Doi Takahiro, Takagi Hideaki, Shimizu Nobutaka, Igarashi Noriyuki, Sakurai Shinichi
Advanced and Applied Research Institute, Nichiban Co., Ltd., Nihongi-Shinmachi, Anjo, Aichi 446-8531, Japan.
Photon Factory, High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801, Japan.
ACS Omega. 2021 Jul 1;6(27):17299-17313. doi: 10.1021/acsomega.1c01367. eCollection 2021 Jul 13.
The relationship between the mechanical properties and the structure of block copolymers mixed with tackifiers whose relative solubility to the respective components of block copolymers differs was examined. Coated layers were prepared by solution coating using a block copolymer composed of polystyrene (PS) and polyisoprene (PI), which forms spherical microdomains of PS in the PI matrix, mixed with three types of tackifiers: aliphatic (C5) resin, aliphatic-aromatic (C5-C9) resin, and rosin ester (RE) resin. Furthermore, the correlation between the changes in the nanostructure and mechanical properties including the stress-relaxation behaviors was clarified by two-dimensional small-angle X-ray scattering measurement. The amount of the PI-bridge conformation in the case of C5 resin is the lowest, resulting in the lowest stress. On the contrary, the largest amount of RE resin was solubilized in the PS phase so that it can be considered that pulling out of the PS chains took place easily. We were able to explain the stress-relaxation behavior by fitting with the three-component exponent functions. The triple exponential decay functions indicate the hierarchy of the structures that are the origins of the ″fast mode″ relating to the local relaxation due to the rotation of the repeating unit of polymer chains; the ″intermediate mode″ of the disentanglement of the mid-PI chains; and the ″slow mode″ relating to, in this particular case, pulling out of the PS chains from the PS sphere.
研究了与增粘剂混合的嵌段共聚物的力学性能与结构之间的关系，这些增粘剂对嵌段共聚物各组分的相对溶解度不同。使用由聚苯乙烯（PS）和聚异戊二烯（PI）组成的嵌段共聚物通过溶液涂布制备涂层，该嵌段共聚物在PI基质中形成PS的球形微区，并与三种增粘剂混合：脂肪族（C5）树脂、脂肪族-芳香族（C5-C9）树脂和松香酯（RE）树脂。此外，通过二维小角X射线散射测量，阐明了纳米结构变化与包括应力松弛行为在内的力学性能之间的相关性。在C5树脂的情况下，PI桥构象的量最低，导致应力最低。相反，大量的RE树脂溶解在PS相中，因此可以认为PS链的拔出很容易发生。我们能够通过用三组分指数函数拟合来解释应力松弛行为。三重指数衰减函数表明了结构的层次，这些结构是与聚合物链重复单元旋转引起的局部松弛相关的“快速模式”、PI中间链解缠结的“中间模式”以及在这种特定情况下与PS链从PS球体中拔出相关的“慢速模式”的起源。
