Comonomer reactivity ratios are important parameters for understanding and controlling both copolymer microstructure and product uniformity. Traditional batch approaches to determine reactivity ratios are labor intensive. We have designed a continuous flow system to improve the accuracy and reproducibility of determining reactivity ratios while minimizing the required experimental effort. This novel system utilizes three benefits of continuous flow chemistry: i) the precise control of reaction time, ii) the improved heat transfer, and iii) the ability to dynamically alter continuous variables within a single experiment. The result is a flow system that produces nine unique copolymer samples reacted to low conversions with varied comonomer compositions in under one hour. These copolymer samples can be fit to a model of terminal copolymerization to provide accurate estimates of comonomer reactivity ratios. The continuous-flow system was validated by experimental determination of eight different comonomer reactivity ratios that provided good agreement with literature values. This presentation will discuss this flow system and its ability to streamline the determination of especially challenging comonomer systems, such as those with fast kinetics or disparate reactivity. I will also detail our current efforts determining the reactivity ratios of previously uncharacterized comonomer pairs for applied efforts in sustainable polymers and biomedical imaging.

Continuous-flow chemistry for the determination of comonomer reactivity ratios

2019 Fall National Meeting

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