Pekol Collin, Furst Jacob, Li Yuzhan, Keum Jong, Harper David P
Department of Materials Science and Engineering, The University of Tennessee, Knoxville, Tennessee 37996-4519, United States.
School of Materials Science and Engineering, University of Science and Technology, Beijing 100083, China.
ACS Omega. 2024 Sep 17;9(39):40801-40809. doi: 10.1021/acsomega.4c05664. eCollection 2024 Oct 1.
A two-component liquid crystalline epoxy network (LCEN) with shape memory behavior was developed and evaluated as a candidate material for 3D printing. The cure kinetics of the uncured material and the shape memory properties of the cured LCEN were investigated by using parallel plate rheology and dynamic mechanical analysis, respectively. A commercially available fumed silica additive was introduced to the neat, uncured material to improve the rheological properties for 3D printing. The addition of fumed silica was found to increase the yield stress, shear-thinning behavior, and toughness of the uncured epoxy ink. Polarized light microscopy, differential scanning calorimetry, and wide-angle X-ray scattering measurements between the neat and additive-modified LCEN suggested a reduction in liquid crystalline alignment in the modified LCEN, owing to interactions between crystalline domains and fumed silica, which in turn influenced the mechanical behavior. Overall, the additive was found to be successful in preserving the shape memory properties of LCEN while improving its printability.
开发了一种具有形状记忆行为的双组分液晶环氧网络（LCEN），并将其作为3D打印的候选材料进行评估。分别使用平行板流变学和动态力学分析研究了未固化材料的固化动力学和固化后LCEN的形状记忆性能。将市售的气相二氧化硅添加剂引入到纯净的未固化材料中，以改善用于3D打印的流变性能。发现添加气相二氧化硅可提高未固化环氧油墨的屈服应力、剪切变稀行为和韧性。纯净的和添加剂改性的LCEN之间的偏光显微镜、差示扫描量热法和广角X射线散射测量表明，由于晶域与气相二氧化硅之间的相互作用，改性LCEN中的液晶排列减少，这反过来又影响了机械性能。总体而言，发现该添加剂在保持LCEN形状记忆性能的同时提高其可打印性方面是成功的。
