A bifurcation analysis for continuous nonlinear free-radical polymerization subject to gel formation is presented. The analysis uses the Numerical Fractionation technique and studies the multiplicity and dynamics of the sol and gel polymer properties for bulk, nonisothermal, vinyl-divinyl copolymerization. The bifurcation analysis has revealed s-shape, mushroom, and isola-type multiplicity structures; multiple critical gel transitions; and interesting dynamics for the system investigated.