PSI - Issue 17

Anurag Singh et al. / Procedia Structural Integrity 17 (2019) 857–864 Author name / Structural Integrity Procedia 00 (2019) 000 – 000

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Figure 4: SEM analysis of a) pristine b) 30- minute functionalized MWCNT’s separated by DMF and c) 30- minute functionalized MWCNT’s filtrate (insoluble in DMF) at a length scale of 500 nm.

Table 2: Results of various element fractions present in different carbon nanotube samples a) by weight b) by atomic weight

Figure 5 :EDS analysis of pristine and functionalized MWCNTs samples a) Pristine MWCNTs b) functionalized MWCNT’s

4.6 Mechanical properties Mechanical characterization was carried out according to the previously mentioned ASTM D638 standard, for neat resin samples, samples with a wt% content of 0.5 and 1 of prostine MWCNTs, and samples with a wt% content of 0.05, 0.1, 0.25, 0.5 and 1%. The tests were performed on five samples per each typology of nanocomposite. In Figure 6 and Figure 7 the mean values of the Elastic tensile modulus and tensile stress at break are respectively reported together with the corresponding standard deviation. In general, the standard deviation is very low when evaluated in terms of elastic tensile modulus and it is higher when evaluated for the tensile stress at break. The tensile properties of the neat resin, used as a benchmark, lay in the range suggested by the TDS of the producer. When pristine MWCNTs were introduced into the resin matrix, a decrease of both elastic modulus and tensile stress at break was observed. The introduction of functionalized MWCNTs into the same bio-based resin matrix causes an increase of both the mechanical properties until 0.1-0.25 wt% content, afterwards they start to decrease again. Particularly for the selected preparation method and a percentage of 0.25% of functionalized MWCNTs filled resin, type NC7000, both elastic modulus and tensile stress at break reach the same order of magnitude of the neat resin specimens, thus confirming the indication of the TDS of the product NC7000 of retention of the original mechanical properties.