Thermoreversible Crosslinking of Maleic Anhydride Grafted Butyl Rubber With Multiple Hydrogen Bonding Arrays

Thermoreversible crosslinking supramolecular rubber with multiple hydrogen bonds are prepared via reaction of maleic anhydride grafted butyl rubber (MAn-g-IIR) with 3-amino-1,2,4-triazole catalyzed by tetrabutyl ammonium bromide. Then, the hydrogen bonding arrays are introduced via the reaction between the obtained amide triazole-carboxylic acid groups. Microphase-separated aggregates that acts as physical crosslinks in the MAn-g-IIR is significantly tightened and strengthened after introducing multiple hydrogen bonds, resulting in increasing of X-ray powder diffraction intensity and drastically improvement of tensile strength. After heating-cooling treatment up to three cycles, no evidence of chemical change is observed from Fourier transform infrared spectra, and the tensile strength of thermoreversible crosslinking IIR was still much higher than that of the MAn-g-IIR. The reprocessability of this material was due to the thermoreversibility of hydrogen bond at elevated temperature, while the maintenance of tensile properties is due to the recovery of hydrogen bond during cooling. (C) 2013 Society of Plastics Engineers