Abstract
Understanding the structural integrity of polymer composites in service conditions is of practical importance for the applications of polymer composites. In this work, we investigate the solvent-induced crack growth in poly(methyl methacrylate)/multiwalled carbon nanotube (PMMA/MWCNT) composites in respective organic solvents of 2-ethylhexyl alcohol (2 EA), cyclohexanol, and 1-butanol at different temperatures after being immersed in methanol at 50 °C for 25 min. The areal density of crack lengths and growth rate of a single crack in the PMMA/MWCNT composites increase with the immersion time and temperature for the solvents of 2 EA and cyclohexanol. The areal density of crack lengths in the PMMA/MWCNT composites immersed in 1-butanol is largest at 30 and 40 °C and smallest at 50 °C. The 1-butanol solvent causes the fastest, steady-state crack growth at 30 and 40 °C and the slowest crack growth at 50 °C. Increasing the fraction of MWCNTs reduces the areal density of crack lengths and the growth rate of a single crack in the healed and non-cracked areas. The crack growth is controlled by a thermally activated process. The crack growth rate is faster in the healed area than in the non-cracked area for the same composite and solvent. The activation energy for the motion of polymer chains associated with the single-crack growth in the non-cracked area is smaller than that for solvent-induced cracking because the interaction between cracks hinders crack growth.
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•Methanol desorption controls the cracking in composites for 2 EA and cyclohexanol.•1-butanol absorption controls the cracking in composites for 1-butanol at high temp.•Methanol desorption controls the cracking in composites for 1-butanol at low temp.•Increasing the MWCNT fraction hinders the growth of the cracks in composites.•The crack growth in PMMA/MWCNT composites is a thermally activated process.