Skip to main content Accessibility help

Out-of-plane orientation and crystallinity of biaxially stretched polyethylene terephthalate

  • Sudheer Bandla (a1), Masoud Allahkarami (a1) and Jay C. Hanan (a1)


The dependence of polymer properties on their processing history can be used advantageously. Polyethylene terephthalate (PET), a semi-crystalline polymer, exhibits a microstructure reliant on process and thermal history. PET undergoes strain-induced crystallization, making it sensitive to mechanical stretching. As the level of crystallinity in PET governs its mechanical behavior, it is necessary to quantify the effect of crystallinity and molecular orientation for efficient use. The present research is focused on an approach that will aid in correlating the stretch ratio of PET films to the percent crystallinity and mechanical properties. PET films with different local stretch ratios were obtained through bi-axially stretching injection-molded cylinders of increasing thickness and weight. Percent crystallinity of the PET films with different stretch ratios was measured using X-ray diffraction. Film samples were marked with respect to the stretch directions for measuring their longitudinal (primary stretch direction) and transverse mechanical properties. Local molecular orientation in the form of pole figures was mapped using the (100) plane corresponding to the PET lattice. This will help in linking the physical sample directions and processing to the molecular orientation. Associating the mechanical properties with molecular alignment helps in designing production processes that realize the material's structural potential.


Corresponding author

a)Author to whom correspondence should be addressed. Electronic mail:


Hide All
Bandla, S. and Hanan, J. (2012). “Microstructure and elastic tensile behavior of polyethylene terephthalate-exfoliated graphene nanocomposites,” J. Mater. Sci. 47(2), 876882.
Bandla, S., Winarski, R., and Hanan, J. (2013). Nanotomography of Polymer Nanocomposite Nanofibers. Imaging Methods for Novel Materials and Challenging Applications, edited by Jin, H., Sciammarella, C., Furlong, C., and Yoshida, S. (Springer, New York), Vol. 3, pp. 193198.
Bashir, Z., Al-Aloush, I., Al-Raqibah, I., and Ibrahim, M. (2000). “Evaluation of three methods for the measurement of crystallinity of pet resins, preforms, and bottles,” Polym. Eng. Sci. (USA) 40(11), 24422455.
Daubeny, R. D. P., Bunn, C. W., and Brown, C. J. (1954). “The crystal structure of polyethylene terephthalate,” Proc. R. Soc. Lond. A, Math. Phys. Sci. 226(1167), 531542.
Jabarin, S. A. (1992). “Strain-induced crystallization of poly(ethylene terephthalate),” Polym. Eng. Sci. 32(18), 13411349.
Jog, J. P. (1995). “Crystallization of polyethyleneterephthalate,” J. Macromol. Sci. – Polym. Rev. (USA) 35(3), 531553.
Johnson, J. E. (1959). “X-ray diffraction studies of the crystallinity in polyethylene terephthalate,” J. Appl. Polym. Sci. 2(5), 205209.
Lyons, W. J. (1958). “Theoretical values of the dynamic stretch moduli of fiber-forming polymers,” J. Appl. Phys. 29(10), 14291433.
Mahendrasingam, A., Martin, C., Fuller, W., Blundell, D. J., Oldman, R. J., Harvie, J. L., MacKerron, D. H., Riekel, C. and Engström, P. (1999). “Effect of draw ratio and temperature on the strain-induced crystallization of polyethylene terephthalate at fast draw rates,” Polymer 40(20), 55535565.
Meijer, H. E. H. and Govaert, L. E. (2005). “Mechanical performance of polymer systems: the relation between structure and properties,” Prog. Polym. Sci. (UK) 30(8–9), 915938.
Michaeli, W. and Leopold, T. (2010). Modeling the Structural Performance of Stretch-Blow Moulded PET Bottles, ANTEC 2010 (Society of Plastics Engineers, Orlando).
Silberman, A., Omer, M., Ophir, A., and Kenig, S. (1998). The Effect of Stretch and Heat Transfer on the Thermo-Mechanical Properties of PET Bottles. ANTEC 1998 (Society of Plastics Engineers, Atlanta).
Smith, M. R., Cooper, S. J., Winter, D. J., and Everall, N. (2006). “Detailed mapping of biaxial orientation in polyethylene terephthalate bottles using polarised attenuated total reflection FTIR spectroscopy,” Polymer 47(15), 56915700.
Thompson, A. B. (1959). “Strain-induced crystallization in polyethylene terephthalate,” J. Polym. Sci. 34(127), 741760.
Viswanathan, A., Wiff, D. R., and Adams, W. W. (1976). An Investigation of Structure-Property Correlation in Polyethylene Terephthalate Films, Air Force Materials Laboratory, 127.


Related content

Powered by UNSILO

Out-of-plane orientation and crystallinity of biaxially stretched polyethylene terephthalate

  • Sudheer Bandla (a1), Masoud Allahkarami (a1) and Jay C. Hanan (a1)


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed.