Anisotropic swelling of rubber: extension of the Flory theory

Abstract The anisotropy of the swelling rubber is examined both theoretically and experimentally. Flory theory extended to account for anisotropic swelling, allowing determination average molecular weight between cross-links with first time. In addition, specimens from five commercial rubbers manufactured using either compression-moulding or sheet-rolling processes are swollen in appropriate organic solvents. Their linear dimensions mass carefully recorded before state, after drying, obtain three ratios which can differ by up 10% within each specimen. Compression-moulded shown be transversely isotropic moulding, whereas rolled exhibit full anisotropy, different all directions. None were found truly isotropic. new applied experimental data determine cross-links, determined as 0.5% larger than value obtained theory.