abstract
Four-dimensional (4D) printing combines stimulus-responsive materials with additive manufacturing (AM) technologies. This new concept of printing three-dimensional (3D) objects opens the possibility for solving processing issues, through the production of complex geometries that can undergo programmed temporal changes in response to external stimuli. However, as 4D technology emerges from AM, various challenges still need to be explored, such as the controlled morphing effect. Understanding the aspects related to this behavior, both at the macroscopic level of the structure and at the microscopic level of the polymeric chain, is fundamental. Focused on thermoplastic poly(lactic acid) (PLA) printed by fused deposition modeling, this review addressed the influence of molecular weight, polymeric chain modifications, and 3D printing parameters on the shape change effect of a PLA-based material. The glass transition temperature proved to be a highly important parameter, which can be modified by molecular weight changes. Nozzle temperature, fill density, print patterns, and raster angle are 3D printing parameters that influence the material shape change. Shape recovery is highly dependent on the recovery temperature. Potential applications for shape memory structures are also addressed in this review.
keywords
SHAPE-MEMORY POLYMERS; PLA; TECHNOLOGY; MECHANISMS
subject category
Engineering; Materials Science
authors
Cadete, MS; Gomes, TEP; Gonçalves, I; Neto, V
our authors
Idalina José Monteiro Gonçalves
Junior ResearcherProjects
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
acknowledgements
Thanks are due to the University of Aveiro, FCT/MCTES for the financial support of TEMA research unit (FCT Ref. UIDB/00481/2020 and UIDP/00481/2020) and CICECO- Aveiro Institute of Materials (FCT Ref. UIDB/50011/2020, UIDP/50011/2020, and LA/P/0006/2020), and CENTRO01-0145-FEDER-022083-Regional Operational Program of the Center (Centro2020), within the scope of the Portugal 2020 Partnership Agreement, through the European Regional Development Fund. The authors also acknowledge FCT- Fundacao para a Ciencia e a Tecnologia, I.P. for the Individual Call to Scientific Employment Stimulus (I.G., Ref. CEECIND/00430/2017) and the PhD Grants Ref. 2020.04681.BD (M.S.C.) and SFRH/BD/143429/2019 (T.E.P.G.).