Solid state polymerization process for foamed poly(ethylene naphthalate)

摘要

A porous for making a high M.wt. solid state polymerised poly(ethylene naphthalate) (PEN) foam comprises (a) dispersing a inert gas into molten PEN of intrinsic viscosity I.V. 0.25-0.55 dl/g to form a foamed PEN with a void fraction of 0.10 to 0.50; (b) forming the foamed PEN into granules; (c) devolatilising the PEN granules at 80-140[deg]C; (d) crystallising th devolatilised PEN at 150-260[deg]C; and (e) solid state polymerising the crystallised PEN at 210-265[deg]C.