PSI - Issue 14

Vivek Khare et al. / Procedia Structural Integrity 14 (2019) 215–225 Vivek Khare, Shubham srivastava, Sudhir kamle, G.M.Kamath / Structural Integrity Procedia 00 (2018) 000 – 000

219

5

functionalization with high stress loading and its impact on stiffness. Linearity threshold for stress and time was determined from creep tests and used as input for cyclic testing.

3.3. Fractography

The surface morphology and fractography was observed by Field emission scanning electron microscopy (FESEM) imaging with gold coatings to investigate state of dispersion of MWCNT in to polypropylene matrix.

3.4. Dynamic characterization

Thermo-mechanical response of specimens (30 x 10 x 0.35 mm 3 ) was investigated using dynamic mechanical analyzer under temperature ramp tests from 0°C to 100°C at 4°C/min ramp rate by exerting dynamic sinusoidal excitation of 1Hz constant frequency, static and dynamic displacements of amplitudes 100 µm and 20 µm respectively to obtain its storage modulus. 4. Results and discussions

4.1. TGA Analysis

Fig. 3. Thermogravimetric analysis results (a) MWCNT-Pristine-PP; (b) MWCNT-COOH Functionalized-PP nanocomposites

Thermal stability of polymer and both grades of nanocomposites was investigated for consecutive heating cooling from 20°C-200 °C and vice-versa using thermogravimetric analysis as shown in Figure. 3. The curves showed no significant loss in weight % of nanocomposites.

4.2. Static characterization

Tensile properties of material were determined at room temperature. Tensile strength and strain at failure (%) were obtained for polymer and nanocomposites as shown in Figure. 4. Nanocomposites with functionalized MWCNT exhibits increase in strength and failure strain % than pristine MWCNT as listed in Table. 3 and 4. This is to be noted that 1% sample showcase 54.09% increase in tensile strength than neat PP. Moreover 2% pristine sample showed 31.44% lower strength. The repeatability of results was checked by conducting three tests on each sample.