conference Proceedings 1736, 020152 (2016); doi: 10.1063/1.4949727 View online: http://dx.doi.org/10.1063/1.4949727 View Table of Contents: http://scitation.aip.org/content/aip/proceeding/aipcp/1736?ver=pdfcov Published by the AIP Publishing Articles you may be interested in Electrical transport in carbon black-epoxy resin composites at different temperatures J. Appl. Phys. 114, 033707 (2013); 10.1063/1.4815870 Characterizing epoxy composites filled with carbonaceous nanoparticles from dc to microwave J. Appl. Phys. 113, 124103 (2013); 10.1063/1.4798296 Thermal properties of epoxy resins at cryogenic temperatures AIP Conf. Proc. 614, 211 (2002); 10.1063/1.1472545 Pressure dependence of the thermal conductivity of an epoxy resin J. Appl. Phys. 44, 705 (1973); 10.1063/1.1662247 Limits of Linear Viscoelasticity and Yield of a Filled and Unfilled Epoxy Resin Trans. Soc. Rheol. 14, 253 (1970); 10.1122/1.549189
Thermal Investigation of Tetrafunctional Epoxy Resin Filled with Different Carbonaceous Nanostructures Vittorio Romano1*, Carlo Naddeo1, Luigi Vertuccio1, Khalid Lafdi2, Liberata Guadagno1 Department of Industrial Engineering, University of Salerno Via Giovanni Paolo II, 132 - 84084 Fisciano (SA), Italy 2 University of Dayton, 300 College Park Dayton Ohio 45440 USA 1
Corresponding author
*
Abstract. This paper presents a preliminary investigation of thermal behaviour of epoxy nanocomposites containing different types of nanofillers, such as 1-D Multiwall Carbon Nanotubes (MWCNTs) and 2-D predominant shape of Exfoliated Graphite nanoparticles (EG). The cure behavior of the different epoxy formulations (filled and unfilled) was studied by Differential Scanning Calorimetry (DSC). The DSC technique is particularly advantageous for studying the cure of reactive epoxy systems because the curing process is accompanied by the liberation of heat. For all the epoxy nanocomposites analyzed in this work, Differential Scanning Calorimetry (DSC) investigation shows curing degree (DC) values higher than 92% for the curing cycle up to 200°C, reaching up to 100% for the samples filled with Exfoliated Graphite nanoparticles (EG). The calorimetric results also show that Exfoliated Graphite nanoparticles accelerate the curing process of the epoxy resin of about 20°C. Transient Plane Source measurements of thermal conductivity show that this acceleration is directly related to the better heat conduction obtained through the incorporation in the epoxy matrix of carbonaceous nanostructures with predominantly two-dimensional shape (Exfoliated Graphite nanoparticles). The experimental results clearly demonstrate that the use of graphene sheets is very hopeful for obtaining nanocomposites characterized by high performance that are able to meet the ambitious requirements in the aeronautical field. Keywords: Epoxy nanocomposites, Carbonaceous nanofillers, Thermal Conductivity. PACS: 65.80g; 65.80ck; 81.05t; 81.07b
INTRODUCTION
There is currently an increasing demand for advanced materials with better properties to meet new industrial requirements for replacing existing materials. In the field of aeronaultical materials, carbon fiber reinforced composites (CFRCs) have been driven by the need to reduce structural weight. Aircraft components made of composites have a much lower environmental impact compared with similar structures made from metal or metal alloys. In fact, a 1 kg of fuel saved equates to a reduction of 3.15 kg of CO2 emissions. The high performance of continuous fiber (e.g. carbon fiber, glass fiber) reinforced polymer matrix composites is well known and documented. However, these composites have some disadvantages related to the matrix dominated properties which often limit their wide application and create the need to develop new types of composite materials. In the aerospace industry, the addition of nanoparticles such as exfoliated graphite, carbon nanofibers and carbon nanotubes plays a promising role due to their potential applications in order to improve mechanical, electrical and thermal performance in composites used in the aerospace field 1-3. The low thermal conductivity negatively impacts on the design of anti-icing systems. The thermal conductivity of resins used to impregnate CF can be enhanced by embedding carbon nanoparticles in the resin 4. Designing and or modifying carbon nanostructured form is possible to impart specific properties to the polymeric matrix of aeronautic composites. In this regard, graphite platelets are reported to be a potential alternative to carbon nanotubes with regard to the cost and some desired properties. Graphite platelets are about 500 times less expensive than carbon nanotubes 5. In this work, the thermal behaviour of the tetrafunctional epoxy resin cured with the DDS and their corresponding nanocomposites was studied. Differential Scanning Calorimetry analysis (DSC) and Transient Plane Source Technique (TPS) were used for monitoring the cure degree and the thermal transport properties characterization. Materials
EXPERIMENTAL
The epoxy matrix was prepared by mixing the epoxy precursor, tetraglycidyl methylene dianiline (TGMDA) (epoxy equivalent weight 117–133 g/eq), with an epoxy reactive monomer 1-4 butanedioldiglycidyl ether (BDE) that acts as a reactive diluent. The curing agent used for this study is 4,4-diaminodiphenyl sulfone (DDS). The epoxy mixture was obtained by mixing TGMDA with BDE monomer at a concentration of 80%:20% (by wt) VIII International Conference on “Times of Polymers and Composites” AIP Conf. Proc. 1736, 020152-1–020152-4; doi: 10.1063/1.4949727 Published by AIP Publishing. 978-0-7354-1390-0/$30.00
020152-1
epoxide to flexibilizer. The curing agent was added at stoichiometric amount with respect to the epoxy rings (TGMDA and BDE). The use of a reactive diluent BDE inside the unfilled and nanofilled epoxy precursor based on TGMDA has proven to be of benefit to decrease the viscosity of the epoxy matrix 6,7. This decrease is especially advantageous for thermosetting resins filled with nanoparticles which tend to dramatically increase the viscosity of the resin 1,8. It increases the mobility of reactive groups resulting in a higher cure degree than the epoxy precursor alone. This effect is particularly advantageous for nanofilled resins where higher temperature treatments are needed, compared to the unfilled resin, to reach the same cure degree. Different carbon nanostructured forms, Multiwall Carbon Nanotubes MWCNTs and Exfoliated Graphite EG, were embedded in the epoxy matrix with the aim of improving other physical properties of the resin. The MWCNTs (3100 Grade) were purchased from Nanocyl S.A. TEM investigation has shown for MWCNTs an outer diameter ranging from 10 to 30 nm. The length of MWCNTs is from hundreds of nanometers to some micrometer. The number of walls varies from 4 to 20 in most nanotubes. The specific surface area of MWCNTs determined with the Brunauer– Emmett–Teller (BET) method is around 250-300 m2/g; the carbon purity is 95% with a metal oxide impurity
