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A theory of swelling of macromolecular networks at least partially accounting for excluded volume of macromolecules is developed. For tetrafunctional crosslinkages the following relationship results: $$\mathrm{—}[\ln (1\mathrm{—}{v}_2)+v_2+{\chi }_1{v}_2^2]=V_1\frac{\nu }{V_0}\left(\frac{5}{3}{v}_2^{1/3}-\frac{7}{6}{v}_2\right)$$ where ${𝒳}_1$ is the polymer-solvent interaction parameter, $v_2$ the equilibrium volume fraction of polymer in the gel, $V_1$ the molar volume of solvent and $\frac{\nu }{V_0}$ the numer of moles of chains per volume unit.

The theory of rubber elasticity is reformulated on the basis of a statistical distribution of the end-to-end distance partially accounting for intramolecular ecluded volume. The relationship between the uniaxial stress, $\sigma$, and the elongation ratio, $\alpha$, is: $$\sigma =\frac{5}{3}\nu kT\left(\alpha -\frac{1}{{\alpha }^2}\right)-\nu kT\mathrm{\Phi }(\alpha )$$ where $\nu$ is the number of effective chains per unit volume, and $\mathrm{\Phi }(\alpha )$ is a function with a maximum close to $\alpha =2,5$. The elastic modulus for $\alpha =1$ turns out to be 1.27 times the value calculated by the classical Gaussian theory.

A poly-Schiff base consisting of an alternating double bonds chain, having side groups capable of forming complex salts, has been synthesized. Electrical conductivity measurements at room temperature at different times were performed on the original polymer and on its complex salts with Ni, Cu, Co, Cr. It appears that complex salts have an electrical conductivity that is lower by one or two order of magnitude than that of the original polymer. Furthermore the electrical conductivity of both polymer...