Polymer Science and Engineering

Projects involving properties and/or processing of polymeric materials.

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Inorganic-Organic Hybrid Polymers

Linear inorganic-organic hybrid polymers are receiving increasing attention, particularly in an effort to better understand performance enhancement that enable efficient material design for specific applications. Linear hybrid polymers encompass a materials chemistry approach distinct from past efforts in sol-gel systems, which often yielded cross-linked systems. Moreover, the motivation for the study of linear hybrid polymers is the increasing level of supporting evidence for nanoscale reinforcement of material properties and alteration of chain and segmental dynamics. Specifically, we investigated polymers with chemical incorporation of polyhedral oligomeric silsesquioxane (POSS) to the backbone of linear polymers. A typical POSS macromer is a well-defined cluster with inorganic silica-like core surrounded by organic corner groups. The efficiency in property enhancement depends on complex interactions between POSS-POSS and POSS-polymers. We are also interested on how POSS macromer affect the kinetics of polymerization.

Investigators (PI is linked): Andre Y. Lee
Categories: Polymer Science and Engineering

Extensional Viscosity of Elastomers and Thermoplastic Elastomers

The strain hardening of random copolymer elastomer melts is being investigated as a function of composition, strain rate and temperature. Sensitivity to detailed experimental procedures with two different instruments -- the RME and the rotary EVF fixture on the ARES-- has been investigated specifically for elastomers in this project.

Investigators (PI is linked): Krishnamurthy Jayaraman
Categories: Polymer Science and Engineering, Rheology and Multiphase Flow

Engineering and Design of Natural-Synthetic Polymer Composite Systems

New approaches to tailor-made cellulose/starch/lignin-synthetic polymer graft copolymers with precise control over molecular weight, degree of substitution, backbone-graft linkage, and the overall grafting process are being studied. Cross-linked graft copolymers with exactly defined polymer chain segments between crosslink points have been prepared. The graft copolymers exhibit a two-phase morphology and can function effectively as compatibilizers/interfacial agents to alloy cellulosic and lignocellulosic materials with synthetic polymers. This approach opens up new opportunities for economically combining lignocellulosic materials with plastics to engineer new materials with unique balance of properties targeted for precise end-use applications. Structure-property relationship, morphological studies, processability and potential applications of such binary and ternary blend systems are under intense study. Some exciting applications are in the preparation of biodegradable plastics for packaging applications.

Investigators (PI is linked): Ramani Narayan
Categories: Polymer Science and Engineering

Reactive Extrusion Processing

The ability of extruders to function as "mini-reactors" and the favorable environmental impact of not using any solvent makes this area an exciting one. Studies are underway to functionalize synthetic polymers via reactive extrusion and to model such processes. Using maleic anhydride functionalized synthetic polymers, preparation of cellulose/starch - synthetic polymer alloys are being studied. In-situ grafting reaction between the hydroxyl group on the natural polymer backbone and the anhydride functionality on the synthetic polymer the graft copolymer compatibilizing agent.

Investigators (PI is linked): Ramani Narayan
Categories: Polymer Science and Engineering

Extrusion and extensional flow of thermoplastic elastomers

Thermoplastic vulcanizates (TPVs) investigated here consist of micron-sized, crosslinked EPDM rubber particles dispersed at high volume fractions in a 0.8 MFR polypropylene matrix with a high-temperature paraffinic oil. The morphology and rheology of these suspensions is complicated by the presence of oil in both phases. One area of interest is in understanding the evolution of two-phase morphology with slip flow and boundary lubrication during extrusion of TPVs. Another is to develop procedures for using profile dies in estimating strain averaged extensional viscosity of TPV melts at higher strain rates.

Investigators (PI is linked): Krishnamurthy Jayaraman
Categories: Polymer Science and Engineering, Rheology and Multiphase Flow

Molecular Dynamics in Polymeric Glass Transition

Unlike small molecules, the glass transition in polymers is influenced by the long-chain nature of polymers. Using model thermoset systems, we are currently investigating the effect of molecular network structures on the glass-like behavior of polymers. More specifically, we are interested in the influence of molecular network connectivity on the structural recovery processes that occured during physical aging of polymer glasses.

