Highly Improved Thermal Properties of Hydroxyl-Containing Polymers via Modification by Benzoxazine Groups

Isocyanate functional benzoxazine (NCO-4HBA-a) is used for coupling with hydroxyl-group-containing molecules. Glycerol is used in a model reaction to study the urethane bonds formed between the NCO-4HBA-a and the glycerol's hydroxyl groups. The model supports a reaction between NCO-4HBA-a and poly(vinyl alcohol) (PVA), which leads to an improved char yield, determined by thermogravimetric analysis. Glycerol-based benzoxazine is also an attractive benzoxazine synthesized from the products of biofuel production. Upon functionalization with benzoxazine and subsequent thermal treatment, the hydroxyl-containing polymer gains thermal stability shown by improved char yield of polybenzoxazine cross-linked PVA.