Effects of Smectic Layer Deformation on Mechanical Properties of Glassy Liquid Crystal Polymer Fibers
Effects of Smectic Layer Deformation on Mechanical Properties of Glassy Liquid Crystal Polymer Fibers
复制标题
近晶层变形对玻璃态液晶聚合物纤维力学性能的影响
DOI：
10.1002/macp.202300032
复制
发表时间：
2023
影响因子：
2.5
通讯作者：
Tokita Masatoshi
中科院分区：
文献类型：
--
作者：
Kawahara Katsuki;Suzuki Ryoji;Tokita Masatoshi
在这项工作中，它表明，玻璃态近晶液晶（LC）聚合物纤维的应力响应在很大程度上取决于层的变形。通过拉伸熔融的主链LC聚酯制备的具有沿纤维轴沿着堆叠的近晶层的纤维（纤维A）通过在LC状态下的拉伸变形使层变形，产生具有从纤维轴倾斜的层的纤维（纤维B）和具有分开的层的纤维（纤维C）。玻璃态LC状态下的这些纤维在杨氏模量（E）、屈服应力和应变（σy，εσy）以及断裂应变（εB）方面不同。纤维A的εB= 30%;然而，纤维B的延展性更大（εB> 290%）。纤维C具有比纤维A（E= 0.33MPa和σy= 33 MPa）高的E = 0.97GPa和σy= 82 MPa。在LC状态下退火纤维C产生具有大面积层的纤维D，类似于纤维A。纤维D的E = 0.74GPa，σy= 25 MPa，与纤维A相当。因此，分层提高了E和σy。这种通过分层来增强玻璃态近晶液晶的方法适用于具有层状结构的其他聚合物，包括层状嵌段共聚物和半结晶聚合物。
In this work, it is demonstrated that the stress response of glassy smectic liquid crystal (LC) polymer fibers is largely dependent on layer deformations. Fibers with smectic layers stacked along the fiber axis (fiber A), prepared by stretching a molten main‐chain LC polyester, deform the layers by tensile deformation in the LC state, yielding fibers with layers tilted from the fiber axis (fiber B) and those with divided layers (fiber C). These fibers in the glassy LC state differ in Young's modulus (E), yield stress and strain (σy,εσy), and strain at break (εb). Fiber A hasεb= 30%; however, fiber B is much more ductile (εb> 290%). Fiber C has higherE= 0.97 GPa andσy= 82 MPa than fiber A (E= 0.33 MPa andσy= 33 MPa). Annealing fiber C in the LC state yields fiber D with large‐area layers, similar to fiber A. Fiber D hasE= 0.74 GPa andσy= 25 MPa, comparable to those of fiber A. Thus, dividing layers improvesEandσy. This strengthening of glassy smectic LC by dividing layers applies to other polymers with layered structures, including lamellar block copolymers and semi‐crystalline polymers.