The factor governing the stability of micelles and hence controlling the rheological behavior of aqueous solutions of cetyltrimethylammonium bromide (CTAB) containing sodium salicylate (NaSal) was investigated.The solutions containing fully entangling threadlike micelles of CTAB-NaSal complexes may be modeled by a Maxwell model with a single relaxation time. Concentrations Cs* of free salicylate ions in the systems were estimated by carrying out XH NMR measurement on deuterium oxide solutions with varying CTAB (CD) and NaSal (Cs) concentrations. The results of NMR measurement suggested that the threadlike micelles existed in the form of a 1:1 complex between CTAB and NaSal. Thus, the relation Cs* = Cs -CD was obtained in the range Ds > CD. On the other hand, we confirmed that the relaxation time rm is influenced only by Cs* independently of Cd, and thus the factor controlling rm is Cg*. Furthermore, consideration on the basis of a quasi-network model led to an idea that the free salicylate ions are behaving as a catalyst for a disentangling reaction.

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Via batch process in an autoclave, we conducted foam processing on polypropylene (PP)/clay nanocomposite (PPCN) by using supercritical CO2 as foaming agent under 10 MPa at 134.7 °C. Through transmission electron microscopy observation, the biaxial flow-induced alignment of clay particles along the cell boundary was identified. Such aligning behavior of clay particles helps cells to withstand the stretching force from breaking the so thin cell wall and to improve the modulus of the foam.