Dynamic mechanical properties of paper: effect of density and drying restraints

摘要: The tensile dynamic mechanical properties of paper sheets with densities between 300 and 1000 kg m−3 have been measured at room temperature in the frequency range 0.1 to 10 Hz. Two series investigated; one which had restrained during drying other allowed shrink freely. In general, was found be a non-linear viscoelastic material. modulus decreased loss factor increased as strain amplitude applied sinusoidal deformation increased. character more pronounced lower sheet densities. strongly increasing density always higher for that drying. were anisotropic ratio machine direction (MD) cross-direction (CD) order 2 3.5 depending on conditions. (extrapolated zero amplitude) CD than MD. freely dried characterized by value factor, tan δ, It is suggested influence restraints dynamica associated interfibre friction and/or bending shearing cellulose fibres.