Investigators (PI is linked): Andre Y. Lee
Categories: Polymer Science and Engineering

Polymer nanocomposites and foams with nanoparticles

The goal of the project is to develop new cost-effective thermoplastic elastomer nanocomposite foam with a semi-crystalline polymer matrix such as polypropylene. Improving the melt strength of the polymer is essential for this task. Recent work by Pathak and Jayaraman (2007) shows evidence of improvements in melt strength of linear polypropylene by incorporation of anisotropic nanoparticles. Optimum foaming process conditions will be developed for both extrusion and injection molding of polymers and blends reinforced with nanofibers and nanolayers to control the cell size distribution in the foamed product.

Investigators (PI is linked): Krishnamurthy Jayaraman
Categories: Polymer Composites, Polymer Science and Engineering, Rheology and Multiphase Flow

Structure-Property Relationships of Polymer Nanocomposites

The goal of this research program is to understand the effect of a new class of structurally well-defined, nanometer scale, molecular clusters on long chain polymers. Using polysiloxanes as model system, we are able to demonstrate a significant enhancement in the association of polymer chains for system containing molecularly dispersed nano-clusters. Furthermore, it is possible to control the rate of enhancement by altering the chemistry of these nanometer molecular clusters. This new concept of nano-reinforcement is to be extended for other polymers in order to examine the general applicability for all polymer systems.

Investigators (PI is linked): Andre Y. Lee
Categories: Polymer Science and Engineering

Engineering Surfaces and Interfaces

Self-assembly, microcontact printing, and layer-by-layer assembly techniques for surface tuning and patterning are utilized to develop new opto-electronic and bio applications. A variety of materials, such as organic and inorganic molecules, polymers, particles, and biomolecules including cells are used to prepare topologically and functionally structured surfaces for their desired purposes using novel self and directed assembly techniques.

Investigators (PI is linked): Ilsoon Lee
http://www.egr.msu.edu/~leeil/ilsoon_research.html#Ilsoon%20Lee%  Categories: Nanomaterials, Biomaterials, Electronic Materials, Polymer Composites, Structural Materials, Polymer Science and Engineering, Colloid and Interface Science, Biotechnology

Self-assembled, Nanostructured Biomimetic Interfaces

Living cells efficiently perform many vital sensing, signaling, catalytic, and bioelectronic processes at the molecular scale. These processes typically occur at cell membranes, whose principal components include a bilayer lipid membrane (BLM) and membrane proteins. The BLM's nanoscale thickness (5 nm) and high electrical resistance give it unique optical and bioelectronic properties. A diverse array of membrane proteins embedded in the BLM imparts the highly specific activities exhibited by cell membranes. These activities can, in principle, be mimicked in the laboratory by reconstituting appropriate membrane proteins into artificial BLM. We are using self and directed assembly tools to fabricate functional and nanostructured biomimetic-interfaces that use lipid bilayers, membrane proteins (such as neuropathy target esterase), and other nanostructured components (e.g. polyelectrolyte multilayers) to reproduce cell-membrane processes. These systems have outstanding potential for conducting fundamental studies of nanoscale biological processes and for developing new technologies, including high-throughput drug screening systems, research tools to study membrane proteins, and high-performance biosensors.

Investigators (PI is linked): Ilsoon Lee
http://www.biomimetic.org/  Categories: Nanomaterials, Biomaterials, Polymer Composites, Structural Materials, Polymer Science and Engineering, Colloid and Interface Science, Biotechnology

Bio-Carbon Nanomaterials

Carbon nanoparticles are available in several geometries, including spherical fullerenes, cylindrical nanotubes and planar nanoplatelets. While these nanoparticles all share the same graphenic structure that imparts semiconductor properties, the diverse geometries afford a spectrum of unique chemical, electrical, magnetic, and optical properties. Composite materials containing carbon nanoparticles electrically coupled to biomolecules could yield an array of high-performance technologies. Inclusion of a biological recognition element, and any necessary cofactor or mediator, allows the composite electrode to serve as an integrated, bioactive electrode unit (i.e., bio-carbon network). This work includes (1) development of simple and rapid methods to modify and process carbon nanoparticles for self and directed assembly, (2) incorporation of the nanoparticles into bio-carbon networks, and (3) characterization of the network’s fundamental properties.

