Transport Characteristics of Filled Poly(ethylene-co-vinyl acetate) Membranes
The effect of carbon black fillers on the solvent transport behaviour of ethylene-co-vinyl acetate (EVA) was studied using petrol, diesel and kerosene as probe molecules. Semi-reinforcing furnace (SRF), high abrasion furnace (HAF) and intermediate super-abrasion furnace (ISAF) blacks were used for the reinforcement of the matrix. EVA filled with SRF showed the highest solvent uptake, followed by HAF and then ISAF. The observations have been correlated with the morphology of the systems, as attested by scanning electron micrographs and interpreted on the basis of the particle size of the reinforcement, and also in terms of the bound rubber content. The molar mass between crosslinks has been calculated from the sorption data. Arrhenius activation parameters for the process of diffusion and permeation and thermodynamic quantities such as enthalpy and entropy were also determined. The first order equation was used to study the sorption kinetics. The mechanism of transport was found to deviate slightly from the regular Fickian trend, observed with conventional rubbers. A sorption (S)-desorption (D)-resorption (RS)-redesorption (RD) experiment was carried out to study the structural changes occurring in the filled matrix during solvent transport.