A series of glass are synthesized via a melt quenching technique based on the Li_(2)O-Ni O-P_(2)O_(5) system.The concentration of nickel oxide varies from 5%to 15%in molar fraction.XRD pattern verifies the amorphous n...A series of glass are synthesized via a melt quenching technique based on the Li_(2)O-Ni O-P_(2)O_(5) system.The concentration of nickel oxide varies from 5%to 15%in molar fraction.XRD pattern verifies the amorphous nature of prepared glass samples with 5%,and 10%nickel oxide in molar fraction.While Li_(3)P and Ni_(2)P_(4)O_(12)phases are precipitated with a high nickel content up to 15%in molar fraction.As nickel is substituted for lithium,a systematic increase in glass transition temperature(T_(g))and glass softening temperatures(T_(s))is observed.This is greatly related to the increased structure,coherence in the glass network.Structural investigation showed that Ni_(2+) spectra are present in both octahedral and tetrahedral sites.Physical properties such as glass density((2.38±0.1)-(2.46±0.1)g/cm^(3)),and molar volume((42.28±0.1)-(39.15±0.1)cm^(3)/mol)are examined.The NiO/Li_(2)O replacements led to a decrease in the dissolution rate of the resultant amorphous materials from 1.53×10^(-5)to 3.20×10^(-6)g/(cm^(2)·min).Thermal expansion coefficients CTE of the glasses are diverse from 157×10^(-7) to 96×10^(-7)℃^(-1) over the temperature range of 25-250℃.The prepared glasses are expected to be useful as a low-temperature sealing material.展开更多
A series of nonionic polyacrylamide hydrogels, using acrylamide as monomer and N,N＇-methylene diacrylamide as crosslinking agent, were prepared by the free radical polymerization in aqueous solution. Swelling equilib...A series of nonionic polyacrylamide hydrogels, using acrylamide as monomer and N,N＇-methylene diacrylamide as crosslinking agent, were prepared by the free radical polymerization in aqueous solution. Swelling equilibria for the gels were carried out in aqueous solutions of NaCl, KCI, CaCl2, Na2HPO4 and K2HPO4 with concentration ranging from 10^-3 to 5mol/kgH2O at 25 ℃. Experimental results revealed that the chlorides and phosphates cause a different behavior at higher salt concentration. The swelling ratio increases with increasing concentration of chlorides salts, while decreases with the increased phosphates salt concentration. The phenomena seem to be related to the different interactions of chloride and hydrogen phosphate ions with the network groups. Furthermore, the effects of different concentration of crosslinking agent and total monomers on gel swelling performance were also investigated.展开更多
文摘A series of glass are synthesized via a melt quenching technique based on the Li_(2)O-Ni O-P_(2)O_(5) system.The concentration of nickel oxide varies from 5%to 15%in molar fraction.XRD pattern verifies the amorphous nature of prepared glass samples with 5%,and 10%nickel oxide in molar fraction.While Li_(3)P and Ni_(2)P_(4)O_(12)phases are precipitated with a high nickel content up to 15%in molar fraction.As nickel is substituted for lithium,a systematic increase in glass transition temperature(T_(g))and glass softening temperatures(T_(s))is observed.This is greatly related to the increased structure,coherence in the glass network.Structural investigation showed that Ni_(2+) spectra are present in both octahedral and tetrahedral sites.Physical properties such as glass density((2.38±0.1)-(2.46±0.1)g/cm^(3)),and molar volume((42.28±0.1)-(39.15±0.1)cm^(3)/mol)are examined.The NiO/Li_(2)O replacements led to a decrease in the dissolution rate of the resultant amorphous materials from 1.53×10^(-5)to 3.20×10^(-6)g/(cm^(2)·min).Thermal expansion coefficients CTE of the glasses are diverse from 157×10^(-7) to 96×10^(-7)℃^(-1) over the temperature range of 25-250℃.The prepared glasses are expected to be useful as a low-temperature sealing material.
基金Sci.and Tech. Ministry of Fujian (2005I010)Natural Sci. Foundation of Fujian (C0410006).
文摘A series of nonionic polyacrylamide hydrogels, using acrylamide as monomer and N,N＇-methylene diacrylamide as crosslinking agent, were prepared by the free radical polymerization in aqueous solution. Swelling equilibria for the gels were carried out in aqueous solutions of NaCl, KCI, CaCl2, Na2HPO4 and K2HPO4 with concentration ranging from 10^-3 to 5mol/kgH2O at 25 ℃. Experimental results revealed that the chlorides and phosphates cause a different behavior at higher salt concentration. The swelling ratio increases with increasing concentration of chlorides salts, while decreases with the increased phosphates salt concentration. The phenomena seem to be related to the different interactions of chloride and hydrogen phosphate ions with the network groups. Furthermore, the effects of different concentration of crosslinking agent and total monomers on gel swelling performance were also investigated.
