IXTKKACTION OF I'OI.V.M KKS AM) MKCIIAXK AL WAVES 321 



the plastic, polyst yi'ene, 



— CHo-C— . 



()tli('r stu(li(>s in |)i'()<>i'(\ss on licinid polyhuladicnc, i<()l>'is()i)r('n(', poly- 

 propylene, and ])olypropyl('n(' sehacatc tVoni which t'nrthci' inlorniation 

 ahout intra-chain stiffness may l)e derixed, will also be noted. 



PropcM'lies of the polyisobutylenes studied are summarized in Table 

 I\', some additional molecular weights in this range appear as extra 

 pomts in some of the hioh-fre(iuency graphs. The molecular weights Af, 

 are "inti'insic viscosity" averages "' '"'' and, with reasonable estimations 



Mn 



ot the ,rv~ ratio, check with cryoscopic number average, Mn , values on 



such materials, which are in tui'u listed in the table as expressed by melt 

 \iscosity relations of Fox and Flory. '" These molecular weights repre- 



sent i-easonable a\'erages rather than absolute values for these hetero- 

 geneous polymers. The DP values are just the number of isolnitylene 

 units per average chain. The r? values are the steady flow viscosities at 

 low rates of shear — usually determined by a falling ball. 



Rigidit]) atid Viscosity Mmjnilndes 



The properties of these li([uids I'anging from polymer A liaving only 

 forty times the viscosity of water to E, which begins to approach fluid- 

 ities of technical polymer melts (polyamidcs, for instance), were exploi'ed 



