REENTRANT TRANSFORMATION-METHODS IN CLOSED CELL FOAMS

Open-cell foams have been transformed in prior studies, to a re-entran t (inward bulging) cell structure which gives rise to a negative Poiss on's ratio. Different methods were used for polymer foams with and wit hout a softening point. In this study, methods based on air pressure w ere developed for the transformation of closed cell polymer foams. Low density polyethylene foam was successfully transformed, however polym ethacrylimide foam was densified without transformation.