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

Abstract

The anionic block copolymerization of 4,4'-vinylphenyl-N,N-bis(4-tert-butylphenyl)benzenamine (A) with furfuryl isocyanate (B) was carried out using potassium naphthalenide (K-Naph) in tetrahydrofuran at −78 and −98°C to prepare well-defined block copolymers containing furan groups for the formation of thermoreversible networks via a Diels-Alder (DA) reaction. While no block copolymerization was observed in the absence of sodium tetraphenylborate (NaBPh 4 ) due to side reactions, well-defined poly-copolymers with controlled molecular weights (M n = 18 700-19 500 g mol −1 ) and narrow molecular weight distributions (M w /M n = 1.08-1.17) were successfully synthesized in the presence of excess NaBPh 4 . The occurrence of the undesirable side reactions during polymerization of B was effectively prevented by NaBPh 4 , which results in the change in the countercation from K + to Na + for further polymerization of B. The cross-linking via the DA reaction between the furan groups of PBAB and bismaleimide was proved by FT-IR and differential scanning calorimetry (DSC), and the thermoreversible properties of the cross-linked polymer were subsequently investigated using DSC and solubility testing. † Electronic supplementary information (ESI) available. See

Dual‐Responsive Self‐Healable Carboxylated Acrylonitrile Butadiene Rubber Based on Dynamic Diels–Alder “Click Chemistry” and Disulfide Metathesis Reaction

“…However, from the figure it was observed that the exotherm was broad as well as weak, which might be due to the fast cooling of the sample that hinders the accomplishment of the DA reaction. In several previous reports, this phenomenon [ 46,47 ] has already been reported. Table S1 (Supporting Information) summarizes the results obtained from the DSC analysis of the functionalized XNBR and DA‐crosslinked XNBR.…”

Dynamic covalent polymers

“…Kang et al recently reported the formation of thermoreversible block copolymers containing pendant triphenylamine (A) and furan (B) by anionic polymerization, resulting in an A–B–A block copolymer . Upon addition of a bis maleimide crosslinker at 50 °C a crosslinked polymer was formed, as evidenced by DSC, which showed a large increase in T g due to reduction in chain mobility.…”

“…To date, most of the reported DC polymers that are based on the Diels‐Alder reaction, rely on furan as the diene . Both the groups of Bapat et al and Barthel et al relied on a thermoreversible Diels‐Alder reaction to control the crosslinking of micelles.…”

Precise Synthesis of Functional Block Copolymers by Living Anionic Polymerization of Vinyl Monomers Bearing Nitrogen Atoms in the Side Chain

“…Based‐on the previous successful block copolymerization with HIC, another isocyanate derivative, furfuryl isocyanate (FIC), was used in the second stage of polymerization in the presence of excess NaBPh 4 at −98 °C . The undesired side reactions did not occur during polymerization, leading to well‐defined block copolymers, poly(VPTBTPA)‐ b ‐poly(FIC), with controlled M n (18 700–19 500 g mol ‐1 ) and narrow MWD ( M w / M n = 1.08–1.17).…”