Preparation and composite properties of 3-(trimethoxysilyl)propyl methacrylate functionalized graphene oxide reinforced photosensitive resin for 3D printing

Stereolithography (SLA) is an advanced additive manufacturing technique whose performance is largely dictated by its primary feedstock, photosensitive resin (PR). However, PRs often suffer from limited strength, poor toughness, and low thermal stability. Graphene oxide (GO) is an ideal reinforcement for PRs owing to its large specific surface area, superior thermal stability, and intrinsic mechanical properties. In this study, GO was synthesized via a modified Hummers method and subsequently functionalized with three silane coupling agents: 3-aminopropyltriethoxysilane (KH550), (3-glycidyloxypropyl)trimethoxysilane (KH560), and 3-(trimethoxysilyl)propyl methacrylate (KH570). Among these, KH570 afforded the most effective modification, yielding functionalised graphene oxide (FGO) that was dispersed in a PR to fabricate FGO/PR composites. The influence of FGO content on the performance of the 3D-printed parts was then systematically evaluated. The results showed that at 0.6 wt% FGO, the composite exhibited outstanding mechanical properties: tensile strength, elongation at break, and impact resistance increased by 30.8%, 12.7%, and 42.6%, respectively, relative to pure resin. Its curing shrinkage was 5.22%. At 600°C, the mass retention of FGO/PR was 25% higher, and T10%, T50%, and Tmax shifted upward by 76°C, 5.3°C, and 5°C, respectively. Consequently, the composite demonstrated superior strength, toughness, and thermal stability.