New cyclotriphosphazene based nanotweezers bearing perylene and glycol units and their non-covalent interactions with single walled carbon nanotubes

Cardanol derived P, Si and N based precursors to develop flame retardant phenolic foam

A novel eco-friendly halogen-free cardanol-based flame retardant with P, Si, and N on the chain backbone (PSNCFR) was synthesized and incorporated into phenolic foams (PFs). PSNCFR was comprehensively investigated via Fourier transform infrared spectroscopy and nuclear magnetic resonance. PSNCFR endowed PFs with flame retardancy, contributed to generating a composite char defense against flames, and efficiently prevented smoking from PFs. PSNCFR introduction improved the flexural strength of the PFs to approximately 155% of that of pristine PF. PSNCFR-modified PFs displayed a high limiting oxygen index value of 41.9%. The results of cone calorimeter show that the mean heat release rate, mean effective heat of combustion, and total heat release of the PSNCFR-modified PFs reduced by 26.92%, 35.71%, and 31.25%, respectively. In particular, the total smoke production of the PSNCFR-modified PFs decreased by 64.55%, indicating excellent smoke inhibition. As for the mechanism, the condensation and gas phases during pyrolysis were responsible for the synergistic flame retardancy in the modified PFs. The findings demonstrate that PSNCFR can be used in PF preparation to overcome their drawbacks of internal brittleness and flammability.

New perylenebisimide decorated cyclotriphosphazene heavy atom free conjugate as singlet oxygen generator

Perylenebisimide-cyclotriphosphazene based inorganic-organic system was synthesized by a multistep procedure. The substitution reaction of asymmetric perylenebisimide (PBI) derivative with the hexachloroyclotriphosphazene (trimer) resulted in the formation of fully PBI decorated cyclotriphosphazene (5). The identity of newly synthesized compound (5) was confirmed by using ³¹P, ¹H and ¹³C NMR spectroscopies and mass spectrometry. The photophysical (UV- Vis absorption, fluorescence emission, fluorescence lifetime and fluorescence quantum yield) and photochemical (the singlet oxygen generation, and photostability) properties of this conjugate were investigated as novel heavy atom free triplet photosensitizer. The singlet oxygen quantum yield of the PBI-cyclotriphosphazene (5) was calculated to be 0.86 which is good for a heavy atom free triplet photosensitizer. These results will add to the development of cyclotriphosphazene based heavy atom free singlet oxygen triplet photosensitizer systems for applications in organic oxygenation reactions.