Vides ietekme uz viedo ar oglekļa nanopildvielām modificētu kompozītu un šķiedru plastikātu fizikālajām īpašībām strukturāliem pielietojumiem / Environmental effects on physical properties of smart composites and FRP modified by carbonaceous nanofillers for structural applications
Browsing Vides ietekme uz viedo ar oglekļa nanopildvielām modificētu kompozītu un šķiedru plastikātu fizikālajām īpašībām strukturāliem pielietojumiem / Environmental effects on physical properties of smart composites and FRP modified by carbonaceous nanofillers for structural applications by Subject "flexural properties"
The aim of this paper was to estimate the effect of moisture and temperature on the
flexural properties of the epoxy filled with single and hybrid carbon nanofillers (CNTs and
CNFs) and to reveal the most environmentally stable NC. Water absorption at 70 °C until
equilibrium moisture content and heating at 70 °C for 4 weeks were followed by freezing at -
20 °C for 8 weeks. Microstructural characterization of optical images revealed homogeneous
dispersion of all carbon nanofillers in the epoxy resin at microscale. Positive nanofiller effects
were found for sorption, flexural and thermophysical characteristics of the epoxy resin. The
most environmentally stable NC was epoxy filled with 0.1 wt. % of CNTs/CNFs hybrid, which
had the lowest effect of temperature and moisture on mechanical characteristics, along with the
lowest equilibrium water content and diffusivity.
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.