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Polymer Processing and Rheology



Professor Jayaraman's research group at Michigan State University is developing processing strategies, flow models and design tools for shaping polymeric materials into products for various industry sectors: automotive, energy and building or construction. This research is applied to develop processing strategies for polymer composites, recycled polymers and polymer nanocomposites to make foam core panels, multilayer blown film, stronger light weight building materials and porous plastic sheets.  Dr. Jayaraman's research interests and expertise are processing, rheology and microstructure development in polymer materials.  

              

Current Projects

Melt Rheology of Polyolefin-Clay Nanocomposites with Coupling Agents
Polymer nanocomposites with layered silicates have two different types of interface sites: edges with hydroxyl groups and gallery faces with oxygen atoms. The polymer-particle interface at either site may be strengthened by silane coupling agents. Effects of reactive coupling by the silane and a long chain polymeric compatibilizer at different interface sites have been investigated on the morphology and rheology of polypropylene nanocomposites in the melt-compounded state. In the illustration below, two different organoclays were used to obtain the different coupling effects. The resulting state of dispersion and uniaxial extensional viscosity behavior are shown in the adjacent figure.



Reactive coupling at the interface produces finer dispersions and strain hardening in uniaxial extensional flow of polymer-layered silicate nanocomposites; more so with both coupling at faces and edges.
Note that the organoclays used in the two cases are different: the aspect ratio of the organoclay is lower in the second case -- hence the viscosity level is lower in the second case; however, the extent of strain hardening however is clearly higher when the silane coupling is obtained at both edges and faces.


 

Molding of Flexible and Rigid Polypropylene Foams and TPO foams with Nanostructured Additives

Foaming of linear polypropylene melts with chemical blowing agents gives mean cell sizes in the range of 37 to 150 microns when the linear PP is compounded with nanoclay and coupling agents.

see US Patent #9,279,046 


High Performance Additives with Nanoparticles for Polypropylene Film

New masterbatch additives have been developed that may be compounded with bulk polyolefins and used to produce films with good tensile strength and tear strength while also having much improved barrier to water vapor.  These films were produced by two different methods: (1) film blowing and (2) equibiaxial stretching of extruded film                               

 


The Action of Lubricants and Other Rheology Modifiers in Polymer Compounds

Lubricants can be effective in different ways: (a) by forming a wall layer that is less viscous than the bulk and thus producing apparent slip or (b) by reducing the viscosity of the bulk. The presence of other modifiers such as thickeners or interfacial agents may affect the action of lubricants in the formulation. This is being studied with polymer composites and thermoplastic elastomer blends. 




PolymerComposites Processing and Rheology is a research group in the
Chemical Engineering & Materials Science Department at Michigan State University,
headed by Professor K. Jayaraman.

MSU Polymer Processing and Rheology Group