Final Report Summary - BME CLEAN SKY 032 (Resin, Laminate and Industrial Nanoparticles Concept and Application. Industrialization)
This project aimed at development of hybrid epoxy resin composites, where both the matrix and the carbon fibre reinforcement contain nanoparticles, in order to improve the mechanical, electrical and thermal properties of the carbon fibre reinforced aeronautical structures. In WP1 two kinds of untreated multiwall carbon nanotubes (MWCNTs) have been characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM) tests in terms of aggregate structure. Composites with two MWCNT types have been compared through mechanical tests. Based on mechanical test results Bayer BT C150 HP MWCNTs have been selected for further use. Rheological and mechanical characterization of four epoxy resins combined with six curing agents has been performed with multiple amounts of MWCNTs. For further use the low viscosity AH-12 epoxy resin with T-111 curing agent has been chosen. According to the results of the mechanical and electric conductivity tests performed on MWCNT/ carbon fibre (CF) reinforced hybrid composites prepared by vacuumbag technology 0.3 wt% MWCNT filling has been selected. The masterbatch dispersion method has been characterized and compared to a competitor direct mixing technology. WP2 aimed at developing processes to produce polymer nanofibres loaded with carbon nanotubes (CNTs), for CF production.
The concentration and viscosity of polyacrilonitrile (PAN) solutions were optimized for electrospinning. A novel technique involving both mechanical and ultrasonic mixing was developed for dispersion of CNTs and the efficiency was evaluated. Nanofibre samples were produced with NanoSpiderTM method. The nanofibrous mats were examined by SEM and AFM. The average fiber diameters were found to be approximately 200 nm. The stabilization and carbonization processes were optimized using differential scanning calorimetry (DSC), thermogravimetry (TG), Fourier transform infrared spectrometry (FTIR) and wide angle X-ray spectroscopy (WAXS). The suggested heat treatment program consists of a hot-stretching, a multistep stabilization taking 10 minutes, respectively, and a two step carbonization at higher temperatures. Carbon nanofibers with a diameter of approximately 100 nm were successfully produced.
In WP3 four samples (unwoven carbon nanofabric reinforced MWCNT filled epoxy, unwoven carbon nanofabric reinforced epoxy, CF reinforced MWCNT filled epoxy and CF reinforced epoxy) have been prepared to characterize the effect of CNT filling and to be able to compare the developed nanofiber reinforced composites to the conventional microsized CF reinforced ones in guarded hot plate thermal conductivity and four-pin surface resistivity measurements. The thermal conductivity of the samples has increased by approximately 3 times with the inclusion of MWCNTs in the carbonized nanofibers. The electrical conductivity is significantly higher in case of MWCNT containing carbonized nanofiber reinforced composites compared to the CF reinforced composites. The inclusion of MWCNTs in the PAN precursor fibers is essential for the formation of conductive carbonized nanofibers by the mediation of the formation of a more perfect and aligned graphite structure.
The concentration and viscosity of polyacrilonitrile (PAN) solutions were optimized for electrospinning. A novel technique involving both mechanical and ultrasonic mixing was developed for dispersion of CNTs and the efficiency was evaluated. Nanofibre samples were produced with NanoSpiderTM method. The nanofibrous mats were examined by SEM and AFM. The average fiber diameters were found to be approximately 200 nm. The stabilization and carbonization processes were optimized using differential scanning calorimetry (DSC), thermogravimetry (TG), Fourier transform infrared spectrometry (FTIR) and wide angle X-ray spectroscopy (WAXS). The suggested heat treatment program consists of a hot-stretching, a multistep stabilization taking 10 minutes, respectively, and a two step carbonization at higher temperatures. Carbon nanofibers with a diameter of approximately 100 nm were successfully produced.
In WP3 four samples (unwoven carbon nanofabric reinforced MWCNT filled epoxy, unwoven carbon nanofabric reinforced epoxy, CF reinforced MWCNT filled epoxy and CF reinforced epoxy) have been prepared to characterize the effect of CNT filling and to be able to compare the developed nanofiber reinforced composites to the conventional microsized CF reinforced ones in guarded hot plate thermal conductivity and four-pin surface resistivity measurements. The thermal conductivity of the samples has increased by approximately 3 times with the inclusion of MWCNTs in the carbonized nanofibers. The electrical conductivity is significantly higher in case of MWCNT containing carbonized nanofiber reinforced composites compared to the CF reinforced composites. The inclusion of MWCNTs in the PAN precursor fibers is essential for the formation of conductive carbonized nanofibers by the mediation of the formation of a more perfect and aligned graphite structure.
