Synthesis and thermodynamic characterization of poly(methyl methacrylate)/multiwall carbon nanotube nanocomposite

Abstract

In the first part of this study, poly(methyl methacrylate) (PMMA)/multiwall carbon nanotube (MWCNT) nanocomposite was synthesized by adding carbon nanotube before polymerization with bulk polymerization. Surface morphology of the PMMA/MWCNT nanocomposite and the PMMA/MWCNT nanocomposite with Chromosorb W was characterized by scanning electron microscopy (SEM). Surface and thermodynamic properties of the PMMA/MWCNT nanocomposite were investigated by inverse gas chromatography (IGC). The surface acid base character and dispersed surface energy of the PMMA/MWCNT were determined at infinite dilution. The entropy of adsorption, ∆SS, the specific free energy of adsorption, ∆GS, and the enthalpy of adsorption, ∆HS, of selected polar solvents were determined on the PMMA/MWCNT nanocomposite. The values of ∆HS were correlated with both the acceptor and donor numbers of the solvents to determine the Lewis acidic constant KA and the Lewis basic constant KD of the PMMA/MWCNT nanocomposite. The PMMA/MWCNT nanocomposite selectivity was investigated using the acetate and alcohol isomers by IGC at temperatures between 393.2 and 403.2 K. Glass transition temperature (Tg) was determined using differential scanning calorimetry (DSC) and IGC method.The interactions between the PMMA/MWCNT nanocomposite and 12 solvents were propped at a temperature range (423.2–448.2 K). The Flory–Huggins interaction parameter, and the weight fraction activity coefficient, of the PMMA/MWCNT nanocomposite solvent system were estimated at temperatures between 423.2 and 448.2 K. The solubility parameter of the PMMA/MWCNT nanocomposite, δ2, was calculated as 14.0 (cal/cm3)1/2.