Polyethylenes endowed with low densities of in-chain hydrolyzable and photocleavable groups can improve their circularity and potentially reduce their environmental persistency. We show with model polymers derived from acyclic diene metathesis polymerization that the simultaneous presence of both groups has no adverse effect on the polyethylene crystal structure and thermal properties. Post-polymerization Baeyer-Villiger oxidation of keto-polyethylenes from non-alternating catalytic ethylene-CO chain growth copolymerization yield high molecular weight in-chain keto-ester polyethylenes (M ≈50.
View Article and Find Full Text PDFDue to chain transfer events being competitive with chain growth, ethylene polymerization by P,O-chelated Ni(II) complexes usually affords low molecular weight polymers or oligomers. We now show that appropriately bulky substituted phosphinophenolato Ni(II) can polymerize in a living fashion, virtually devoid of chain transfer. Aqueous polymerizations with microemulsions of [κ--2-(2-(2',6'-(MeO)CH)CH)(Ph)P-6-(3',5'-(CF)CH)CHO-NiMe(pyridine)] () at 30 °C yield polyethylenes with narrow molecular weight distributions (/ 1.
View Article and Find Full Text PDFThe world’s most abundantly manufactured plastic, polyethylene, consists of inert hydrocarbon chains. The introduction of reactive polar groups in these chains could help overcome problematic environmental persistence and enhance compatibility with other materials. We show that phosphinophenolate-coordinated nickel complexes can catalyze nonalternating copolymerization of ethylene with carbon monoxide to incorporate a low density of individual in-chain keto groups in polyethylene chains with high molecular weight while retaining desirable material properties.
View Article and Find Full Text PDFIn several fields of research, like e.g. photosensitization, photovoltaics, organic electroluminescent devices, dynamic nuclear polarization, or pulsed dipolar electron paramagnetic resonance spectroscopy, triplet state kinetics play an important role.
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