Polímeros: Ciência e Tecnologia
Polímeros: Ciência e Tecnologia
Scientific & Technical Article

The influence of long chain branches of LLDPE on processability and physical properties

Dartora, Paula Cristina; Santana, Ruth Marlene Campomanes; Moreira, Ana Cristina F.

Downloads: 0
Views: 239


Two polyethylene-based on single-site metallocene catalyst (mLLDPE) were selected to characterize the effect of long chain branching (LCB) on blown film processability, optical and mechanical properties. 13C NMR and parallel plate rheology were used to identify LCB presence on LLDPEs. Blown films were produced from 100% LLDPEs using three different machine direction (MD) stretch ratios. When the same processing conditions for the two LLDPEs grades were used, better processability was observed for LLDPE with LCB. In relation to mechanical and physical properties, Elmendorf tear and optical properties were highly influenced by the presence of LCB. Tear resistance is affected by film orientation and is inversely proportional to the level of LCB in the polymer. It was observed a reduction of 50% in the MD tear strength when comparing with the polymer without LCB. However, haze decreases significantly with the presence of LCB, about 40%.


LLDPE, metallocene, long chain branching, NMR, rheology, mechanical properties.


1. Coutinho, F. M. B., Melo, I. L., & Maria, L. C. S. (2003). Polietileno: principais tipos, propriedades e aplicações. Polímeros: Ciência e Tecnologia, 13(1), 1-13. http://dx.doi.org/10.1590/S0104-14282003000100005.

2. Berk, Z. (2013) Food packaging. In S. L. Taylor (Ed.), Food process engineering and technology (pp. 621-636). London: Academic Press.

3. Kropf, D. H. (2004) Packaging: techonology and films. In W. K. Jensen (Ed.), Encyclopedia of meat science (pp. 943-949). New Zealand: Elsevier.

4. Yang, Q., Jensen, M. D., & McDaniel, M. P. (2010). Alternative View of Long Chain Branch Formation by Metallocene Catalysts. Macromolecules, 43(21), 8836-8852. http://dx.doi.org/10.1021/ma101469j.

5. McDaniel, M. (2003). Long chain branching in polyethylene from the Phillips Catalyst. In Proceeding of the 59th Southwest Regional Meeting of the American Chemical Society. Oklahoma: American Chemical Society.

6. Golriz, M., Khonakdar, H. A., & Morshedian, J. (2014). Thermorheological behavior of peroxide-induced long chain branches linear low density polyethylene. Thermochimica Acta, 590, 259-265. http://dx.doi.org/10.1016/j.tca.2014.07.010.

7. Munstedt, H. (2008). Rheological experiments as a versatile tool to analyse long-chain branches in polymers. Polymer Preprints, 49(1), 81-82. Retrieved in 26 April 2013, from http://library.sut.ac.th:8080/ACS/V49N01Y2008/files/0192.pdf

8. Williamson, G. R., & Cervenka, A. (1974). Characterization of low-density polyethylene by gel permeation chromatography—II. Study on the Drott method using fractions. European Polymer Journal, 10(3), 295-303. http://dx.doi.org/10.1016/0014-3057(74)90121-9.

9. Small, P. A. (1975). Long-chain branching in polymers. In Macroconformation of polymers. (Advances in Polymer Science, Vol. 18, pp. 1-64). Berlin: Springer-Verlag Berlin Heidelberg. http://dx.doi.org/10.1007/3-540-07252-7_1.

10. Randall, J. C. (1989). A review of high resolution liquid 13carbon nuclear magnetic resonance characterizations of ethylenebased polymers. Journal of Macromolecular Science, Part C: Polymer Reviews, 29(2-3), 201-317. http://dx.doi.org/10.1080/07366578908055172.

11. Hou, L., Fan, G., Guo, M., Hsieh, E., & Qiao, J. (2012). An improved method for distinguishing branches longer than six carbons (B6+) in polyethylene by solution 13C NMR. Polymer, 53(20), 4329-4332. http://dx.doi.org/10.1016/j.polymer.2012.07.053.

12. Lee, H. Y., Kim, D. H., & Son, Y. (2008). Anomalous rheological behavior of polyethylene melts in the gross melt fracture regime in the capillary extrusion: effect of long-chain branching. Journal of Applied Polymer Science, 107(4), 2350-2355. http://dx.doi.org/10.1002/app.27382.

13. Stadler, F. J., Piel, C., Kaminsky, W., & Münstedt, H. (2006). Rheological characterization of long-chain branched polyethylenes and comparison with classical analytical methods. Macromolecular Symposia, 236(1), 209-218. http://dx.doi.org/10.1002/masy.200690057.

14. Gabriel, C., & Munstedt, H. (1999). Creep recovery behavior of metallocene linear low-density polyethylenes. Rheologica Acta, 38(5), 393-403. http://dx.doi.org/10.1007/s003970050190.

