|
Optical three-dimensional printing (O3DP) have become an advanced and widespread technology for the realization of 3D computer aided models (CAD) to free-form objects. It has evolved to desktop stereolithographic (SLA) devices allowing rapid, accurate and high spatial resolution prototyping out of photoreactive resins. Most of commercially available resins are not cheap and often of unknown chemical ingredients, which limits their wider applicability. Recent advances have shown that renewable raw materials can be applied for preparation of polymers. For example, glycerol, the by-product of biodiesel refining, is a promising candidate which can be used as monomer in the synthesis of bio-based resins as it is or after chemical modification [1]. The primary substance for the photosensitive material was chosen glycerol diglycidyl ether (GDGE) [2]. The following composition was: GDGE, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate (30 mol %), radical (phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide) and cationic (diphenyliodonium hexafluorophosphate) photoinitiators and N-vinylcarbazole as an additive. Autodesk’s open source 3D optical printer Ember (AutoDesk) employing 405 nm light was implemented for dynamic projection lithography (DPL). It allowed selective photopolymerization on demand, later followed by characterization of various photosensitive materials. The bio-based resin was compared to standard materials: Formlabs Clear and Autodesk PR48. It turned out, that the resin had much longer curing time (>10 min for a single layer). Despite this fact, fine structural features were formed and their morphology was characterized using optical profilometer and scanning electron microscopy. It was assessed, that by increasing energy dose, higher structures were acquired and this dependency is linear, thus enabling tabletop graytone lithography out of renewable bioresins.
|
