Synthesis, flame retardancy, and thermal degradation behaviors of novel organo-phosphorus compounds derived from 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO)
A
series of novel organo-phosphorus compounds was synthesized from
9,10-dihydro-9-oxa-10-phosphaphenanthrene- 10-oxide (DOPO) in an attempt
to obtain high phosphorus (P) containing halogen-free flame retardant
(FR). The success of synthesis was confirmed by 1H and 31P NMR spectra.
The P content of FR varied from 12.95 to 19.22 wt%. Thermal stabilities
of synthesized FRs and their flame retardancy for
Acrylonitrile-Butadiene- Styrene copolymer (ABS) were investigated by
thermal gravimetric analysis (TGA) and the classification of UL-94 V-0
rating, respectively. 27.5-30.0 wt% FR loadings gave the V-0 rating for
the ABS/FR mixtures and no fume emission was observed. It was found that
the flame retardancy strongly depends on the P content of FR and
5.03-5.30 wt% P is required in the formulation to exhibit
self-extinguishing ability when phosphinate or phosphonate FRs are
employed. The mode of flame retardancy action is also discussed.
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