Aliphatic ditopic nitrile N-oxide crosslinker: Synthesis, chemical stability, and catalyst-free crosslinking reactions. (20th January 2021)

• Record Type: Journal Article
• Authors: Sogawa, Hiromitsu; Wang, Chen-Gang; Monjiyama, Shunsuke; Akae, Yosuke; Takata, Toshikazu
• Is Part Of: Polymer. Volume 213(2021)
• Publication Date: 2021-01-20
• Subjects: Nitrile N-oxide -- 1, 3-dipolar cycloaddition -- Crosslinking reaction; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2020.123291
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: Nitrile N -oxides are useful reagents and crosslinkers for catalyst- and byproduct-free 1, 3-dipolar cycloaddition reactions. The stability of nitrile N -oxides can be enhanced by introducing bulky substituents, whereas their reactivity decreases concomitantly. Herein, an isolatable aliphatic ditopic nitrile N -oxide was synthesized and applied to catalyst-free crosslinking of unsaturated bond-containing polymers. By decreasing the steric hindrance around the nitrile N -oxide moiety compared with a related crosslinker previously developed in our group, the operating temperature of the crosslinking reaction could be lowered. Efficient crosslinking of natural rubber (NR) was achieved at 40 °C in chloroform to give crosslinked NR without formation of byproducts. Furthermore, polyacrylonitrile and nitrile butadiene rubber can be used as the scaffolds for efficient catalyst- and solvent-free crosslinking reactions. Graphical abstract: Image 1 Highlights: Novel isolatable aliphatic ditopic nitrile N -oxide was synthesized. Efficient catalyst- and solvent-free crosslinking of unsaturated bond-containing polymers was successfully achieved. The decrease of the steric hindrance allowed to lower the operating temperature of crosslinking reaction.