Abstract
In this research work, the rheological properties of Wood-Plastic Composites (WPC) with some selected compositions are investigated. WPC is being recognized as a green composite that, in the past 20 years, has emerged to a commercial product. A study on rheological properties of these materials can give insight into the proper selection of composition and processing condition. Two grades of polypropylene (PP) with two different melt flow indexes (MFI) were selected to prepare WPCs with three different wood contents (50, 60 and 70 % wt.). Four types of rheological experiments were performed utilizing a rotational plate rheometer: (1) strain sweep, (2) frequency sweep, (3) temperature sweep and (4) steady shear rate sweep. The independent variables were chosen as wood content, MFI of polymer (two types), melt temperature, frequency or shear rate, the gap between the plates, and strain percentage. The strain sweep tests specified the linear and non-linear viscoelastic zones of each experiment. The results of frequency sweep experiments indicated that increasing the wood content and frequency and also decreasing the strain percentage and the gap distance, lead to an increase in the storage modulus. Regarding the loss modulus, wood percentage and the gap distance presented positive effects and strain percentage showed a negative effect. The behavior of complex viscosity was almost similar to that of the storage modulus but increasing the frequency caused a decrease in the complex viscosity. In case of temperature sweep experiments, it was observed that the rheological properties exhibit a rapid change near to a temperature of 160 °C. The results also showed that beyond this point, increasing the wood content and also MFI of polypropylene caused an increase in the storage modulus. The results of steady shear rate sweep experiments specified that increasing wood content and also decreasing the MFI of PP, the gap distance and shear rate lead to an increase in both viscosity and shear stress.
Similar content being viewed by others
Abbreviations
- \( \dot{\gamma }_{a} \) :
-
Apparent shear rate (s−1)
- R :
-
Radius of rheometer plates (mm)
- ω :
-
Angular velocity (rad/s)
- H :
-
Gap between the rheometer plates (mm)
- Ω :
-
Torque of the rheometer (N × mm)
- τ R :
-
Shear stress (MPa)
- η * :
-
Complex viscosity (Pa × s)
- η ′ :
-
Dynamic viscosity (Pa × s)
- η ′′ :
-
Elastic viscosity (Pa × s)
- G ′ :
-
Storage modulus (Pa)
- G ′′ :
-
Loss modulus (Pa)
- L :
-
Screw length (mm)
- D :
-
Screw diameter (mm)
- W :
-
Weight percentage of wood (mm)
- M :
-
Polymer melt flow index (g/10 min )
- S :
-
Strain percentage
- T :
-
Temperature (°C)
- F :
-
Frequency (Hz)
- η :
-
Viscosity (Pa × s)
References
Klyosov AA (2007) Wood-plastic composites. Wiley, New Jersey
Jafarian-Jam N, Behravesh AH (2007) Flow behavior of HDPE-fine wood particles composites. J Thermoplast Compos Mater 20:439–451
Niska KO, Sain M (2008) Wood-polymer composites. CRC Press, New York
Jafarian-Jam N, Behravesh AH (2009) Challenge to the production of fine wood-plastic injection molded composite. J Reinf Plast Compos 28:73–82
Soury E, Behravesh AH, Ghasemi-Nasrabadi H, Zolfaghari A (2009) Design and manufacture of and extrusion die for wood plastic composite. J Reinf Plast Compos 28(2):1433–1439
Karmaker AC, Hoffmann A, Hinrichsen G (1994) Influence of water uptake on the mechanical properties of jute fiber-reinforced polypropylene. J Appl Polym Sci 54:1803–1807
Hristov V (2007) Rheological aspects of wood polymer composites extrusion. PhD Thesis of Chemical Engineering, McMaster University, Hamilton
Talimi M (2011) Characterization of lightweight, biodegradable natural fibre-reinforcement reinforced composites. Master of Applied Science Thesis of Mechanical Engineering, University of Ontario Institute of Technology, Oshawa
Dealy J, Wissburn KF (1990) Melt rheology and its role in plastics processing. Van Nostrand Reinhold, New York
Jam NJ (2007) Production of high wood content wood-plastic composite injection molded parts. Master of Science Thesis of Mechanical Engineering, Tarbiat Modares University, Tehran
Dealy JM, Wissbrun KF (1990) Melt rheology and its role in plastic processing, Rheol Multiphase Syst 393–409
Shenoy AV (1999) Rheology of filled polymer systems. Kluwer, Boston
Heinemann H (2005) Polymer processing instabilities. Marcel Dekker, Berkeley
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Soury, E., Behravesh, A.H., Rizvi, G.M. et al. Rheological Investigation of Wood-Polypropylene Composites in Rotational Plate Rheometer. J Polym Environ 20, 998–1006 (2012). https://doi.org/10.1007/s10924-012-0502-x
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10924-012-0502-x