INTERACTION OF POLYMERS AND MECHANICAL WAVES 



337 



perature range is shown in Fig. 13, and of A'o , in Fig. 14. Fig. 14 })rings 

 out the significant point that in the present arrangement, wliere the 

 osciUating crystal is innnei'sed in the li(iui(l stuched, the (liclcrlr/c pvop- 

 erties of the hciuid are important. Apparently the dielectric losses e\'eii 

 of thes(> pm'iHed hydrocarbons are dilTerent enough so that K> at 80 kc 

 is (|uit(> dilfereiit for IxMizene and cyclohexaiie. (I)iel(M'tric studies ha\'e 

 previously indicated difliculty in preparing benzene ha\'ing theoi'etically 

 expected loss.) It is also possible that slight differences in wetting the 

 crystal cause Ko to vary with the liijuid used. 



The A'l and /vo valu{\s determined for all the various conditions above 

 were then used und(M- these conditions for measurements on the polymer 



10 15 20 25 30 35 40 



TEMPERATURE IN DEGREES CENTIGRADE 



Fig. 14 — Temperature variation of crystal constant K2 over a frequency range 

 witli l)enzene and cj^clohexane as standard fluids. 



solutions in the kilocycle range. In the megacycle range, the balanced 

 shear wave reflectance technique gave satisfactory results over certain 

 concentration zones which could fairly well be extrapolated to high 

 dilutions. Thus, over the whole spectrum, there seems to be no doubt 

 al)out the reality of the effects described below. That is, their magnitude 

 far exceeds experimental uncertainty, as demonstrated in this section. 



POLYISOBUTYLENE SOLTTIOXS; DYNAMICS OF SEPARATE CHAINS 



Solutions of i)olyisobutylcne of M, = 1.2 X 10*' from about 0.1 to 

 1.0 wt. per cent concentration in cyclohexane yield R m and Xm curves 

 as shown in Fig. lo. The points coincide for the i)ure soh'ent, as they 



