A biobased epoxy vitrimer/cellulose composite for 3D printing by Liquid Deposition Modelling

Conventional epoxy polymers are obtained from oil-based resources and their structure is formed by permanent covalent crosslinks. Therefore, this class of materials is now considered non environmentally friendly as they are neither renewable nor reprocessable and recyclable. In this study, we prepared a vitrimeric material based on an epoxy-functionalised cardanol cured with a biobased polycarboxylic acid. In the presence of a zinc-containing catalyst, a soft polyester with a Tg = −13 °C was obtained; its reprocessability by a chemical method was demonstrated to be feasible without any relevant change in properties once a second curing cycle was completed. The vitrimeric polyester was then used in combination with cellulose powder for the preparation of a sustainable and biobased composite. The matrix/filler mass fraction was tailored to obtain a composite paste with suitable rheological properties for 3D printing via Liquid Deposition Modelling (LDM). Preliminary printing tests were successful, and the vitrimeric printed parts were then thermally cured retaining the shape. The suitability of the vitrimeric composite for additive manufacturing was thus confirmed: the new material can provide a solution to 3D printing of recyclable thermosetting biobased polymers.