An investigation of polyamide 6 and 12 synthesis in an oscillatory baffled reactor
Laska, Ross David Frank
MetadataShow full item record
This work focuses on the investigation of the synthesis of polyamide-12 (PA-12) particles in an oscillatory baffled reactor (OBR) and was funded by Polymer Technology Ltd (PTL). Despite considerable usage in industry, there is very little information available for both synthesis and reaction kinetics of PA-12 synthesis. As a result, the initial effort was directed to the study and the understanding of reaction kinetics and parameters affecting kinetics for the PA-6 synthesis, a sister reaction, for which there are some literature and recipes on public domain. For the PA-6 reaction, the effects of various operational conditions on molecular weight, particle size and melting point were investigated using the design of experiment (DOE) technique. The results of the DOE studies indicated that temperature, the rate of chain initiator injection and agitation speed had the most influence over specifications of PA-6 particles. A new method for measuring reactant concentration by FTIR was devised, allowing reaction kinetics to be extracted. By switching from a batch to a semi-continuous reactor, the reaction order could change from 1st to zeroth, depending on the injection rate and reaction temperature. The biggest deviation from batch conditions was that monomer to catalyst ratio in the semicontinuous reactor did not have any effect over polymer properties. From the learning of PA-6 synthesis, the PA-12 recipe was formulated and tested. By using continuous injection of the chain initiator and by adding small amounts of caprolactam and N, N-Ethylene bis(stearamide), PA-12 particles were successfully synthesised. As with PA-6, reaction temperature, injection rate and stirring rate had a strong influence over PA-12 particle properties. However, while increasing the injection rate lead to an increase in the size of PA-12 particles it caused PA-6 particles to decrease in size. Provided that the reaction recipe can be developed further to stop the build-up of material between baffle columns the next steps would be study the reaction under continuous conditions.