Mega-supramolecules by end-association of very long telechelics: Highly potent rheology modifiers

Abstract

To favor linear end-to-end assocn. of telechelic polymers, very long chain lengths are used to inhibit cyclic configurations. Specifically, based on theor. predictions, telechelic polymers with high mol. wt. (Mw>400k g/mol) were synthesized to see if they could mimic multi- million MW polymers- and they did (in shear rheol. and mist suppression). Building on the Hilmyer- Macosco protocol for ROMP of cyclooctadiene with CTAs bearing functional groups, improvements in monomer purifn. enabled synthesis of telechelics with unprecedented length. The importance of chain length was confirmed by examg. telechelics from 75k to >400k g/mol. To test theor. expectations that donor-acceptor assocn. would yield more potent rheol. modifiers than self-assocn., carboxylate- functional telechelics were paired with amine-functional ones and they did increase viscosity more strongly than self-assocg. chains of similar assocn. energy, length and concn. Motivated by rheol. evidence of difference in supramol. structures, SANS measurements were performed and preliminary results correspond with theor. expectations.

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