Grafting reactions onto poly(organophosphazenes). VI. Thermooxidative stabilization of poly[bis (4-benzylphenoxy)phosphazene] by grafting acrylate polymers containing HALS groups |
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Authors: | Francesco Minto Valerio Borzatta and Mario Gleria |
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Affiliation: | (1) Sezione di Legnaro, Istituto di Fotochimica e Radiazioni d'Alta Fnergia del CNR, Via Romea 4, Legnaro, 35020 Padova, Italy;(2) Divisione Additivi, Ciba-Geigy S.P.A., Via Pila 6 3 Ponteechio Marconi, 40044 Bologna, Italy |
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Abstract: | Polybist 4-benzylphenoxy phosphazene] is heated at 200 C in air and the oxidation of the 4-diphenylmethane side substituent to phosphazene-supported benzophenone, benzhydrol, and hydroperoxides is observed. The thermo-oxidative stabilization of the polymer is obtained by light-induced grafting copolymerization of the acrylic acid 2.2.6.6-tetramethyl-piperidin-4-yl ester onto the polyphosphazene substrate. The HALS moieties grafted onto the polyphosphazene films prevent the oxidative modification of the substituents and preserve the polymer against thermal damage. This process, investigated by IR. UV, and EPR spectroscopy, is basically dependent on the amount of HALS groups grafted onto the polyphosphazene matrix and on the composition of the reaction medium used to carry out the grafting process. The comparison between the thermooxidative stabilization process and the corresponding photooxidative stabilization reaction is also discussed.Presented at the 1st Italian Workshop on Cyclo- and Poly(phosphazene) Materials. Lebruary 15–16, 1996, at the CNR Research Area in Padova, Italy. |
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Keywords: | Poly(organophospha/enes) grafting reactions thermooxidative stabilization acrylate polymers poly[bis(4-benzylphenoxy)phosphozene hindered amine light stabilizer (HALS) groups |
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