346 THE BELL SYSTEM TECHNICAL JOURNAL, MARCH 1952 



3.500 



1.500 ;=— — 



0.250 0.500 0.750 



CONCENTRATION IN GRAMS PER 100 ML. OF SOLUTION 



Fig. 22 — Inherent viscosity of polyisobutylene (Af, = 3.87 X 10'') in benzene, 

 at various temperatures. 



more flexible compositions are often produced with low compatibility 

 plasticizers — indeed, sometimes with those on the verge of phase sepa- 

 ration than with those with highly favorable heats of solution. This 

 would mean that the bad solvents would compress the chains so that 

 they would be more easily strained than if they were in a "free cham" 

 or even extended configuration. If single chain, visco-elastic stiffnesses 

 are acting this way, the dynamic mb would then actually decline as heat 

 of mixing become more positive. 



2 1200 



Fig. 23- 

 20 kc. 



0.125 0.250 0.375 0.500 0.625 0.750 0.875 1.000 



CONCENTRATION IN GRAMS PER 100 ML OF SOLUTION 



-Rigidity of polyisobutylenes in cyclohe.xane and benzene at 25°C and 



