Synthesis and Application Studies of DOPO-Based Organophosphorous Derivatives to Modify the Thermal Behavior of Polybenzoxazine

Thorben Sören Haubold; Andreas Hartwig; Katharina Koschek

doi:10.3390/polym14030606

Synthesis and Application Studies of DOPO-Based Organophosphorous Derivatives to Modify the Thermal Behavior of Polybenzoxazine

Polymers (Basel). 2022 Feb 3;14(3):606. doi: 10.3390/polym14030606.

Authors

Thorben Sören Haubold^{1

2}, Andreas Hartwig^{1

2}, Katharina Koschek¹

Affiliations

¹ Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Wiener Strasse 12, 28359 Bremen, Germany.
² Department 2 Biology/Chemistry, University of Bremen, Leobener Strasse 7, 28359 Bremen, Germany.

Abstract

The DOPO-based flame-retardant additives DOPO-HQ, DOPO-AP and DOPO-Van were synthesized in varying numbers of phenolic hydroxyl groups and amine groups. Moreover, their influence on the polymerization of a bisphenol F-based benzoxazine, as well as the thermal properties of the resulting materials, were studied. All DOPO-based derivatives influenced the polymerization temperature onset with a reduction of up to 20 °C, while thermo-mechanical properties remained high. Surprisingly, phosphorous content below 0.4 wt% significantly improved the reaction against small flames yielding an increase in the limited oxygen index by 2% and a V-0 rating in the UL-94 test. DOPO-HQ proved to be the most effective additive regarding the reaction against small flames at an astonishingly low phosphorous concentration of below 0.1 wt%, whereas DOPO-AP and DOPO-Van simultaneously lowered the polymerization temperature.

Keywords: DOPO; UL-94 test; benzoxazine; halogen-free flame retardant.