Polymers for Advanced Laundry Applications

Dye transfer in the laundry occurs whereby dye molecules are removed from darker garments and deposit onto lighter garments. This results in greying and discolouration of the lighter coloured garments, shortening the lifespan of the clothing, or resulting in the need to separate washes into ‘light’ and ‘dark’ laundry loads. Therefore, dye transfer inhibitors are added to laundry detergent formulations to prevent dye transfer and preserve the appearance of consumer garments.
This thesis explores a variety of means to combat dye transfer, including biopolymeric particles and synthetic polymers which act in a variety of ways to preserve garment appearance. Firstly, biopolymeric hydrogels were investigated for their ability to adsorb dyes from aqueous solution. Chitosan hydrogels were found to be particularly effective, owing to the presence of free primary amine groups which may electrostatically attract anionic dye molecules. Therefore, microsphere biopolymer particles were explored for their ability to encapsulate dye molecules in simulated laundry wash loads to prevent dye transfer. It was found that dye transfer was reduced in the presence of anionic particles, suggesting the particles deposit onto the fabric and repel dye deposition.
Polymers which were designed to interact with the fabric and repel dye deposition were then researched, and methoxy-poly(ethylene glycol)-co-polyesters were found to be effective at preventing the deposition of indigo dye, alongside methoxy-poly(ethylene glycol)-co-poly(amino acid)s. Polymers based on gamma-benzyl-L-glutamate were found to be most effective at preventing the deposition of indigo. The synthetic polymers therefore provide a large amount of scope for future detergent applications of dye transfer inhibition polymeric agents.