The effect of aluminum phosphinate on char formation of phosphorus-containing deoxybenzoin polymer

The introduction of aluminum diethlyphosphinate (AlPi; <2% by weight) to 4,4 '-bishydroxydeoxybenzoin-polyphosphonates (BHDB-PPNs) increased the char yield rate of BHDB-PPN from about 54% to 63% at 600 degrees C. The increase of char yield rate might be attributed to the reaction among the degraded products from AlPi and BHDB-PPN to form stable intermediates which increased the activation energy of cleavage of P-C bond in the BHDB-PPN and reduced the release of benzene to the gas phase. It was found that the char yielded from BHDB-PPN and BHDB-PPN/AlPi comprised about 90% carbon element, which was characterized as main sp(2) carbon structure by Raman spectrum.