Out-of-plane Poisson's ratios of paper and paperboard

The deformation of a test piece under a uniaxial load is in general three-dimensional. This means that the test piece deforms not only in the direction of loading but also in directions perpendicular to this direction. This is known as the Poisson effect, which is quantified by Poisson's ratios. In this paper, a new device for measuring out-of-plane Poisson's ratios for a paper material is presented. The general trend, for a variety of paper and paperboard grades is that the thickness increased when the paper was subjected to tensile straining in an in-plane direction resulting in negative Poisson's ratios.