A highly efficient flame retardant and smoke suppression oligomer, oligo(phenylphosphonic dihydroxypropyl silicone oil) (PPSO), was synthesized by a one-step reaction. The chemical structure of PPSO was confirmed by Fourier transform infrared (FTIR), 31 P nuclear magnetic resonance ( 31 P NMR), and 29 Si nuclear magnetic resonance ( 29 Si NMR). The flame-retardant effect of PPSO on the polycarbonate (PC) matrix was investigated by limiting oxygen index, UL-94 vertical burning test, and cone calorimetry, respectively. The results showed that PC/PPSO composites passed UL-94 V-0 rate testing with only 1.3 wt. % PPSO. Furthermore, the incorporation of PPSO can suppress the release of smoke. The flame-retardant mechanism was also investigated via thermogravimetric analysis-fourier transform infrared spectroscopy (TG-FTIR), field-emission scanning electronic microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. From the result of pyrolysis gas and char residue, PPSO played a synergistic flame-retardant mechanism including the gas phase and the condensed phase.Polymers 2019, 11, 1977 2 of 12 and it was used together with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) to fabricate a flame-retardant system for epoxy resins (EP) [20]. When 3% PSiN and 7% DOPO were incorporated, the LOI value of EP was found to be 34% and the UL-94 test was found to be class V-0. The microstructures observed by scanning electron microscopy and FTIR indicated that the surface of the char for the EP/DOPO/PSiN system holds a more cohesive and dense char structure when compared to the pure EP and EP/DOPO systems. Many works have been performed on the compounds containing two or more flame-retardant elements including phosphorus, nitrogen, sulfur, and boron [21][22][23][24][25]. However, few studies have reported on flame retardants containing both phosphorus and silicon, and the weight ratios of the flame retardants were too high [26,27]. For example, Yang group designed a novel polyhedral oligomeric silsesquioxane containing 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO-POSS) and incorporated it into the PC matrix, and the PC/DOPO-POSS composites passed UL-94 V-0 rate testing, but the weight ratio (6 wt. %) of the flame retardant was relative high [26]. Recently, a polymer flame retardant named HSPCTP has been prepared by our group and incorporated into the PC matrix, and the PC/HSPCTP composites passed UL-94 V-0 rating testing with only 3 wt. % HSPCTP [13]. This excellent property resulted from the synergistic effect of a gas phase flame retardant and condensed phase flame. These results suggest that phosphorus and silicon are a good combination to prepare a flame retardant. But the synthesis of this flame retardant is complicated. Therefore, it is worth preparing a high efficient flame retardant with a simple method.In this study, a novel oligomer flame retardant containing phosphorus and silicon was synthesized by a one-step reaction and then blended with PC. Combining the advantages of ph...

Silicone diphenylsulfonate (SDPSF) was synthesized via nucleophilic substitution reaction between dihydroxyalkyl‐terminated silicone oil and benzene sulfonyl chloride, and its chemical structure was confirmed by Fourier transform infrared (FTIR) and 1H NMR. The effect of SDPSF on the flame retardancy, thermal stability, combustion behavior, and mechanical properties of PC/SDPSF blends were investigated. The PC/2 wt% SDPSF blend achieved the UL‐94 (3 mm) V‐0 rating and limiting oxygen index value of 30.3% together with the lowest values of the total heat release (32.2 MJ/M2), peak heat release rate (239.5 kW/M2), CO production (0.48 kg/kg), and fire growth index (1.09 kW/s·m2). It demonstrated that the SDPSF improved evidently the flame retardancy and fire safety of the polycarbonate (PC) matrix. The blend also gave a slightly reduced tensile strength (60.0 MPa) and notched impact strength (57.0 kJ/m2). The TG‐FTIR spectra of the pyrolysis gases demonstrated that the SDPSF promoted the decomposition of PC matrix on advance to release much more nonflammable gases in the early combustion process, meanwhile, the analysis of the char residues confirmed that the SDPSF facilitated the formation of compact and continuous layers with higher graphitization degree to isolate the transfer of heat and combustible volatiles.