Rheology for Wood Plastic Composite Extrusion Part 2: Process Simulation and Experimental Verification

Area of Science:

• Materials Science
• Polymer Engineering
• Rheology

Background:

• Rheological data for wood plastic composites (WPCs) is scarce in scientific databases.
• This data gap hinders the effective design of WPC processing methods like extrusion.
• Independent research is often required to obtain necessary rheological information.

Purpose of the Study:

• To investigate and validate alternative methods for obtaining WPC rheological data.
• To assess the suitability of Melt Flow Index (MFI) and on-line testing as substitutes for High-Pressure Capillary Rheometry (HPCR).
• To utilize rheological data for extrusion process simulation and evaluation.

Main Methods:

• Laboratory rheological tests using High-Pressure Capillary Rheometry (HPCR) and Melt Flow Index (MFI).
• On-line rheological measurements during extrusion, monitoring die pressure and throughput.
• Extrusion process simulations using viscosity data and models, validated against experimental results.

Main Results:

• Melt Flow Index (MFI) viscosity and on-line viscosity measurements were compared with HPCR data.
• The two-point MFI method and on-line tests were found to be viable alternatives when HPCR data is unavailable.
• The MFI method, particularly with the power-law model, provides a fast, simple approach for analytical solutions in processing.

Conclusions:

• Melt Flow Index (MFI) and on-line testing provide practical and reliable alternatives for characterizing WPC rheology.
• These methods facilitate the design and simulation of WPC extrusion processes, overcoming data limitations.
• On-line tests offer the advantage of reflecting real-world processing conditions, unlike some laboratory settings.