The Bayesian design approach is an experimental design technique which has many advantages over standard experimental designs. It incorporates prior knowledge about the process into the design to suggest a set of future experiments in an optimal, sequential, and iterative fashion. Since for many complex polymerizations prior information is available, either in the form of experimental data or mathematical models, the use of Bayesian design methodology could be beneficial. Exploiting this technique in complex polymerizations could hopefully lead to optimal performance in fewer trials, thus saving time and money. Advantages of the Bayesian design approach are illustrated via case studies drawn from the nitroxide-mediated radical polymerization as an example. However, since this technique is perfectly general, it can be potentially applied to other polymerization variants.
IntroductionFor many complex polymerizations some sort of experimental information might be available (even in preliminary form) either from industrial or exploratory laboratory work. In addition, mathematical models (of different level of detail, empirical, or semi-mechanistic) usually do exist, albeit with unreliable and/or highly correlated parameters and sometimes even unverified mechanistic bases. Hence, ideas from the modelbased design of experiments applied as early as possible (in the design/brainstorming stage) can be very beneficial for the clarification of polymerization kinetics.Standard experimental design methods, e.g., (fractional) factorial designs, have been employed extensively and are useful in optimizing a wide variety of systems. However, these designs usually suffer from several limitations and cannot handle certain situations, as listed in Tab. 1. In addition, these approaches do not take direct advantage of the considerable prior knowledge that is available about the reaction system to design experiments. As prior information is already available within existing data, it is logical that it should be used in order to contribute to the optimality of the designed experiments, and hence to improved models and performance of the process in question.Although some of the issues with standard designs cited in Tab. 1 have solutions, these are usually known only to experts in the design of experiments. Hence, it often happens that the practicing scientist or engineer is not aware of the solutions, cannot easily handle the issues faced, and gives up on the use of statistical designs altogether. Using more efficient experimental designs which can accommodate these restrictions could lead to optimal performance in fewer trials, thus saving time and money.Such efficient designs can be found in the family of Bayesian approaches. The Bayesian design is a powerful and in the poly- [9]. The common characteristic of all these Bayesian framework applications (including the ones mentioned above as well as others from the scientific literature not cited herein for the sake of brevity), to a split of about 7 or 8 to 2, is that they are concern...