Hydrothermal Aging of an Epoxy Resin Filled with Carbon Nanofillers

Abstract

The effects of temperature and moisture on flexural and thermomechanical properties of neat and filled epoxy with both multiwall carbon nanotubes (CNT), carbon nanofibers (CNF), and their hybrid components were investigated. Two regimes of environmental aging were applied: Water absorption at 70 °C until equilibrium moisture content and thermal heating at 70 °C for the same time period. Three-point bending and dynamic mechanical tests were carried out for all samples before and after conditioning. The property prediction model (PPM) was successfully applied for the prediction of the modulus of elasticity in bending of manufactured specimens subjected to both water absorption and thermal aging. It was experimentally confirmed that, due to addition of carbon nanofillers to the epoxy resin, the sorption, flexural, and thermomechanical characteristics were slightly improved compared to the neat system. Considering experimental and theoretical results, most of the epoxy composites filled with hybrid carbon nanofiller revealed the lowest effect of temperature and moisture on material properties, along with the lowest sorption characteristics.

Recent Advances and Trends of Nanofilled/Nanostructured Epoxies

“…A variant of CNTs is represented by multi-walled carbon nanotubes (MWCNTs), possessing an average outer diameter from 5 to 50 nanometers and a length of 0.5–200 µm, that demonstrated to give the epoxy resin, and the relative FRPs, excellent mechanical, thermal, and durability characteristics [ 34 , 35 , 36 , 37 ]. It is also worth mentioning that the addition of montmorillonite or silica nanoparticles to MWCNT aimed to obtain epoxy-based hybrid composites with exceptional properties, due to the synergistic effect raised from both the combination of different nanofillers and the interactions between them [ 38 , 39 ].…”

“…It is worth mentioning that the mechanical properties of nanofilled epoxy resins significantly decline as a consequence of water absorption, even at low amounts of absorbed water. This behavior has been ascribed to the weakening of the interface between the epoxy matrix and the nanofillers which hinders the transfer of the stresses under mechanical loads [ 36 , 110 ].…”

Basalt Fibre Composite with Carbon Nanomodified Epoxy Matrix under Hydrothermal Ageing

“…Nevertheless, the durability of FRP composites is a complex phenomenon and it depends on the degradation of both polymer matrix and fibres, as well as on their interface bond behaviour [ 7 , 8 , 9 ]. The epoxy resins which are usually applied for the impregnation of FRPs may have changes in their physical and chemical properties due to environmental effects (e.g., moisture, temperature, and UV radiation) [ 10 , 11 , 12 ] leading to plasticization of the epoxy resins, chemical reactions, and post-curing.…”

“…The addition of homogeneously dispersed carbon nanofillers such as nanotubes (CNT), nanofibres (CNF), and graphene and could lead to environmental stability enhancement of mechanical, thermal, and electrical properties [ 8 , 11 , 13 , 14 , 15 ]. Besides, it may introduce additional functionality to nonconductive polymer resins and FRPs [ 14 ] and it provides structural health monitoring, i.e., the control of mechanical properties through the changes in electrical properties.…”

Hydrothermal Carbon as Reactive Fillers to Produce Sustainable Biocomposites with Aromatic Bio-Based Epoxy Resins

“…Thermoset-based composites are materials that have had an innovative development in recent years. According to the reported studies, among the optimal fillers used for polymeric (nano)composites with superior mechanical, electrical, and chemical properties are the carbon nanotubes and grapheme [ 14 , 15 , 16 , 17 , 18 ]. Unfortunately, this type of material leads to a high production cost.…”