Lewis acid–base properties of cellulose acetate phthalate‐polycaprolactonediol blend by inverse gas chromatography

The net retention volumes, V_N, of n‐alkanes and five polar probes are determined on cellulose acetate phthalate–polycaprolactonediol blend column by inverse gas chromatography in the temperature range 323.15–363.15 K. The dispersive surface energy, $\gamma _{\bf S}^{\bf d}$ , of the blend has been calculated using the V_N values of n‐alkanes and the $\gamma _{\bf S}^{\bf d}$ at 333.15 K is 12.6 mJ/m². The $\gamma _{\bf S}^{\bf d}$ values are decreasing linearly with increase of temperature. The V_N values of the five polar solutes are used to calculate the specific component of the enthalpy of adsorption, ${\Delta }{H}_{\bf a}^{\bf S}$ . The Lewis acid–base parameters, K_a and K_b, are derived using ${\bf \Delta }{H}_{\bf a}^{\bf S}$ values and are found to be 0.019 and 0.403, respectively. The K_a and K_b values indicate that the blend surface contain more basic sites and interact strongly with the acidic probes. The acid–base parameters have been used to analyze the preferential interaction of the solid surface with acidic and basic probes. POLYM. ENG. SCI., 2013. © 2013 Society of Plastics Engineers