Unstable flows during compounding of highly filled suspensions

U. Yilmazer, C. G. Gogos, D. M. Kalyon

Research output: Contribution to journalConference articlepeer-review


Extrusion processability and capillary flow of highly filled suspensions were studied. The experimental studies revealed flow instabilities, basically arising from the time dependent formation of mats, which induce filtering of the polymeric matrix out of the suspension. This demixing generally leads into oscillations in pressure as the mats developed are broken under progressively increasing stresses. Such flow instabilities are less likely to occur for suspensions incorporating either matrices with high viscosities or fillers with smaller particle sizes. Furthermore, operating conditions, which involve increasing the matrix viscosity (lower temperature), increasing the shear stress at the wall (high volumetric rates) and greater diameter dies, also can generate stable processing conditions for such suspensions. These experimental findings were further elucidated and can be explained in a coherent fashion by a proposed mechanism involving the slip and filtration rates in such highly filled suspensions.

Original languageEnglish (US)
Pages (from-to)191-195
Number of pages5
JournalAnnual Technical Conference - Society of Plastics Engineers
StatePublished - 1989
Externally publishedYes
EventANTEC 89 - 47th Annual Technical Conference of SPE - New York, NY, USA
Duration: May 1 1989May 4 1989

All Science Journal Classification (ASJC) codes

  • General Engineering


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