Thermal stabilities and flame retardancies of phloroglucinol‐based organo phosphates when applied to polycarbonate

Abstract

SUMMARY A series of organo phosphorus flame retardants (FRs) based on aromatic phosphate and cyclic phosphate were synthesized in an attempt to develop an efficient FR for polycarbonate. Their successful synthesis was confirmed by FT‐IR and 1 H and 31P NMR. Their thermal stability and flame retarding efficiency as a single‐component additive were investigated and compared with the commercial FR, resorcinol bis(diphenyl phosphate). The thermogravimetric analysis results revealed that the aromatic phosphate synthesized in this study, phloroglucinol diphenyl phosphate (PDP), shows a higher thermal degradation temperature and better flame retardancy even though it has a lower P content than cyclic phosphate‐based FRs. The flame retarding efficiency was evaluated by the UL‐94 test method. The V‐0 rating was achieved at a PDP loading of 2 wt% in polycarbonate in the presence of an anti‐dripping agent (1 wt%), which is better than that of resorcinol bis(diphenyl phosphate) and cyclic phosphate‐based FRs. The high thermal stability and P–OH generation tendency is responsible for the better flame‐retarding performance of PDP. The degradation path of PDP is also discussed. Copyright © 2012 John Wiley & Sons, Ltd.

Flame‐retardant behavior of a phosphorus/silicon compound on polycarbonate

“…Recently, phosphonium salts have received attention because of their high thermal stability, high charring yield, and good solubility to polymers . In these studies, cyclic phosphates, phenyl phosphine oligomer, phosphonium sulfonates, and rigid steric hindering spiro‐bisphosphates were all disclosed to have an excellent flame‐retardant effect on PC . On the other hand, silicon‐containing compounds gradually attracted attention because of their environmentally friendly properties .…”

Micro-intumescent flame retardant polyamide 6 based on cyclic phosphate grafting phenol formaldehyde

“…Absorptions of the char residue for PFCP under N 2 are phosphoric or polyphosphoric acid (3442 cm À1 , . These changes imply the formation of P-O-P structure [29] which leads to the crosslinking. At lower temperature (<300°C), the PF has not been degraded, so the P-O stretching is not evident.…”

“…The chemical shifts of PFCP's phosphoryl groups are in the typical range of neopentyl aryl phosphates. [29] The small peak of about 2.5 mol% of total phosphorous is caused by the pyrophosphate, an impurity introduced during the synthesis which was resistant to be washed out.…”

“…The peak at 960 cm À1 caused by the P-O stretching vibration moves to a high frequency of 990 cm À1 , and the stretching vibration of P¼O at 1317 cm À1 shifts to a low frequency at 1078 cm À1 . These changes imply the formation of P-O-P structure [29] which leads to the crosslinking. At lower temperature (<300°C), the PF has not been degraded, so the P-O stretching is not evident.…”

Solubility of Phloroglucinol Tris(cyclic 2,2-dimethyl-1,3-propanediol phosphate) in Different Solvents

“…1, CAS Registry No. 1192839-99-8) has been applied in polycarbonate (PC) and acrylonitrile-butadiene-styrene copolymer (ABS) with high thermal stability and excellent fire retardancy [4,5]. The merits that may be attributed to the PCDMPP flame retardant include high P content, good hydro-stability, non-toxicity and minimal adverse change in the overall properties of the polymer [6].…”