Microfibrillated cellulose nanofibers from eucalypt wood: Mechanical extraction and application in starch films

3^rd International Conference and Exhibition on Materials Science & Engineering

October 06-08, 2014 Hilton San Antonio Airport, USA

Reis K C, Ferreira T S, Fonseca J and Tonoli G D

Accepted Abstracts: Material Sci Eng

Abstract :

The effects of addition of eucalyptus microfibrillated cellulose nanofibers on the optical, mechanical, and microstructural properties of corn starch (plasticized with glycerol) films were studied. The microfibrillated cellulose nanofibers were obtained in a grinder by mechanical defibrillation. Starch films with 0%, 1%, 2% and 3% (by wt%) content of microfibrillated cellulose nanofiber were prepared. The starch/nanofiber films exhibited higher transmittance and lower ultraviolet absorption and reflexion. The presence of nanofibers has not showed influence in the transparency and color parameters of the plain starch films. The presence of nanofibers in the starch films increased the puncture strength. The morphology of the fracture surface of the films produced was investigated by SEM. Agglomerates of ghost granules of starch were observedon the cross section of the starch/nanofiber films. These structures are envelopes of gelatinized starch granules remaining after majority of internal starch polymers have been released. Films with 1% and 2% (by wt%) of cellulose nanofibers presented the higher rate of water vapor transmission (WVTR) compared to plain starch film and films with 3% of nanofibers. The lower WVTR for films with 3% of nanofibers is probably consequence of the closed net formed by the nanofibers into the starch film, which turn difficult the permeability of the film. The starch/nanofiber films obtained in this work presents potential to a wide range of applications such as optical instruments, flexible polymer substrates for flexible OLEDs (organic light-emitting diodes), architecture of engineered composites, agricultural uses and food packaging with antimicrobial properties. These studies have been conducted by our research group as well as by other research Brazilian teams.