Síntese e caracterização de scaffolds compósitos de álcool polivinílico/nanotubos de carbono com poros ordenados por ice-templating

Abstract

In this work, we demonstrated that it is possible to prepare three-dimensionally ordered macroporous polymer structures by an ice-templating approach. Four freezing routes were used: unidirectional freezing with liquid nitrogen, unidirectional freezing in a domestic freezer, radial freezing, and bidirectional freezing with liquid nitrogen. Polyvinyl alcohol (PVA) has been used as a model system in this study, but the manufacturing route proposed herein can be applied to other polymer systems. Multi- walled carbon nanotubes (MWCNTs) were incorporated into the PVA matrix to investigate the influence of this addition on the mechanical and electrical behavior of PVA. The pore structures resulting from the four different freezing routes significantly affected the mechanical behavior of the samples. The addition of MWCNTs had a strengthening effect on PVA, especially when added at loadings up to 2 wt.%. Samples prepared by unidirectional freezing displayed larger Young´s Modulus and Yield Strength, but the materials derived from radial or bi-directional freezing showed greater electrical conducting capacity and a more stable electrical behavior in a wider frequency range than unidirectional samples. These materials exhibited porosity above 85 %, which can be of great interest in applications in tissue engineering, separation processes and supercapacitors.