Polyglycerol resin towards sustainable 3D-printing

Additive manufacturing (AM) techniques, also named three-dimensional (3D)-printing, have been widely recognised as promising technologies for rapid production of novel, personalised drug-delivery systems and scaffolds for biofabrication, and in food applications and many more fields. Although there has been promising progress in identifying new materials for 3D-printing, the range of resins/polymers available is still limited, with big reliance on petroleum-derived materials and the advancement is not up to date with the fast-developing hardware. Therefore, new building blocks that are renewably sourced and biodegradable are desirable for expanding applicability and recyclability. Specifically, glycerol, a readily available waste product from biodiesel processing, is highly functionalisable since it bears three hydroxyl groups. We previously reported that an acrylated glycerol-based oligomer, polyglycerol-6-acrylate, fulfils all the necessary criteria for volumetric printing (transparency, photo-reactivity and viscosity) and was successfully used to print a variety of models with intricate geometries and good resolution. In the present work, we want to expand the use of (meth)acrylated-polyglycerols (4 and 6 units of glycerol) to stereolithography (SLA), as this technique presents numerous advantages, being also more commercially available. Printability parameters, different geometries, and biocompatibility are explored to confirm the amenability of SLA to these "greener" resins. In addition, as initial proof of concept, the replacement of (meth)acrylate moieties is explored by ring opening of maleic and norbornene anhydrides in order to achieve acrylic-free resins and preliminary curability tests on these bioderived resins were performed. By developing and testing these new acrylic/acrylic-free resins based on glycerol, we aim to accelerate the adoption of greener alternatives in AM, contributing to a more sustainable future in the 3D-printing world.