No abstract

Stress oscillations were produced and analyzed in partly-crystalline syndiotactic polypropylene (sPP) and in poly(ethyleneterephthalate) (PET) in cold drawing experiments. Strain oscillations, which always occur in connection with stress oscillations, were also investigated. The experiments were performed varying the parameters temperature, sample geometry and drawing velocity. This article gives first results of our investigations, which show discrepancies to the existing theories.

No abstract

Different adsorber and ion exchange resins have been sonicated with ultrasound of different frequencies in a fixed bed. Afterwards, the sonicated particles were investigated by scanning electron and light microscopy. Also, different mechanical properties, like fracture load, maximum flattening and Young's modulus were measured in compression tests and compared to the results of the ultrasonication experiments. Cavitational collapses cause cracks in resins with a high fracture load and a high Young's modulus as well as a low deformation at fracture. Complete destruction of adsorbent particles due to acoustic cavitation is observed with particles of low fracture loading and low Young's modulus. No or only little destruction is observed with particles which inhibit both sufficient strength and deformation properties. On the basis of these findings it is concluded that resin particles with optimum resistance to ultrasound show both a sufficient fracture load as well as high mechanical flexibility. Copyright © 2002 John Wiley & Sons, Ltd.

No abstract