β-丁内酯，环氧化物和CO <sub>2的</sub>三元聚合：化学选择性CO <sub>2转换</sub>及其对动力学和材料性能的影响,Macromolecules

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β-丁内酯，环氧化物和CO _2的三元聚合：化学选择性CO _2转换及其对动力学和材料性能的影响
Macromolecules ( IF 5.1 ) Pub Date : 2019-11-01 , DOI: 10.1021/acs.macromol.9b01777
Sebastian Kernbichl ₁ , Marina Reiter ₁ , Josef Mock ₂ , Bernhard Rieger ₁

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提出了在两种不同的CO ₂压力下与环氧化物CO ₂和β-丁内酯（BBL）的混合单体原料进行的三元聚合反应。路易斯酸性锌络合物BDI ^CF3 - Zn -N（SiMe ₃）₂1能够催化BBL的开环聚合（ROP）和环氧化物与CO ₂的开环共聚。因此，二氧化碳浓度显示出一种有吸引力的工具，用于化学选择性地将两种单体类型结合成嵌段或统计构型。高CO ₂压力（40 bar）导致形成块状结构，而3 bar CO ₂允许两个催化循环（BBL的ROP和环己烯氧化物和CO ₂的开环共聚）以相似的速率进行。这导致统计聚合行为。将CO ₂压力从40 bar降低到3 bar涉及到CO ₂反应顺序的变化从零到一阶依赖。统计聚合途径为具有一个混合玻璃化转变温度的三元共聚物提供了一条有希望的途径，该温度可以在5到115°C之间调节。嵌段结构的三元共聚物显示两个分离的玻璃化转变。该相分离也通过原子力显微镜证实。关于所得三元共聚物的机械性能，由于引入了柔软的聚（3-羟基丁酸酯）（PHB），与非常脆的聚碳酸环己烯酯相比，嵌段和统计结构的杨氏模量均降低了。）。当分子量超过100 kg / mol时，表明嵌段结构的断裂伸长率提高。生物基单体氧化烯也成功与CO _2进行了三元聚合和BBL。有趣的是，嵌段结构显示出可调节的应力-应变行为，具体取决于三元共聚物中PHB的量。

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Terpolymerization of β-Butyrolactone, Epoxides, and CO2: Chemoselective CO2-Switch and Its Impact on Kinetics and Material Properties

Terpolymerization reactions with a mixed-monomer feedstock of epoxides, CO₂, and β-butyrolactone (BBL) at two different CO₂ pressures are presented. The Lewis acidic zinc complex BDI^CF3–Zn–N(SiMe₃)₂1 is able to catalyze both the ring-opening polymerization (ROP) of BBL and the ring-opening copolymerization of epoxides and CO₂. The carbon dioxide concentration thereby displays an attractive tool for the chemoselective tailoring of the incorporation of both monomer types to either a block or a statistical configuration. A high CO₂ pressure (40 bar) leads to a block structure, whereas 3 bar CO₂ allows the two catalytic cycles, ROP of BBL and ring-opening copolymerization of cyclohexene oxide and CO₂, to proceed with similar rates. This results in a statistical polymerization behavior. Reducing the CO₂ pressure from 40 to 3 bar involves a change in the reaction order of CO₂ from zero- to first-order dependency. The statistical polymerization pathway offers a promising route to terpolymers with one mixed-glass transition temperature that can be adjusted in a range between 5 and 115 °C. Terpolymers in block structure show two segregated glass transitions. This phase separation was also confirmed via atomic force microscopy. Referring to the mechanical behavior of the resulting terpolymers, a decrease of the Young modulus for both the block and the statistical structure compared to the very brittle poly(cyclohexene carbonate) is observed due to the incorporation of soft poly(3-hydroxybutyrate) (PHB). An enhanced elongation at break is revealed for the block structure when the molecular weights exceed 100 kg/mol. The biobased monomer limonene oxide is also successfully terpolymerized with CO₂ and BBL. Interestingly, the block structure shows a tunable stress–strain behavior depending on the amount of PHB in the terpolymer.

更新日期：2019-11-01

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