Some rheological properties of an interpolymer complex formed in the mixtures of aqueous solutions of poly(acrylic acid) and methyl cellulose are investigated. In a diluted state, the complex exhibits polyelectrolyte properties, and in the shear field, it flows like a pure poly(acrylic acid) solution. From the experimental data obtained from the mixture flow in a longitudinal field, an effective relaxation time was calculated. It turned out to be higher than that for the initial components. The deviation of the experimental values of the viscosity from the calculated additive ones allowed us to determine the critical molecular weight of the poly(acrylic acid) below which the complex is not formed: M cr Ϸ 6 ϫ 10 4 , which is one order of magnitude higher than for the mixtures of spatially complementary macromolecules. The increase of the total polymer concentration in the mixture first leads to an increase of the complex size. Further increase of the polymer concentration and transition to the semidiluted state decreases the complex size and also decreases its solubility in water.
Academy of Sciences of the USSR, Institute of Macromolecular Compounds, 199 004 Leningrad/USSRThe uncoiling of chains of high molecular weight polystyrene in dilute solutions under the influence of a longitudinal hydrodynamic field has been investigated. The experimental results were interpreted in the framework of a non-linear dumbbell model for a macromolecule with varying friction coefficient. I t is shown that a stationary virtually completely uncoiled state of the macromolecules is developed in the longitudinal field requiring a continuous supply of mechanical energy, which may be referred to the class of spatial dissipative structures.
Der dynamiscke Phasenubergang vom Knauel zur gestreckten Kette in einem longitudinalen FeldDie Entknauelung der Ketten von Polystyren mit hoher Molekulmasse in verdunnter Losung unter dem EinfluS eines longitudinalen hydrodynamischen Feldes wurde untersucht. Die experimentellen Ergebnisse werden auf Basis eines nichtlinearen Hantelmodells der Makromolekiile mit variierendem Reibuiigskoeffizienten interpretiert. Es wird gezeigt, daS sich in dem longitudinalen Feld ein praktisch vollstandig entknauelter stationarer Zustand der Makromolekule aufbaut, der eine kontinuierliche Zufuhrung von mechanischer Energie erfordert und der Klasse der raumlichen dissipativen Strukturen zugeordnet werden kann. jlunammecmii $aaoaaaii nepexoa ,,ixybonpamepnymaa yenb" 8 npoi3ofibnow nofie mCCJIeAOBaH0 paaBOpa9HBaHHe UeIIet BbICOKOMOJleK~JIJIpHO~O IIOJIHCTHpOJra B pa36aBJIeHHbIX PaCTBOpaX IIpH B03AefiCTBHH IlpOAOJIbHOrO rHApOAHHaMH9eCKOrO IIOJIR. Pe3YJIbTaTbI 3KCIlepHMeHTOB HHTepIIpeTHpOBaHbI B paMKaX HeJIHHeflHO~ r a H T e J I b H 0~ MOAeJIH MaKpOMOJIeKyJIbX C HeIlOCTORHHbIM K03@@HQHeHTOM TpeHHFI. U O K a 3 a H 0 , 9TO
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