Physico‐mechanical properties and flammability of PUR/PIR foams containing expandable graphite core‐shell composite particles

In this work, polyurethane/polyisocyanurate (PUR/PIR) foams were modified by two types of expandable graphite (EG) core‐shell composite particles. The pulverized EG core‐shell composite particles were prepared during emulsion polymerization using methyl methacrylate or glycidyl methacrylate for the synthesis of the polymeric shells (poly(methyl methacrylate) (PMMA) and poly(glycidyl methacrylate) (PGMA)), and then the obtained EG_PMMA and EG_PGMA particles were used for a modification of the PUR/PIR foams. The Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) observations well demonstrated that the EG_PMMA and EG_PGMA particles were successfully synthesized via emulsion polymerization. The foams with different content of EG or EG core‐shell particles were prepared by the single‐step method at NCO/OH ratio equals 2.5. The prepared materials were analyzed in terms of their morphology, flammability, thermal conductivity, and basic physical and mechanical properties. POLYM. COMPOS., 40:3805–3813, 2019. © 2019 Society of Plastics Engineers