Flexible Polyurethane Foam with the Flame-retardant Melamine

Abstract

Flexible polyurethane (PU) foams are widely used in many industrial applications, such as upholstered furniture and mattresses, automotive applications, etc. The chemical nature of the PU, the high air permeability, and the high inner surface area of the foam structure cause this material to be highly flammable. Consequently, the application of flame retardants to flexible PU foams is an important issue. The use of halogenated flame retardants is not considered optimal, in part due to the high emission level and the possible phase-out by the European Risk Assessment Body. Consequently, melamine as a nonhalogenated flame retardant is applied more and more frequently. However, little data is available regarding the application of melamine as an additive in flexible PU. This paper is concerned with the influence of melamine on the synthesis of the PU foam and the resulting material-specific properties. Especially, the increase of viscosity and the high heat capacity of melamine lead to a decrease in foaming growth and rising height with increasing melamine content. This is caused by the reduced drainage rate between the struts and the plateau borders in the foam-forming process. Here, the increase in viscosity follows the Dougherty—Krieger equation with the intrinsic viscosity of k = 3.3. The mechanical properties such as density and compression strength increase with increasing melamine content. Other properties like tensile strength and elongation decrease because of the embedding of the melamine in the PU matrix, which weakens the structure. The air permeation and number of cells also decreases because of the thickened struts caused by the reduced drainage rate in the foaming process. Furthermore, the reaction between the amino groups of melamine and the isocyanate of the PU formulation was investigated by FTIR.

Salen based Schiff bases to flame retard thermoplastic polyurethane mimicking operational strategies of thermosetting resin

“…L2 and L3 have hydroxy group at 4 and 5 position respectively on the aromatic group due to which they can expand the supramolecular interaction by intermolecular H-bonding. L1-L3 were blended in TPU and the resulting formulations were characterized by FTIR, 13 C MAS NMR, TGA, DSC and microscopic techniques. Pyrolysis combustion ow calorimetry (PCFC), cone calorimetry and limiting oxygen index (LOI) are the evaluating tools for re properties.…”

“…The observed ame retardancy is broadly discussed examining condensed phase and gas phase mode of action to elucidate the mechanism of ame retardancy. Samples for the condensed phase analysis were collected from cone calorimetry experiment which represents different stages of degradation and studied by FTIR, 13 C MAS NMR, SEM and EPMA. Gas phase analysis were studied by TGA coupled FTIR and py-GCMS.…”

“…13 C MAS NMR on TPU and L2-TPU at different degradation steps (onset, peak, descending and end refers to samples collected from mass loss calorimetry based on HRR curve which are at different stages of decomposition; L2-300 is a stage 24 in the thermal decomposition of L2).…”

Polyurethane Flexible Foam Fire Behavior

“…This is due to the increase the heat capacity of the entire system because of high heat capacity of melamine and EG. When melamine and EG content increases in the system, the heat capacity of the system increases and the system temperature reduces, therefore, the foam height and consequently expansion factor reduces [11].…”

High-resolution X-ray computed tomography for 3D microstructure characterization of a cellulose particle filled polymer foam

“…However, because of the complicated three-dimensional (3D) structures of foams, measuring foam features manually is time consuming, and often requires destruction of the sample since these methods give only information about the foam surface. 2,3,[10][11][12] In addition, some distinguishing features of foams, including cell volume and anisotropy, are extremely difficult to measure using traditional microscopic techniques, since information about the inner structure is necessary. These problems and restrictions are even more severe if the foam is filled with particles or fibers and the distribution of the fillers within the 3D foam structure has to be measured.…”