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4699956 
Journal Article 
Efficient Synthesis of alpha,omega-Divinyl-Functionalized Polyolefins 
Patil, VB; Saliu, KO; Jenkins, RM; Carnahan, EM; Kramer, EJ; Fredrickson, GH; Bazan, GC 
2014 
1 
Macromolecular Chemistry and Physics
ISSN: 1022-1352 
215 
11 
1140-1145 
WOS:000337626500010 
A facile one-step olefin metathesis-mediated ethenolysis reaction on polyolefins containing 1,4-inserted butadiene units yields alpha,omega-divinyl telechelic polymers. These reactions can be successfully performed with well-defined thermally stable ruthenium catalysts to yield essentially complete metathesis of internal double bonds. The reaction progress is monitored by H-1 NMR spectroscopy over time, by tracking the disappearance of the signal due to internal unsaturation of 1,4-butadiene at ca. 5.5 ppm in toluene-d(8) solvent. The reaction conditions are optimized for ethylene pressure, temperature, catalyst loading, and reaction time. Catalyst loading of 45:1 1,4-butadiene unsaturation to catalyst at 90 degrees C with 25 psi ethylene pressure is successful in removing internal unsaturation with no detectable isomerization side reactions. High-temperature gel-permeation chromatography (GPC) analysis of the depolymerized product correlates to the calculated molecular weight based on the number of internal double bonds observed in the H-1 NMR analysis of the starting polyolefin. This method offers a single step, rapid, and clean route toward divinyl-terminated telechelic polymers based on commodity materials in high yields. 
ethenolysis; olefin metathesis; depolymerization; polyolefins; telechelic polymers