Dynamic mechanical properties of neoprene type W

The dynamic mechanical properties of cured Neoprene Type W gum stock have been measured on a commercial Fitzgerald Transducer from 30 to 3000 cycles/sec. at twelve temperatures from −7.1 to 71.1°C. The results are reduced to 25°C. by the method of temperature‐frequency superposition to obtain master curves for real and imaginary components of complex compliance which encompass over ten logarithmic time scales. The shift factors, log a T , are found to obey the WLF equation of log a T = 10.6 ( T − T 0 )/(93.6 + T − T 0 ); T 0 = 25.0°C. The equilibrium shear modulus is calculated to be 10 6.82 dynes/cm. 2 . The relaxation and retardation spectra are presented. The magnitude of its monomeric frictional coefficient (1.8 × 10 −6 dynes‐sec./cm.) at 25°C. as well as the implied appearance of the loss tangent peak at relatively high frequency reflect a very high degree of local flexibility. This result appears to be unusual when compared with other common elastomers, e.g., polyisobutylene, vulcanized natural rubber, and Hypalon‐20.