Thermal degradation of poly(isobornyl acrylate) and its copolymer with poly(methyl methacrylate) via pyrolysis mass spectrometry

In this work, the thermal degradation characteristics of poly(isobornyl acrylate) (PIBA), and its copolymer with PMMA, P(MMA-co-IBA) were investigated via direct pyrolysis mass spectrometry. Thermal degradation behavior of poly(isobornyl methacrylate) (PIBMA) was also studied for a better understanding of thermal degradation mechanism of PIBA. For both PIBA and PIBMA, γ-H transfer from the isobornyl ring to the carbonyl group was predominantly effective in thermal degradation. As a consequence of evolution of isoborylene, poly(acrylic acid) was produced. Trans-esterification reactions due to intermolecular interactions lead to evolution of H2O. Upon loses of CO2 and CO crosslinked units with higher thermal stabilities were generated. In case of P(MMA-co-IBA), intermolecular interactions between PIBA and PMMA chains were detected. Based on evolution of methanol, a trans-esterification reaction between the MMA and acrylic acid units generated by loss of isobornylene from PIBA chains was proposed.

► Evolution of isoborylene during the degradation of PIBA generates poly(acrylic acid).
► Poly(acrylic acid) decomposes by trans-esterification reactions eliminating H2O.
► Intermolecular interactions between PIBA and PMMA are effective.