Supramolecular Poly(tetrahydrofuran) Based on a Pyrimidinone Associating Motif

Self-assembly of low molecular weight oligomers through reversible hydrogen bond motifs can result in materials with polymer-like properties in bulk as well as in solution. The self-assembly supramolecular polymerization has become a rapid growing area of research due to the temperature sensitive behaviour of the supramolecular polymers. The synthesis and characterization of pyrimidinone (2-ureido-4[1H]-pyrimidinone, UPy) terminated poly(tetrahydrofuran) (PTHF(UPy)2), a supramolecular poly(tetrahydrofuran) is reported here. A low molecular weight poly(tetrahydrofuran) diol (PTHF(OH)2) was functionalized with a strongly dimerizing UPy functional groups at both ends and their chemical structure as well as the material properties were studied. It is shown that PTHF(OH)2, which is a waxy material at room temperature, behaves like thermoplastic elastomers upon functionalization with UPy end groups. PTHF(UPy)2 resembles a strong material with tensile strength and tensile modulus of about 15 and 85 MPa, respectively. The rheological studies revealed that the supramolecular structure of poly(tetrahydrofuran) is stable upon heating up to about 80؛C. Above this temperature the supramolecular interactions start to dissociate, which are indicated by a sharp decrease in viscosity. Therefore, processing of PTHF(UPy)2 is possible at considerably low temperatures (slightly above 80؛C).