超支化聚缩水甘油的合成及性能.

Hyperbranched polyglycerol (hPG) with controlled molecular weight and narrow polydispersity has been synthesized by one-step anionic ring-opening polymerization (ROP) reaction, in which monomer glycidol (2,3-epoxy-1- propanol) was added dropwise to the mixture solution of timethylolpropane (TMP) initiator, potassium tert-butoxide (K-t- OBu) base, and anhydrous N-methylpyrrolidone solvent, for the prevention of cyclized byproduct. hPGs with three different molecular weights were synthesized through tailoring the molar ratio of initiator to monomer. Various techniques including 1H-NMR, inverse gated (IG) NMR spectroscopy, gel permeation chromatography (GPC) and Fourier transform infrared spectroscopy (FT-IR), were employed to characterize the chemical structure, degree of branching (DB), molecular weight and polydispersity of the synthesized hPG. Differential scanning calorimetry (DSC), thermogravimetric (TG), analyzer particle size and Zeta analyzer were used to analyze their glass transition temperature (Tg), thermal stability and solution properties, respectively. Results demonstrate that three hPGs were synthesized with targeted molecular mass (1.5×103, 4.6×103, 11.2×103) and polydispersities in the range of 1.82 -2.05. Importantly, the solvent N-methylpyrrolidone could rapidly increase the molecular weight of hPG during the reaction and improve its mono-dispersity compared to the non-solvent system. Moreover, the glass transition temperature (Tg) and thermal degradation temperature (Td) of hPG were increased slightly with the increasing molecular weight from 1.5×103 to 11.2×103. [ABSTRACT FROM AUTHOR]