Pyridine shape memory polyurethanes

Chen S.,Hu J,Yuen C. and Chan L. (2009),Novel moisture-sensitive shape memory polyurethanes containing pyridine moieties. Polymer, 50 pp. 4424-4428. 

Key words supramolecular shape memory polyurethane, pyridine, thermal-responsive shape memory effect, shape memory mechanism, N,N-bis(2-hydroxyl ethyl) isonicotinamide. 

Synthesis of shape memory polyurethanes (SMPUs) containing pyridine moieties... 

Abstract This chapter presents the thermaUy-indnced shape memory properties of supramolecular shape memory polyurethane (SMPU) containing pyriine moieties, and compares them with those of other types of SMPU. llie influence of the BINA content and the MDI-BDO content on the thermally-induced shape memory effects (SMEs) of these SMPUs are discussed, including shape fixity, shape recovery and shape recovery stress, as well as the temperature-dependent strain recovery process. A description and analysis of the mechanism of thermaUy-induced SMEs is also provided, covering the effect of temperature and pyridine content on the hydrogen bonds present in SMPUs. 

Abstract This chapter introduces the moisture-induced shape memory effect (SME) observed in supramolecular shape memory polymers, particularly shape memory polyurethane (SMPU), containing pyridine moieties. The moisture absorption of polyurethane networks containing pyridine moeties (PUPy) is discussed followed by an investigation into the effect of relative humidity (RH), temperature, BINA content and MDI-BDO content. The induence of moisture absorption on both the thermal properties and the dynamic mechanical properties of SMPUs is also described, along with the moisture-induced SME mechanism. 

Synthesis routine of shape memory polyurethane with pyridine unit (reprinted with kind permission of Elsevier Ltd). 

Chen SJ, Hu JL, Chen SG. Studies of the moisture-sensitive shape memory effect of pyridine-containing polyurethanes. Polym Int 2012 61(2) 314—20. 

Chen, S. J., Hu, J. L., Yuen, C. W., Chan, L. K. (2009b), Supramolecular polyurethane networks containing pyridine moieties for shape memory materials. Mater. Lett., 63, 1462. ... 

Most recently, Zhu et al. (2009) and Chen et al. (2009) reported another new type of supramolecular polyurethane network that contains a relatively high fraction of UPy groups for shape memory materials (SMMs). However, to date there has been no systematic account of the SMEs of pyridine-containing polyurethanes (PUPys), and previous studies have not explained the relationship between SMEs and non-covalent bonds. This chapter aims to fill that gap with a detailed study of the thermally-induced SMEs of BIN-SMPUs based on an investigation of their morphology and properties. The influence of the BINA content and pyridine ring fractions on shape fixity, shape recovery, shape stability, thermal-dependent shape recovery and shape recovery force is also systematically examined. 

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