15. Ramachandran, R., Beaucage, G., McFaddin, D., Merrick-Mack, J., Galiatsatos, V., & Mirabella, F. (2011). Branch length distribution in TREF fractionated polyethylene. Polymer, 52(12), 2661-2666. http://dx.doi.org/10.1016/j.polymer.2011.04.005.

16. Peacok, A. J. (2000). Handbook of polyethylene: structures, properties and applications. New York: Marcel Dekker.

17. American Society for Testing and Materials – ASTM. (2013). ASTM D-1003: standard test method for haze and luminous transmittance of transparent plastics. West Conshohocken: ASTM.

18. Parvez, M. A., Rahaman, M., Soares, J. B. P., Hussein, I. A., & Suleiman, M. A. (2014). Effect of long chain branching on the properties of polyethylene synthesized via metallocene catalysis. Polymer Science, Series B, 56(6), 707-720. http://dx.doi.org/10.1134/S156009041466004X.

19. Butler, T. I. (2009). PE Processes. In J. R. Wagner Jr. (Ed.), Multilayer flexible packaging (pp. 15-30). Oxford: William Andrew.

20. Borse, N., Aubee, N., & Tas, P. (2010). Enhancement in tear properties of single-site catalyzed LLDPE blown films at higher draw-down. In Proceedings of the 26th Polymer Processing Society Annual Meeting. Banff-Canadá: Polymer Processing Society.

21. Rigo, M., Bezerra, J. R. M. V., & Córdova, K. R. V. (2010). Estudo do efeito da temperatura nas propriedades reológicas da polpa de butiá (Butia eriospatha). Ambiência - Revista do Setor de Ciências Agrárias e Ambientais, 6(1), 25-36. Retrieved in 05 May 2013, from http://revistas.unicentro.br/index.php/ambiencia/article/view/972/973

22. Becker, M. R., Forte, M. M. C., & Baumhardt, R., No (2002). Preparação e avaliação térmica e reológica de mistura de PEBD/PELBD. Polímeros: Ciência e Tecnologia, 12(2), 85-95. http://dx.doi.org/10.1590/S0104-14282002000200007.

23. Kulin, L. I., Meijerink, N. L., & Starck, P. (1988). Long and short chain branching frequency in Low Density Polyethylene (LDPE). Pure and Applied Chemistry, 60(9), 1403-1415. http://dx.doi.org/10.1351/pac198860091403.

24. Bueche, F. (1962). The physical properties of polymers. New York: John Wiley&Sons.

25. Bretas, R. E. S. & D’avila, M. A. (2000). Reologia de polímeros fundidos. São Carlos: UFSCar.

26. Dealy, J. M., & Wissbrun, K. F. (1990). Melt rheology and its role in plastics processing. London: Chapman&Hall.

27. Malkin, A. Y. (1994). Rheolgy fundamentals. Toronto: ChemTec.

28. Butler, T. I. (2005). Film extrusion manual: process, materials, properties. Norcross: Tappi Press.

29. Guerrini, L. M., Paulin, F. P. I., & Bretas, R. E. S. (2004). Correlação entre as propriedades reológicas, óticas e a morfologia de filmes soprados de LLDPE/LDPE. Polímeros: Ciência e Tecnologia, 14(1), 38-45. http://dx.doi.org/10.1590/S0104-14282004000100012.

30. Alvarez, V. B., & Pascall, M. A. (2011). Packaging. In J. W. Fuquay (Ed.), Encyclopedia of dairy sciences (pp. 16-23). New York: Academic Press.

31. Zhang, X. M., Elkoun, S., Ajji, A., & Huneault, M. A. (2004). Oriented structure and anisotropy properties of polymer blown films: HDPE, LLDPE and LDPE. Polymer, 45(1), 217-229. http://dx.doi.org/10.1016/j.polymer.2003.10.057.

32. Krishnaswamy, R. K., & Sukhadia, A. M. (2000). Orientation characteristics of LLDPE blown films and their implications on Elmendorf tear performance. Polymer, 41(26), 9205-9217. http://dx.doi.org/10.1016/S0032-3861(00)00136-1.

33. Dartora, P. C., Moreira, A. C. F., Stocker, M. K., & Santos, F. P. (2013). Análise de polietileno linear de baixa densidade metalocênico por microscopia: efeito de ramificações longas. In Anais do 12° Congresso Brasileiro de Polímeros. Florianópolis: Associação Brasileira de Polímeros.

34. Liu, Z. J., Ouyang, J., Zhou, W., & Wang, X. D. (2015). Numerical simulation of the polymer crystallization during cooling stage by using level set method. Computational Materials Science, 97, 245-253. http://dx.doi.org/10.1016/j.commatsci.2014.10.038.
588371c97f8c9d0a0c8b4a70 polimeros Articles
Links & Downloads

Polímeros: Ciência e Tecnologia

Share this page
Page Sections