Solventless synthesis of high performance polybenzoxazine using bio-based phenol | Poster Board #1426

Polybenzoxazines are thermoset resins derived from benzoxazine monomers and synthesized using a phenol, a primary amine, and an aldehyde. Due to their superior thermal and chemical stability, high glass transition temperature, high char yield, and a lack of volatile byproducts, polybenzoxazines are desirable materials for components exposed to high temperatures or corrosive chemicals. Unfortunately, current synthesis methods typically employ bisphenol-A as the phenol reagent, which is a chemical known to cause adverse health effects and is an environmental concern because it is manufactured from petroleum resources. To combat the limitations of petroleum-based phenol, this study aims to synthesize high-performance polybenzoxazines at high yield and purity using bio-based phenols such as cardanol, vanillin, and guaiacol instead of petro-based bisphenol-A. These bio-based benzoxazine monomers are synthesized using a solventless Mannich-condensation reaction method in which the bio-based phenol, amine, and paraformaldehyde reagents are combined and allowed to react before extraction and washing steps. This solventless reaction further decreases waste and environmental concerns, as well as simplifies the recovery process. NMR testing proves that benzoxazine monomers can be synthesized from the bio-based phenols at high purity, and FT-IR characterization shows that degradation does not appear during the curing process. Based on these results, the bio-based polybenzoxazine produced in this study should prove to be a more sustainable alternative to petroleum-based polybenzoxazine, mitigate the health hazards of the synthesis process, and retain or potentially improve upon the superior thermomechanical properties of polybenzoxazine.