Issue 46

K.I. Tserpes et alii, Frattura ed Integrità Strutturale, 46 (2018) 73-83; DOI: 10.3221/IGF-ESIS.46.08 76 Differentiation of the curves of the MWCNT/PP 2 wt% and 5 wt% materials is not obvious due to the large scatter. Tab. 1 lists the Young’s moduli and maximum stress for each specimen. The Young’s modulus has been computed using the measurements from the strain gauges. The comparison between the average values of the properties reveals a significant increase in both the Young’s modulus and maximum stress of the nanofilled material. The increase is greater for the maximum stress. In addition, the comparison between the 2 wt% and 5 wt% materials reveals clearly that the larger content of MWCNTs leads to a larger increase in the properties of the PP material something that is not obvious in the stress-strain curves. Figure 1 : The stress-strain curves measured by the ARAMIS system for all tests. Specimen Young’s modulus (MPa) Maximum stress (MPa) Average Young’s modulus (standard deviation) Average maximum stress (standard deviation) PP_01 1629.2 - 1 1641.33 (85.75) 31.55 (0.33) PP_02 1515.6 - 1 PP_03 1592,0 31.22 PP_04 1767.6 31.40 PP_05 1687.9 31.98 PP_06 1657.5 31.61 MWCNT 2 wt%_01 1885.2 41.06 1974.73 (146.7) 39.80 (3.22) MWCNT/PP 2 wt%_02 2092.1 43.36 MWCNT/PP 2 wt%_03 2057.3 43.41 MWCNT/PP 2 wt%_04 2007.8 36.43 MWCNT/PP 2 wt%_05 2086.8 36.94 MWCNT/PP 2 wt%_06 1719.2 37.57 MWCNT/PP 5 wt%_01 2175.3 44.61 2055.22 (121.82) 42.06 (2.06) MWCNT/PP 5 wt%_02 1965.8 40.54 MWCNT/PP 5 wt%_03 1912.4 40.49 MWCNT/PP 5 wt%_04 2182.9 43.38 MWCNT/PP 5 wt%_05 2039.7 43.68 MWCNT/PP 5 wt%_06 2075.2 2 39.68 Table 1 : Measured mechanical properties of the PP and nanocomposite. 1 No data are available from the ARAMIS system 2 Estimated from the ARAMIS system due to strain gauge failure. 0 5 10 15 20 25 30 35 40 45 50 0 0.05 0.1 0.15 0.2 0.25 0.3 Stress (MPa) Strain PP MWCNT/PP 2 wt% MWCNT/PP 5 wt%