12-(cis-5-Norbornene-exo-2,3-dicarboximido)dodecanoate pentafluorophenyl ester (exo-NBC12-PFP) was used as a norbornene-substituted end-capping terminator of living anionic polymers. Polystyrene with a terminal 1,1diphenylethyllithium (PSt(DPE) − Li + ), poly(2-vinylpyridine) with a terminal 2-pyridinylethyllithium (P2VP − Li + ), and poly(benzyl methacrylate) with a terminal lithium ester enolate (PBzMA − Li + ) reacted with exo-NBC12-PFP under appropriate reaction conditions to generate norbornenyl-ω-end macromonomers, NBC12-PSt, NBC12-P2VP, and NBC12-PBzMA, respectively, each with a 12-carbon spacer. To estimate the efficiency of end-capping, these macromonomers were polymerized by grafting-through ring-opening metathesis polymerization (ROMP). The end-capping reaction of PSt(DPE) − Li + and P2VP − Li + suffered from side reactions resulting in low end-capping efficiencies and the generation of by-products. On the other hand, the side reactions were minimal in the end-capping reaction of PBzMA − Li + , resulting in a high end-capping efficiency of 95%. The ROMP of NBC12-PBzMA allowed the synthesis of poly[12-(5-norbornene-exo-2,3-dicarboximido)dodecanoylate]-graft-poly(benzyl methacrylate)s (PNBC12-g-PBzMAs) with a wide range of controlled molecular weights (M n = 436−4048 kDa, Đ = 1.07−1.23).
A molecular-level ordered supramolecular nanostructure is formed of P4VPPy and FDA, using a solvent vapor thermal annealing process that initiates hydrogen bonding directed self-assembly.
A number of unreported salen aluminum complexes bearing Schiff base ligands starting from (R,R)-1,2-diammoniumcyclohexane mono-(+)-tartrate salt were synthesized. These complexes were characterized by 1 H, 13 C NMR, and elemental analysis. These complexes were employed as initiators for the ring-opening polymerization (ROP) of Llactide and rac-lactide. Complex 3 (R = Br) showed the highest activity for the ROP of L-lactide among these complexes, and complex 2 (R = i Pr) possessed the highest stereoselectivity for the ROP of rac-lactide among these aluminum isopropoxides. The kinetics studies of the polymerization employed complex 2 as initiator indicated that the polymerization rate was first-ordered in lactide and initiator.
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