GOALI: Rheological Investigation of Polymer Melts in Equibiaxial Elongational Flows

ABSTRACT

PROPOSAL NO.: CTS-0327955

PRINCIPAL INVESTIGATORS: DAVID C. VENERUS

INSTITUTION: ILLINOIS INST. OF TECH.

GOALI: RHEOLOGICAL INVESTIGATION OF POLYMER MELTS UN EQUIBIAXIAL ELONGATIONAL FLOWS

This collaborative study, funded through the GOALI program, involves an academic institution and two companies: a major instrument manufacturer (TA Instruments), and a major producer of polymer resin (BPAmoco Chemical Company). The results of this study will significantly deepen our understanding of polymer melt flow behavior and have a direct impact on both the engineering and science of this important class of materials. A modified lubricated squeezing flow technique, for which a U.S. Patent was issued to the principal investigator of this project, will be further developed to enable a quantitative rheological study of molten polymers in equibiaxial elongational flows. The new technique will be capable of performing constant strain rate and constant stress tests over a range of parameters that equal or exceed those of any currently available device or technique for equibiaxial elongational flow rheological measurements. The new technique will be used to study the rheological behavior of a series of polyethylene and polypropylene melts in constant strain rate stress growth and constant stress creep flows. The polymers considered include resins synthesized using both conventional and metallocene catalysts allowing for a systematic study of branching structure and molecular weight distribution on rheological behavior. The equibiaxial elongational flow data will be complemented by data from shear and uniaxial elongational flows. These new data will provide previously unavailable insight to the importance of molecular structure and flow type that will benefit several aspects of polymer materials development ranging from synthesis to plastics manufacturing. The unique educational experience and training acquired by students in this collaborative project involving academia and industry greatly enhances their ability to make significant contributions as future engineers or educators.