Thermomechanical Characterization of Poly(β-amino ester)-(Meth)acrylate Copolymers

Shape memory polymers (SMP) are a broad class of materials that can undergo large amounts of deformation, and under a specific stimulus return to their original, pre deformed shape. One common method for exploiting the shape memory effect is to use a temperature transition for polymers that display a stark phase change from their solid "glassy" state to the solid "rubbery" state as temperature increases. By deforming the material in the "rubbery" region and subsequently holding the deformation while cooling into the "glassy" regime, a new shape can be maintained. Upon reheating into the "rubbery" region the material will transform back to its original shape. A group of SMP's, Poly(β-amino ester)-(Meth)acrylate Copolymers , were chosen for this study for multiple reasons, but most importantly because of their biocompatibility allowing them to be used for medical applications. The study found that by varying the relative composition of the copolymers by weight, it was possible to adjust the transition region such that the material would hold its deformed shape at room temperature and recover at body temperature. A range of copolymer mixtures were found to display this property while having different material strengths. Subsequently, mechanical characterization of these various polymers was observed.