Microstructure and free volume evaluation of poly(vinyl alcohol) nanocomposite hydrogels

被引：0

作者：

Paranhos, Caio M. ^{[1
]}

Soares, Bluma G. ^{[1
]}

Machado, José C. ^{[2
]}

Windmöller, Dario ^{[2
]}

Pessan, Luiz A. ^{[3
]}

机构：

[1] Institute of Macromolecules, Rio de Janeiro Federal University, Centro de Tecnologia, Bloco J, Ilha do Fundão, Rio de Janeiro, RJ 21945-970, Brazil

[2] Laboratory of Positron Annihilation Spectroscopy, Minas Gerais Federal University, Av. Antônio Carlos 6627, Belo Horizonte, MG 31270-901, Brazil

[3] Department of Materials Engineering, São Carlos Federal University, Rodovia Washington Luiz, Km 235, São Carlos, SP 13565-905, Brazil

来源：

European Polymer Journal | 2007年 / 43卷 / 12期

关键词：

A new type of organic/inorganic nanocomposite hydrogel was prepared by introducing small amount of natural montmorillonite (MOM) into a poly(vinyl alcohol) (PVA)/sulfonated polyester (PES) system. The crystalline structure and crystallinity degree were determined by differential scanning calorimetry (DSC) and wide angle X-ray spectroscopy (WAXS). The presence of PES leads to an increase in the crystallinity degree of the PVA matrix and a significant decrease in the melting temperature. The addition of small amount of clay (1-5%) resulted in an increase of the average crystallite dimension; crystallinity degree and melting temperature; as compared to the PVA/PES system. The presence of the clay resulted in a substantial increase on the free volume size; as suggesting by positron annihilation lifetime spectroscopy (PALS). This result suggests a lower packing efficiency of the PVA chain and the formation of a PVA-MOM interfacial layer. This interfacial layer and the increasing of the mobility of the PVA chain by the presence of the clay reflects also in a decrease of the glass transition temperature; determined by dynamic mechanical analysis. © 2007 Elsevier Ltd. All rights reserved;

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摘要：

Journal article (JA)

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页码：4882 / 4890