MECHANICAL PROPKHTIES OF POLYMERS 



137 



components are equal but as llu> pcicontage of polyisobutylene is in- 

 creased, the resistance iucreas(\s more rapidly tluin the reactance. 



By solving equation (9) for 77,1 , rj/j and m/j in terms of R antl A' measured 

 at one fre(|uency and 77,1 + >?/; the solntion viscosity, we find 



dip 



Va 



fJ-B = 



C0p(7J.i + TJb) — 2RX 



{R~ — X") wriB 



2RX 



Vb 



= (va + Vb) — 



Va 



(10) 



cop(rj.4 + Vb) 



Applying these formulae to the measured results, the curves of Fig. 11 

 result. The shear elasticity is directly proportional to the concentration, 

 the viscosity tja is only slightly larger than the solvent viscosity while 

 the main part of the measured viscosity resides in tjb the viscosity asso- 

 ciated with chain motion. Fig. 12 shows these three quantities for a one 

 per cent solution measured as a function of temperature. The apparent 



0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 

 GRAMS PER 100 CC OF SOLUTION 



Fig. 11 — Shear stiffness, series viscosity tja and molecular viscosit}^ tjb for 

 poh'isobutylene (molecular weight of 3,930,000) in cyclohe.xane plotted as a 

 function of grams per 100 cc of solution. 



