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

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

RATIONALE

Synthesis of copolymer is one of the major approaches to establish sophisticated polymers. In copolymer analysis in mass spectrometry (MS), an increase in the number of monomer unit species and/or the polymer molecular weight results in complex mass spectra, and a method is required to solve this problem.

METHODS

In this study, electrospray ionization-ion mobility spectrometry-mass spectrometry was employed to analyze styrene/methyl methacrylate/n-butyl acrylate (St/MMA/nBA) terpolymers via Kendrick mass defect (KMD) analysis. An expanded Fourier transform-based noise reduction method for the copolymer was developed to improve the decrease in the signal/noise ratio observed in the higher m/z region.

RESULTS

Low-mass terpolymers (0.7 kDa) were identified by comparing the observed and theoretical results using a two-dimensional KMD plot. For the 1.5 kDa terpolymer, the signal overlap, of which KMD value was not matched with the theoretical one, was interpreted by the shift from the theoretical value in the KMD plot. For the 3.0 kDa terpolymers, the compositional candidates were determined by the prediction based on the compositional information of low-mass terpolymers previously analyzed. The 4.5 kDa terpolymer was interpreted after the expanded noise filtering.

CONCLUSIONS

The terpolymers, whose molecular weight was up to 4.5 kDa, were successfully characterized at a molecular level. The dependency of the St/MMA/nBA composition on molecular weight was observed; that is, the nBA content decreased with an increase in the molecular weight.

Latest Trends in Pyrolysis Gas Chromatography for Analytical and Applied Pyrolysis of Plastics

Pyrolysis is considered to be a promising method for polymer characterization (in the field of analytical pyrolysis) and for chemical feedstock recovery from plastic wastes (in the field of applied pyrolysis) because it can decompose any polymeric material into smaller molecules by applying heat alone in an inert atmosphere. Pyrolysis-gas chromatography (Py-GC) involves pyrolyzing polymeric materials in a micropyrolyzer and a subsequent direct GC analysis of pyrolyzates. Py-GC has immense potential for applications in the fields of both analytical and applied pyrolysis, as it allows for rapid and accurate analysis of pyrolyzates. This is beneficial for elucidating microstructure and composition of polymers and for a rapid screening of pyrolysis conditions for designing feedstock recycling processes. In this review, we examined the latest research trends in Py-GC applications for polymer characterization, analysis of plastics in the environment, and chemical feedstock recovery from plastics.