Thermoreversible rheological responses of biscarbamates and tricarbamates in uncured epoxy composite pastes caused by their self‐assembly in an epoxy matrix

Abstract

We investigated the rheological behaviors of diglycidyl ether of bisphenol A (epoxy resin) composite pastes with fumed SiO 2 , biscarbamates, and tricarbamates with the same terminal alkyl chains of C 16 , respectively. The rheological measurement results show that the rheological responses of both carbamates in the epoxy composite pastes were stronger than that of fumed silica at the same concentrations, especially at low concentrations, and the rheological behaviors of the epoxy composites with them were thermally reversible and concentration dependent. IR, thermal, differential scanning calorimetry, and polarized microscopic analyses demonstrated that their different excellent rheological responses in epoxy composite pastes came from their different self-assemblies in the epoxy matrix, which were caused by the different intermolecular interactions, mainly including hydrogen-bonding and van de Waals interactions, and the intermolecular interactions for carbamates were closely related to their molecular structures. V C 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46032.

Small molecule self‐assembly in polymer matrices

“…We discussed the cases of hydrogen‐bonding (carbamates and biscarbamates) and π‐interaction mediated (phthalocyanines) self‐assembly of small molecules in polymer matrices and the influence of solvents used for preparing the films. Since the self‐assembly is reversible, recently, Zhang et al used the self‐assembling features of biscarbamates and tricarbamates by incorporating them into epoxy composites to facilitate thermo‐reversible rheological responses. The phenomena of solvent‐induced depression of glass transition temperatures and solvent‐induced crystallization were investigated a few decades ago, but are finding new applications.…”