Investigators (PI is linked): Ilsoon Lee
Categories: Nanomaterials, Biomaterials, Polymer Composites, Structural Materials, Polymer Science and Engineering, Colloid and Interface Science, Biotechnology

Novel Fabrication of Nanostructured Particles with an Arbitrary Shape

Convenient methods for the fabrication of complex nanostructures are emerging in the growing field of nanotechnology for novel optical, electrical, magnetic, and also biological functions. Recently we have developed a simple and effective method to produce various kinds of nanostructured particles like nanorice and nanospears (i.e., tapered nanorods) using alumina membrane as templates. The nanocylindrical pores of anodized alumina membranes are filled with spherical polymer nanoparticles by a solvent assisted nano-injection. Then the membranes are heated in an oven above the glass transition temperature of the polymer. Due to the non-uniform heating, non-equilibrium capillary forces, and the wetting property of the polymer nanospheres confined in the nanocylinders, the spherical nanoparticles coalesce to form both aspect ratio and end-shape controlled nanorods which are shaped in the forms of nanorice, nanospears or tapered nanorods. Other novel nanostructures include nanorods, nanograss, nanodisks, and broken nanodonuts using vaious nanomaterials such as polymers, metals, inorganic particles, and biomolecules.

Investigators (PI is linked): Ilsoon Lee
Categories: Rheology and Multiphase Flow, Colloid and Interface Science, Polymer Science and Engineering, Structural Materials, Nanomaterials

Nanomixing or Nanodispersion of Nanomaterials

We have established a strategic partnership with the Primix Corporation to study the nanomixing, nanodispersion, and nanoparticulate processes. Due to the enhanced high shear forces, the dispersed nanomaterials have superior stability in solvents. We are currently studying why it helps the stability of the nanodispersion. The mixer, named T.K. Filmics, uses a multiphase swirling flow to achieve extremely high energy dissipation and achieve the dispersion. The mixer has a stationary outer cylinder, within which an inner cylinder rotates very rapidly. The two phases are introduced separately from the bottom and the particulates are dispersed by shear in the annular region between the two cylinders. The high shear force, thin film mixing system has been newly developed from the conventional mixers by the Primix Corporation located in Japan (http://www.primix.jp/en/index.html).

Investigators (PI is linked): Ilsoon Lee
http://www.primix.jp/en/index.html  Categories: Nanomaterials, Polymer Science and Engineering, Rheology and Multiphase Flow, Colloid and Interface Science

Fabrication of Large Diffractive Optical Element Solar Concentrator Panels by Extrusion

The low density of optically clear thermoplastics compared to inorganic glass makes them the materials of choice for making large area diffractive lenses with very low mass per unit area or areal density to be used as solar concentrators in space applications. Smaller optical components have been produced on a large scale by injection molding thermoplastic polymers; however optical elements in the present application will cover areas of up to 50 square meters. Hence the goal of this project is to achieve tight tolerances on thickness profiles over large areas of diffractive optical elements produced with an extrusion line from optical grade thermoplastic.

Investigators (PI is linked): Krishnamurthy Jayaraman
Categories: Structural Materials, Polymer Science and Engineering, Rheology and Multiphase Flow, Energy Production

Processing of Particulate Polymer Composites Below the Melting Point

The goal of the proposed project is to gain a scientific understanding of microstructure development in processing polymer composites below the melting point Tm. The filler/matrix interaction when processing below Tm is being examined in various flow fields.

Investigators (PI is linked): Krishnamurthy Jayaraman
Categories: Polymer Composites, Structural Materials, Polymer Science and Engineering

Wrinkle-free Nanomechanical Films

Wrinkling or buckling is a common natural phenomenon which occurs in numerous forms on many different length scales. Common forms of buckling include the wrinkling of human skin, the surface of many dried fruits, and even the formation of mountain ranges. Generally buckling occurs when a stiff upper material on a more compliant substrate is compressed. Compressive forces can be generated physically (e.g., stretching or compressing a compliant substrate) or simply by raising or lowering the temperature of the materials. Wrinkling and related phenomena in various materials have been studied from the standpoint of micro and bio mechanics. How and why wrinkles form has been well studied; however, preventing the occurrence of such a phenomenon remains a challenge. The goal of this proposed work is to study how nanoparticles influence the mechanical (or thermal) wrinkling (or buckling) of thin films, and to develop such wrinkle free films for various applications.

Investigators (PI is linked): Ilsoon Lee
Categories: Biotechnology, Colloid and Interface Science, Polymer Science and Engineering, Structural Materials, Polymer Composites, Nanomaterials