Shape memory polymers (SMP) Flashcards
Define a shape memory polymer.
It is a polymer that remembers its initial shape, when heated up and mechanical load is applied it obtains a temporary shape. When reheated again it will retake its initial shape.
Give an example of SMPs.
Thermoinduced sutures. To be able to do the not of the suture only using temperature, just by heating the polymer it will go back to its original shape which is like a knot.
Explain the visco-elastic behavior.
When little load is applied the polymer is in the elastic regime and will when load is removed go back to its original shape, that is no energy is lost. But when in the nonlinear viscous/plastic regime it looses some energy and cannot go back to the original shape. In the viscous regime crosslinks between the polymers are broken.
Explain the structure of a SMP, what happens with the structure when it is reheated.
A SMP need always to be built-up of 2 different polymers, immiscible or miscible. When heating the first time a crystalline structure will be organised, and when cooling down this will stay. But when reheating energy is added and the crystalline structure is broken.
