The photochemistry of poly[bis(4-isopropylphenoxy)phosphazene] (PIPP) sensitized by hexakis(4-benzoylphenoxy)cyclophosphazene and by poly[bis(4-benzoylphenoxy)phosphazene] was investigated both in solution and in film. Air-equilibrated CH2Cl2 solutions of this polymer, also containing the above-mentioned benzophenone-containing phosphazene substrates, were irradiated with light absorbed exclusively by the carbonyl substituent. The irradiation causes a sharp decrease of the viscosity, attributed to chain scission of the PIPP backbone. In this process the solvent plays a key role. On the other hand, no photochemical change was observed for the same pair of molecules in the solid state. X-ray diffraction studies and DSC investigations on PIPP films, doped with benzophenone-substituted cyclo- or poly-phosphazenes, reveal that the lack of photoreactivity is due to phase segregation in these systems.
PHOTOCHEMICAL BEHAVIOR OF POLY(ORGANOPHOSPHAZENES) .8. FURTHER INVESTIGATIONS ON THE SENSITIZED PHOTOCHEMISTRY OF POLY[BIS(4-ISOPROPYLPHENOXY)PHOSPHAZENE]
MEILLE, STEFANO VALDO
1990-01-01
Abstract
The photochemistry of poly[bis(4-isopropylphenoxy)phosphazene] (PIPP) sensitized by hexakis(4-benzoylphenoxy)cyclophosphazene and by poly[bis(4-benzoylphenoxy)phosphazene] was investigated both in solution and in film. Air-equilibrated CH2Cl2 solutions of this polymer, also containing the above-mentioned benzophenone-containing phosphazene substrates, were irradiated with light absorbed exclusively by the carbonyl substituent. The irradiation causes a sharp decrease of the viscosity, attributed to chain scission of the PIPP backbone. In this process the solvent plays a key role. On the other hand, no photochemical change was observed for the same pair of molecules in the solid state. X-ray diffraction studies and DSC investigations on PIPP films, doped with benzophenone-substituted cyclo- or poly-phosphazenes, reveal that the lack of photoreactivity is due to phase segregation in these systems.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
