3D printing of polyurethane/nanocellulose shape memory composites with tunable glass transition temperature

Abstract

Shape memory polyurethane (SMPU) has been widely recognized as promising potential smart materials. While, porous SMPU presented imperfect shape memory and mechanical properties. In this work, nanocellulose was incorporated in SMPU to improve the comprehensive properties of the porous SMPU by 3D printing prototyping. The shape fixation ratio (Rf) and the shape recovery rate (Rr) were improved to above 99.0%, with adding appropriate proportion of cellulose nanocrystals (CNCs) and ball milled nanocellulose (BMC). And the highest tensile strength of the 3D printed SMP composite was 12.05 MPa, which was 71% higher than pure PU (7.02 MPa), more importantly, these composites have tunable glass transition temperature (Tg), that is to say, when under the appropriate preparation, the composites with Tg close to human body temperature can be obtained, which enables the potential applications in smart biomaterials.