Abstract

Nowadays carbon fibre reinforced epoxy laminates represent the standard material in the designing and manufacturing of aeronautical composite structures. However, advantages related to metals manufacturing could represent an important menace for the role of composite materials in this industry. Therefore, new improvements in composite structures have to be seek in order to improve their competitiveness.

Graphene is a nanomaterial that possess the higher stiffness and strength ever measured. Therefore, the use of Graphene Related Material (GRM) for enhancing composite laminate materials could represent an important advance in order to reduce their impact vulnerability and to improve the performance of Resin Transfer Molding (RTM) composites.

  In this work epoxy resin doped with GRM were used to manufacture carbon fiber aeronautical composites by RTM. Low velocity impacts and Compression After Impact (CAI) tests were performed. Regarding experimental methodology, ASTM standard was followed, also new measuring techniques were used as 3D High Speed Digital Image Correlations. All tests were performed on GRM enhanced material and reference material to compare their results. Under impact loads, elastic behavior, peak force or damage results do not depend on the addition of graphenic particles. Whereas, a minor improvement enhanced with GRM in compression preserving the visible damage for an impact equivalent to the tool drop (30 J). Is important to keep this effect in order to detect damages in the composites structures.

Abstract

The present work shows the development of temperature sensors based on flexible polymers reinforced with carbon nanoparticles. More specifically, they have been manufactured with polydymethysiloxane (PDMS) reinforced with graphene nanoplatelets (GNPs). The analysis of electrical properties reveal that an increase of the GNP contents promotes an enhancement of the electrical conductivity due to the higher number of conductive pathways inside the material. On the other hand, the electrical conductivity decreases with temperature because of the polymer expansion, as well as due to some scattering effects in the contacts between adjacent nanoparticles. This decrease is more significant at lower GNP contents as, in this case, the scattering effects inside the matrix are also very prevalent. The analysis of the proof-of-concept as temperature sensors shows an outstanding sensitivity, especially at low GNP contents, with a linear-exponential correlation of the electrical resistance with temperature. Their use as alarm sensors is proved due this excellent thermal sensitivity.