High-performance acrylate-free co-cured coatings enabled by tailoring itaconic acid-modified dual-phase photocurable resins

Photocured coatings with tailoring functionalities are required to match their ever-expanding practical applications, yet there is always a trade-off between versatile photosensitive resin performances and synthetic simplification as well as sustainable chemistry. Herein, we present the synthesis of two biomass-derived itaconic acid (IAc)-based photocurable aromatic resins based on 1,6-naphthalene diglycidyl ether (NDE) and tetramethyl diphenol diglycidyl ether (TDDE) molecular backbones. To optimize the curing efficiencies and thermal-mechanical properties of the acrylate-free cured products, itaconic anhydride (IA) monomer was employed to further obtain the IA-extending IAc/NDE (IEN) and IA-extending IAc/TDDE (IET). Moreover, the photo-polymerization kinetics of the IEN and IET were systematically investigated, with 46.6 % for IEN and only 31.5 % for IET. Meanwhile, the molecular chain in curing IET rendered a broad relaxation region. Compared with exploiting IEN and IET resins solely, interestingly, a binary blend of photocured thermoset IEN/IET (IENxTy, x and y represent the individual solid contents) resin with a densified cross-linking network exhibited excellent thermal-mechanical properties, which can be controlled by the blended ratios. As a result, the photocured IEN5T1 revealed that the glass transition temperature (T-g, 141.2 degrees C) and stress/strain (96.7 MPa/6.7 %) increased significantly as the formulation ratio of IEN: IET was 5:1, in contrast to those of other rivals, which decreased as the IET content rose. Most importantly, the IEN5T1 demonstrated a favorable alkali elution ability due to abundant dangling carboxyl groups in the reticular covalent network, which offers a sustainable competitive advantage strategy for the design and fabrication of high-compatible co-curing materials.