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γ-丁内酯开环聚合成功 可循环利用生物聚合物
2016-01-31 12:09:41 浏览次数:4590
【易塑网咨讯中心】讯:通过开环聚合(ROP)法将环酯或内酯小分子化学合成可生物降解的脂肪族聚酯大分子的功能虽然强大。但是令人惋惜的是,其所制备的生物衍生性五元γ-丁内酯(γ-BL)由于其应变能量低,通常被认为是“非聚合的”。以往研究者们仅仅只能在超高压(20000个大气压,160℃)条件下通过ROP法合成聚(γ-丁内酯)(PγBL),并且只能获得低聚物。
来自美国科罗拉多州立大学Eugene Y.-X. Chen教授团队打破了这一传统束缚,于本月末报道了一种数均分子量高达30kg/mol、具备可调控的线型和/或环状拓扑结构的PγBL材料(Completely recyclable biopolymers with linearand cyclic topologies via ring-opening polymerization of γ-butyrolactone, Nature chemistry, 2391, 2015)。其合成方法同样是基于γ-BL的开环聚合,不同的是他们在该体系中引入了合适的催化剂,从而使得合成体系在常压下的转化率高达90%。尤为瞩目的是,这两种PγBL材料(线型和环状)经过简单的加热处理1小时后,即可定量回复到单体状态,因此实现其完全循环利用。
其研究思路一是在足够低温条件下实施ROP聚合,降低熵罚;二是调节反应条件。文中首次介绍了四种不同催化体系(镧系均配物,钇型异配物,主族二丁基镁和有机催化剂TBD和DBU)及反应条件(温度,溶剂,浓度)对产物性能的影响。该项研究工作不仅仅是推陈出新地提出了一种可控型PγBL生物大分子的有效合成方法,更重要的是,这也为今后基于其他五元内酯ROP聚合法,开发新型可持续性(可再生性,可循环性)生物材料
摘要速递
Completely recyclable biopolymers with linear and cyclic topologies via ring-opening polymerization of γ-butyrolactone
NATURE CHEMISTRY
PUBLISHED ONLINE: 23 NOVEMBER 2015
DOI: 10.1038/NCHEM.2391
Ring-opening polymerization (ROP) is a powerful synthetic methodology for the chemical synthesis of technologically important biodegradable aliphatic polyesters from cyclic esters or lactones. However, the bioderived ?ve-membered γ-butyrolactone (γ-BL) is commonly referred as ‘non-polymerizable’ because of its low strain energy. The chemical synthesis of poly(γ-butyrolactone) (PγBL) through the ROP process has been realized only under ultrahigh pressure(20,000 atm, 160 °C) and only produces oligomers. Here we report that the ROP of γ-BL can, with a suitable catalyst,proceed smoothly to high conversions (90%) under ambient pressure to produce PγBL materials with a number-average molecular weight up to 30 kg mol –1 and with controlled linear and/or cyclic topologies. Remarkably, both linear and cyclic PγBLs can be recycled back into the monomer in quantitative yield by simply heating the bulk materials at 220 °C (linear polymer) or 300 °C (cyclic polymer) for one hour, which thereby demonstrates the complete recyclability of PγBL.
相关阅读:检测材料细小裂缝 - 变色聚合物
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