Rheology of high melt strength polypropylene for additive manufacturing

¹Technical University of Denmark, Department of Mechanical Engineering, Kongens Lyngby, 2800, Denmark

²Vienna University of Technology, Institute of Materials Science and Technology, Getreidemarkt 9, 1060 Vienna, Austria

Adv. Mater. Lett., 2017, 8 (6), pp 712-716

DOI: 10.5185/amlett.2017.1450

Publication Date (Web): Apr 30, 2017

Copyright © IAAM-VBRI Press

E-mail: thohofs@mek.dtu.dk

Abstract

Rheological measurements of high melt strength polypropylene (HMS-PP) were used in order to generate master curves describing the shear-dependent viscosity in comparison to acrylonitrile butadiene styrene copolymer (ABS). The latter material showed specific disadvantages in terms of thermal stability, whereas HMS-PP showed a more stable behavior at the investigated temperatures. Hereafter, the material was used in a fused deposition modeling additive manufacturing process, focusing on the investigation of possible improvements of HMS-PP over ABS. Based on the extrusion parameters for ABS, adapted parameters for HMS-PP were determined using a fused deposition modeling test bench. The rheological survey clearly showed changes in the melt viscosity of both ABS and HMS-PP due to thermal degradation. However, the comparison of rheological data of the virgin materials with those of printed material showed negligible changes. This leads to the conclusion that the thermal degradation of HMS-PP and ABS during the fused deposition modeling process is negligible, due to the short exposure time to elevated temperatures.

Keywords

Additive manufacturing technology, ABS, fused deposition modeling, HMS-PP, rheology.