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

Abstract

A composite foam, polyurethane–melamine formaldehyde (PU/MF) foam, was prepared through foaming PU resins in the three‐dimensional netlike skeleton of MF foam. The chemical structure, morphology, cell size and distribution, flame retardancy, thermal properties and mechanical properties of such composite foam were systematically investigated. It was found that the PU/MF foam possessed better fire retardancy than pristine PU foam and achieved self‐extinguishment. Moreover, no melt dripping occurred due to the contribution of the carbonized MF skeleton network. In order to further improve the flame retardancy of the composite foam, a small amount of a phosphorus flame retardant (ammonium polyphosphate) and a char‐forming agent (pentaerythritol) were incorporated into the foam, together with the nitrogen‐rich MF, thus constituting an intumescent flame‐retardant (IFR) system. Owing to the IFR system, the flame‐retardant PU/MF foam can generate a large bulk of expanded char acting as an efficient shielding layer to hold back the diffusion of heat and oxygen. As a result, the flame‐retardant PU/MF foam achieved a higher limiting oxygen index of 31.2% and exhibited immediate self‐extinguishment. It exhibited significantly reduced peak heat release rate and total heat release, as well as higher char residual ratio compared to PU foam. Furthermore, the composite foam also showed obviously improved mechanical performance in comparison with PU foam. Overall, the present investigation provided a new approach for fabricating a polymer composite foam with satisfactory flame retardancy and good comprehensive properties. © 2018 Society of Chemical Industry

Nitrogen/phosphorus synergistic flame retardant-filled flexible polyurethane foams: microstructure, compressive stress, sound absorption, and combustion resistance

“…Hence, the dissipation of sound energy increased and the sound absorption coefficient of FPUF decreased. 27 To sum up, when 1-3 wt% melamine was present, the resulting FPUFs exhibited similar cell structures and thus comparable sound absorption. When the melamine content was 5 wt%, it could be distributed in FPUF evenly, which in turn strengthened the mechanical properties of the cell walls and the frame.…”

Polyurethane: Recent Engineering Contributions

“…A PU/melamine formaldehide composite foam was prepared through foaming PU. The foam composite showed satisfactory fire retardancy and good comprehensive properties [72].…”

Crack-Resistant Amino Resin Flame-Retardant Coatings Using Waterborne Polyurethane as a Co-Binder Resin

“…The molten resin formed the char skeleton. Moreover, MUF decomposed and released NH 3 and CO 2 , blowing the char skeleton to form a swollen char at this stage [6,26] Tonset is the onset decomposition temperature (5% mass loss); a and b denote the weight loss rate peak of the second and third degradation stage, respectively.…”

“…to improve their flexibility by forming PU/EP-IPN [19][20][21], PU/polyacrylate-IPN [22,23], PU/polysiloxane-IPN [24], and PU/vinyl ester-IPN [25], respectively. PU was also added into MF rigid foams, and the resulting composite foams maintained the high compressive stress of MF and high tensile stress of PU [26,27]. Even though it has been widely used as a toughening resin, PU has not been applied in IFR coating systems.…”