The Role of Intra- and Intermolecular Cohesion in Fracture Initiation of High Polymers
The ultimate behavior of solid high polymers depends critically on the elastic energy stored within molecular chains. In this paper, the mechanism of the axial loading of chains through secondary bonds is studied in detail. For polyethylene and 6-polyamide, the maximum stresses which can be exerted by a defect-free crystallite in static equilibrium onto a chain are calculated. They are 0.75 × 1011 dynes/cm2 (PE) and 2.24 × 1011 dynes/cm2 (6-PA), respectively. The thermal excitation of stressed chains causes dislocations to migrate into the crystallite. The energy of dislocations and that of their activation are calculated as a function of molecular stresses. The effect of dislocation motion on chain breakage and macroscopic strength is discussed.
KeywordsFracture Initiation Chain Scission Atom Group Crystal Boundary Chain Breakage
Unable to display preview. Download preview PDF.
- 2.DeVries, K. L., private communication.Google Scholar
- 3.Becht, J., Dissertation, Technische Hochschule, Darmstadt, 1970.Google Scholar
- 4.Lindenmeyer, P., Mechanical Behavior of Materials,Soc. Mat. Sci., Japan (1972), Special Vol., p 74.Google Scholar
- 5.Baur, H., and Wunderlich, B., Fortschr. d. Hochpolymeren Forschung, 7, 388 (1970).Google Scholar
- 7.Kausch, H. H., and Langbein, D., J. Polymer Sci., Polymer Physics Edition, Vol 11 (1973).Google Scholar
- 8.Fowler, R., and Guggenheim, E. A., Statistical Thermodynamics, University Press, Cambridge (1952), p 495.Google Scholar
- 10.Tomashevskii, E. E., Soviet Physics — Solid State, 12, 2588 (1971).Google Scholar