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>Study of the degradation of polyurethanes. I. The effect of various metal acetylacetonates on the photodegradation of polyurethanes
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Study of the degradation of polyurethanes. I. The effect of various metal acetylacetonates on the photodegradation of polyurethanes
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机译：Study of the degradation of polyurethanes. I. The effect of various metal acetylacetonates on the photodegradation of polyurethanes
AbstractPhotodegradation of polyurethanes based on polyester diol‐diphenylmethane‐p,′p‐diisocyanate in the absence and presence of various metal acetylacetonates (Ti, V, Cr, Mn, Co(II), Co(III), Fe, Ni, Cu, Zn, Mg, Al, and Sn) was carried out; and the effect of these metal compounds on the degradation was examined by investigating the changes in the stress–strain properties and infrared‐ and ultraviolet‐visible spectra of the polymer. The results obtained were as follows: Co(III), Co(II), Cu, Ti, and Sn acetylacetonates substantially enhanced the photo‐oxidation of the polyurethane; and Al, Ni, and Zn acetylacetonates scarcely affected, or slightly retarded, it. The other metal acetylacetonates accelerated more or less the photo‐oxidation of the polymer. Co(III), Co(II), and Cu acetylacetonates extremely degradation. Wavelength of the irradiated light was responsive to photochemical reactions of functional groups in the polymer. CN and CO bonds of urethane groups were very accessible to the photo‐irradiation both without and with a glass filter, while methylene groups were rather stable to the irradiated light longer than 300 nm, through a glass filter. The effect of the metal compounds on the coloration of the polymer was also consistent with that of mechanical strength and in
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