Polylactones. 40. Nanopretzels by Macrocyclic Polymerization of Lactones via a Spirocyclic Tin Initiator Derived from Pentaerythritol
Polylactones. 40. Nanopretzels by Macrocyclic Polymerization of Lactones via a Spirocyclic Tin Initiator Derived from Pentaerythritol
复制标题
聚内酯。
作者：
H. Kricheldorf;Soo
以二丁基氧化锡和季戊四醇为原料合成了一种螺环引发剂。通过元素分析、核磁共振谱和与γ-硫代丁内酯的化学计量反应对该螺环二锡氧烷进行了表征。e-己内酯（e-CL）在70 °C下随着单体/引发剂比率的变化而本体聚合。分子量约为M/I比，得到高分子量聚（e-CL）（Mw达160000）。相反，在75 °C下本体均聚β-d，l-丁内酯（β-d，l-BL）没有得到高分子量（Mw高达25 000），但产率高。用二巯基乙烷对螺环大环聚（e-CL）进行选择性开环，得到了四环星星型聚酯。通过1H NMR光谱鉴定端基。此外，还通过β-d，l-BL和e-CL的间歇共聚制备了螺环嵌段共聚物。此外，β-d，l-丁内酯与e-CL共混可得到螺环无规共聚酯。那个...
A spirocyclic initiator was synthesized from dibutyltin oxide and pentaerythritol. This spirocyclic distannoxane was characterized by elemental analyses, NMR spectroscopy, and a stoichiometric reaction with γ-thiobutyrolactone. e-Caprolactone (e-CL) was polymerized in bulk at 70 °C with variation of the monomer/initiator ratio. The molecular weights paralleled roughly the M/I ratio and high molecular weight poly(e-CL) was obtained (Mw’s up to 160 000). In contrast, homopolymerizations of β-d,l-butyrolactone (β-d,l-BL) in bulk at 75 °C did not give high molecular weights (Mw up to 25 000) but high yields. The spiro-macrocyclic poly(e-CL) was selectively ring-opened with dimercapto ethane, whereby a four-around star polyester was obtained. The end groups were identified by 1H NMR spectroscopy. Furthermore, spirocyclic block copolymers were prepared by batchwise copolymerization of β-d,l-BL and e-CL. Furthermore, spirocyclic random copolyesters were obtained from mixtures of β-d,l-butyrolactone and e-CL. The...