Unprecedented Nonflammable Organic Adhesives Leading to Fireproof Wood Products

We
report an excellent water-based inflammable organic wood adhesive
that is able to protect wood products from burning by generating inflammable
gases, a porous thick char layer, and radicals that consume the oxygen
and hydrogen radicals required in the burning process. The organic
adhesive is obtained by the formation of hard supramolecular phases
composed of high-density flame-retardant N and P elements through
hydrogen bonding and acid–base interaction between the phytic
acid and branched polyethylenimine (b-PEI). The phytic acid molecules
are packed densely in the framework of the flexible b-PEI so that
a porous char layer that would reduce heat conduction can be formed
as the adhesive is heated. Together with the formation of inflammable
NH3 gas to dilute the oxygen concentration and a PO• radical to capture the H• and O• radicals, the adhesive-treated wood product displays
an extremely high limited oxygen index of 100% and a negligible heat
release rate, total heat release, and total smoke release. The current
flame-retardant water-based organic adhesive is so far the best adhesive
for green and safe wood products from burning.