Jing Xin, Mi Hao-Yang, Huang Han-Xiong, Turng Lih-Sheng
Department of Industrial Equipment and Control Engineering South China University of Technology, Guangzhou, China; Wisconsin Institute for Discovery University of Wisconsin, Madison, WI, USA.
Department of Industrial Equipment and Control Engineering South China University of Technology, Guangzhou, China.
J Mech Behav Biomed Mater. 2016 Dec;64:94-103. doi: 10.1016/j.jmbbm.2016.07.023. Epub 2016 Jul 22.
Thermally responsive shape memory polymers have promising applications in many fields, especially in biomedical areas. In this study, a simple method was purposed to prepare thermoplastic polyurethane (TPU)/poly(ε-caprolactone) (PCL) blends that possess shape memory attributes. TPU and PCL were melt compounded via a twin-screw extruder and injection molded at various ratios. Multiple test methods were used to characterize their shape memory properties and reveal the underling mechanism. The blends containing 25% TPU and 75% PCL possessed the best shape memory properties as indicated by a 98% shape fixing ratio and 90% shape recovery ratio. This was attributed to the hybrid crystalline and amorphous regions of PCL and TPU. We also found that PCL and TPU had good miscibility and that the PCL domain in TPU25% had higher crystallinity than neat PCL. The crystalline region in TPU25% could deform and maintain its temporary shape when stretched, which contributed to its high shape fixing attribute, while the rubbery TPU region assisted in the recovery of the sample upon heating by releasing the deformation energy stored. Moreover, the TPU25% string prepared could knot itself in a hot water bath, indicating a potential for suture applications. Lastly, the 3T3 fibroblast cells cultured on the TPU/PCL blends showed high viability and active substrate-cell interactions.
热响应性形状记忆聚合物在许多领域都有广阔的应用前景，尤其是在生物医学领域。在本研究中，我们提出了一种简单的方法来制备具有形状记忆特性的热塑性聚氨酯（TPU）/聚己内酯（PCL）共混物。通过双螺杆挤出机将TPU和PCL进行熔融共混，并以不同比例注塑成型。采用多种测试方法对其形状记忆性能进行表征，并揭示其潜在机制。含有25%TPU和75%PCL的共混物具有最佳的形状记忆性能，形状固定率为98%，形状回复率为90%。这归因于PCL和TPU的混合结晶区和非晶区。我们还发现PCL和TPU具有良好的相容性，并且TPU25%中的PCL域比纯PCL具有更高的结晶度。TPU25%中的结晶区在拉伸时可以变形并保持其临时形状，这有助于其高形状固定特性，而橡胶状的TPU区域通过释放储存的变形能量，在加热时协助样品恢复。此外，制备的TPU25%细绳在热水浴中可以自行打结，表明其在缝合应用方面具有潜力。最后，在TPU/PCL共混物上培养的3T3成纤维细胞显示出高活力和活跃的底物-细胞相互作用。
