Synthesis And Application Of Novel Dyes For Polylactide Fibers

Dyes always show high affinity with fibers if they are compatible with each other. According to this theory,the hydrophobic dyes bearing different hydrophobic functional groups are designed and synthesized for hydrophobic polylactide fiber in this thesis.And the lightfast dyes with photostable functional group are also designed and synthesized for polylactide fiber based on the low light fastness of the thraditonal commercial dyes on polylactide fiber.It is expected that these dyes have high exhaustions and color fastness on polylactide fabrics.Two series of anthraquinone dyes are synthesized by the reaction of different amines with 1-nitroanthraquinone and 1,5-dichloroanthraquinone,respectively.Also,seven (2'-chloro-4'-nitro)azobenzene dyes are synthesized via diazotization in NaNO₂/H₂SO₄ by using 2-chloro-4-nitroaniline as raw material.Five single crystals of the azo dyes are obtained in acetone and analyzed by X-ray.The structures of these dyes are also characterized by FTIR, ¹H NMR and mass spectrometry.Three yellow azo anthraquinone dyes are synthesized from 1-aminoanthraquinone via diazotization in NaNO₂/H₂SO₄/HBF₄ and coupling with pyrazolones.In order to improve dye affinity with polylactide fiber,four novel yellow azo anthraquinone dyes with hydrophobic alkyl chains are also synthesized in four steps from 1-aminoanthraquinone and 1-(4'-sulfo)-phenyl-3-methyl-pyrazolone-5.Their structures are also characterized by FTIR, ¹H NMR,mass spectrometry and elemental analysis.¹H NMR results indicate that these azo dyes exist in the tautomer of hydrazone.Representative dyes of each series are selected to apply to polylactide fabrics in high-temperature exhaust dyeing.It is shown from the dyeing results that the introduction of proper hydrophobic alkyl chains to the dye molecules can markedly increase the dye exhaustions on polylactide fabric,resulting from the improvement of dye affinity with polylactide fiber.And hydrophobic azo dyes 3-2 show high affinity with polylactide fiber, resulting in their exhaustions higher than 97%on polylactide fabrics.It is also found that all azo anthraquinone dyes have excellent light fastness on polylactide fabric,over 6 ratings.