Multishape and Temperature Memory Effects by Strong Physical Confinement in Poly(propylene carbonate)/Graphene Oxide Nanocomposites
2016-10-04T00:00:00Z (GMT) by
The importance of filler–matrix interactions is generally recognized for mechanical property enhancement; their direct impact by physical confinement on diverse functional properties has remained poorly explored. We report here our effort in achieving versatile shape memory performances for a biodegradable poly(propylene carbonate) (PPC) matrix containing high contents of graphene oxide (GO). The excellent dispersion in the entire filler range (up to 20 wt %) allows precise morphological tuning, along with physical filler–matrix interactions, contributing overall to a strong nanoconfinement effect that positively affects the thermomechanical properties of nanocomposites. Only one glass-transition temperature (<i>T</i><sub>g</sub>) of PPC is detected when the GO content is below 10 wt %, corresponding to a slightly confined system, whereas two distinct <i>T</i><sub>g</sub>’s are observed with a GO content over 10 wt %, corresponding to a highly confined system. As such, a tunable multishape memory effect can be achieved simply by tuning the filler contents. A dual-shape memory effect (DSME) is observed for a slightly confined system, whereas a triple-shape memory effect (TSME) can be achieved by deformation at two distinct <i>T</i><sub>g</sub>’s for a highly confined system. More importantly, it is interesting to find that the switch temperature (<i>T</i><sub>sw</sub>) evolves linearly with the programing temperature (<i>T</i><sub>prog</sub>) for both slightly and highly confined systems, with <i>T</i><sub>sw</sub> ≈ <i>T</i><sub>prog</sub> for a highly confined system but <i>T</i><sub>sw</sub> < <i>T</i><sub>prog</sub> for a slightly confined system. Our work suggests a highly flexible approach to take advantage of the strong nanoconfinement effect by tuning the content of GO within a single polymer to access versatile SMEs, such as DSME and TSME, and the temperature memory effect.