Cationic polymerization of α-methylstyrene catalyzed by boron trifluoride etherate in 1,2-dichloroethane under an electric field

The cationic polymerization of α-methylstyrene with boron trifluoride etherate was studied in 1,2-dichloroethane under an electric field. The electric field was again found to increase the polymerization rate. This field effect was independent of monomer concentration, as was found previously. The effect, however, became greater as the catalyst concentration was lowered, unlike previous findings with various cationic systems. Furthermore, the field effect became smaller with rising temperature, whereas it had been practically independent of temperature in previous studies. The field effect increased linearly with the field strength. At 2.7 kv./cm. the rate was almost tripled. The field effect was small at lower dielectric constants, as had been observed previously. The large field effects observed and their “exceptional” behavior led to the interpretation that “partial” desolvation of free, growing chain ends, in addition to the field-facilitated dissociation, was responsible for the effect. Specific conductivities of polymerizing solutions and catalyst solutions were measured and are discussed.