Dielectric properties of poly(vinyl alcohol) hydrogels prepared by freezing/thawing technique

The dielectric behavior of poly(vinyl alcohol) –PVA– crosslinked hydrogels obtained by the repeated freezing/ thawing (F/T) technique have been investigated by dielectric relaxation spectroscopy (DRS) and differential scanning calorimetry (DSC). The crosslinked polymer is produced by the clustering of chains caused by the association of a polar group of the dissolved polymer followed by polymer crystallization. The dielectric spectra obtained from -50 °C to -10 °C show a broad secondary relaxation process associated to local mobility, ß relaxation, which is related to the terminal polar groups (OH). This process is strongly affected by the freezing/thawing cycles applied. The values of tan d are below 1 indicating the dielectric phenomenon is predominant in all samples. The effect of crosslinking PVA on the dynamics of the secondary relaxation process was further analyzed.

• Autores: Londoño, M. E. (Martha Elena); Jaramillo, Juan Manuel; Sabater I Serra, Roser; Vélez, Juan Manuel
• Tipo de recurso: Article of journal
• Fecha de publicación: 2012
• Institución: Universidad EIA .
• Repositorio: Repositorio EIA .
• Idioma: eng
• OAI Identifier: oai:repository.eia.edu.co:11190/116
• Acceso en línea: https://repository.eia.edu.co/handle/11190/116
• Palabra clave: REI00195; TECNOLOGÍAS PARA LA SALUD; TECHNOLOGY IN HEALTH; POLYVINYL ALCOHOL; PHARMACEUTICAL SOLUTIONS; SOLUCIONES FARMACÉUTICAS; ALCOHOL POLIVINÍLICO; DIELECTRIC PROPERTIES; HYDROGELS; FREEZING / THAWING; DIELECTRIC SPECTROSCOPY; PROPIEDADES DIELÉCTRICAS; HIDROGELES; CONGELAMIENTO / DESCONGELAMIENTO; ESPECTROSCOPIA; DIELÉCTRICA
• Rights: openAccess
• License: Derechos Reservados - Universidad EIA, 2020