Evaluation and comparison of analytical methods for monitoring polymer depolymerization: application to poly(bisphenol A carbonate) methanolysis.

The enhancement of polymer depolymerization represents a significant challenge to reduce the environmental impact of plastic pollution and the utilization of raw materials. Recently, there has been a demand to optimize degradation analysis approaches, which have been observed to be sometimes used inappropriately or incompletely. This article proposes an analysis strategy for monitoring the depolymerization of poly(bisphenol A carbonate) (PBPAC), using methanolysis as model method. It is based on five analytical methods, which our study attempts to combine and compare according to their ideal use case: size exclusion chromatography, liquid chromatography and FT-IR, NMR and MALDI-TOF spectroscopy. This strategy allows for both a qualitative approach to be taken, whereby the depolymerization products can be identified, along with a quantitative one, whereby the percentages of polymer degradation can be determined. As a result, the range of applications for each method is assessed, and a guide to the minimum methods to be used to qualify and quantify degradation is proposed, in relation to the progress of degradation and the yields obtained. This has enabled us to characterize and propose a new quantitative FT-IR based methodology, compatible with high-throughput screening, to the degradation of PBPAC, allowing to quantify degradation from 10 % onwards.