Synthesis And Application Of Poly(Acrylic Acid) Dyes

Polymeric dyes have good application in the fields of dyeing and printing due to their excellent properties of film forming, resistance to migration and solvent, and not easily absorbed by human body. With this understanding, a series of polymeric dyes were designed and synthesized based on poly(acrylic acid). These dyes had an excellent utilization efficiency of near100%and very good fastness when they were applied for fabric pigment dyeing and pigment printing. The dyeing and printing procedure was simple and nearly zero colorful wastewater and volatile organic compounds(VOC) were discharged, which showed the environmental friendly characteristics.The low molecular weight poly (acrylic acid) was synthesized by precipitation polymerization with the yield over90%. Under the optimized polymerization conditions, the average yield was92.6%and solvent recovery was over95%when the residue after polymerization was recycled for5times. In this case, the average molecular weight (Mw) of the obtained poly(acrylic acid) was in the range of1000-1300.A series of poly(acrylanilide-co-acrylic acid) were synthesized in N,N-dimethylaceamide through a facile one-pot condensation of the prepared poly(acrylic acid) with aromatic amines in the presence of thionyl chloride. Their structures were characterized by Fourier-transform infrared spectroscopy. thin layer chromatography and nuclear magnetic resonance spectroscopy. The reaction efficiency of aromatic amine was over80%, even up to96%after lasting for14h when the molar ratio of aromatic amine to acrylic acid unit was1:4. The reaction can work well with aniline, p-nitro aniline, p-methoxy aniline and3-(N,N-diethylamino)aniline, which provides a feasible approach for the synthesis of poly(acrylanilide-co-acrylic acid).Polymeric intermediates DA with the grafting ratio of25%and35%were synthesized by the condensation of poly(acrylic acid) with3-(N,N-diethylamino)aniline.13poly (acrylic acid) dyes were synthesized by the coupling of DA(35%) with aromatic and heterocyclic amines diazonium salts. And another2poly (acrylic acid) dyes were synthesized by the coupling of DA(25%) with aromatic diazonium salts. Through the condensation of poly(acrylic acid) with p-nitroaniline, a polymeric intermediate with a grafting ratio of15%was also synthesized, which was followed by reduction, diazotization and coupling with pyridone intermediates to synthesize2yellow polymeric dyes. All the synthesized dyes were characterized by Fourier-transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. For dyeing and printing with the poly(acrylic acid) dyes,12binders based on polymeric acrylate were synthesized, which showed good compatibility with poly(acrylic acid) dyes.The dyeing conditions were optimized with the synthesized poly(acrylic acid) dyes and polymeric acrylate binders. Under optimized dyeing conditions, take the example of the polymeric dyes synthesized from DA (35%), the dry fastness to rubbing, fastness to wash and wet fastness to rubbing was up to4,4and3ratings in the presence of15%non-crosslinked binder of No.O which didn’t contain N-hydroxymethylacrylamide; while under this condition the dyed PET fabric had the fastness up to4ratings. When printing in the presence of6%sodium alginate, the quality of the printed fabric was good enough for the practical application. Under the same conditions, the wet fastness to rubbing and color change ratings on the printed cotton and PET fabrics were0.5-1rating higher when cross-linked binders were used, compared to the non-crosslinked binders.It was investigated that the relationship between the fabric dyeing properties and the chromophore structures of poly(acrylic acid) dyes, which indicated that the dyes containing nitro or cyano group contributed to a better fastness to rubbing and washing. In the case of the same chromophore structure, the poly(acrylic acid) dyes with a higher grafting ratio resulted in a better fastness to rubbing and washing.