EUCALYPTUS CELLULOSE MICRO/NANOFIBRILS IN EXTRUDED FIBER-CEMENT COMPOSITES

ABSTRACT

Extrusion is an alternative process for fiber-cement production and allows many advantages such as different geometries for the extruded products and the low initial investment for industrial production. In this context the aim of this study was to produce cellulose micro/nanofibrils from Eucalyptus pulp and evaluate the properties of cementitious composites made with different contents of cellulose micro/nanofibrils. Cellulose micro/ nanofibrils were produced using a mechanical defibrillator, and characterized for their morphology. Extruded composites were produced with 0.5 to 1.0% (by mass) of micro/ nanofibrils and compared to unreinforced composites. Composites reinforced with 1.0% of micro/nanofibrils presented higher water absorption and apparent porosity than their counter parts. No significant differences were observed for modulus of rupture (MOR), limit of proportionality (LOP) and final specific deformation, between the composites reinforced with 0.5% and 1.0% of micro/nanofibrils and those with no reinforcement. The static elastic modulus (MOE) increased and specific energy decreased with the inclusion of 1.0% of micro/nanofibrils. Dynamic elastic modulus (E) of the composites increased with the increase of micro/nanofibrils content and of weathering exposition. This study indicates that fiber-cements are sensitive to changes in structural composition and time of ageing (135 days). This information can be useful for developing of new products based on cellulose micro/nanofibrils.

Keywords:
Vegetable nanofibers; Dynamic elastic modulus; Natural frequencies of vibration; Durability