Funian Mo,Jianfeng Ban,Lulu Pan,Bo Shi,Shaorong Lu
In this study, a novel series of supramolecular liquid crystalline (LC) polyurethane composites, named SMPU–#HOBA (# represents the molar ratio of HOBA/BINA), were successfully prepared by incorporating hexadecyloxybenzoic acid (HOBA) into pyridine-containing polyurethane (PU). The effect of HOBA on the structure, morphology, and properties has been carefully investigated. The results demonstrate that the obtained SMPU–#HOBA composites not only maintained the LC property of the HOBA mesogen, but also enhanced the intrinsic crystallization of the soft segment phase. Thus, the composites showed an excellent multi-shape memory property with two crystalline temperatures. Moreover, self-gripping was demonstrated revealing reversible bidirectional shape memory by virtue of molecular flipping and movement of the hard segment domain. These composites display a rare combination of LC properties, multi-shape memory properties, and reversible bidirectional shape memory properties, which makes them ideal for many potential applications in smart temperature sensitive devices.
Shaojun Chen,Hongming Yuan,Shiguo Chen,Haipeng Yang,Zaochuan Ge,Haitao Zhuo,Jianhong Liu
Supramolecular liquid crystalline polymers and shape memory polymers are attracting increasing interest as materials. In this paper, we describe the development of a supramolecular liquid crystalline shape memory polyurethane (SLCSMPU) complex that exhibits both liquid crystalline properties and shape memory properties. The complex is formed by incorporating 4-hexadecyloxybenzoic acid (HOBA) into a pyridine-containing shape memory polyurethane (PySMPU). The HOBA is tethered to the PySMPU by strong hydrogen bonding between the pyridine rings and the COOH of the HOBA, forming a SLCSMPU complex. Heat treatment plays an important role in the formation of hydrogen-bonded supramolecular liquid crystalline structures in these SLCSMPU complexes. Thus, the SLCSMPU complex not only maintains the intrinsic liquid-crystalline properties of HOBA, but can also form a stable polymeric film for various shape memory applications. Additionally, the SLCSMPU complex forms a two-phase separated structure composed of an amorphous polyurethane matrix and a HOBA crystalline phase, which includes the hydrogen-bonded crystalline HOBA phase and the free HOBA crystalline phase. Therefore, a simple one-step programming process is developed that produces SLCSMPU complexes with excited triple-shape functionalities due to their multiple phase transitions, especially when the molar ratio of HOBA/BINA is less than 0.8.
危险品化学品经营许可证（带存储）