Synthesis of Shape-Memory Polyurethanes: Combined Experimental and Simulation Studies

Abstract

The presented research focuses on the synthesis and structure–properties relationship of poly(carbonate-urea-urethane) (PCUU) systems including investigations on shape memory effect capability. Furthermore, we approached the topic from a broader perspective by conducting extensive analysis of the relationship between the synthesized compounds and the results of computer simulations by means of the Monte Carlo method. For the first time, by using a unique simulation tool, the dynamic lattice liquid model (DLL), all steps of multi-step synthesis of these materials were covered by the simulations. Furthermore, broad thermal, mechanical, and thermomechanical characterization of synthesized PCUUs was performed, as well as determining the shape memory properties. PCUUs exhibited good mechanical properties with a tensile strength above 20 MPa, elongation at break around 800%, and an exhibited shape memory effect with shape fixity and shape recovery ratios above 94% and 99%, respectively. The dynamic lattice liquid model was employed to show the products and their molar mass distribution, as well as monomer conversion or the dispersity index for individual reaction steps. The results obtained in the following manuscript allow the planning of syntheses for the PCUUs of various structures, including crosslinked and soluble systems, which can provide a broad variety of applications of these materials, as well as a better understanding of the composition–properties relationship.

Electrospun Poly(carbonate-urea-urethane)s Nonwovens with Shape-Memory Properties as a Potential Biomaterial

“…The strain-induced crystallization can result in partial microphase separation, and thus, the T g of the soft segment shifted down. Values of Δ H m of nonwovens in the first run (18–40 J·g –1 ) were higher than in casted materials (18 J·g –1 ), which indicates an increase in the order of the structure and, consequently, an increase in the crystalline phase. This is a consequence of strain-induced crystallization, which occurs during ES .…”

“…A detailed analysis of the starting material, casted PCUU, has been reported in our previous work. 64 molar mass (M n ) of 3000 g•mol −1 , estimated based on 1 H NMR and confirmed by MALDI-TOF analysis. The molar excess of IPDI to the level of the OCD was equal to 3, which led to 18 wt % hard segments in the structure.…”

“…A detailed analysis of the starting material, casted PCUU, has been reported in our previous work . It allowed us to determine the polymer composition and enabled the selection of soluble structures of PCUU.…”

“…The motivation for this investigation was based on the fact that the casted PCUUs exhibit very good shape-memory properties, with a shape-recovery ratio (R r ) of 99.6 ± 0.1% and a shapefixity ratio (R f ) of 95.8 ± 0.1%. 64 In the present studies, similar shape-memory parameters were observed for the nonwovens obtained by ES. In the case of samples prepared on a plate collector, we observed good shape-memory performance with R r around 99% and R f around 96% (Table 5).…”

“…63 Based on these findings, we found it crucial to continue studies on the potential usage of PCUU in the field of tissue engineering. For the purposes of the project, we selected PCUU materials exhibiting SME, 15,64,65 which are known for good hydrolytic stability, and used them as substrates in electrospinning of nanofibers. We investigated the effect of the ES parameters on the nonwoven morphology and the thermal and mechanical parameters.…”