Synthesis of Biodegradable Polymers for Environmentally Friendly Fabric Care Formulations

The increasing presence of synthetic garments in consumer wash loads has made polyester soil release polymers (SRPs) a highly sought-after additive in fabric care formulations. These polymers enhance cleaning efficiency and provide environmental benefits by enabling effective cleaning at low wash temperatures and shorter cycles, thus reducing energy and water consumption. Conventional polyester SRPs comprise of hydrophobic poly(alkylene terephthalate) subunits which facilitate the deposition of SRPs onto the synthetic fiber surface, and hydrophilic poly(ethylene glycol) subunits which render the surface hydrophilic. The terephthalate structural units in conventional polyester SRPs are derived from terephthalic acid, which is primarily produced through the catalytic oxidation of petroleum sourced p-xylene. Recent research has explored alternative monomers that can be derived from biomass for the synthesis of more sustainable polymers.

Biodegradable polymers are of particular interest in the drive to move away from petrochemical based monomers with lignocellulosic biomass providing a plethora of potential monomers for their synthesis. Therefore, the aim of this project has been to develop sustainably sourced SRPs and investigate their viability as potential replacements to conventional SRPs via anti-redeposition and soil release performance tests, conducted at P&G’s Newcastle Innovation Center. Additional insights into polymer behaviour were explored using dynamic light scattering, contact angle measurements and scanning electron microscopy to probe SRPs self-assembly capabilities in aqueous solution, in addition to their surface modification potential. A structure-function relationship was identified with SRPs forming smaller aggregates typically correlating to a good performance, with molecular modelling studies performed by Professor Mark Wilson and group to gain further insights. Preliminary work has explored the stability of diesters mimicking core SRP structures to probe potential end-of-life persistence. Further investigation is needed to gain a better understanding regarding the biodegradability potential of these SRPs to ensure they meet sustainability goals.