Effects of Composition and Processing Conditions on Morphology and Properties of Thermoplastic Elastomer Blends of SEBS-PP-Oil and Dynamically Vulcanized EPDM-PP-Oil

Abstract

This work presents a comparative study of the morphology and structure-related properties of thermoplastic elastomer blends based on SEBS-PP-oil and dynamically vulcanized EPDM-PP-oil prepared under identical conditions. Compositions of each blend type with three different SEBS-PP and EPDM-PP ratios by weight were made in a co-rotating twin-screw extruder and a Brabender internal mixer. A comparative study of different electron microscopic techniques for studying the morphology of these oil-extended blends is reported. Morphological characterization using different microscopic techniques showed a co-continuous morphology for the SEBS-PP-oil blends and droplet-matrix morphology for the thermoplastic vulcanizate (TPV) blends. The particle size distribution of the EPDM-phases in the TPVs prepared in the twin-screw extruder was wider than for the Brabender mixer. No difference in the morphology was observed for the SEBS-PP-oil blends prepared in the twin-screw extruder and Brabender, except for the blend with the highest PP content. The elongation-at-break values were significantly higher for the SEBS-PP-oil blends as compared to the TPV blends. The gel content of the TPVs was the main factor determining the stress-strain properties, as influenced by the preparation method. Also the crystallinity of the PP-phase for both SEBS-PP-oil and TPV blends was investigated and, although being dependent on the preparation method for the SEBS-PP-oil blends, did not reflect in the stress-strain properties.

Keywords

morphology blends microscopy twin-screw extruder internal mixer thermoplastic elastomers

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References

1. Holden, G. (2002). Understanding Thermoplastic Elastomers, Chapter 7, Hanser Gardner Publication Inc., Cincinnati, OH.

2. Abdou-Sabet, S. (1998). In: Bailley, J.E. and Bonet, M. (eds), Ulmann’s Encyclopedia of Industrial Chemistry, Electronic Release, 6th edn, WileyVCH, Weinheim .

3. Chung, O. and Coran, A.Y. (1997). Rubber Chem. Technol., 70: 781-797 .

4. Radusch, H.J. and Pham, T. (1996). Kautsch. Gummi Kunstst., 49: 249-257 .

5. Goharpey, F. , Katbab, A.A. and Nazockdast, H. (2001). J. Appl. Polym. Sci., 81: 2531-2544 .

6. Abdou-Sabet, S. and Patel, R.P. (1991). Rubber Chem. Technol., 64: 769-779 .

7. Ellul, M.D. (2001). Presentation at the 160th Meeting of the ACS, Paper No: 85, Rubber Division, Cleveland OH, Oct. 16-19.

8. Xiao, H.W. , Huang, S.Q. , Jiang, T. and Cheng, S.Y. (2002). J. Appl. Polym. Sci., 83: 315-322 .

9. Boyce, M.C. , Kear, K. , Socrate, S. and Shaw, K. (2001). J. Mech. Phys. Solids., 49: 1073-1098 .

10.

10. Ohlsson, B. , Hassender, H. , and Tornell, B. (1996). Polym. Eng. Sci., 36: 501-510 .

11.

11. Veenstra, H. , van Lent, B.J.J. , van Dam, J. and de Boer, A.P. (1999). Polymer, 40: 6661-6672 .

12.

12. Information obtained from from DSM Research B.V.

13.

13. Information obtained from Kraton Polymers B.V.

14.

14. Internal procedure of DSM Elastomers B.V.

15.

15. A Public Domain Image Analysis Programme Developed at the U.S. National Institute of Health and Available on the Internet at http://www.scion.com.

16.

16. Charlesby, A. (1953). J. Polymer Sci., 11: 513-520 .

17.

17. Orazio, L.D. , Mancarella, C. , Martuscelli, E. , Sticotti, G. and Ghisellini, R. (1994). J. Appl. Polym. Sci., 53: 387-404 .

18.

18. Brown, G.M. and Butler, J.H. (1997). Polymer, 38: 3937-3945 .

19.

19. Jayraman, K. , Kolli, G. and Ellul, M.D. (2002). Presented at the International Rubber Conference, Prague, July 1-4.

20.

20. Plochocki, A.P. , Dagli, S.S. , Starita, J. and Curry, J.E. (1986). J. Elastomers Plast., 18: 256-266 .

21.

21. Favis, B.D. and Therrein, D. (1991). Polymer, 32: 1474-1481 .

22.

22. Scott, C.E. and Macosko, C.W. (1995). Polymer, 36: 461-470 .

23.

23. Lee, B.J. , Argon, A.S. , Parks, D.M. , Ahzi, S. and Bartczak, Z. (1993). Polymer, 34: 3555-3575 .

24.

24. Manson, J.A. and Sperling, L.H. (1976). Polymer Blends and Composites, Chapter 4, Plenum Press, Hayden .