synopsisThis work used a conventional thermomechanical analyzer (TMA) to measure the depth of indentation a t room temperature of elastomers and Finkin's equation to calculate Young's moduli of elastomers, which have been measured by Drutowski, from the radius of contact of an indentor on thin sheets of sample. Data obtained from the TMA are compared with those measured by radius of contact and Hertz contact theory and are found in good agreement. Measurements of Young's modulus as a function of temperature at different heating rates by TMA were made for an acrylic elastomer. The results are compared with theory and the deviations from theory are discussed.

SynopsisA method for measuring the internal energy change of elastomers under compression is demonstrated using a conventional thermomechanical analyzer. The method is rapid and convenient and has a major advantage in that only a very small sample is required. Results are reported for natural rubber cured with two different, crosslinking agents. The results are compared with previous work on similar materials in tension and torsion.

SynopsisEmpirical correlations of flow properties of poly( vinyl chloride) were made using data reported by a number of investigators. Correlation was made by plotting the reduced variable viscosity q/qL versus ( q o y a w ) / ( p R T ) or (q0.iii?w0.5)/(pRT) for unplasticized PVC and versus (qojMwo.6)/(pRTWp) with polymer concentration, W2, for Pvc containing plasticizer.

A detailed review of the material published to date on the flow properties of poly(vinyl chloride) is given. The dependence of viscosity on concentration molecular weight, molecular weight distribution, shear and temperature for concentrated and molten poly (vinyl chloride) is considered. Polymer blends and plastisols are also included.