Jeongeun Kim, Eun-Hye Kang, and Tae-Lim Cho
http://pubs.acs.org/doi/pdf/10.1021/mz300250b
A 1,6-heptadiyne monomer containing a Meldrum acid (ketene precursor)
functional group was copolymerized with monomers 1 or 2 (see figure) to
afford solubility using cyclopolymerization with the third generation
Grubbs catalyst. Studies from AFM, NMR, and DLS suggested these polymers
self-assembled into core-shell type nanoparticles with the insoluble
Meldrum's acid facing toward the center. Upon heating to 200 C,
Meldrum's acid releases CO2 and acetone and generates a ketene. The
formation of ketene was tested through thermal gravimetric analysis, in
which a drop in the weight was observed; and infrared spectroscopy. Also
upon heating to 240 C for ten minutes, IR signal suggested the ketenes
started to react through [2+2] cycloaddition to give cyclobutanedione,
which permanently crosslinked the cores.
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