EAP - Proceedings of the Estonian Academy of Sciences

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SINCE 1952

proceedings
of the estonian academy of sciences

ISSN 1736-7530 (Electronic)
ISSN 1736-6046 (Print)

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The effect of modality on linear low-density polyethylene crystallization behaviour at high and very high supercoolings; pp. 53–57

PDF | doi: 10.3176/proc.2009.1.09

Authors

Triin Märtson, Andres Krumme, Veronika Gavrilkina, Anti Viikna

Abstract

Isothermal crystallization rates of uni- and bimodal linear low density polyethylenes having similar average molar mass and branching content were analysed at various temperatures in a very high supercooling range by means of a novel method – chip nanocalorimetry. At a particular crystallization temperature within the lower range of temperatures the bimodal material crystallized slower than the unimodal one, whereas at moderate supercooling temperatures bimodal polyethylene materials have earlier been reported to crystallize faster. Comparison to a high and moderate range of supercoolings was also made using an in-house built hot stage polarized light microscopy system. The difference gives evidence of a different crystallization mechanism caused by modality, which can have a strong impact on the application properties of the material.

References

1. Zhang, M., Lynch, D. T., and Wanke, S. E. Effect of molecular structure distribution on melting and crystallization behavior of 1-butene/ethylene copolymers. Polymer, 2001, 42, 3067–3075.
doi:10.1016/S0032-3861(00)00667-4

2. Krumme, A., Lehtinen, A., Adamovsky, S., Schick, C., Roots, J., and Viikna, A. Crystallization behavior of some unimodal and bimodal linear low-density polyethylenes at moderate and high supercooling. J. Polym. Sci., Part B, 2008, 46, 1577–1588.
doi:10.1002/polb.21494

3. Kim, M.-H. and Phillips, P. J. Nonisothermal melting and crystallization studies of homogeneous ethylene/α-olephin random copolymers. J. Appl. Polym. Sci., 1998, 70, 1893–1905.
doi:10.1002/(SICI)1097-4628(19981205)70:10<1893::AID-APP4>3.3.CO;2-Y

4. Vega, J. F., Otegui, J., Exposito, M. T., Lopez, M., Martin, C., and Martinez-Salazar, J. Structure and physical properties of polyethylenes obtained from dual catalysis process. Polym. Bull., 2008, 60, 331–342.
doi:10.1007/s00289-007-0871-9

5. Alt, F. P., Böhm, L. L., Enderle, H.-F., and Berthold, J. Bimodal polyethylene – interplay of catalyst and process. Macromol. Symp., 2001, 163, 135–144.
doi:10.1002/1521-3900(200101)163:1<135::AID-MASY135>3.0.CO;2-7

6. Scheirs, J., Böhm, L. L., Boot, J. C., and Leevers, P. S. PE100 resins for pipe applications: continuing the development into the 21st century. Trends Polym. Sci., 1996, 4, 408–415.

7. Böhm, L. L. The ethylene polymerization with Ziegler catalysts: fifty years after the discovery. Angew. Chem. Int. Ed., 2003, 42, 5010–5030.
doi:10.1002/anie.200300580

8. Feng, L. and Kamal, M. R. Spherulitic crystallization behavior of linear low-density polyethylene.Polym. Eng. Sci., 2005, 45, 74–83.
doi:10.1002/pen.20231

9. Krishnaswamy, R. K., Yang, Q., Fernandez-Ballester, L., and Kornfield, J. A. Effect of the distribution of short-chain branches on crystallization kinetics and mechanical properties of high-density polyethylene. Macromolecules, 2008, 41, 1683–1704.
doi:10.1021/ma070454h

10. Gupta, P., Wilkes, G. L., Sukhadia, A. M., Krishnaswamy, R. K., Lamborn, M. J., Wharry, S. M., Tso, C. C., DesLauriers, P. J., Mansfield, T., and Beyer, F. L. Does the length of the short chain branch affect the mechanical properties of linear low density polyethylenes? An investigation based on films of copolymers of ethylene/1-butene, ethylene/1-hexene and ethylene/1-octene synthesized by a single site metallocene catalyst. Polymer, 2005, 46, 8819–8837.

11. Minakov, A., Wurm, A., and Schick, C. Superheating in linear polymers studied by ultrafast nanocalorimetry. Eur. Phys. J. E, 2007, 23, 43–53.
doi:10.1140/epje/i2007-10173-8

12. Wagner, J., Abu-Iqyas, S., Monar, K., and Phillips, P. J. Crystallization of ethylene–octene copolymers at high cooling rates. Polymer, 1999, 40, 4717–4721.
doi:10.1016/S0032-3861(99)00077-4

13. Zhang, M., Lynch, D. T., and Wanke, S. E. Characterization of commercial linear low-density polyethylene by TREF-DSC and TREF-SEC cross-fractionation. J. Appl. Polym. Sci., 2000, 75, 960–967.
doi:10.1002/(SICI)1097-4628(20000214)75:7<960::AID-APP13>3.0.CO;2-R

14. Minakov, A. and Schick, C. Ultrafast thermal processing and nanocalorimetry at heating and cooling rates up to 1 MK/s. Rev. Sci. Instr., 2007, 78, 073902.
doi:10.1063/1.2751411

15. Krumme, A. Measuring crystallization kinetics of high density polyethylene by improved hot-stage polarized light microscopy. Polym. Test., 2004, 23, 29–34.
doi:10.1016/S0142-9418(03)00058-8

16. Vanden Eynde, S., Mathot, V. B. F., Koch, M. H. J., and Reynaers, H. Thermal behaviour and morphology of homogeneous ethylene-1-octene copolymers with high comonomer contents. Polymer, 2000, 41, 4889–4900.
doi:10.1016/S0032-3861(99)00712-0

17. Hosoda, S., Nomura, H., Gotoh, Y., and Kihara, H. Degree of branch inclusion into the lamellar crystal for various ethylene/α-olefin copolymers. Polymer, 1990, 31, 1999–2005.
doi:10.1016/0032-3861(90)90030-3

18. Feng, L. and Kamal, M. R. Crystallization and melting behavior of homogeneous and heterogeneous linear low-density polyethylene resins. Polym. Eng. Sci., 2005, 45, 1140–1151.
doi:10.1002/pen.20389

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