Dynamic rheology of agar cel based aqueous binders

Dynamic theology was used to study the gelation behavior of agar gel based aqueous binders (1-3 wt%) for powder injection molding. Typical gelation te mperatures, T-gel, and liquefaction temperatures, T-liq, were 36 degrees an d 78 degreesC, respectively. The thermal history of the gels was found to i nfluence T-gel and the asymptotic storage modulus, G', A higher degree of u ndercooling (DeltaT = T-gel - T-hold) enhanced the driving force for gelati on, G' master curves were created and revealed a relatively weak frequency dependence. G' increased significantly with agar content. The shape of the gel's relaxation spectrum was found to be independent of agar content, indi cating that the nature of the relaxation processes does not change signific antly.