Silane-based particle-matrix coupling in intumescent flame retardant systems for PBF-LB/P

Le résumé fourni par la source

Flame retardancy for samples manufactured in laser-based powder bed fusion (PBF-LB/P) is one of the major concerns to overcome for the application of the materials in environments with high safety standards. However, the trade-off between flame retardant and mechanical properties remains challenging. In this study, we demonstrate the enhancement of mechanical properties of an intumescent flame retardant (FR) system based on ammonium polyphosphate (APP), Pentaerythritol (PER) and manganese(II)-oxide (MnO) through chemically enhanced filler-matrix adhesion. We introduce the silane-based modifications of organic and inorganic flame retardant additives based on the aminosilane compounds APTES and TMSPED alongside the stable processing of surface-functionalized PA12-FR systems in PBF-LB/P. Mechanical testing of the samples show an increase of tensile strength by 24% and elongation at break by 58%, showing a dependence on the applied energy density and the used aminosilane compound. Corresponding micrographs of fracture surfaces unveil the enhanced adhesion between additives and polymer matrix. Further investigation demonstrate no negative influence of the surface modification on crystallization behaviour, tested via X-ray Diffraction (XRD), or fire properties of the samples. Whilst limiting oxygen index (LOI) results remain unaffected by the aminosilane treatment, corresponding cone calorimeter results show a decline in total heat release (THR) by 10%, which demonstrates enhanced full-fire burning characteristics.

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