The polymerisation of acrylonitrile

In part I of this thesis, the kinetics of the photoinitiated polymerisation of acrylonitrile, in bulk, in a precipitating medium, and in solution, have been studied and compared. Polyacrylonitrile is insoluble in the monomer and the precipitating medium consisted of appropriate mixtures of acrylonitrile (AN) and dimethylformamide (DMF). At higher molar ratios of DMF:AN, the polymer produced remained in solution. a,c0-azo-bis-iso-butyronitrile was used as the photosensitiser in all cases. The rate dependences on monomer and initiator were found. For solution polymerisation, the following rate relationship was found to hold up to 10% conversion: Rate K [c]0.5 [M]1.0 (1) where K is a constant of proportionality, [C] is the concentration of the initiator, and [M] is the monomer concentration. Two separate rate relationships were found for the bulk polymerisation. In the very early stages of the reaction, the kinetic scheme approximated closely to that shown in equation (1). At later stages of the reaction, the following relationship was obtained: Rate K [C]0.56 - 0.65 [M]~2.5 (2) The initiator exponent was found by using AIBN as a thermal initiator at 6