Intracranial aneurysms (ICAs) are focal dilations in the brain's arteries. When left untreated, ICAs can grow to the point of rupture, accounting for 50–80% of subarachnoid hemorrhage cases. Current treatments include surgical clipping and endovascular coil embolization to block circulation into the aneurysmal space for preventing aneurysm rupture. As for endovascular embolization, patients could experience aneurysm recurrence due to an incomplete coil filling or compaction over time. The use of shape memory polymers (SMPs) in place of conventional platinum coils could provide more control and predictability for mitigating these complications. This study was focused on characterization of an aliphatic urethane-based SMP to evaluate its potential as a novel biomaterial for endovascular embolization. Twelve compositions of the SMP were synthesized and their thermomechanical properties together with the shape recovery behavior were comprehensively investigated. Our results showed that the SMPs experienced a significant decrease in storage and loss moduli as heated above their glass transition temperatures (32.3–83.2 °C), and that all SMPs were thermally stable up to 265 °C. Moreover, the SMPs exhibited both composition-dependent stress relaxation and a decrease in elastic modulus during cyclic loading. The shape recovery time was less than 11 s for all SMP compositions, which is sufficiently short for shape changing during embolization procedures. Several candidate compositions were identified, which possess a glass transition temperature above body temperature (37 °C) and below the threshold of causing tissue damage (45 °C). They also exhibit high material strength and low stress relaxation behavior, suggesting their potential applicability to endovascular embolization of ICAs.

颅内动脉瘤（ICAs）是大脑动脉的局灶性扩张。如果不及时治疗，ICAs可能会发展到破裂点，占蛛网膜下腔出血病例的50–80％。当前的治疗方法包括外科手术夹闭和血管内线圈栓塞术，以阻止循环进入动脉瘤空间，以防止动脉瘤破裂。至于血管内栓塞，随着时间的推移，线圈填充不完全或压紧，患者可能会出现动脉瘤复发。使用形状记忆聚合物（SMP）代替传统的铂金线圈可以为减轻这些并发症提供更多的控制和可预测性。这项研究的重点是基于脂族氨基甲酸酯的SMP的表征，以评估其作为血管内栓塞的新型生物材料的潜力。合成了十二种SMP组合物，并综合研究了它们的热机械性能以及形状恢复行为。我们的结果表明，当加热到高于其玻璃化转变温度（32.3–83.2°C）时，SMP的存储模量和损耗模量显着降低，并且所有SMP在高达265°C的温度下都具有热稳定性。此外，在循环加载过程中，SMP既表现出与组成有关的应力松弛，又表现出弹性模量下降。对于所有SMP组合物，形状恢复时间均小于11s，这对于在栓塞程序期间改变形状而言足够短。确定了几种候选组合物，它们的玻璃化转变温度高于体温（37°C），并且低于引起组织损伤的阈值（45°C）。