Moisture Absorption and Mechanical Properties Characterization of Polyurethane Foams with and without Nanoclay

摘要

Polyurethane foam with its high modulus to weight ratio has the potential to replace conventional materials in the structural field. Of particular significance is the use of these cellular materials in water borne applications. In the light of the recent advancement in nanotechnology, it has been necessary to evaluate and understand the capabilities of nanoparticles to act as competent fillers for such applications. The present study investigates the moisture absorption behavior of both neat and nanoclay infused polyurethane foams. The effect of specimen thickness, cell orientation, exposed surface area are also examined. The effect of moisture on compression properties of neat and nanophased polyurethane foam was also studied. The moisture behavior was evaluated based on diffusion coefficient and moisture content at saturation, and the post-moisture behavior was examined based on compression strength and modulus. Microstructural stuides showed that the average cell dimension of the neat foam is larger in the case of flow direction as compared to the rise direction. The addition of modified nanoclay platelets reduced the cell size. It was found that the specimen thickness has negligible effects on moisture behavior whereas the cell orientation and the exposed surface area have significant effect. The addition of modified nanoclay to the foam increased both the saturation mass as well as the diffusion coefficient. The compressive properties were significantly reduced by the addition of modified nanoclay. The presence of water molecules decreased the compressive properties of both the neat and the modified nanoclay infused foams, however the degradation effect was found to be lower in the case of nanoclay infused foams.