Absorbable poly(p-dioxanone) pellets made from slow-to-crystallize ground resin and its fines

A process for making uniform poly-para-dioxanone (PDS) pellets from a PDS material having non-sieved fines comprising:

• a) Polymerizing dioxanone monomers in a vessel under an elevated temperature to generate polymer chains of PDS materials in molten form;
• b) Discharging the molten PDS materials from the reaction vessel into one or more containers within a second reaction vessel for sufficient time and under appropriate temperature and pressure conditions to cause said PDS material to increase molecular weight via solid state polymerization;
• c) Grinding said solid PDS material into a PDS material comprising large granules of PDS and PDS fines;
• d) Feeding said PDS material comprising large granules of PDS and PDS fines into an inlet of an extruder having a cylindrical barrel with one or more screw, at least one outlet and a plurality of temperature zones arranged sequentially along the length of the cylindrical barrel from the inlet to the at least one outlet;
• e) Heating the PDS material within the extruder to form a flowable PDS mass,
• f) Conveying said PDS mass along the length of said cylindrical barrel by action of the screw to produce a PDS extrudate in the form of a rod or filament,
• Wherein in the sequential measurable temperature zones along the length of the cylindrical barrel, the PDS mass is subjected to sufficient energy to produce an inverted temperature profile as having a highest measurable temperature in the vicinity of the inlet and a lowest measurable temperature at the die, with each of the remaining sequential measurable temperatures zones having steadily decreasing measurable temperatures from the highest measurable temperature zone to the lowest measurable temperature zone,
• g) Quenching the PDS extrudate after extrusion from the outlet by either air cooling or in a water bath;
• h) Cutting the quenched PDS extrudate material to produce uniform PDS pellets.