Effect of PBS on Dynamic Mechanical Behavior of Copolymer Networks, The

Shape-memory materials (smart materials) are classified as having the capability "to recover to a predetermined and programmed shape after significant mechanical deformation in response" to surrounding environmental forces (Yakacki). This research involved the fabrication, preparation, and analysis of photopolymerizable shape-memory polymers (SMPs) that could be used in biomedical applications. A Dynamic Mechanical Anlayzer (DMA) was used to test a variety of polymer compositions to determine their Glass Transition Temperatures (Tg) and Storage Modulii. These properties are useful to determine how polymers will behave under certain conditions. For example, maximum toughness will occur at temperatures at or slightly below the Tg. Both dry and wet samples (soaked in phosphate buffered saline, PBS) were tested to observe property changes under biological conditions. Duplicate tests for each composition were necessary to make any reasonable conclusions about the polymers' thermomechanical properties. The most notable results show that the Tg decreased for wet samples. The more hydrophilic (ability to absorb PBS) the sample, the greater the decrease in Tg. This is important because in biomedical applications the toughness of SMPs is crucial to their performance. Through the results, this research demonstrates that major changes in the mechanical properties of SMP's occur when used in biomedical applications.