Characterizing chain‐end structures formed during initiation reactions of radical polymerization for MMA‐St‐BA terpolymer using pyrolysis‐gas chromatography/atmospheric pressure chemical ionization high‐resolution time‐of‐flight mass spectrometry

Abstract

Rationale Analyzing polymer end groups using pyrolysis (Py) gas chromatography/mass spectrometry (GC/MS) in multi‐component polymer samples is not an easy task because of the insufficient sensitivity, selectivity, and mass resolution of conventional Py‐GC/MS systems. Methods A new Py‐GC/MS system using an atmospheric pressure chemical ionization (APCI) source combined with high‐resolution time‐of‐flight mass spectrometry (TOFMS) was used for end‐group analysis of a methyl methacrylate (MMA)‐styrene (St)‐butyl acrylate (BA) terpolymer (P (MMA‐St‐BA)), which was radically polymerized using 2,2′‐azobis(2‐methylbutyronitrile) (AMBN) as an initiator. Results Five possible pyrolyzates, comprising an AMBN fragment and a monomer unit, formed during the initiation reactions from one of the three types of end groups, were selectively detected and exclusively identified in their respective extracted ion chromatograms for molecule‐related ions, such as M+ and [M + H]+, with a narrow mass window of ±2 milli m/z units. Conclusions It was demonstrated that Py‐APCI‐TOFMS is a powerful technique to characterize in detail the complex end groups in multi‐component polymer samples, because of the soft ionization nature of APCI and the high mass resolution of TOFMS.

Characterization of styrene/methyl methacrylate/n‐butyl acrylate terpolymer with Kendrick mass defect analysis in electrospray ionization‐ion mobility spectrometry‐mass spectrometry

“…The St/MMA/nBA random terpolymer was synthesized by radical polymerization using 2,2′‐azobis(2‐methylbutyronitrile) (AMBN) as the initiator 21 . The chemical structures of the terpolymer characterized in this study are shown in Figure 1.…”

“…The St/MMA/nBA random terpolymer was synthesized by radical polymerization using 2,2 0 -azobis(2-methylbutyronitrile) (AMBN) as the initiator. 21 The chemical structures of the terpolymer characterized in this study are shown in Figure 1. The reaction schemes including termination reactions (recombination and disproportionation) are shown in Figure S1 (supporting information).…”