Changes in the Structure and Mechanical Properties of Hard Elastic and Porous Polypropylene Films upon Annealing and Orientation
The effect of the annealing temperature on the characteristics of hard elastic polypropylene samples obtained by annealing of extruded films and having an oriented lamellar structure is studied. It is established using the methods of X-ray scattering and differential scanning calorimetry that the lamellae thickness, the large period, and the degree of orientation of the folded lamellae increase with an increase in the annealing temperature, which is accompanied by an increase in the melting temperature and enthalpy. Porous films are obtained by uniaxial extension of the annealed samples in the orientation direction. It is shown that the porosity and permeability of the porous films increase with an increase in the annealing temperature, owing to an increase in the number and sizes of the through channels. The mechanical characteristics (strength, elastic modulus, and break elongation) of the hard elastic and porous films are measured, and their relationship with changes in the structure and orientation of the samples, depending on the annealing temperature, is established.
Unable to display preview. Download preview PDF.
- 2.Ph. H. Geil, Polymer Single Crystals (Wiley-Interscience, New York, 1963).Google Scholar
- 3.V. A. Marikhin and L. P. Myasnikova, Supramolecular Structure of Polymers (Khimiya, Leningrad, 1977) [in Russian].Google Scholar
- 4.S. Ya. Frenkel and G. K. Elyashevich, in Orientation Phenomena in Polymer Solutions and Melts (Khimiya, Moscow, 1980), p. 9 [in Russian].Google Scholar
- 5.V. A. Marikhin and L. P. Myasnikova, in Oriented Polymer Materials, Ed. by S. Fakirov (Huthig and Wepf, Heidelberg, 1996).Google Scholar
- 6.R. E. Kesting, Synthetic Polymer Membranes. A Structural Perspective, 2nd ed. (Wiley, New York, 1985).Google Scholar
- 8.G. K. Elyashevich, E. Yu. Rozova, and E. A. Karpov, RF Patent No. 2140936 (1997).Google Scholar
- 10.E. A. Karpov, V. K. Lavrentyev, E. Yu. Rozova, and G. K. Elyashevich, Vysokomol. Soedin., Ser. A 37, 2035 (1995).Google Scholar
- 13.G. K. Elyashevich, E. Yu. Rozova, and E. A. Karpov, Vysokomol. Soedin., Ser. B 33, 723 (1991).Google Scholar
- 15.B. Wunderlich, Macromolecular Physics. Crystal Melting (Academic, New York, 1980), Vol.3.Google Scholar
- 16.G. K. Elyashevich, A. G. Kozlov, and E. Yu. Rozova, Polymer Sci., Ser. A 40, 567 (1998).Google Scholar