Structural transitions in polyoxypropylene

Study of cryostructuration of polymer systems. XVII. Poly(vinyl alcohol) cryogels: Dynamics of the cryotropic gel formation

“…10,12,16 ) using the modified Kargin-Sogolova dynamometric balance. 17 The measurements were done at 22 Ϯ 1°C, the load was 4.9 mN, the punch had a spherical top 5 mm in diameter. The rheological parameter calculated from the creep data was an apparent instantaneous shear modulus, G 0 .…”

On nonlinear effects in the extensional flow of polymeric liquids

“…This effect was absent in the experiments with polyisobutylene P-20, apparently because of some technical difficulty in attaining the value e = 102. Data for e(r) showing a flat region after a period of sharp growth have been presented in [18,19] for a crystallizable polyisobutylene, but its viscosity exceeded the viscosity of the polyisobutylene P-20 by several orders of magnitude (in [18,19] the experiments lasted several days). In [19] the recoverable strain a was found to decrease with increasing s after a period of growth, however this fact does not agree with the experimental and theoretical results of this work.…”

Study of cryostructurization of polymer systems VII. Structure formation under freezing of poly(vinyl alcohol) aqueous solutions

“…Rheological properties of cryoPVAGs were studied with the help of the modified Kargin-Sogolova balance [11] at 22 + I~ using the method of spherical indentor penetration into the gel [12] in conditions which prevented samples drying out. Preliminary tests have shown that under used load (4.905-10 -3 N) there was no any moisture separation from the cryoPVAG, which could, for example, be connected with sineresis or deswelling.…”