A novel and well-defined comb-copolymer

ethyl cellulose-graft-poly(-caprolactone) (EC-g-PCL) was synthesized via ring-opening polymerization (ROP) of -caprolactone (CL) with ethyl cellulose as the macroinitiator.The following coupling reaction of 1-pyrenebutyric acid with hydroxyl-terminated poly(-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.