Maleic anhydride has been homopolymerized, contrary to accepted beliefs. Polymerization of either molten or dissolved monomer was initiated with the use of gammaradiation and free‐radical initiators. An anhydride having [η] = 0.146 dl./g. in acetophenone had a molecular weight of 23,100 (free acid), DP = 199, by the light‐scattering method. The carboxyl group propinquity is responsible for peculiar behavior of aqueous solutions of salts of the poly‐acid.

S31tween Flory's and Hermans' equations cannot be made a t this time as a result of this work. The wide rurrent discussions on the theory of network ~t r u c t u r e s~-~ indicate that a rigorous analysis of this very complex problem must await further experimental data on numerous other polymer systems.