Effects of Blend Morphology on the Foaming of Polypropylene/ Low-density Polyethylene Blends during a Batch Foaming Process

Abstract

The effect of blend morphology on the foaming of polypropylene (PP)/low-density polyethylene (LDPE) blends with different blend ratios has been studied in this work. The results showed that the cell morphology of a foamed blend was significantly impacted by the blend morphology and foaming conditions. When the foaming temperature was close to the melting temperature of LDPE, cells were nucleated at the interfaces of PP droplets and LDPE matrix in the 10/90 and 25/75 PP/LDPE blends and grew in the LDPE matrix. Also, cells could only grow in the LDPE phase in the 90/10 and 75/25 PP/LDPE blends and consequently their sizes were determined by the sizes of the LDPE droplets. However, when the foaming temperature was close to the melting temperature of PP, cells with bimodal cell size distributions were generated in the pure PP, 90/10 and 75/25 PP/LDPE foams. In particular, fine open-cell structure was formed in the co-continuous 50/50 PP/LDPE blend.

Keywords

PP/LDPE blends foam blend morphology cell morphology.

Get full access to this article

View all access options for this article.

References

Matuana, L.M. , Park, C.B. and Balatinecz , J.J. (1998). Structures and Mechanical Properties of Microcellular Foamed Polyvinyl Chloride , Cellular Polymers, 17(1): 1-16.

Collias, D.I. , Baird, D.G. and Borggreve , R.J.M. (1994). Impact Toughening of Polycarbonate by Microcellular Foaming, Polymer, 35(18): 3978-3983.

Huang, Q. , Seibig, B. and Paul, D. (2000). Melt Extruded Open-cell Microcellular Foams for Membrane Separation: Processing and Cell Morphology Relationship, Journal of Cellular Plastics, 2: 112-125.

Ahmed, M.Y.S. , Park, C.B. and Atalla, N. (2006). Control of the Structure and Morphology for Production of Novel LDPE Acoustical Foams, Cellular Polymers, 25: 277-292.

Arora, P. and Zhang, Z. (2004). Battery Separators, Chemical Reviews , 104: 4419-4462.

Hentze, H.-P. and Antonietti, M. (2002). Porous Polymers and Resins for Biotechnological and Biomedical Applications, Reviews in Molecular Biotechnology, 90: 27-53.

Doroudiani, S. , Park, C.B. and Kortschot , M.T. (1998). Processing and Characterization of Microcellular Foamed High-density Polyethylene/ Isotactic Polypropylene Blends, Polymer Engineering and Science , 38: 1205-1215.

Rachtanapun, P. , Selke, S.E.M. and Matuana , L.M. (2003). Microcellular Foam of Polymer Blends of HDPE/PP and Their Composites with Wood Fiber, Journal of Applied Polymer Science, 88: 2842-2850.

Rachtanapun, P. , Selke, S.E.M. and Matuana , L.M. (2004). Relationship Between Cell Morphology and Impact Strength of Microcellular Foamed High-density Polyethylene/Polypropylene, Polymer Engineering and Science, 44: 1551-1560.

10.

Zhang, P. , Zhou, N.Q. , Wu, Q.F. , Wang, M.Y. and Peng, X.F. (2007). Microcellular Foaming of PE/PP Blends, Journal of Applied Polymer Science, 104: 4149-4159.

11.

Krause, B. , Diekmann, K. , van der Vegt, N.F.A. and Wessling, M. (2002). Open Nanoporous Morphologies from Polymeric Blends by Carbon Dioxide Foaming, Macromolecules, 35: 1738-1754.

12.

Lee, P.C. , Naguib, H.E. , Park , C.B. and Wang, J. (2005). Increase of Open-cell Content by Plasticizing Soft Regions with Secondary Blowing Agent, Polymer Engineering and Science, 45: 1445-1451.

13.

Lee, P.C. , Wang, J. and Park, C.B. (2006). Extruded Open-cell Foams Using Two Semicrystalline Polymers with Different Crystallization Temperatures , Industrial and Engineering Chemistry Research, 45: 175-181.

14.

Lee, J.K. and Han, C.D. (1999). Evolution of Polymer Blend Morphology during Compounding in an Internal Mixer, Polymer, 40: 6277-6296.

15.

Lee, J.K. and Han, C.D. (2000). Evolution of Polymer Blend Morphology during Compounding in a Twin-screw Extruder, Polymer, 41: 1799-1815.

16.

Willemse, R.C. , Boer, A.P. , Dam , J.V. and Gotsis, A.D. (1999). Co-continuous Morphologies in Polymer Blends: The Influence of the Interfacial Tension, Polymer, 40: 827-834.

17.

Sarazin, P. and Favis, B.D. (2005). Influence of Temperature-induced Coalescence Effects on Co-continuous Morphology in Poly(ε-caprolactone)/ Polystyrene Blends, Polymer, 46: 5966-5978.

18.

Bhadane, P.A. , Champagne, M.F. , Huneault , M.A. , Tofan, F. and Favis, B.D. (2006). Erosion-dependant Continuity Development in High Viscosity Ratio Blends of Very Low Interfacial Tension , Journal of Polymer Science, Part B: Polymer Physics, 44: 1919-1929.

19.

Xu, Z.-M. , Jiang X.L. , Liu , T. , Hu , G.H. , Zhao, L. , Zhu , Z.N. and Yuan, W.K. (2007). Foaming of Polypropylene with Carbon Dioxide, Journal of Supercritical Fluids, 41: 299-310.

20.

Sakellarides, S.L. and Mchugh, A.G. (1987). Structure Formation during Polymer Blend Flows. Polymer Engineering and Science , 27: 1662-1987.

21.

Favis, B.D. (2000). Polymer Blends, Vol. 1: Formulation, Wiley, New York.

22.

Veenstra, H. , Dam, J.V. and de Boer, A.P. (2000). On the Coarsening of Co-continuous Morphologies in Polymer Blends: Effect of Interfacial Tension , Viscosity and Physical Cross-links, Polymer, 41: 3037-3045.

23.

Jiang, X.-L. , Liu, T. , Xu , Z.-M. , Zhao, L. , Hu , G.-H. and Yuan, W.-K. Effects of Crystal Structure on the Foaming of Isotactic Polypropylene using Supercritical Carbon dioxide as a Foaming Agent, Journal of Supercritical Fluids , Doi: 10.1016/j.supflu.2008.10.006, In press.

24.

Zhang, C.L. , Feng, L.F. , Zhao, J. , Huang, H. , Hoppe, S. and Hu, G.H. (2008). Efficiency of Graft Copolymers at Stabilizing Co-continuous Polymer Blends during Quiescent Annealing, Polymer, 49, 3462-3469.

25.

Si, M. , Araki, T. , Ade, H. , Kilcoyne, A.L.D. , Fisher, R. , Sokolov, J.C. and Rafailovich, M.H. (2006). Compatibilizing Bulk Polymer Blends by Using Organoclays, Macromolecules, 39, 4793-4801.