Tuning the shape memory effect of PLAA with the addition of low molecular weight PEG for minimal invasive surgery applications

Abstract

Poly(ʟ-lactic acid) (PLLA) is an interesting polymer for the engineering and medical field because of its high elastic modulus, good tensile strength and sustainability. The only major obstacle for these applications, like the shape memory effect, is its brittleness. In this study, a series of poly(L-lactic acid) polymers are blended with different percentage of polyethylene glycol (PEG) plasticizer of molecular weight of 600 g/mol. We investigated the effect of PEG percentage on the shape memory behaviour, the mechanical and thermal properties of the polymer through DSC, ATG, DMTA and tensile tests. We then determined the right concentration of PEG needed to maximize the shape memory effect for medical application. The experimental results reveal that introduction of appropriate PEG content improves the shape memory behaviours, by reducing the glass transition temperature and the brittleness of PLLA.