Abstract
This article describes the copolymerization of methyl vinyl ketone (MVK), methyl acrylate (MA), and methyl methacrylate (MMA) with styrene (St) as reference monomer at 3.4 MPa and 335 K with toluene as solvent. In addition, the effect of pressure on the binary copolymerizations of St‐Ma‐MMA is discussed. It appearsthat in case of conjugated monomers reactivity decreases as the electron‐donating character of the substituents increases, whereas the reverse is found in unconjugated monomers. This is explained by the finding that in conjugated monomers resonance effects induced by polar factors play a dominant role, whereas in unconjugated monomers mainly polar factors are governing the relative reactivities. The r values at 3.4 MPa are compared with those predicted by means of the Q‐e scheme and Patterns. No definite conclusions could be drawn about the applicability and validity of either scheme, although Patterns shows excellent result in case of the H function of Mayo. In vinyl ester copolymerizations and Le Noble and Asano's example of the menshutkin reaction one single factor (polarity and steric hindrance, successively) dominates Δ__G__#, Δ__G__ and Δ__V__#. This allows a straight forward interpretation of the result with the Hammond postulate and is in full agreement with Evan's potential‐energy calculations. In conjugated monomers, however, an interplay of reasonance and polar factors is found. The general validity of these findings needs further experimental and theoretical support.