Congresos y reuniones científicas
Título:
Pore Size, Surface Interactions and Evaporation Kinetics in Swollen Porous Polymer Networks Determined By NMR Relaxation
Autor/es:
EMILIA V. SILLETTA; MANUEL I. VELASCO; CESAR G. GOMEZ; MIRIAM C. STRUMIA; GUSTAVO A. MONTI; RODOLFO H. ACOSTA
Reunión:
Encuentro; V Encuentro Argentino de Materia Blanda (2014 MAB5); 2014
Institución organizadora:
INIFTA - Universidad Nacional de la Plata - CONICET
Resumen:
In this work, we describe the study of the pore structure of the macroporous
polymer of ethylene glycol dimethacrylate and 2-hydroxyethyl methacrylate
[poly(EGDMA-co- HEMA)] in the dry and in the swollen state by measuring relaxation
times of liquids contained in the polymer network [1 , 2]. This information allows the
characterization of the matrices in terms of pore distribution, water uptake, and
swelling. The behaviour of polar liquids during evaporation and deswelling dynamics is
monitored and described. An internal migration of water from the swollen polymer
mesh into expanding pores takes place. With this procedure, it is possible to obtain
information about the microscopic morphology behaviour of the matrix during
evaporation and deswelling. Additionally, the pore diameter can be determined by
measuring diffusion which is encoded though magnetic field distortions that arise due
to heterogeneities in the magnetic field, which are produced by changes in magnetic
susceptibilities in going from the pore wall to the pore void (DDIF - Decay due to
Diffusion in Internal Field) [3]. Comparison of the relaxation times present in different
pore sizes provides information on surface interaction [4], in particular the influence of
hydrogen bond between water and hydroxyl groups as a function of the amount of
crosslinker is determined.