Relationship of Rheological Study with Morphological Characteristics of Multicomponent (Talc and Calcium Carbonate) Filled Polypropylene Hybrid Composites

Abstract

Polypropylene (PP) copolymer reinforced with talc, CaCO₃, or multicomponent fillers (a combination of talc and CaCO₃) were compounded in a Brabender Plasti-Corder^® internal mixer. These compounds then experienced an extrusion process by means of a capillary rheometer. The rheological and morphological (SEM) properties of the extrudate were analyzed to investigate the effect of shear stress, filler type, and temperature. The rheological studies revealed that the incorporation of multicomponent fillers has increased the melt viscosity. However, different ratio of filler type demonstrates no significant effect. It is also shown that the system appears pseudoplastic over one range of shear rates but dilatant over another. The presence of filler seems to have a pronounced influence on dilatant flow in filled PP. Observation on SEM analysis at high shear stress showed that large CaCO₃ agglomerates are seen to be randomly dispersed whereas talc particles are more uniformly distributed and oriented to flow direction, suggesting better mixing.

Keywords

talc calcium carbonate polypropylene multicomponent pseudoplastic dilatant.

Get full access to this article

View all access options for this article.

References

Guerrica-Echevarria, G. , Eguiazábal , J. and Nazábal, J. (1998). Influence of Moulding Conditions and Talc Content on the Properties of Polypropylene Composites, Eur. Polym. J., 34(8): 1213-1219.

Kim, K.J. and White, J.L. (1999). Rheological Investigations of Suspensions of Talc, Calcium Carbonate and their Mixtures in a Polystyrene Melt, Polym. Eng. and Sci., 39(11): 2189-2196.

Zuiderduin, W.C.J. , Westzaan, C. , Huétink , J. and Gaymans, R.J. (2003). Toughening of Polypropylene with Calcium Carbonate Particles, Polymer, 44: 261-275.

Da Silva, A.L.N. , Rocha, M.C.G. , Moraes, M.A.R. Valente, C.A.R. and Coutinho , F.M.B. (2002). Mechanical and Rheological Properties of Composites Based on Polyolefin and Mineral Additives, Polymer Testing, 21: 57-60.

Tanaka, H. and White, J.L. ( 1980). Experimental Investigations of Shear and Elongational Flow Properties of Polystyrene Melts Reinforced with Calcium Carbonate, Titanium Dioxide and Carbon Black, Polymer and Engineering, 20(14): 946-956.

Wang, Y. and Wang, J.J. ( 1999). Shear Yield Behavior of Calcium Carbonate-Filled Polypropylene , Polymer Engineering, 39(1): 190-198.

Leong Y.W. ( 2003). Characterization of Talc and Calcium Carbonate-Filled Polypropylene Hybrid Composites: Mechanical, Thermal and Weathering Properties , MSc Thesis, Universiti Sains Malaysia.

Saha, S. ( 2001). Rheological and Morphological Characteristics of Polyvinylchloride/Polychloroprene Blends-Effect of Temperature and Mixing Speed, European Polymer Journal, 37: 399-410.

Premalal, H.G.B. , Ismail, H. and Baharin, A. (2002). Comparison of the Mechanical Properties of Rice Husk Powder Polypropylene Composites with Talc Filled Polypropylene Composites, Polymer Testing, 21: 833-839.

10.

Miller, E. ( 1996). Introduction to Plastics and Composites: Mechanical Properties and Engineering Applications, Marcel Dekker Inc., New York.

11.

Hohenberg, W. ( 2001). Fillers and Reinforcements/Coupling Agents, In Plastics Additives Handbook, Zweifel, H. (ed.), pp. 901-915, Hanser Publishers, Munich.

12.

Pogodina, N.V. , Lavrenko, V.P. , Srinivas, S. and Winter, H.H. (2001). Rheology and Structure of Isotactic Polypropylene Near the Gel Point: Quiescent and Shear Induced Crystallization, Polymer, 42: 9031-9043.

13.

Nagasawa, T. , Matsumura, T. , Hoshino, S. and Kobayashi, K. ( 1973). Film Forming Process of Crystalline Polymer. I. Factors Inducing a Molecular Orientation in Tubular Film, Applied Polymer Symposium, 20: 275-293.

14.

Ferrage, E. , Martin, F. , Boudet, A. , Petit, S. , Fourty, G. , Jouffret, F. , Micoud, P. , De Parseval, P. , Salvi, S. , Bourgerett, C. , Ferret, J. , Saint-Gerrard, Y. , Buratto, S. and Foutune J.P. ( 2002). Talc as Nucleating Agent of Polypropylene: Morphology Induced by Lamellar Particles Addition and Interface Mineral-Matrix Modelization , J. Mat. Sci., 37: 1561-1573.

15.

Vishay (2000). ‘Glossary’, (Interactive Guide to Strain Gage Technology), Available: http://www.vishay.com/brands/measurements_group/guide/glossary/iso_mat.htm (Accessed: 2004, February, 10)

16.

Masubuchi, Y. , Watanabe, K. , Nagatake, W. , Takimoto, J.I. and Koyama, K. (2001). Thermal Analysis of Shear Induced Crystallization by the Shear Flow Thermal Rheometer: Isothermal Crystallization of Polypropylene, Polymer, 42: 5023-5027.

17.

Lellingerc, D. , Floudasa, G. and Aligc, I. (2003). Shear Induced Crystallization in Poly(1-caprolactone): Effect of Shear Rate, Polymer, 44: 5759-5769.