Effects of Different Reactive Oxyanionic Initiators on the Anionic Polymerizaition of n-Hexyl Isocyanate

Abstract

Poly(n-hexyl isocyanate) was synthesized by anionic polymerization using various oxy-initiators, including sodium phenoxide (Na-PO), sodium benzhydroxide (Na-BH), and sodium methoxyphenylethoxide (Na-MPE). We optimized polymerization conditions. To confirm the living natures of the polymerization, we carried out various polymerizations changing mole ratio between monomers and initiators and a postpolymerization by sequential monomer addition method. Our results indicated that the anionic polymerization of n-hexyl isocyanate was not controlled using Na-PO and Na-MPE. However, Na-BH as an initiator is favorable for the living anionic polymerization of n-hexyl isocyanate because it has a dual function in the initiation and in the efficient prevetion of trimerization by reducing the reactivity at the growth chain ends. Polymers were thus synthesized with predictable molecular weights (MW), narrow molecular weight distributions (MWD), and high yields.

Anionic Polymerization of Reactive 3‐Chloropropyl Isocyanate

“…So far, in situ polymerization of isocyanates with protic side groups has not been feasible without proper protecting groups due to proton abstraction and chain transfer . Advanced anionic polymerization techniques, such as using additives and self‐aggregated initiators, have allowed the preparation of polyisocyanates with living properties by protecting the living chain ends from depolymerizable cyclic trimerization . Initiators and chain ends are often sufficiently stabilized to prevent chain transfer onto protic side groups in the polymerization of isocyanate monomers with bulky carbamate groups, resulting in high yield, predictable molecular weight (MW) and narrow molecular weight distribution (MWD) .…”

Precise synthesis of thermoreversible block copolymers containing reactive furfuryl groups via living anionic polymerization: the countercation effect on block copolymerization behavior

“…Thus, polyisocyanates have been used for various applications such as chiral recognition and optical switches, and as liquid crystalline materials. 18,19 Building on the successful achievement of living anionic polymerization of HIC, we have sought to establish novel synthetic methods to prepare well-defined functional block copolymers containing HIC blocks. To overcome this problem, we have sought efficient ways to prevent trimerization.…”

Enolate anionic initiator, sodium deoxybenzoin, for leading living natures by formation of aggregators at the growth chain ends

“…Effects of structures and reactivity among oxy anionic initiators as following aromatic, secondary, and primary oxy anion for living anionic polymerization were studied. We found the relation between structures and reactive effects 12…”

“…The living polymerization of isocyanate is difficult because trimer formation can cause depolymerization. Numerous strategies to avoid depolymerization during the polymerization of isocyanate have been investigated 4–13…”