Synthesis, characterization and application of surface active initiators

Abstract

Abstract Surface active azo initiators have been synthesized starting from 2,2′‐azoisobutyronitrile (AIBN) and different a, o‐diols. Values of the production rate of free radicals from these initiators (2fkd) were obtained from ESR investigations of initiator solutions with a spin labelling technique as well as from solution polymerization of acrylonitrile and from emulsion polymerization of vinyl chloride under monomer starved conditions. The 2fkd values from the polymerization experiments were higher than those from the ESR investigations. Furthermore, the results show an influence on the kinetic constants and latex properties of the initiator structure. The emulsion polymerization of styrene was investigated at temperatures from ambient to 373 K with different initiator‐emulsifier systems (IES) including persulphate, AIBN and surface active initiators. From these data were obtained Arrhenius plots for the mean degree of polymerization (DP) and for the particle number (N ), and overall activation energies were estimated. These activation energies show a strong dependence on the IES employed.