resumo
The preparation and characterization of new nanocomposite films based on two acrylic emulsions, composed of random copolymers of butyl acrylate and methyl methacrylate, and bacterial cellulose is reported. The new composite materials were obtained through a simple and green approach by casting water-based suspensions of the acrylic emulsions and bacterial cellulose nanofibrils. The excellent compatibility between these matrices and the natural reinforcing fibers, observed by scanning electron microscopy (SEM), was reflected in the enhanced thermal and mechanical properties of the ensuing composites. Thus, an increase of around 30 degrees C in the maximum degradation temperature was observed for a 10% content of bacterial cellulose. The new composites showed glass-rubber transition temperature profiles comparable to those of the pristine matrices, as shown by DMA, and increasing elastic moduli with increasing the bacterial cellulose content. The tensile tests revealed a substantial increase in Young's modulus and tensile strength and a corresponding decrease in elongation at break with increasing bacterial cellulose load. (C) 2010 Elsevier Ltd. All rights reserved.
palavras-chave
OPTICALLY TRANSPARENT COMPOSITES; SURFACE MODIFICATION; FIBERS; WHISKERS; NANOFIBERS
categoria
Materials Science
autores
Trovatti, E; Oliveira, L; Freire, CSR; Silvestre, AJD; Neto, CP; Pinto, JJCC; Gandini, A
nossos autores
Alessandro Gandini
Investigador
Armando Jorge Domingues Silvestre
Professor Catedrático
Carlos Pascoal Neto
Diretor do Raiz
Carmen Sofia da Rocha Freire Barros
Investigador Coordenadoragradecimentos
The authors thank FCT for L. Oliveira's Postdoctoral Research grant (SFRH/BPD/38515/2007) and for the funding within the scope of the