4D-printed continuous carbon fiber reinforced shape memory polymer composite in medical supports

Abstract

Aalto University Advanced Manufacturing and Materials research group has a long background in additive manufacturing (AM). Especially they have studied how AM can be utilized in medical applications. In the group, there are experience of for example multi-material extrusion and shape memory metals. Now the goal is to develop this expertise to purer 4D printing and expand the materials to composites.

In this study 4D-printed continuous carbon fiber (CCF) reinforced shape memory polymer (SMP) composite is researched. The printability of the composite is studied and improved. Also, the effect of continuous carbon fiber infill into the shape memory effect (SME) of the used SMP is examined.

In this thesis was found out that 4D-printed continuous carbon fiber reinforced shape memory polymer can give new possibilities to body-external prostheses because of its ability to change its shape while having good mechanical properties thanks to the reinforcing fibers. The printability of the material combination and the printing quality of the fibers are the main two things that need to be researched more to achieve a suitable level for further use of this technology.

Totally 20 different parameters were changed to achieve better print quality and printability. Clogging of SMP hotend was a significant issue in the progress of this work. A new extension part was made to hinder clogs and an idea of modifying the hotend is shown. In the shape memory recovery test were found that CCF strengthens the shape memory recovery capabilities of the sample.

Overall, this thesis presents novel insights into the printing of continuous fiber-reinforced shape memory polymer composites with the in-situ co-extrusion method.