A theoretical method to calculate the mode of polyurethane（PU） prepolymers grafted to polyacrylic（PAC） was presented. Using hydroxyethyl acrylate（HEA） as coupling agent, polyurethane-acrylics（PU-AC） hybrid lat...A theoretical method to calculate the mode of polyurethane（PU） prepolymers grafted to polyacrylic（PAC） was presented. Using hydroxyethyl acrylate（HEA） as coupling agent, polyurethane-acrylics（PU-AC） hybrid latexes were prepared with varying HEA level and the reaction of HEA with PU prepolymers at different temperatures, and PU grafted to PAC was experimentally determined. The results show that PU grafted to PAC regularly increased, and the non-grafted and linear free PU regularly decreased with increase in HEA/NCO（isocyanate group）. The grafted PU on PAC was not proportional to HEA. More than half of linear PU prepolymers were grafted to PAC when HEA was at a low level with HEA/NCO at 0.33. While grafted PU increased to 84.80%（mass fraction）, when HEA/NCO increased to 1.0. The results were interpreted based on the theoretical calculation of PU grafted to PAC by the present method.展开更多
A new pH-responsive block copolymer, methoxy poly（ethylene glycol）-b-poly[5-methacrylamido- pentylamine hydrochloride]（mPEG-b-PMAAPA） was synthesized and characterized in this paper. The monomer 5-methacrylamido-p...A new pH-responsive block copolymer, methoxy poly（ethylene glycol）-b-poly[5-methacrylamido- pentylamine hydrochloride]（mPEG-b-PMAAPA） was synthesized and characterized in this paper. The monomer 5-methacrylamido-pentylamine hydrochloride（MAAPA） and the macroinitiator（mPEG-ACVA） were synthesized, re- spectively, and mPEG-b-PMAAPA was then obtained by free radical polymerization. The structure and molecular weight of mPEG-b-PMAAPA were cont]rmed by hydrogen nuclear magnetic resonance（~H NMR） spectroscopy and gel permeation chromatography with multiangle laser light scattering（GPC-MALLS） measurements. At a low pH, it is hydrophilic due to the protonation of the primary amine groups. With increasing pH value, deprotonation occurs and the hydrophobicity of PMAAPA block increases. This molecular feature leads to interesting aggregation behavior of mPEG-b-PMAAPA in aqueous solutions at different pH values as revealed by dynamic light scattering（DLS） measurements, transmission electron microscopy（TEM） observations and resonance light scattering（RLS） measure- ments.展开更多
基金Supported by the National Natural Science Foundation of China(No20874040)the Research Fund from University of Jinan, China(NoXKY0721)
文摘A theoretical method to calculate the mode of polyurethane（PU） prepolymers grafted to polyacrylic（PAC） was presented. Using hydroxyethyl acrylate（HEA） as coupling agent, polyurethane-acrylics（PU-AC） hybrid latexes were prepared with varying HEA level and the reaction of HEA with PU prepolymers at different temperatures, and PU grafted to PAC was experimentally determined. The results show that PU grafted to PAC regularly increased, and the non-grafted and linear free PU regularly decreased with increase in HEA/NCO（isocyanate group）. The grafted PU on PAC was not proportional to HEA. More than half of linear PU prepolymers were grafted to PAC when HEA was at a low level with HEA/NCO at 0.33. While grafted PU increased to 84.80%（mass fraction）, when HEA/NCO increased to 1.0. The results were interpreted based on the theoretical calculation of PU grafted to PAC by the present method.
基金Supported by the National Basic Research Program of China（No.2009CB930103） and the Natural Science Foundation of Shandong Province of China（No.ZR2011BM002）.
文摘A new pH-responsive block copolymer, methoxy poly（ethylene glycol）-b-poly[5-methacrylamido- pentylamine hydrochloride]（mPEG-b-PMAAPA） was synthesized and characterized in this paper. The monomer 5-methacrylamido-pentylamine hydrochloride（MAAPA） and the macroinitiator（mPEG-ACVA） were synthesized, re- spectively, and mPEG-b-PMAAPA was then obtained by free radical polymerization. The structure and molecular weight of mPEG-b-PMAAPA were cont]rmed by hydrogen nuclear magnetic resonance（~H NMR） spectroscopy and gel permeation chromatography with multiangle laser light scattering（GPC-MALLS） measurements. At a low pH, it is hydrophilic due to the protonation of the primary amine groups. With increasing pH value, deprotonation occurs and the hydrophobicity of PMAAPA block increases. This molecular feature leads to interesting aggregation behavior of mPEG-b-PMAAPA in aqueous solutions at different pH values as revealed by dynamic light scattering（DLS） measurements, transmission electron microscopy（TEM） observations and resonance light scattering（RLS） measure- ments.
