Papers by Keyword: Sulfonic Group

Abstract: The effect of sodium sulfate on the dispersion of polycarboxylate superplasticizer (PC) was studied in this paper. The study of fluidity of cement paste shown that the carboxyl groups did more to improve the fluidity of cement paste than the sulfonic groups, and a quick loss of fluidity was much more likely arisen by slufonic groups in PC comparing with the carboxyl groups. The methods of zeta potential and fluidity of cement paste were applied to investigate the dispersal ability of cement particles when different PC used in the present of different concentration of sodium sulfate. The result showed that the sulfonic group was more sensitive to sodium sulfate than carboxyl groups in PC.

Abstract: Apatite formation on polyamide films containing either carboxyl or sulfonic groups was compared in 1.5SBF, whose ion concentrations are 1.5 times those of a simulated body fluid (SBF). The sulfonic groups induced the apatite nucleation earlier than the carboxyl groups. In contrast, the rate of crystal growth depended not on the kind of functional group, but on the degree of supersaturation of the surrounding solution. The more ready association of sulfonic groups with calcium ions may lead to earlier apatite nucleation than that of carboxyl groups. Adhesive strength of the apatite layer to polyamide film containing sulfonic groups was significantly lower than that with carboxyl groups depending on the chemical interactions as well as on the mechanical properties of the polyamide film.

Abstract: Apatite formation in living body is essential condition for artificial materials to exhibit bone-bonding ability, i.e. bioactivity. It has been recently revealed that sulfonic group triggers apatite nucleation in body environment. Organic-inorganic hybrids consisting of organic polymer and the sulfonic group are therefore expected to be useful for novel bone-repairing materials exhibiting flexibility as well as bioactivity. In the present study, organic-inorganic hybrids were prepared from vinylsulfonic acid sodium salt and hydroxyethylmethacrylate (HEMA), a kind of acrylic polymer. Bioactivity of the hybrids was assessed in vitro by examining their acceptance of apatite formation in simulated body fluid (SBF, Kokubo solution). The obtained hybrids showed the apatite deposition after soaking in SBF within 7 d.