The hydrogen\|bond defect of water in aqueous solution of a well\|defined poly(2\|hydroxyethyl acrylate)(PHEA) with different molecular weights and concentrations was studied by Raman spectrum analysis. The pre\|desig...The hydrogen\|bond defect of water in aqueous solution of a well\|defined poly(2\|hydroxyethyl acrylate)(PHEA) with different molecular weights and concentrations was studied by Raman spectrum analysis. The pre\|designed molecular weight of PHEAs with narrow polydispersities (<1 20) were synthesized via atom transfer radical polymerization (ATRP). It was found that in a low concentration PHEA aqueous solution(5?wt%), with the increase of molecular weight, the hydrogen bond defect increased markedly, but in a high concentration solution (25?wt%), the hydrogen bond defect was not sensitively affected by the molecular weight of PHEA. At higher temperature, the N value decreased due to the destroying of the hydrogen bond formation between water and the hydrophilic polymer chain in aqueous solutions.展开更多
Tetraacryloxyethoxysilane syntheslied by the reaction of 2-hydroxyethyl acrylatewith silicon tetrachloride was used in preparation of the transparent poly (2-hydroxyethylacrylate)/silicon dioxide composites by sol-gel...Tetraacryloxyethoxysilane syntheslied by the reaction of 2-hydroxyethyl acrylatewith silicon tetrachloride was used in preparation of the transparent poly (2-hydroxyethylacrylate)/silicon dioxide composites by sol-gel method. The composition of the compositeswere analyzed by electronic energy spectroscopy, elemental analysis and thermogravimetry.The composites have transparency greater than 80%, with thermal stability being increasedwith the silicon dioxide content.展开更多
Silk was grafted using 2-hydroxyethyl methacrylate(HEMA)by atom transfer radical polymerization(ATRP)method.The amino groups and hydroxyl groups on the side chains of the silk fibroin was reacted with 2-bromoisobutyry...Silk was grafted using 2-hydroxyethyl methacrylate(HEMA)by atom transfer radical polymerization(ATRP)method.The amino groups and hydroxyl groups on the side chains of the silk fibroin was reacted with 2-bromoisobutyryl bromide(BriB-Br)to obtain efficient macroinitiator for ATRP.And the macroinitiator was grafted with HEMA in water aqueous using CuBr/N,N,N',N",N"-pentamethyldiethylenetriamine(PMDETA)as catalyst system.The effects of monomer concentration,the proportion of CuBr and PMDETA,grafting temperature and time on the silk grafting were discussed,and the optimal grafting technology was obtained.FT-IR characterization of the grafted silk showed a peak corresponding to HEMA,which indicated that HEMA was grafted onto the surface of silk.ATRP method could be applied on the silk modification and this technique provided a new way for silk grafting.展开更多
To obtain porous alumina ceramic with high strength,a novel gelcasting system based on 2-hydroxyethyl methacrylate(HEMA)dissolved in tert-butyl alcohol(TBA)was developed.The polymerization of the HEMA-TBA gelcasting s...To obtain porous alumina ceramic with high strength,a novel gelcasting system based on 2-hydroxyethyl methacrylate(HEMA)dissolved in tert-butyl alcohol(TBA)was developed.The polymerization of the HEMA-TBA gelcasting system,the thermal behavior of obtained green body,and the microstructures and mechanical properties of the sintered bodies were investigated by rheometer,TG-DSC,SEM and bending strength testing,respectively.The results show that,(1)10 mg/mL of the initiator(benzoyl peroxide)is the optimal amount for polymerization of this gelscasting system at 25 ℃;(2)The alumina suspension of the HEMA-TBA gelcasting system showing shear-thinning behavior is sufficiently low for gelcasting process;(3)The bending strength of porous alumina ceramic samples,whose porosities range from 42% to 56%,is from(8±0.5)to(91±4.5)MPa.展开更多
Polymer nanoparticles were prepared in the methyl methacrylate (MMA)/buty lmethacrylate (BA) emulsion copolymerization process by a modified microemulsion copolymerization method. 2-Hydroxyethyl methacrylate(HEMA), ac...Polymer nanoparticles were prepared in the methyl methacrylate (MMA)/buty lmethacrylate (BA) emulsion copolymerization process by a modified microemulsion copolymerization method. 2-Hydroxyethyl methacrylate(HEMA), acrylate (AA) and methyl acrylate (MAA) were used as reactive cosurfactants. With this process high polymer: surfactant weight ratios (40:1 or greater),relatively concentrated (~30wt. %) latexes and small (~60nm) particle diameters were obtained.Properties of the latexes were characterized by TEM, DSC, dynamic light scattering, and IR spectroscopy.展开更多
文摘The hydrogen\|bond defect of water in aqueous solution of a well\|defined poly(2\|hydroxyethyl acrylate)(PHEA) with different molecular weights and concentrations was studied by Raman spectrum analysis. The pre\|designed molecular weight of PHEAs with narrow polydispersities (<1 20) were synthesized via atom transfer radical polymerization (ATRP). It was found that in a low concentration PHEA aqueous solution(5?wt%), with the increase of molecular weight, the hydrogen bond defect increased markedly, but in a high concentration solution (25?wt%), the hydrogen bond defect was not sensitively affected by the molecular weight of PHEA. At higher temperature, the N value decreased due to the destroying of the hydrogen bond formation between water and the hydrophilic polymer chain in aqueous solutions.
