A process to form an olefin-based polymer, said process comprising at least the following steps: a) polymerizing a reaction mixture comprising an olefin, in at least one reactor, in a solution polymerization, to form a polymer solution; b) feeding at least a portion of the polymer solution through at least one devolatilizer, to form the olefin-based polymer, in melt form; c) feeding at least a portion of the olefin-based polymer, in melt, form through a heat exchanger, and then into a pastillation apparatus to form polymer particles.