Design and optimisation of a microwave reactor for kilo-scale polymer synthesis

Current industrial production of polymer resins is generally undertaken in large multi-tonne stirred tank reactors. These are characterised by relatively slow heating and cooling cycles, resulting in long vessel cycle times and extended production campaigns. In this work we present a design for a hybrid microwave/oil jacket proof of concept system capable of producing up to 4.1 kg of polymer resin per batch. By exploiting rapid volumetric heating effects of microwave energy at 2.45 GHz, we have optimised the synthetic regime, such that a 3.7 kg batch of polyester resin pre-polymer can be made in only 8 h 20 min, with higher molecular weight (M_n 2100) compared to the conventional process taking 22 h 15 min (M_n 1200), yielding an increase in synthesis rate of at least 265%. The increase in polymer molecular weight also suggests a higher conversion was achieved over a shorter time scale.