Key points are not available for this paper at this time.
New deeply coloured and fluorescent copolyesters and -urethanes with 1,4-dioxo-3,6-diphenylpyrrolo3,4-cpyrrole (DPP) units in the main chain were prepared. The chromophoric units are incorporated in the backbone via their N-alkylated lactam groups. The DPP-containing monomer 1,4-dioxo-2,5-bis(6-hydroxyhexyl)-3,6-diphenylpyrrolo3,4-cpyrrole (2) was obtained by N-alkylation of 1,4-dioxo-3,6-diphenylpyrrolo3,4-cpyrrole (1) with 6-chlorohexanol. Copolyesters were prepared by (a) solution polycondensation of mixtures of 2 and 1,12-dodecanediol with terephthaloyl chloride and (b) melt polycondensation of the diol mixture with dimethyl terephthalate using tetrabutoxytitanium as catalyst. Copolyurethanes were prepared by polyaddition of mixtures of 2 and 1,12-dodecanediol with hexamethylene diisocyanate. The copolyesters are readily soluble in common organic solvents, while the copolyurethanes are only soluble in rather exotic solvents such as p-cresol. Polymer solutions are yellow to orange with optical absorption maximum at 470 nm and fluorescence maximum at 520 nm, the Stokes-shift being about 50 nm. All copolymers are partially crystalline, the crystallinity decreasing with increasing DPP content. Possible origins for the influence of the DPP content on the crystallinity of the polymers are discussed. The thermal stability of the copolyesters is independent of the DPP content, the decomposition temperature being about 646 K. The limit of thermal stability of the copolyurethanes is about 600 K and increases slightly with DPP content.
Lange et al. (Fri,) studied this question.