Mechanically or topologically cross-linked polymers have attracted much attention as novel soft materials in which no chemical bonding exists between chains. Their three-dimensional structures are quite different from those of conventional network polymers formed by chemical or physical cross-linking. Each polymer chain is linked through mechanical linkage via chain threading of ring segment. Since cross-linking points can move, these network polymers are expected to exhibit good swelling properties and high impact strength due to high degrees of freedom in the segmental movement.<br/>In this work preparation of three-dimensional polymers with movable cross-linking points utilizing two-step cross-linking via pseudopolyrotaxane will be reported. The first step is formation of pseudopolyrotaxane composed of cyclic and linear chain segments which can react each other. The second step corresponds to covalent fixation of the two segments to obtain three-dimensional structure. Examples of two-step cross-linking polymers studied in this work involve poly(dimethylsiloxane) (PDMS) and poly(N-isopropylacrylamide) (PNIPAAm). The former was obtained by the ultrasonic treatment of the mixture of cyclic PDMS carrying propargyl group and azide-functionalized linear PDMS followed by thermal Click Chemistry. The latter was obtained by copolymerization of NIPAAm with N-propargylacrylamide in the presence of cyclic polyethylene glycol (cyclic PEG) carrying azide group followed by thermal Click Chemistry.

Preparation of three-dimensional polymers with movable cross-linking points via pseudopolyrotaxane

255th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.