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Urethane-modified epoxy oligomer

Chain Extendable Urethane Modified Epoxy Oligomer. The chain extendable urethane modified oligomers were prepared by combining equimolar amounts of epoxy-diol adduct and half-blocked diisocyanates, and heating the resulting mixture at 80°C for 4-6 hours until the isocyanate Infrared band disappeared. [Pg.118]

Figures la and lb show the OH and NH infrared bands of the oligomer as a function of temperature in uncatalyzed and catalyzed formulations. The uncatalyzed urethane modified epoxy oligomer shows only small changes in the OH/NH absorbance ratio at temperatures below 165°C only about a 60% conversion of the blocked isocyanate was observed. In contrast, sample of the oligomer catalyzed with 0.5% dlbutyl tin dilaurate shows nearly complete chain extension at temperatures as low as 130°C. Figures la and lb show the OH and NH infrared bands of the oligomer as a function of temperature in uncatalyzed and catalyzed formulations. The uncatalyzed urethane modified epoxy oligomer shows only small changes in the OH/NH absorbance ratio at temperatures below 165°C only about a 60% conversion of the blocked isocyanate was observed. In contrast, sample of the oligomer catalyzed with 0.5% dlbutyl tin dilaurate shows nearly complete chain extension at temperatures as low as 130°C.
See other pages where Urethane-modified epoxy oligomer is mentioned: [Pg.117]    [Pg.119]    [Pg.13]    [Pg.440]    [Pg.180]    [Pg.423]    [Pg.174]    [Pg.895]    [Pg.22]   


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