Compound structure and mechanical properties ofthe natural polymeric cellular materials

The compressive yield st ress and modulus of the two natural foam cores of kaoliang stem and corn stemwere tested. Their st ructures and morphologies were determined by scanning elect ron microscope. The differentcompressive deformation mechanics of the foams were discussed. A compound st ructure model made up of hexangular prisms and tubular cells was established f rom the observation on scanning elect ron microscope photographs. Theeffect s of the compound st ructure of the foams on their mechanical properties were studied on the basis of the model.The result s show that the compressive yield st ress and modulus of the two natural foam cores in the axial directionare more than 4 times of those in the radial direction. The compound st ructure of the foams reinforced by the tubularcells has more significant effect s on the corresponding mechanical properties of the foams. The axial compressivemodulus of a tubular cell is 105 times that of an abnormal hexangular prism cell.