报告时间：2014年6月17日（星期二）13:00—14:00

报告地点：龙赛理科楼南楼202报告厅

报告人：Boyu Li, PhD Candidate in Chemistry, California Institute of Technology

报告摘要：

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

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