Products Cited in Publications Worldwide High glass transition catalyst-free polybenzoxazine vitrimer through one-pot solventless method

High glass transition catalyst-free polybenzoxazine vitrimer through one-pot solventless method

Anagwu, Festus Ifeanyi; Dossi, Eleftheria; Skordos, Alexandros A

DOI:

Abstract

A high glass transition polybenzoxazine has been synthesised by a one -pot solventless method via the Mannich condensation of a phenolic disulphide, paraformaldehyde and aniline. The solventless process reduces synthesis time, material costs, and the need for post -synthesis purification. The polybenzoxazine exhibits a glass transition temperature (Tg) of 155°C and thermosetting behaviour below this temperature. Dynamic disulphide bond metathesis associated with a topological freezing temperature of 78°C and an activation energy of 127 kJ/mol delivers vitrimeric functionality with fast, catalyst -free stress relaxation above Tg. This material fully relaxes stress within 5 seconds at 190°C, with thermal degradation beginning above 250°C. It exhibits a glassy modulus of 3.6 GPa, high char yield (57.4%) translating to a high limiting oxygen index (LOI) of 40.5% and excellent environmental resistance, as evidenced by low water uptake (1.4%) after immersion at 75°C for 31 days. The combination of environmental resistance, due to thermosetting character, high glass transition, facile synthesis, high char yield, good processability, and fast stress relaxation position this polybenzoxazine as a promising candidate matrix system for repairable aerospace thermosetting continuous fibre composites.

Keywords

Polybenzoxazine ; vitrimer ; aerospace ; composites

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Elastase-IN-3

A18350215015-57-398%

Elastase-IN-3

70.0/25g

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