文摘Tetraacryloxyethoxysilane syntheslied by the reaction of 2-hydroxyethyl acrylatewith silicon tetrachloride was used in preparation of the transparent poly (2-hydroxyethylacrylate)/silicon dioxide composites by sol-gel method. The composition of the compositeswere analyzed by electronic energy spectroscopy, elemental analysis and thermogravimetry.The composites have transparency greater than 80%, with thermal stability being increasedwith the silicon dioxide content.
基金National Natural Science Foundation of China(No.50673071,No.50973079)Natural Science Fund for Colleges and Universities in Jiangsu Province,China(No.07KJD540188,No.09KJA540001)
文摘Silk was grafted using 2-hydroxyethyl methacrylate(HEMA)by atom transfer radical polymerization(ATRP)method.The amino groups and hydroxyl groups on the side chains of the silk fibroin was reacted with 2-bromoisobutyryl bromide(BriB-Br)to obtain efficient macroinitiator for ATRP.And the macroinitiator was grafted with HEMA in water aqueous using CuBr/N,N,N',N",N"-pentamethyldiethylenetriamine(PMDETA)as catalyst system.The effects of monomer concentration,the proportion of CuBr and PMDETA,grafting temperature and time on the silk grafting were discussed,and the optimal grafting technology was obtained.FT-IR characterization of the grafted silk showed a peak corresponding to HEMA,which indicated that HEMA was grafted onto the surface of silk.ATRP method could be applied on the silk modification and this technique provided a new way for silk grafting.
基金Project(51202296) supported by the National Natural Science Foundation of China
文摘To obtain porous alumina ceramic with high strength,a novel gelcasting system based on 2-hydroxyethyl methacrylate(HEMA)dissolved in tert-butyl alcohol(TBA)was developed.The polymerization of the HEMA-TBA gelcasting system,the thermal behavior of obtained green body,and the microstructures and mechanical properties of the sintered bodies were investigated by rheometer,TG-DSC,SEM and bending strength testing,respectively.The results show that,(1)10 mg/mL of the initiator(benzoyl peroxide)is the optimal amount for polymerization of this gelscasting system at 25 ℃;(2)The alumina suspension of the HEMA-TBA gelcasting system showing shear-thinning behavior is sufficiently low for gelcasting process;(3)The bending strength of porous alumina ceramic samples,whose porosities range from 42% to 56%,is from(8±0.5)to(91±4.5)MPa.
基金CEM Foundation For N & T Joint Academy (Chinese Education Ministry Foundation for Nankai University and Tianjin University Joint Academy)
文摘Polymer nanoparticles were prepared in the methyl methacrylate (MMA)/buty lmethacrylate (BA) emulsion copolymerization process by a modified microemulsion copolymerization method. 2-Hydroxyethyl methacrylate(HEMA), acrylate (AA) and methyl acrylate (MAA) were used as reactive cosurfactants. With this process high polymer: surfactant weight ratios (40:1 or greater),relatively concentrated (~30wt. %) latexes and small (~60nm) particle diameters were obtained.Properties of the latexes were characterized by TEM, DSC, dynamic light scattering, and IR spectroscopy.
