Tough and Thermally Recyclable Semiaromatic Polyesters by Ring-Opening Polymerization of Benzo-thia-caprolactones

作者：Li Linggao, Qiyuan Wang, Zheng Qiu-yang, Fu‐Sheng Du, Zichen Li · 发表于：Macromolecules · 年份：2021 · DOI：10.1021/acs.macromol.1c00497 · 被引用次数：98 · 研究领域：biodegradable polymer synthesis and properties、Advanced Polymer Synthesis and Characterization、Carbon dioxide utilization in catalysis

Thermally recyclable semiaromatic polyesters with good mechanical properties are prepared by ring-opening polymerization (ROP) of benzene-fused caprolactones. Three constitutional isomers of benzo-thia-caprolactones ( BOTO-I, BOTO-II, and BOTO-III ) were synthesized. Their organocatalytic ROPs were systematically investigated and correlated with their structures. The diphenyl phosphate (DPP)-catalyzed ROP of BOTO-II is controllable and can reach high monomer conversion. BOTO-I has a high equilibrium monomer concentration ([ M ] e = 0.15 M) at 30 °C, whose ROP can only be achieved with 1,5,7-triazabicyclo[4.4.0] dec-5-ene (TBD) as the catalyst, but with poor control. BOTO-III can be polymerized with TBD or a binary catalytic system of 1,8-diazabicyclo[5.4.0]-undec-7-ene (DBU) and 1-(3,5-bis(trifluoromethyl)phenyl)-3-cyclohexylthiourea (TU) with poor control. Polymers P(BOTO-I) and P(BOTO-II) are thermally stable up to 270 °C, but P(BOTO-III) starts to decompose at 180 °C. These three polymers are semicrystalline materials with slow crystallization rates. P(BOTO-I) displays the highest T m of 146 °C and a T g of 59 °C. The mechanical properties of these P(BOTO)s were examined by uniaxial tensile tests. Preliminary data indicates that P(BOTO-I) is a tough polymer with superior comprehensive material properties as compared to other reported thermally recyclable polyesters. Catalytic chemical recycling of P(BOTO)s in solution and bulk were examined. Depolymerization in solution is...