Inherently Flame-Retardant Flexible Polyurethane Foam with Low Content of Phosphorus-Containing Cross-Linking Agent

Abstract

A halogen-free phosphorus-containing triol named phosphoryltrimethanol (PTMA) was synthesized and used as a cross-linking agent and a reactive-type flame retardant to prepare inherently flame-retardant flexible polyurethane foam (FPUF). Incorporation of a low content (7.8 wt %) of PTMA into the polyurethane chains can increase the flame retardance of FPUF because of good char formation. The residual chars and evolved gases of PTMA-cross-linked FPUFs were analyzed by SEM, FTIR spectroscopy, inductively coupled plasma-atomic emission spectrometry (ICP-AES), energy-dispersive X-ray (EDX) spectroscopy, and thermogravimetric analysis (TGA) coupled with FTIR spectroscopy. The results indicated that more than 60% of the phosphorus in PTMA-cross-linked FPUF was decomposed into polyphosphoric acid or its derivatives and retained in the char residue. This shows that PTMA mainly played a role in the condensed phase of flame-retardant FPUF. Based on the results, a possible thermal degradation mechanism of PTMA-cross-linked FPUF is proposed.

Flame retardation and thermal stability of novel phosphoramide/expandable graphite in rigid polyurethane foam

“…The results of EDX suggest that EG combined DTP promote RPUF forming phosphorus‐rich and continuous char‐layer, which can act good barrier effect on heat and oxygen during combustion. Like some previous study, the nitrogen element was not detected in the char‐layers due to the releasing of nitrogen‐containing substance into gaseous phase during combustion.…”

Mechanical reinforcement of cellulose nanocrystals on biodegradable microcellular foams with melt-compounding process

“…Two significant issues on the development of the foamed composites are commonly emphasized, which involves the selection of polymeric matrix and the blending fillers. Traditionally, the polymeric matrices for the preparation of the foamed materials mainly include the polymers of poly(vinyl chloride) (Wu et al 2009), polyolefin (Naguib et al 2005), polystyrene (Pushpadass et al 2008) and polyurethane (Chen et al 2014). However, these traditional polymers are generally obtained from the petrochemical feed stocks, which are not environmental-friendly materials due to their low biodegradability.…”

A flame‐retardant composite foam: foaming polyurethane in melamine formaldehyde foam skeleton

“…In addition, the peaks at 1341 and 811 cm −1 correspond to the stretching vibration absorption of CN and the out‐of‐plane bending vibration of triazine rings of MF, respectively. For PU foam, the broad peak centered at 3311 cm −1 is ascribed to the NH stretching vibration, 1601 cm −1 to the bending vibration of NH, 2973 and 2870 cm −1 to the asymmetric and symmetric stretching modes of CH 3 groups, 1720 cm −1 to the CO stretching vibration, 1540 cm −1 to the NH II region, 1225 cm −1 to the stretching mode of CN and 1104 cm −1 to CO stretching vibration . The weak peak at 2273 cm −1 is attributed to the residual NCO groups.…”

“…Incorporating flame retardants (FRs) into PU foams is a common and conventional method to obtain flame‐retardant foams. FRs can be physically blended with prepolymers or chemically bonded into polymer chains . The former technology is simple and many commercial FRs can be selected, but this easily brings about deterioration of mechanical properties due to the poor compatibility of FRs with PU resin .…”