A series of supramolecular polymers based on hydrogen bonds with different structures were synthesized through the reaction between 1
12-diaminododecane (DDA) and acrylic acid (AA)
and then compounded with carboxyl nitrile rubber (XNBR) and other processing agents. After the sample being vulcanized
supramolecular polymers were formed
in situ
in the rubber matrix
thus sulfur crosslinked XNBR with high strength and toughness was prepared. The results showed that the tensile strength
modulus and toughness of the materials were improved by incorporating different supramolecular polymers. Specially
when the supramolecular polymer synthesized with the molar ratio of DDA to AA of 1∶3 was added to XNBR
the tensile strength and fracture energy of the material were 2.1 and 2.7 times that of the blank sample
respectively.This is because the fact that hydrogen bond
as a weak bond
will break prior to covalent bond when the material is under tension
which will dissipate a lot of energy in this process
thus improving the tensile strength and toughness of the material. In addition
the mechanism of energy dissipation and the time dependence of hydrogen bond fracture were further proven by cyclic tensile test and variable speed tensile test.