Novel azaphosphorine flame retardant for epoxy resins

The P–C–N bond containing azaphosphorine, 5-(4-hydroxy)anilinomethyl-1,3-di(4-hydroxy)phenyl-1,3,5-diazaphosphorinane (ADDPP-OH), which could be used as co-curing and flame-retarding agent for epoxy resins (EPs) was characterised.

Compact appearance

Compared with the pure epoxy resins, the ADDPP-OH-EP composites showed increased decomposition temperatures and char yields. When the content of ADDPP-OH was 10 wt%, the cured composites possessed a limiting oxygen index value of 33.7% and passed the V-0 rating of the UL-94 test. The mechanical properties were improved because of the increased crosslinking density. In addition, the morphology of the residual char indicated an intumescent and multiporous structure in the inner space and a compact and continual appearance in the outer layer; this was important in preventing the materials from burning further.

The study is published in: Applied Polymer Science, Volume 135, Issue 9, March 5, 2018.