Three‐arm poly (ε‐caprolactone) by extrusion polymerization

Three‐arm poly (ε‐caprolactone, reactive extruded) (REX‐PCL) polymer was continuously produced using a twin‐screw extruder with aluminum tri‐sec butoxide (ATSB) initiator in residence times of less than five minutes. Monomer conversions in excess of 95% were achieved, and high molecular weight PCL was produced. The number average molecular weight of each arm of REX‐PCL ranged from 30,000 to 200,000 g/mol. A screw configuration comprising entirely of conveying elements was most effective in the extrusion polymerization process. The REX‐PCL polymer was characterized using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and intrinsic viscosity measurements. POLYM. ENG. SCI. 46:235–240, 2006.