Dynamic mechanical and viscoelastic properties of glass fiber reinforced photopolymer composite fabricated using vat-photopolymerization additive technique: Influence of filler volume fraction

The Vat-Photopolymerization (VPP) additive manufacturing process excels in producing intricate components via layering. This study employs an inter-stage stirring method during layering to create composite parts, especially in bottom-up VPP setups with high filler density. Samples with 2–8 % short glass fiber volume fractions in a photopolymer matrix are manufactured using Digital Light Processing-based VPP. Dynamic Mechanical Analysis is utilized to examine the viscoelastic properties and heat deflection temperature (HDT) of these photopolymer composites (PPC) under static and oscillatory conditions, generating a time-temperature-superposition (TTS) master curve for storage modulus (E'). Results show the highest glass transition temperature (T_g ∼ 60 °C), HDT ∼ 85 °C, and E' ∼ 4500 MPa in the 4 % PPC under preloaded static stress. Analysis reveals efficient force transfer in glassy and rubbery zones, indicating improved moduli with 4 % PPC. A Prony series material model accurately replicates the TTS-derived master curve, suggesting enhanced short- and long-term mechanical properties.