Influence of post-processing on the properties of 3D-printed poly(propylene fumarate) star polymer hydroxyapatite nanocomposites

Abstract

Vat photopolymerization is able to produce intricate parts at high print speed, good part fidelity, and strong mechanical properties. However, as materials become more complex and printing technologies advance, the post-printing processing conditions of these parts must be considered. Poly(propylene fumarate) (PPF) 4-arm stars with a of degree of polymerization (DP) of 120 were photochemically 3D printed with 5 wt% hydroxyapatite (HAp) nanoparticles (<200 nm) as a filler in a nanocomposite scaffold targeted for bone regeneration applications. Nanocomposites and pure polymers were subjected to a number of post-printing processing conditions including UV post-curing times, cure temperatures and drying times in a vacuum oven. The impact of these conditions on mechanical properties were analyzed in compression, tension, and dynamic mechanical analysis (DMA). Mechanical behavior is highly tunable with the variation of each of these different processing conditions.