THE RELATIONSHIP BETWEEN MOLECULAR STRUCTURE, MORPHOLOGY, AND THE MECHANICAL PROPERTIES OF POLYMERIC MATERIALS.
Abstract
Crystallization rate and viscoelasticity studies have been made on 1:3:5 tri-alpha-naphthyl benzene over a wide temperature range through the glass temperature. The retardation spectrum extends over nine logarithm decades of time. In applying the free volume theory to the results, it is necessary to assume that the occupied volume is independent of temperature. The temperature dependence of the transport factor in the crystal growth rate differs from that of the viscosity. Viscoelastic studies on polystyrenes of various molecular weights show that the temperature dependence of the primary softening transition differs from that of the part of the recoverable compliance near the rubbery plateau, that there is an unexpected dependence on molecular weight near the glassy level of compliance, that the steady state compliance appears to be insensitive to molecular weight, and that the zero shear viscosity depends on the 3.4 power of the molecular weight. Crystallization studies of high molecular weight poly-(tetramethyl-p-silphenylene)-siloxanes show that the surface energy corresponding to the crystallite ends increases with molecular weight. The molecular weight dependence of the growth rate can be explained in terms of free volume concepts. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1966
- Accession Number
- AD0487484
Entities
People
- Donald J. Plazek
- Hershel Markovitz
- Joseph H. Magill
Organizations
- Carnegie Mellon University