Thermal induced intrinsic self‐healing in epoxy based elastomer coatings provided by disulfide metathesis reactions

Abstract

AbstractSelf‐heal epoxy coatings have been prepared using sulfur–sulfur metathesis reaction as an intrinsic method for inducing self‐healing property. Inducing of the self‐healing property was carried out via insertion of the 3,3′‐dithiodipropionic acid as chain extender functionalized with bisphenol A diglycidyl ether. According to the results, the prepared coatings were capable to recover their mechanical properties after damage and heal their surface as well. Noticeably, the healing yield of the coatings was about 43% and 76% for the samples containing 0.5 and 1.0 equivalents of chain extender, respectively. Furthermore, the mechanical properties of the self‐heal coating were modified in the presence of the disulfide bonds from 0.22 MPa to 1.25 MPa. Regarding to the increment of the crosslinking density due to the presence of the sulfur containing chain expender, the average molecular weights between crosslinkings was reduced from 43.75 × 103 g mol−1 in epoxy sample to 4.61 × 103 g mol−1 in sulfur containing sample. The proposed facilitate method for inducing the self‐healing property make it applicable to a wide range of epoxy coatings.