Taking the Next Step-Model-Based Analysis of Robust and Non-Toxic Zn Catalysts for the Ring Opening Polymerization of Lactide in the Polymer Melt

In the field of bioplastics, complete kinetic models are rare but needed for industrial scale-up. Herein, a complete kinetic model is developed to describe the behavior of robust and nontoxic guanidine carboxy Zn complexes in the lab-scale ring opening polymerization (ROP) of l-lactide, mimicking industrial melt polymerization in the presence of a co-initiator. The model includes inter- and intramolecular transesterification and random chain scission, considering the single site activity of the studied catalyst class, based upon the "asme"-ligand already established in lactide ROP. This allows for the description of reaction rate constants and the prediction of conversion as well as molar mass and dispersity of the obtained polymer. It is further shown that the model can be applied to describe the same characteristics for the faster, next generation catalysts based on the archetype "asme" catalyst. This lays the foundation for a faster catalyst design, targeting the needs of industry in developing fast and nontoxic alternatives for the industrially used toxic ROP catalyst Sn octanoate, bridging the gap between academia and industry.