First Year Assessment of Wen Ye, entitled“High-performance Flame-retardant Microspheres (FRMs) via Controllable Core-Shell Structure: Preparation, Characterization and Mechanisms» – November 11th, 2022 – 09:00 am (online)

A novel series of FRMs was synthesized by suspension polymerization which had coreshell structure and complete spherical morphology. The core material is composed of a variety of flame-retardant components, some phosphate ester flame-retardant such as BDP, RDP, TPP etc. (or several of them) will be chosen to supply basic flame-retardancy, and low boiling point halogenated hydrocarbon will be used as blowing agent which can strengthen flame-retardancy. BDP@FRMs were successfully synthesized, the thermal stability, microsphere morphology and BDP content in BDP@FRMs were investigated systematically by employing TGA, FI-IR, DSC, SEM. The obtained BDP@FRMs is light-yellow solid, with complete spherical morphology shown in the SEM results. The thermal stability was discussed by TGA, T1% and T5% is 204 oC and 295 oC. The FT-IR spectra proved the existence of BDP and shell polymer, and BDP content was measured by chemical analysis method to give a result of 42.4%. From the CCT result, the BDP@FRMs in epoxy resin shown that, the TTI, SPR and TSP was changed little which may probably cause by the decomposition temperature mismatching of BDP and epoxy resin. Different with these results above, the decline trend of HRR significant, pHRR of 20% addition and 30% addition decreased 32.3% and 51.5% when compare with the pHRR of pure resin. MARHE also decreased 43.9% when compared with pure resin. Then four parameters of preparation process: addition of NaCl, monomer/Water ratio, the effect of crosslinker, and BDP content were discussed by singular factor analysis. When the amount of NaCl was increased to 4%, particle size of the microspheres decreased, the distribution became significantly narrow, and the spherical shape became more regular; without changing the specific recipe and process conditions the ratio between the monomer phase and the water phase controlled at 0.5-0.8 is to prefer; with the increasing of crosslinker, Tg increased 28 °C compared to a non-crosslinked sample and the thermal stability also increased to 39 °C (T1%). By the increasing of BDP addition, we found it cannot be added more than 55% in the general recipe in section 5.2.