Polyisobutylene solution

Simmons,J.M. Dynamic modulus of polyisobutylene solutions in superposed steady shear flow. Rheol. Acta. 7,184-188 (1968). 

Fig. 1.7 shows results for the polyisobutylene solution. In this figure, nu — n,2 is, as a function of shear rate q, insignificantly higher than nn — 3.j. Fig. 1.8 shows similar results for the polystyrene solution. In this case no difference is seen between u — 22 and nu — n33. These... 

At this point it should be noted that the conclusion drawn from flow birefringence measurements, viz. that p22 — p33 of polymer systems is very small compared with pn — pn is not always supported by other types of measurement. With the aid of pressure measurements in the walls of various rheometers (e.g. cone-and-plate apparatus) results have been obtained by a number of authors (refs. 26, 43, 44), showing that p23 — p33 should be positive and can have values up to 20 per cent of Pn Pta- 1-7 suggests for the investigated polyisobutylene solution... 

Baaijens HPW, Peters GWM, Baaijens FPT and Mejer HEH (1995) Viscoelastic flow past a confined cylinder of a polyisobutylene solution. J Rheol 39 1243-77. 

It is seen that NMR properties, specific to polymeric systems, are not due to the absence of motions but to the non-isotropic character of these motions. It is worth emphasizing that the search for a characterisation of dynamical properties leads actually to the observation of non-isotropic rotations of monomeric units which result from the presence of entanglements. As3Tnmetry properties are observed instead of dynamic ones. Equation (17) is general and applies also to polyisobutylene solutions or to polyisoprene by using different values of the parameters. 

Figure 10 Viscosity of polyisobutylene solutions at 40°C. Data are presented for PBB in tetrahydrofuran, cyclohexane, and supercritical carbon dioxide.

Pig. 39. Comparison of the K-BKZ prediction (squares) for the half-step normal stress response with the experimental behavior (open circles) for a polyisobutylene solution. After McKenna and Zapas (113). 

G. B. McKenna and L. J. Zapas, The Superposition of Small Deformations on Large Deformations Measurements of the Incremental Modulus for a Polyisobutylene Solution J. Polym. ScL, Polym. Phys. Ed. 23, 1647-1656 (1985). 

Fig. 3-10 Normal and shear stress as a function of shear rate for polyisobutylene solutions [13].

Couette and Poiseuille flow of polyacrylamide and polyisobutylene solutions... 

MA1 Maron, S.H. and Daniels, C.A., Thermodynamics of polyisobutylene solutions. III. Thermal behavior and polymer order, J. Macromol. Sci.-Phys. B, 2, 591, 1968. 

FIG, 17-35. Shear stress growth and relaxation for successive impositions of a constant shear rate with intervening rest periods of different lengths, for a 3% polyisobutylene solution (Mw = 2.8 X 10 ) at 25°C. (Stratton and Butcher. ) Reproduced, by permission, from the Journal of Polymer Science. 

Mechanochemistry of Polyisobutylene Solutions Degradation Energy as a Function of Experimental Conditions ... 

Fig, 2.7 Meehanochemistry of polyisobutylene solutions (a) original polymer (b) sheared in 1,2,4-trichlorobenzene (c) sheared in w-hexadecane. GPC shows bimodal distributions produced in two different solvents [34]. 

Fig. 2.8 Ultrasonic irradiation of a concentrated polyisobutylene solution [39a] initial = 2. Relative changes of and are compared with the theoretical behavior for random scission of a most probable MWD [14a].

Fig. 2,10 Mechanochemistry of polyisobutylene solutions My 1,750,000, 10% in cetane at 40°C) bonds ruptured versus capillary residence time at four shear rates [9].

Ftg. 2.16 Mechanochemistry of polyisobutylene solutions of three different samples... 

To test this result Beavers and Joseph (1975) measured h versus for a polyisobutylene solution. Some of their results are reproduced in Figure 5.3.6. We see that there is an approximately constant static climb, hs(0), with different radii and a fairly large region of linearity in f2. This linearity appears to justify dropping the higher order terms in eq. 5.3.36. From the slopes in Figure 5.3.6, Beavers and Joseph calculate p = 0.97 0.5 g/cm at 26°C. Davis and Macosko (1973) estimated ir, o and V 2,o from the low shear rate limits of N from cone and plate thrust data and N] — N2 from parallel disk data and obtained p = 0.98 0.5 g/cm on the same material. Joseph etal. (1984) have made similar comparisons on a number of polymers. 

Comparison of ERD to other ifaeometers for a 6.8% polyisobutylene solution. From Macosko and Davis (1974). 

Comparison of shear and normal stress determined by parallel plates (solid symbols) and slit rheometer with hole pressure (open symbols) for a polyisobutylene solution at room temperature. From Lodge (1989). 

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