End-group analysis of polycarbonates using evolved gas analysis-time-of-flight mass spectrometry combining principal component analysis and Kendrick mass defect analysis

Abstract

This paper introduces a novel method that uses evolved gas analysis with time-of-flight mass spectrometry coupled with field ionization (EGA-FI-TOFMS) to analyze the end-group structures of polycarbonate. To validate the analytical method, polycarbonates featuring two different types of end groups—tert-butylphenol and cumyl phenol—were analyzed. A data mining technique combining principal component analysis (PCA) and Kendrick mass defect (KMD) analysis was applied to the temperature-dependent mass spectra obtained from EGA-FI-TOFMS to extract key mass information related to specific evolved products arising from the end-group structures of the polycarbonate samples. The products derived from the polymer ends were selectively detected during the early stages of pyrolysis because the terminus-derived products resulted from a single cleavage of the polymer chain. The newly developed method, which integrates EGA-FI-TOFMS, PCA, and KMD analysis, provides insights into the end-group structures of polymer materials without requiring prior knowledge. This capability is particularly advantageous for analyzing industrial polymer materials, for which such prior knowledge is often unavailable.