Microstructural Analysis of Benzoxazine Cationic Ring-Opening Polymerization Pathways.

This paper presents an evaluation of the initial step of benzoxazine polymerization by mass spectrometry, with a focus on differentiating the phenoxy and phenolic products formed by distinct pathways of the cationic ring opening polymerization mechanism (ROP) of polybenzoxazine formation. The use of Infrared Multiple Photon Dissociation (IRMPD) and ion mobility spectrometry (IMS) techniques allows for differentiation of the two pathways and provides valuable insights into the ROP mechanism. The results suggest that the type I pathway is favored in the initial stages of the reaction yielding the phenoxy product, while the type II pathway should be observed at later stages when the phenoxy product would interconvert to the most stable type II phenolic product. Overall, the findings presented in this paper provide important information on the initial step of the benzoxazine polymerization, allowing the development of optimal polymerization conditions and represents a way to evaluate other multifunctional polymerization processes. This article is protected by copyright. All rights reserved.