The poly(organophosphazenes), [NP(OC2H5)2]n, [NP(OCH2CF3)2]n, [NP(OC2H52)0.4(OCH2CF3)1.6]n, and [NP(OC6H5)2]n, as films have been subjected to ultraviolet irradiation under vacuum, and the behavior of these polymers has been compared with that of the crystalline cyclic tetrameric model compounds, [NP(OC2H5)2]4, [NP(OCH2CF3)2]4, [NP(OC6H5)2]4, (NPCl2)4, and [NP(N(CH3)2)2]4. As a class, the polymeric and cyclic phosphazenes were moderately resistant to radiation damage. The general sensitivity to radiation-induced reactions increased in the order [NP(OCH2CF3)2]., > [NP(OC6H5)2]., > [NP(OC2H5)0.4(OCH2CF3)16]n, >[NP(OC2H5)2]n,. However, extensive cleavage of the phosphorus-nitrogen skeleton was not detected. Photolytic cleavage of the C-O bond was the primary reaction, and this resulted in the formation of volatile alkanes and arenes together with cross-linking and discoloration after extended irradiation. Residual P-Cl bonds in the high polymers provided a facile photodecomposition pathway. Secondary photooxidation processes that yielded carbon dioxide were observed for the polymers (but not for the cyclic model systems), and these were attributed to the presence of traces of dissolved molecular oxygen. Photodecomposition pathways are suggested that account for the products.
All Science Journal Classification (ASJC) codes
- Organic Chemistry
- Polymers and Plastics
- Inorganic Chemistry
- Materials Chemistry