The plastic deformation of oriented polypropylene and polyethylene: deformation mechanisms
Polypropylene and high-density polyethylene, oriented by hot drawing, have been tensile testedin situ in a low angle X-ray camera. Two orientations of polypropylene,Θ0=31° andΘ0=60°, and one orientation of polyethylene,Θ0=30°, were examined. (Θ0 is the initial angle between the tensile axis and the molecular axis.) Low-angle and wide-angle X-ray patterns were taken at successive stages of increasing strain up to approximately 100%. The rotations of the molecular axis and lamellar normal for both materials oriented nearΘ0=30° were quantitatively consistent with predominantly intermolecular shear, occurring within the lamellae. In the case of polypropylene, it is proposed that small amounts of interlamellar and interfibrillar shear were also present.
AtΘ0=60°, the polypropylene was shown to deform by void opening or fibril separation, followed by intermolecular shear. The behaviour of polypropylene was consistent with the yield criterion based on a fibre reinforced composite model which was presented in a previous paper .
KeywordsPolymer Polyethylene Plastic Deformation Polypropylene Fibril
Unable to display preview. Download preview PDF.
- 1.D. M. Shinozaki andG. W. Groves,J. Mater. Sci. 8 (1973) 71.Google Scholar
- 2.A. Keller andJ. G. Rider,J. Mater. Sci. 1 (1966) 389.Google Scholar
- 3.T. Seto andY. Tajima,Japan J. Appl. Phys. 5 (1966) 534.Google Scholar
- 4.T. Hinton andJ. G. Rider,J. Appl. Phys. 39 (1968) 4932.Google Scholar
- 5.T. Seto, T. Hara, andK. Tanaka,Japan J. Appl. Phys. 7 (1968) 31.Google Scholar
- 6.R. J. Young, Ph. D. Thesis, University of Cambridge, 1972.Google Scholar
- 7.A. Cowking, J. G. Rider, I. L. Hay, andA. Keller,J. Mater. Sci. 3 (1968) 646.Google Scholar
- 8.A. Cowking andJ. G. Rider,ibid 4 (1969) 1051.Google Scholar
- 9.A. Keller andD. P. Pope,ibid 6 (1971) 453.Google Scholar
- 10.J. J. Point, M. Dosière, M. Gilliot, andA. Goffin-Gérin,ibid 6 (1971) 479.Google Scholar
- 11.R. J. Samuels,J. Polymer Sci. A-2,6 (1968) 1101.Google Scholar
- 12.J. L. Way andJ. R. Atkinson,J. Mater. Sci. 6 (1971) 102.Google Scholar
- 13.R. G. Crystal andD. Hansen,J. Appl. Phys. 38 (1967) 3103.Google Scholar
- 14.A. Peterlin andF. J. Baltá-Calleja,ibid 40 (1969) 4238.Google Scholar
- 15.F. J. Baltá-Calleja andA. Peterlin,J. Mater. Sci. 4 (1969) 722.Google Scholar
- 16.G. W. Groves andP. B. Hirsch,ibid 4 (1969) 929.Google Scholar
- 17.E. Schmid andW. Boas, “Plasticity of Crystals” (Chapman and Hall, London, 1968).Google Scholar