Accession Number : AD0696139

Title :   THERMO-MECHANICS AND STRUCTURE OF ELASTOMERS.

Descriptive Note : Doctoral thesis,

Corporate Author : POLYTECHNIC INST OF BROOKLYN N Y DEPT OF AEROSPACE ENGINEERING AND APPLIED MECHANICS

Personal Author(s) : Glaser,Zorach R. ; Eirich,Frederick R.

Report Date : SEP 1969

Pagination or Media Count : 258

Abstract : This report describes the dilatometric, thermal, mechanical, and thermomechanical studies of some representative elastomeric materials. The investigations were undertaken to provide data for re-testing and extending the theory of non-linear rubber elasticity, primarily for the purpose of making deductions on the changes of the rubber structure in large uniaxial extensions. Experimentally, a wide range of strains, extension rates, temperatures, crosslink densities, and amounts of original specimen crystallinity were used, and were supplemented by calorimetric and dilatometric investigations. Results were obtained on the relative entropic and internal energy contributions (with and without phases changes) to the resistance to stretching. The most complete and far-reaching data of novel character were obtained from the mechanical measurements at high strain rates and thus under quasi-adiabatic conditions. Other important results are that: (a) the density of entanglements is proportional to the strain-rate, (b) a decrease in the rise of moduli from entanglements occurs as the number of chemical crosslinks increases, (c) the bulk volume contraction at intermediate elongations is an almost linear function of the stretch-ratio, and (d) the chain alignment begins at much smaller elongations than has hitherto been assumed. (Author)

Descriptors :   (*ELASTOMERS, MECHANICAL PROPERTIES), RUBBER, CROSSLINKING(CHEMISTRY), CALORIMETRY, STRAIN(MECHANICS), DILATOMETERS, THERMAL PROPERTIES, HYSTERESIS, THESES

Subject Categories : Elastomers and Rubber
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE