High solid content CO_(2)-based cationic waterborne polyurethanes(CWPUs)were prepared using CO_(2)-polyols as soft segment and Nmethyl diethanolamine(MDEA)as hydrophilic group.The resulting stable aqueous dispersion d...High solid content CO_(2)-based cationic waterborne polyurethanes(CWPUs)were prepared using CO_(2)-polyols as soft segment and Nmethyl diethanolamine(MDEA)as hydrophilic group.The resulting stable aqueous dispersion displayed a high solid content of 52%with a low MDEA loading of 3.52 wt%.This novel structural CWPU can provide excellent adhesive strength,whose T-peel strength could reach 173.48N/5cm,20%higher than that of ester-based cationic waterborne polyurethane(87.55 N/5cm).The CO_(2)-based CWPU film showed only 2 wt%swelling percentage after 240 min immersion in water,and no change was observed during its immersion in 5 wt%sodium hydroxide solution.The tensile strength of CO_(2)-WPUs dropped slowly to 91.2%after 480 min immersion in a 5 wt%sodium hydroxide solution,whereas that of esterbased CWPUs dropped quickly to 32%after 240 min and their mechanical properties were lost after 360 min immersion.Meanwhile,the retention of the tensile strength of the CO_(2)-CWPUs was 81.5%even after 720 min immersion in 10 wt%H_(2)O_(2) solution,while it was only ca.38%for the ester-based CWPUs.These results indicated that the cationic CO_(2)-based CWPU may be promising waterborne adhesive with outstanding ageing resistance due to its synergistic effect from carbonate and ether groups of CO_(2)-polyol structure.展开更多
A novel and convenient hydrolysis and oxidation method was first used in preparation of carbon contained Y2O3 phosphor powders. The alloy was hydrolyzed in deionized water and the obtained Y（OH）3 powders were heat t...A novel and convenient hydrolysis and oxidation method was first used in preparation of carbon contained Y2O3 phosphor powders. The alloy was hydrolyzed in deionized water and the obtained Y（OH）3 powders were heat treated in air atmosphere. The final products - Y2O3 powders were micron clusters which were aggregated by hundreds of nanoparticles with the size of about 5 nm. The chemical composition, structural and morphological features of the samples were characterized by means of X-ray powder diffraction （XRD） analysis, transmission electron microscopy （TEM）, Fourier-transform infrared （FT-IR） spectra, X-ray photoelectron spectra （XPS） and carbon sulfur analyzer. The obtained powders showed good bluish-white photoluminescence （PL） emissions （ranging from 430 to 600 nm, peaking at 468 nm and 578 nm） under the xenon light excitation. The luminescent mechanism was ascribed to the carbon impurities in the Y2O3 host.展开更多
基金financially supported by the National Natural Science Foundation of China(No.32071686)。
文摘High solid content CO_(2)-based cationic waterborne polyurethanes(CWPUs)were prepared using CO_(2)-polyols as soft segment and Nmethyl diethanolamine(MDEA)as hydrophilic group.The resulting stable aqueous dispersion displayed a high solid content of 52%with a low MDEA loading of 3.52 wt%.This novel structural CWPU can provide excellent adhesive strength,whose T-peel strength could reach 173.48N/5cm,20%higher than that of ester-based cationic waterborne polyurethane(87.55 N/5cm).The CO_(2)-based CWPU film showed only 2 wt%swelling percentage after 240 min immersion in water,and no change was observed during its immersion in 5 wt%sodium hydroxide solution.The tensile strength of CO_(2)-WPUs dropped slowly to 91.2%after 480 min immersion in a 5 wt%sodium hydroxide solution,whereas that of esterbased CWPUs dropped quickly to 32%after 240 min and their mechanical properties were lost after 360 min immersion.Meanwhile,the retention of the tensile strength of the CO_(2)-CWPUs was 81.5%even after 720 min immersion in 10 wt%H_(2)O_(2) solution,while it was only ca.38%for the ester-based CWPUs.These results indicated that the cationic CO_(2)-based CWPU may be promising waterborne adhesive with outstanding ageing resistance due to its synergistic effect from carbonate and ether groups of CO_(2)-polyol structure.
基金Project supported by Shanghai Science and Technology Commission(11nm0501600)
文摘A novel and convenient hydrolysis and oxidation method was first used in preparation of carbon contained Y2O3 phosphor powders. The alloy was hydrolyzed in deionized water and the obtained Y（OH）3 powders were heat treated in air atmosphere. The final products - Y2O3 powders were micron clusters which were aggregated by hundreds of nanoparticles with the size of about 5 nm. The chemical composition, structural and morphological features of the samples were characterized by means of X-ray powder diffraction （XRD） analysis, transmission electron microscopy （TEM）, Fourier-transform infrared （FT-IR） spectra, X-ray photoelectron spectra （XPS） and carbon sulfur analyzer. The obtained powders showed good bluish-white photoluminescence （PL） emissions （ranging from 430 to 600 nm, peaking at 468 nm and 578 nm） under the xenon light excitation. The luminescent mechanism was ascribed to the carbon impurities in the Y2O3 host.
