High-Performance Digital Light Processing Printing of Hybrid Acrylate/Benzoxazine Network

Abstract

Dual-curing photosensitive resins have been widely used in digital light processing (DLP) printing to obtain outstanding mechanical properties. Although considerable research efforts and advancements have been made in thermosetting resins, numerous challenges still remain in understanding the influence of the photopolymerization network on the curing of thermosetting resins and the synergistic effect of the photothermal polymerization network. In this study, a variety of dual-cure photosensitive resins were synthesized by blending diverse acrylate oligomers or acrylate monomers with acryl-functional benzoxazine. Through an exploration of the photo and thermal polymerization behaviors of the dual-cure resins, it was determined that the curing degree of benzoxazine increased as the cross-link density of the photopolymerized network decreased. Concurrently, the mechanical strength and heat resistance of the dual-cured resins were further enhanced with the incorporation of highly polar or rigid acrylic components. The glass transition temperature (T_g) of P₈B₂-HE₁₀-220 reached 250 °C. Moreover, the 5% weight loss temperature (T_d5) of P₈B₂-AC₁₀-220 and P₈B₂-HE₁₀-220 reached 311 and 296 °C, respectively. Upon dual-curing, a hybrid polymer network (HPN) was formed by combining the photopolymerized networks and the polybenzoxazine networks, which further improved the mechanical strength of the dual-cured photosensitive resins. The introduction of highly polar 2-hydroxyethyl acrylate (HEAA) enabled the tensile strength of P₈B₂-HE₁₀-220 to reach 146.62 MPa, which represents a 13.94% increase compared to that of P₈B₂-220. Meanwhile, the Young’s modulus of P₈B₂-DC₁₀-220 modified with the highly rigid dicyclopentanyl acrylate (DCPA) reached 7.19 GPa, signifying a 17.29% elevation relative to that of P₈B₂-220. These findings will propel the formulation design based on photothermal dual-curing reactions and offer solutions for the efficient manufacturing of a diverse range of high-performance materials with stringent requirements.