Impact of Quenching Agents on Internal Associations and Structure of Amine-Functionalized Polyolefins

We investigated the impact of intermolecular interactions on rheomechanical and self-healing properties of poly(cyclooctene) functionalized with an N -methyl aniline derivative, a form of aminated polyethylene (APE). The amine groups in APEs form reversible associations that aggregate due to the polarity difference with the nonpolar backbone. The structure of the aggregates impacts the long-term self-healing and rheological properties. Potassium tri(1-pyrazolyl) borohydride (KTp) was introduced as a bulky quenching agent during synthesis to efficiently hinder the aggregation of APE’s amine groups. KTp’s shielding effect was compared to that of ethyl vinyl ether (EVE), a standard quenching agent for ring-opening metathesis polymerization (ROMP) using rheology, dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and nuclear magnetic resonance (NMR). When quenched with either EVE or KTp, APEs retained natural viscoelastic behavior. However, when exposed to high temperature, stronger aggregates formed in the EVE-quenched APE compared to the KTp-quenched APE, causing delayed relaxation dynamics and an increase in T g . KTp enhanced the self-healing recovery of APE after prolonged heat exposure, as a sufficient concentration of active groups remained available at the interface to reassociate after damage. 1 H NMR spectroscopic analysis confirmed these findings, supporting the rheological and self-healing observations. This work shows that macroscopic properties can be controlled by tuning the intermolecular associating states.