Radical polymerization of ‘dehydroaspirin’ with the formation of a hemiacetal ester skeleton: a hint for recyclable vinyl polymers

Abstract

A recyclable vinyl polymer was developed via radical polymerization of ‘dehydroaspirin’ derived from acetylsalicylic acid.

Synthesis of degradable and chemically recyclable polymers using 4,4-disubstituted five-membered cyclic ketene hemiacetal ester (CKHE) monomers

“…A main-chain cleavage mechanism was previously proposed for the degradation of the MBDO polymer, for which the mechanism was studied in an acidic condition. 31 No polymer peak observed in the GPC chromatogram (Fig. 3a) suggests that the main-cleavage operated signicantly in the present system so that the polymer chains could degrade into small molecules or oligomers.…”

“…Table 2 Homo-polymerization of PhDL and random copolymerizations of PhDL with co-monomers 31 Thermal properties of the obtained DMDL copolymers (Table 1, entries 3 and 5-7) with MMA, St, AN, and VAc were studied (Fig. S17-S20 in ESI †).…”

“…condition for the acid-assisted degradation of the MBDO polymer. 31 We dissolved a PDMDL (M n ¼ 106 000 and Đ ¼ 1.88) (0.064 g, 2.4 wt%, 1 equiv. of the DMDL monomer unit) in DMSO (2.08 g, 78.7 wt%), which was a colorless transparent solution.…”

“…The studied CKHE was a sixmembered CKHE, i.e., 2-methylene-4H-benzo[d] [1,3]dioxin-4one (MBDO (Scheme 2)). 31 MBDO yielded polymers with ringretained structures, possibly because its ring-opened radical is a phenyl radical, which is unlikely to generate. The homopolymer of MBDO was insoluble in most of common organic solvents.…”

Hemiacetal Ester Exchanges, Study of Reaction Conditions and Mechanistic Pathway

“…The hydrophilic acidic group was then regenerated by hydrolysis in acidic medium (HCl 5 M) to yield an amphiphilic polymer otherwise difficult to prepare. Since then, this hydrolysis reaction was used in other studies to form water-soluble [12] and alternative [13] copolymers, but also de-crosslinkable [14,15] or recyclable/degradable [16,17] polymers.…”