侧链末端含荧光基团芘的EC-g-PCL梳形共聚物的合成与性能研究

SYNTHESIS AND CHARACTERIZATION OF PYRENE-CONTAINING COMB-COPOLYMER ETHYL CELLULOSE-g-POLY(ε-CAPROLACTONE)

首先以乙基纤维素(EC)为大分子引发剂引发ε-己内酯(CL)的开环聚合反应(ROP),合成乙基纤维素接枝聚ε-己内酯的梳形共聚物(EC-g-PCL).之后利用N,N'-二环己基碳二亚胺(DCC)做脱水剂将荧光基团芘(Pyr)引入侧链聚ε-己内酯(PCL)末端,经控制投料比,合成不同含量芘端基的乙基纤维素接枝聚ε-己内酯的荧光梳形共聚物(EC-g-PCL-Pyr).利用傅里叶变换红外(FTIR)、核磁共振(NMR)对其结构进行表征,运用差示扫描量热仪(DSC)和原子力显微镜(AFM)研究其热性能和结晶性能,通过紫外-可见光谱(UV-Vis)、荧光光谱对其光学性质进行研究.研究结果表明该荧光梳形共聚物的荧光强度与芘的接枝量有关.

A novel and well-defined comb-copolymer,ethyl cellulose-graft-poly（ε-caprolactone）（EC-g-PCL） was synthesized via ring-opening polymerization（ROP） of ε-caprolactone（CL） with ethyl cellulose as the macroinitiator.The following coupling reaction of 1-pyrenebutyric acid with hydroxyl-terminated poly（ε-caprolactone）（PCL） was carried out in the presence of dicyclohexylcarbodiimide（DCC） and 4-dimethylaminopyridine（DMAP）.Pyrene-containing comb-copolymers（EC-g-PCL-Pyr） with different graft ratios of pyrene groups were obtained by adjusting the molar ratio of EC-g-PCL and pyrene.The structure of the resultant products was characterized by 1H-NMR and FTIR spectroscopy.Thermal properties and crystalline morphologies were established by differential scanning calorimetric analysis（DSC） and atomic force microscopy（AFM）,respectively.Thermal analysis showed the melting temperature of EC-g-PCL-Pyr was lower than that of EC-g-PCL,because of the change of crystalline form which was demonstrated by AFM photos.Optical feature was determined by UV-Vis and fluorescence spectrometer.Fluorescence analysis indicated that the fluorescence intensity of EC-g-PCL-Pyr comb-copolymers changed with the increasing of the graft ratio of pyrene when the pyrene concentration of their CHCl3 solution was the same.This comb-copolymer could be used in biomedical applications such as fluorescent drug delivery and fluorescent probe.