English Abstract

Syntheses and Property of Rotaxane-Cross-linked Polymers: Influence of Coexisted Covalent Cross-link on The Property

Keisuke IIJIMA
Daisuke AOKI
Toshikazu TAKATA
Department of Chemical Science and Engineering, Tokyo Institute of Technology, Meguro-ku, Tokyo, Japan
Nippon Gomu Kyokaishi,(2019),92(3),101-108 Original Paper in Japanese

To investigate the influence of co-existed covalent cross-link in rotaxane cross-linked polymer (RCP) on the property, several hybrid cross-linked polymers (HCPs) containing both rotaxane- and covalent cross-linked structures were synthesized by the radical polymerization of N,N-dimethylacrylamide(DMAA) using ratio-different mixtures of a vinylic supramolecular cross-linker consisting of γ-cyclodextrin and PEG-based macromonomer as a rotaxane cross-linker and a terminal dimethacrylated polyethylene glycol (PEG) as a covalent cross-linker. The cross-linked polymers were subjected to the investigation on the swelling property and tensile strength. All HCPs showed similar properties to those of a covalently cross-linked polymer (CCP) but considerably different from those of RCP. In particular, the mechanical property of HCPs was much lower than that of RCP in fracture energy and stress. From the results obtained in this work, it was elucidated that the power of the rotaxane-cross-link only appears, when the cross-links of cross-linked polymer mainly contain the rotaxane cross-links, which guarantees the mobility of polymer chains at the cross-link points to prevent the stress concentration, even in water-containing gelled polymers. This finding would provide an important design guide for the polymer toughening.

Keywords: Rotaxane, Network Polymer, Cyclodextrin, Rotaxane-cross-link, Covalent Cross-link, Mechanical Property