Thermoreversible Crosslinking Rubber Using Supramolecular Hydrogen Bonding Networks

Abstract

Thermoreversible crosslinking rubber (TRC-IR) was easily synthesized by modification of isoprene rubber (IR) with maleic anhydride followed by the addition of 3-amino-1,2,4-triazole (ATA), in solid phase. The mechanical properties of the resulting rubber were more similar to the sulfur-vulcanized rubber than general thermoplastic elastomers (ex. SEBS). Although the tensile strength and elongation at break were lower than those of a corresponding sulfur-vulcanized rubber, the moduli were as high as those of sulfur-cured rubber. Re-molding of TRC-IR could be repeated more than 10 times without significantly changing its mechanical properties. Differential scanning calorimetry (DSC) and infrared analyses revealed that the superior mechanical properties and good recyclability are attributable to the strong hydrogen bonding. The TRC-IR showed an endothermic transition peak at around 185 °C on the DSC chart, indicating cleavage of the hydrogen bonding. Infrared analyses also revealed that the absorption peaks of carboxylic acid were shifted to a lower region by the strong hydrogen bonding. The thermoreversible crosslinking system was also applied to EPM, EBM (ethylene-butene rubber), and IIR. These rubbers also showed superior mechanical properties as well as excellent recyclability.

Toughening of poly(L‐lactide) by melt blending with rubbers

“…AEM and EPM rubber compounds were thermoreversibly crosslinked as shown in Figure 1. The addition of the active hydrogen compound, that is, ATA, to maleic anhydride grafted rubber was the step used to generate a hydrogen‐bonding moiety in the rubber phase, creating thermoreversibly crosslinked rubbers 34–36…”

Triple-shape memory effects of modified semicrystalline ethylene–propylene–diene rubber/poly(ε-caprolactone) blends

“…This process was repeated three times and the changes in tensile properties were examined. It was observed that the tensile properties remained similar even after three cycles, indicating the recyclability of the blends [33,34].…”

Mechanical and dismantlement adhesion properties of grafted EPDM-silica hybrid

“…A number of attempts have been made to focus on producing elastomers with hydrogen bonding was reported, in which a recyclable elastomer with mechanical properties similar to cross-linked elastomers was produced by introducing active hydrogen compounds, such as amine, alcohol, and thiol into elastomer. [4][5][6][7][8][9][10][11] Meanwhile, another study focused on producing thermo-reversible elastomers, in which ionic bonding was applied, the mechanical properties were based on the formation of network between introduced ionic groups, and it showed the recycling characteristics as the bonding forces of aggregated molecules got weaker when exposed to high temperature. [12][13][14][15] And, the DSM Company located in Netherlands studied the elastomer with hydrogen and ionic bonding using maleated ethylene-propylene copolymer, and showed improved Cs values rather than the one using only hydrogen bond.…”