Sunscreens are topical agents that absorb or reflect harmful ultraviolet (UV) radiation of the sun and protect the skin against sunburn. Commercial sunscreens are classified into two types. The physical sunscreens such as zinc oxide, stay on the skin surface, and deflect the sunlight. Chemical sunscreens such as oxybenzone are small molecules with chromophores that absorb and convert UV into heat or red-shifted wavelengths. Commercial sunscreens have limitations of photochemical stability, invasive chemical exposure, and short lifetimes. In this work, we present a new class of polymeric sunscreen thermosets that absorb UV and have greater stability to photodegradation.<br/><br/>Polycondensation technique is used to produce crosslinked thermoset polymers from polyfunctional monomers accompanied by the elimination of low molecular weight by-products. Phenolics react with aldehydes containing specific substituents in the presence of an acid or base catalyst to generate hydrophobic, crosslinked, thermoset polymer particles. These thermoset particles displayed excellent UV absorbing properties and photo-oxidation resistance compared to commercial sunscreens, with SPF values as high as 50 maintained constant for up to 6 hours.<br/><br/>Strong UV absorbance and photostability of these thermoset polymers have potential applications as sunscreens, UV screening agents, and additives.

Thermoset polymer particle sunscreens using polycondensation technique

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.