MECHANICAL PROPERTIES OF POLYMERS 



1.55 



4 and 5. Columns 6 and 7 show the values of X and x, the compressional 

 components. A definite longitudinal compressional viscosity is indica- 

 ted which howe\'er is some\\hat smaller than the shear viscosity 77. 



V. MEASUREMENTS FOR SOLID POLYMERS 



Recently two new methods have been devised for accurately measur- 

 ing the properties of solid plastics in the ultrasonic frequency range 



24 



22 

 20 



16 



lU 



I- 16 



LU 



K 14 



Z 

 (U 



^ 12 



IT 

 lU 



a. 



o 

 ? 8 



3 6 

 4 



2 

 



60 80 



0.4 0.6 0.8 1.0 2.0 4.0 



FREQUENCY IN MEGACYCLES PER SECOND 



Fig. 24 — Normal loss in db per centimeter measured as a function of frequency 

 for several rubbers and plastics. 



SCREEN 



^-\|/- SCAL 



SCALE 



Fig. 25 — Debye-Sears cell for making sound waves visible. 



