AI Article Synopsis
- Researchers successfully achieved selective double ring-opening polymerization of spiroorthoester monomers using a simple cationic alkyl gallium catalyst to create high-molecular-weight poly(ether--ester)s, averaging around 90 kDa.
- The formation of these polymers was confirmed via NMR and IR spectroscopy techniques, ensuring the selective polymerization process.
- The materials were extensively characterized for thermal and rheological properties, revealing well-entangled systems with unique viscoelastic behavior at both low and high frequencies, marking a significant advancement in polymer science.
Article Abstract
We report the selective double ring-opening polymerization of presequenced spiroorthoester monomers to form high-molecular-weight (≈90 kDa) poly(ether--ester)s with a simple cationic alkyl gallium catalyst. The selective formation of double ring-opened polymer units was confirmed by NMR and IR spectroscopies. Thermal and rheological properties of homo- and copolymers were further characterized by differential scanning calorimetry, thermogravimetric analysis, and stress-controlled rotational rheometry. Linear viscoelastic moduli show that these systems are well entangled (plateau modulus), thereby possessing nearly terminal relaxation at long time scales (low frequencies) and Rouse segmental dynamics at short time scales (high frequencies) with characteristic slopes. These are the highest-molecular-weight poly(ether--ester)s reported to date.
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| http://dx.doi.org/10.1021/acsmacrolett.3c00758 | DOI Listing |
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