Evaporation kinetics in macroporous polymeric supports evaluated by relaxation measurements

E.V. SILLETTA; G.A. MONTI; C.G. GOMEZ; M.C. STRUMIA; R.H. ACOSTA

Rio de Janeiro

Congreso; 18th ISMAR Meeting; 2013

ISMAR

Macroporous polymer beads show a permanent well-developed porous structure in the dry state, and have a wide range of applications such as support for catalysts, immobilization of enzymes, HPLC columns, liberation of active substances, or adsorbents. Their porous structure improves the diffusion of different solutes through the network. These networks have particular properties as high degree of crosslinking and rigid structure both in swollen and dry state, turning the study of their synthesis conditions of considerable interest. The properties of the polymer mesh change radically due to swelling, a process that strongly depends on the mesh structure; therefore, changes in the content of a selected cross-linker (ethylene glycol dimethacrylate-EGDMA) percentage are studied. Most of the conventional techniques used to characterize these kind of materials are only applicable to the dry state. Therefore, monitoring the kinetics of evaporation of the solvent renders information of the swelling process. We use 1H-CPMG sequences to measure the distribution of transverse relaxation times of polar and non-polar solvents contained in the matrices. As non-polar solvents do not interact with the network, information of the unperturbed porous system is obtained. On the other hand, polar solvents present the L-P interactions that compared to L-L provide information on the swelling process.