Abstract
One of the challenges for the manufacturing processes of polymeric parts is the dedicated control of composite melt flow. In the present work, the predictive capability of the Phan-Thien-Tanner (PTT) viscoelastic model is evaluated in relation to the extrudate swell from slit dies at 200 °C, considering polypropylene and graphite filler, and applying ANSYS Polyflow software. It is shown that for sufficiently low filler amounts (below 10%; volumetric) the PTT accurately reflects the viscoelastic interactions, but at higher filler amounts too large swellings are predicted. One can although obtain insights on the swelling in the height direction and consider a broader range of swelling areas compared to virgin materials. Guidelines are also provided for future experiments and model development, including the omission of the no-slip process boundary condition.
Highlights
Extrusion, which is a material forming operation under melt conditions, is widely used in industrial sectors, including polymeric applications [1,2,3,4,5]
In our previous work [34,35,36], we have extensively studied the extrudate swell behavior of neat PP, high-density polyethylene (HDPE) and low-density polyethylene (LDPE) from a slit die at 200 ◦ C, considering the finite element ANSYS Polyflow solver combined with the viscoelastic constitutive PhanThien-Tanner (PTT) constitutive model of which the parameters have been validated based on independent rheological data
It is found that the original PTT model has an excellent ability to predict G0 and loss modulus for neat/virgin PP and all PP composites at a given temperature (200 ◦ C)
Summary
Extrusion, which is a material forming operation under melt conditions, is widely used in industrial sectors, including polymeric applications [1,2,3,4,5]. Studying how the filler influences the rheological properties and thereby the processing behavior of polymer composites is an important research topic, aiming at controlling the processing conditions to obtain the desired product profiles and macroscopic properties, including increased durability and improved mechanical recycling potential. To fully understand the three-dimensional (3D) flow pattern of composite melts the starting point should be a dedicated understanding of the virgin 3D flow, which has only been achieved very recently In this context, in our previous work [34,35,36], we have extensively studied the extrudate swell behavior of neat PP, high-density polyethylene (HDPE) and low-density polyethylene (LDPE) from a slit die at 200 ◦ C, considering the finite element ANSYS Polyflow solver combined with the viscoelastic constitutive PhanThien-Tanner (PTT) constitutive model of which the parameters have been validated based on independent rheological data. It is shown that the prediction of the width direction is more complicated than the prediction of the height direction, further highlighting the relevance of three-dimensional flow simulations to unravel the complexity of polymer/composite melt stability
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
