Patent ID: 8207291

Claim:
A process for devolatilization of an aromatic alkylene polymer, which comprises: a) providing the aromatic alkylene polymer product in the form of a mass of polymer melt also comprising aromatic alkylene monomer and oligomers, b) subjecting the mass of polymer melt to a first devolatilization step to produce a gaseous first stream comprising aromatic alkylene monomer and oligomers, and a second stream comprising the remainder of the mass of polymer melt, c) adding water as a stripping agent to the second stream to produce a third stream comprising the remainder of the mass of polymer melt and the water, d) subjecting the third stream to a second devolatilization step to produce a gaseous fourth stream comprising the water, aromatic alkylene monomer and oligomers, and a fifth stream comprising the devolatilized mass of polymer melt, e) subjecting the gaseous fourth stream to a separations step to produce a sixth stream comprising the water and aromatic alkylene monomer and a seventh stream comprising the oligomers, f) subjecting the sixth stream to a separations step to separate an eighth stream comprising the water and a reduced quantities of aromatic alkylene monomer from a ninth stream comprising the remainder of the aromatic alkylene monomer, g) subjecting the eighth stream to azeotropic stripping in a stripping column under vacuum using steam to produce an overheads stream comprising steam and the majority of the aromatic alkylene monomer which is passed with the sixth stream to the separations step (f), and a bottoms stream comprising water with a reduced quantity of aromatic alkylene monomer, at least a portion of which is recycled as the stripping agent in step (c).