官能团化聚己内酯的合成与表征

SYNTHESIS AND CHARACTERIZATION OF POLY(ε-CAPROLACTONE) BEARING PENDANT FUNCTIONAL GROUPS

通过分子结构设计合成了新型含有侧基官能团的聚己内酯材料.首先,通过亲核加成反应,由溴乙酸乙酯与烯胺合成2-乙氧甲酰甲基环己酮;然后以间氯过氧化苯甲酸为氧化剂,通过Baeyer-Villiger氧化反应,得到带有官能团的己内酯单体,6-乙氧甲酰甲基-ε-己内酯;该单体在异辛酸亚锡(Sn(Oct)2)的催化下,本体开环聚合得到相应的均聚物及其与ε-己内酯的共聚物.采用1H-NMR、13C-NMR、GPC和DSC表征了聚合物的结构和热力学性能.随着6-乙氧甲酰甲基-ε-己内酯在共聚物中的含量增加,共聚物的分子量降低,同时熔点和熔融焓也随之降低.

Biodegradable aliphatic polyesters such as poly （ glycolide ） （ PGA）, poly （L-lactide） （ PLA ）, poly （ ε- caprolactone） （PCL） and their copolymers have been found widely applications in sutures, tissue engineering, bone fixation and controlled drug delivery due to their excellent bioeompatible and biodegradable properties. But the shortage of functional pendant groups and low hydrophilieity limited their further applications. In this work, we explored a synthetic strategy of aliphatic polyesters functionalized with the pendant carboxylic groups through the ring-opening polymerization of novel funetionalized laetone. First, 2-ethoxycarbonylmethyl-cyclohexanone was synthesized 7;ia nucleophilic addition. Second, 6-ethoxyearbonylmethyl-ε-caprolactone（ECL） was generated by the Baeyer-Villiger oxidation of the 2-ethoxyearbonylmethyl-cyclohexanone. Then, homopolymer and copolymers were accomplished in bulk （130℃） by ring-opening polymerization in the presence of stannous 2-ethyl hexanonate （Sn（Oet）2） as catalyst. All the polymers were characterized by FTIR, ^1H-NMR, ^13C-NMR, GPC, and DSC. The melting temperature （ Tm） decreased with an increase of ECL content because the molecular weight decreased in corresponding. It was also noted that Δ H∞, for eopolymers increased with an increase in the molecular weight because the relative number of copolymer chain ends and pendant functional groups decreased with a decrease of content of ECL.We think the availability of pendent groups on poly（ε-caprolaetone） has great potential for applications in medicine, surgery, and tissue engineering. K