Photosensitive naturally derived resins toward optical 3-D printing

Recent advances in material engineering have shown that renewable raw materials, such as plant oils or glycerol, can be applied for synthesis of polymers due to ready availability, inherent biodegradability, limited toxicity, and existence of modifiable functional groups and eventually resulting to a potentially lower cost. After additional chemical modifications (epoxidation, acrylation, double bonds metathesis, etc.), they can be applied in such high-tech areas as stereolithography, which allows fabrication of three-dimensional (3-D) objects. "Autodesk's" 3-D optical printer "Ember" using 405-nm light was implemented for dynamic projection lithography. It enabled straightforward spatio-selective photopolymerization on demand, which allows development of various photosensitive materials. The bio-based resins' photosensitivity was compared to standard "Autodesk" "PR48" and "Formlabs" "Clear" materials. It turned out that the bioresins need a higher energy dose to be cured (a least 16 J . cm(-2) for a single layer varying from 100 to 130 mu m). Despite this, submillimeter range 2.5-D structural features were formed, and their morphology was assessed by optical profilometer and scanning electron microscope. It was revealed that a higher exposition dose (up to 26 J . cm(-2)) results in a linear increase in the formed structures height, proving controllability of the undergoing process. Overall, the provided results show that naturally derived resins are suitable candidates for tabletop gray-tone lithography. (C) 2018 Society of Photo-Optical Instrumentation Engineers (SPIE)