3D printing and characterization of hydroxypropyl methylcellulose and methylcellulose for biodegradable support structures

The currently available support materials used with 3D printing technology have challenges of poor dissolvability in chemical solution and difficulty to be removed from the finished part. Current support materials are usually petroleum based which has a negative impact on the environment.

The goal of the project is to identify a suitable biomaterial for support structures that will eliminate the challenges of poor dissolvability and toxic waste generated by the current material. In this study, three biodegradable cellulose derivatives of methylcellulose (MC) and hydroxypropyl methylcellulose (HPMC), with different degree of substitution of hydroxyl group were used. We investigated the effect of concentrations (8, 10, and 12% w/v) of various cellulose derivatives on the rheological properties for understanding their printability.

The rheological analysis revealed that all hydrogels exhibit shear-thinning properties with relatively low yield stress. Effects of printing parameters (extrusion rate, nozzle diameter, and printing speed) were optimized to obtain the desired three-dimensional structures. The water dissolution of the MC and HPMC hydrogels allowed easy removal of the support structures from the build material. Biopolymers like MC and HPMC help in moving closer towards sustainable manufacturing. More on extrusion based 3D-printing