DOPO-based aluminum phosphinate

named as DOPO-Al

was synthesized from 10-hydroxy-9-oxa-10- phosphorphenanthrene-10-oxide (DOPO-OH) and aluminum chloride hexahydrate. Its structure was characterized by the infrared spectrum

scanning electron microscope

energy spectrum

phosphorus nuclear magnetic resonance spectrum and thermogravimetry. The flame-retardant epoxy resin based on DOPO-Al was prepared

and it flame-retardant and thermal properties were analyzed using limiting oxygen index (LOI)

cone calorimetry

thermogravimetry and differential scanning calorimetry. The results showed that DOPO-Al was a high-temperature flame retardant

and its initial thermal decomposition temperature (

T

5%

) was as high as 595.5℃. The flame-retardant property and heat resistance of epoxy resin were improved by incorporation of DOPO-Al. When 7.5% (wt) DOPO-Al was introduced into the epoxy resin

the LOI value of epoxy resin was increased from 24.1% to 31.3%

and during the combustion

its peak heat release rate

average heat release rate

total heat release

total smoke release and total smoke production were all reduced

and the increase rate of the residue was up to 135%. The analysis of carbon layer suggested that DOPO-Al existed the condensed-phase flameretardant mechanism. Its

T

5%

and glass transition temperature were up to 368.9℃ and 161.8℃

respectively. The prepared flame-retardant epoxy resin had the good thermal properties.