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研究了合成环状大分子的一种新方法,即借助活性开环聚合反应和高效双键易位闭环反应(RCMR)合成环状聚ε-己内酯.首先,ε-己内酯在环状引发剂2,2-二丁基-2-锡-1,3-二氧环庚烷(DSDOP)的作用下,进行活性开环聚合反应,获得双羟基封端的聚ε-己内酯(PCLOH);然后,在对甲苯磺酸、1,3-二环己基碳二亚胺(DCC)和4-二甲氨基吡啶(DMAP)的作用下,将PCLOH与3-丁烯酸反应转化为双烯丙基封端的聚ε-己内酯(allylPCL);在Grubbs催化剂(Cl2(Cy3)2Ru CHPh)的作用下,将allylPCL经RCMR环化成环状聚ε-己内酯,并采用SEC,NMR,TGA以及DSC等技术对聚合物的结构和热力学性能进行了表征,SEC和黏度表征结果显示环状聚ε-己内酯具有较小的动态力学体积,TGA和DSC表征结果显示环状聚ε-己内酯的热分解温度较其线型前体高13℃,环化的结果使其熔点和结晶度下降.结果表明allylPCL在较稀(2.5×10-5mol/L)体系中,借助Grubbs催化剂进行的RCMR分子内环化反应效率高,环化产物无需进一步分离提纯.
A new method for the synthesis of cyclic macromolecules has been developed, which is the synthesis of cyclic poly (ε-caprolactone) by means of active ring-opening polymerization and the efficient double bond translocation ring-closing reaction (RCMR) 2,2’-dibutyl-2-tin-1,3-dioxetane (DSDOP) as a polymerization initiator, a living ring-opening polymerization reaction was carried out to obtain a bishydroxy terminated poly ε-caprolactone PCLOH); then, PCLOH was reacted with 3-butenoic acid under the action of p-toluenesulfonic acid, 1,3-dicyclohexylcarbodiimide (DCC) and 4- dimethylaminopyridine (DMAP) AllylPCL; allylPCL was cyclized to cyclic poly (ε-caprolactone) via RCMR under Grubbs catalyst (Cl2 (Cy3) 2Ru CHPh), and SEC, NMR, TGA and DSC were used to characterize the structure and thermodynamic properties of the polymer. The SEC and viscosity characterization results showed that the cyclic poly (ε-caprolactone) had a smaller dynamic mechanical volume. The results of TGA and DSC showed that cyclic poly The thermal decomposition temperature of ε-caprolactone was 13 ℃ higher than that of its linear precursor, and the melting point and crystallinity of the ε-caprolactone decreased as a result of the cyclization.The results showed that allylPCL was more stable in 2.5 × 10 -5 mol / L Grubbs catalytic RCMR molecules high reaction efficiency of the cyclization, the cyclization product was used without further separation and purification.