Takashi Fujimaki

Molecular weight distribution and branched structure of biodegradable aliphatic polyesters determined by s.e.c.-MALLS

Molecular weight distribution and mean square radius as a function of molecular weight for biodegradable aliphatic polyesters have been measured by multiangle laser light scattering (MALLS) detector for size exclusion chromatography (s.e.c.). The difference of their molecular structures is discussed in relation to the melt elasticity, which contributes to processability for extrusion coating and extrusion foaming. The evaluated values of branching ratio indicate the existence of long chain branched structures.

Hydrogen absorbing reaction of LaNi5 in the presence of other gases

Abstract LaNi 5 powder was placed in a tube and exposed to a mixture of hydrogen with other gases such as CO, CO 2 , helium, nitrogen and argon at a total pressure of 30 kg cm −2 G and the temperature of iced water. The hydrogen absorption rates decreased sharply as the concentration of the other gases increased from zero to 8%. A reaction model is proposed in which the other gases are absorbed and reach equilibrium on the LaNi 5 surface and block the hydrogen absorption. The rate constant of the hydrogen absorbing reaction and the equilibrium constants of the other gases are determined and the experimental results are discussed.