Biobased Epoxy Resin with Inherently Deep-UV Photodegradability for a Positive Photoresist and Anticounterfeiting

Biobased epoxy resins have received widespread attention due to their substitution for petroleum-based ones in conventional fields but are rarely reported in functional materials. Herein, a biobased epoxy resin with inherently deep-UV photodegradability was reported. The strategy was based on the [2 + 2] photocycloaddition of trans-cinnamic acid, a renewable resource, to generate a cyclobutane structure in the backbone, which was cleaved upon <280 nm light irradiation. The as-prepared epoxy resin showed high thermal stability and good thermomechanical properties. Meanwhile, owing to the ozonosphere blocking the UV light with a wavelength of <290 nm, the stability of this epoxy resin was guaranteed under a normal environment. When exposed to deep-UV light irradiation, degradation occurred. The degradation mechanism study demonstrated that molecular packing (crystalline/amorphism) was important in determining its degradability. Based on its photoresponsive features, the feasibility of this epoxy resin in the fields of a positive photoresist and anticounterfeiting was well explored. This work provides an attractive strategy for developing biobased epoxy resins to expand their potential application fields.