Laser-Based Additive Manufacturing of Polypropylene-Agarose Composites: Processing Properties and Compressive Mechanical Properties

Gelling polymers, used for the fabrication of hydrogels, are employed for various applications in medical engineering. The present paper explores a novel approach for the additive manufacturing of polypropylene-hydrogel composites by applying laser-based powder bed fusion of powder blends at ambient temperatures, hence allowing for the integration of additives sensitive to heat degradation. Based on applying superposed fractal exposure strategies for the temporally and spatially discretized melting of prepared powder blends, the processing of composites containing a proportion of up to 75% of agarose can be demonstrated. Prepared specimens depict a water absorption exceeding 100 wt-% while exhibiting non-linear, progressive mechanical properties under compressive stress and enhanced stress relaxation similar to human cartilage tissue. The results illustrate the suitability of fractal exposure strategies for the processing of materials sensitive to heat degradation with divergent thermal properties. Furthermore, the proposed approach provides a novel process route for the fabrication of functionalized polymer components, representing a foundation for the integration of hydrogels for medical applications, such as drug delivery applications and functionalized, load-bearing scaffolds.