Dyeing For Green Textiles

By incorporating a chromophore into an aluminum polymerization catalyst, chemists can now prepare colored polymers in just one step (Angew. Chem. Int. Ed., DOI: 10.1002/anie.201004920). The so-called DyeCat process places the dye directly into the backbone of poly(lactic acid), or PLA, thereby circumventing current coloration techniques in which polymers must be scoured, dyed, and then treated for colorfastness. “Hence the consumption of energy, water, chemicals, and time, as well as effluent production, are all avoided,” writes the research team from the University of Leeds, in England, led by Patrick C. McGowan. The dye molecule can be incorporated in three different ways: It can be appended to the ligand framework that stabilizes the aluminum center, designed to act as the aluminum-stabilizing ligand, or used to initiate polymerization. With the latter method, the researchers prepared yellow, red, and purple PLA. Mixing the yellow and purple polymers, McGowan’s group made black PLA filaments—a color that is popular in textiles but tough to prepare because it requires high dye loading and tends to leach. The black filaments were woven into a dress that is currently on display at the Science Museum in London.