A novel polyhedral oligomeric silsesquioxanes derivative: Synthesis and characterization

Novel polyhedral oligomeric silsesquioxanes derivative, N-((4-hydroxyphenyl)-N-(9, 10-dihydro-9-oxa-10-phosphaphenanthene-10-yl) methyl) aminopropyl silsesquioxane (denoted as HDP) was successfully synthesized via the classical Kabachnik-Fields reaction using 3-aminopropyl POSS (POSS-NH2), 4-hydroxybenzaldehyde and 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) as raw materials and well-characterized by FT-IR, 1H, 31P NMR and mass spectroscopy. Herein, particular attention was focused on the solubility between HDP and DGEBA as well as the effect of HDP on flame retardancy of EP. X-ray diffraction (XRD) result showed that HDP owned a low crystallinity and exhibited a good solubility in DGEBA. Thermogravimetry analysis (TGA) in combined with limiting oxygen index (LOI) demonstrated that HDP had the perfect thermal stability and can improved the flame retardancy of EP in some extent (LOI value increase from 25.4% to 28.3%).