Poly(lactic acid) or Poly(Lactide) (PLA) has been extensively used both in food packaging and in biomedical applications. In fact this material is a thermoplastic polyester, which is compostable and so it can be used as an alternative to PET for food applications. Moreover it is a biocompatible and bio absorbable material and for this reason is used in biomedical area. It can be used with hydroxyl apatite for the production of composite materials used as scaffolds in bone tissue engineering, or as drug delivery system. In this work bulk melt ring-opening-polymerization (ROP) of L-Lactide (cyclic dimer of lactic acid) has been studied. Starting from the kinetic scheme developed by (Yu et al., 2011) an isothermal model has been developed and validated with experimental data obtained in laboratory. Once kinetic constants were evaluated, a complete model of a batch reactor for PLA production for biomedical applications has been developed. Finally a PI temperature control has been implemented on the reactor, in order to satisfy process targets (MW of 100[kDa] and conversion of 95%) in the shortest possible time period.