Cellulose Micro/Nanocrystals Reinforced Polyurethanes

MARCOVICH, NORMA E.; AUAD, MARÍA L.; BELLESI, NATALIA E.; NUTT, STEVE; ARANGUREN, MIRTA I.

JOURNAL OF MATERIALS RESEARCH

MATERIALS RESEARCH SOC

Año: 2006 vol. 21 p. 870 - 881

0884-2914

Cellulose crystals in the nano/micron size were prepared and utilized as reinforcements for polyurethane composites. The cellulose crystals obtained from microcrystalline cellulose (MCC) were incorporated into a polar organic solvent, dimethylformamide (DMF) and ultrasonicated to obtain a stable suspension. The suspension was an effective means for incorporating the cellulose crystals into the polyol-isocyanate mixture, utilized to produce polyurethane composite films. It is considered that the use of DMF presents an interesting alternative for the use of cellulose crystals as reinforcement of a broad new range of polymers. Moreover, the rheology of the uncured liquid suspensions was investigated and the analysis of the results indicated the formation of a filler structure pervading the liquid suspension. Besides, films were prepared by casting and thermal curing of the stable suspensions. Thermo-mechanical and mechanical testing of the films were carried out to analyze the performance of the composites. The results indicated that a strong filler-matrix interaction was developed during curing as a result of a chemical reaction occurring between the crystals and the isocyanate component. Keywords: cellulose crystals, nanocomposites, interfacial interaction, suspension rheology.