FTIR and NMR characterization of thermosetting methyl methacrylate terminated poly(2,6-dimethyl-1,4-phenylene oxide)—triallyl isocyanurate copolymer

Thermosetting Polyphenylene oxide (PPO)/Triallyl isocyanurate (TAIC) based composite systems have attracted considerable attentions in recent years due to their excellent performance as the substrate for printed circuit boards (PCBs) used for 5G networks. Since the residuals of -OH and -C = C- groups have significant effects on the properties of the substrate, especially the dielectric properties and thermal stability, it is critical to establish valid methods for characterizing these systems. In this work, FTIR, 1 H-NMR and 13 C-SSNMR were employed to qualitatively and quantitatively characterize the -OH and -C = C- groups in the methyl methacrylate (MMA) terminated PPO/TAIC co-cured system. No -OH groups were detected on the molecular chains of PPO oligomers, indicating that almost all the phenolic hydroxyl groups in the precursor had been substituted. During the curing, no new -OH groups were generated but some -C = C- groups were left unreacted. FTIR quantitative analysis showed that these -C = C- groups belonged to TAIC and the residual ratio of -C = C- could be as high as 60.37%.