THE MULTI-SCALAR EFFECT OF INCORPORATING NANOFILLERS AND CELLULOSIC-BASED REINFORCEMENTS INTO POLYURETHANE FOAMS: TOWARDS THE DEVELOPMENT OF LOW COST STRUCTURAL LIGHTWEIGHT MATERIALS

摘要

In the present work polyurethane foams containing different low cost cellulosic-based reinforcements and variable concentrations of a silicate-layered nanoclay were prepared and characterized, with the objective of developing multi-scalar rigid foams for structural applications. The incorporation of an organically-modified nanoclay, though promoted the formation of foams with finer and more homogeneous cellular structures, also contributed to important density reductions, globally resulting in foams with lower compressive elastic moduli and collapse stresses when compared to the unfilled ones. On the other hand, the addition of the macroscopic cellulosic-based materials led to foams with similar collapse strengths as the unfilled PUR foams even at lower relative densities, demonstrating their effectiveness as mechanical reinforcements of rigid PUR foams and opening up new possibilities in terms of developing low cost lightweight materials.