synopsisThe melt rheology of high density polyethylene was investigated. Linear viscoelasticity, capillary flow properties, and molecular weight parameter were measured with a plate relaxometer, capillary rheometer, and gel permeation chromatography, respectively. Intimate correlations among the slope of relaxation modulus curve, nonNewtonian flow behavior, Barus effect, and molecular weight parameter, M E ( M I +~) / M W , respectively, were found.

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SynopsisWe elucidated the effect of the molecular weight of poly( N-methyl-4-vinylpyridinium chloride) (PMW) on its adsorbed or ion-exchanged amount on the cation-exchange membrane and the preferential permselectivity of the membrane for sodium ion to calcium ion. The amount of the admrbed or ion-exchanged PMVP increases with time and then attains to a definite value at a definite concentration. Also, the ultimate value increases with increasing the concentration of PMVP. When the molecular weight of PMVP is 3090, the ratio of the pyridinium groups of PMW ion-exchanged with the sulfonic acid groups on the membrane surface to the total pyridinium groups of the cohered PMVP is in the range of 70-80%. The relative transport number of calcium ions to sodium ions(Pa) decreases with increasing the amount of adsorbed or ion-exchanged PMVP and the number of non-ion-exchanged pyridinium groups of PMVP on the membrane surface. The smaller the molecular weight of PMVP, the more the adsorbed or ion-exchanged amount and the more preferable the permselectivity for sodium ion.

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