Highly thermally stable copolymers of epoxy and trifunctional polybenzoxazine

• Published in: Materials today communications 2021-11, Vol.30
• Main Authors: de Souza, Lucio Rossi, d’Almeida, José Roberto M., Cheng, Xiang, Rong, Li-Han, Caldona, Eugene B., Advincula, Rigoberto C.
• Format: Article
• Language: English
• Subjects: Benzoxazine; Copolymers; Epoxy; High temperature; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Thermal stability; Thermosets
• ISSN: 2352-4928; 2352-4928

Here, in this work, we report the copolymerization of a triamine-based benzoxazine and a commercial difunctional epoxy resin, and investigate their synergistic effect on improved thermal properties using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Results showed that a glass transition temperature increase of up to 268 °C was obtained for the copolymer with as low as 25 wt% epoxy. A higher thermal performance was also achieved with an onset degradation of nearly 400 °C and char yield of 39 wt% at 800 °C for the copolymer with 52 wt% epoxy. The behavior was compared to previously reported benzoxazine/epoxy combinations and was found to be advantageous. The curing behavior of different copolymer compositions was also investigated via DSC and a methodology for matching each peak with its corresponding reaction was developed. Results showed that the alternating favorability of the reactions was dependent on the benzoxazine/epoxy ratio. Overall, the prepared PBZ/epoxy copolymers displayed higher thermal stability than their individual components, indicating suitability for a number of potential extended uses including utility in higher temperature applications.