Research Interests
Structure-property relationships; irreversible deformation,
crack propagation and fracture of polymers, blends and
composites; microlayer processing of polymers;
structure-function relationships in collagenous tissues;
biostability of biomaterials.
Overview of Research
One area of interest focuses on exploring the
structure-processing-property relationships in polymeric
materials. Pioneering contributions have been made in
understanding the connections between hierarchical structure
and irreversible deformation and damage processes, and
fracture of polymer blends and composites. New insights have
been developed into mechanisms of compatibilisation and
toughening of polymer blends. We have pioneered in the
development of effective industry/academic research
cooperation. As an example, with Dr. S. P. Chum of The Dow
Chemical Company, a unique and comprehensive study of the
structure-property relationships of metallocene-catalysed
ethylene-octene copolymers was carried out, which has led to
a definitive theoretical understanding of the connections
between microstructure, morphology and mechanical
properties. This work has, in turn, produced predictive
models which have assisted the development of a new
commercially-successful family of ethylene-based elastomers.
Motivated by the need for new processing technologies for
creating engineered microstructures of incompatible
polymers, ground-breaking studies have been undertaken to
explore the unique advantages that can be achieved with
microlayering coextrusion. This layer-multiplying technology
permits continuous processing of sheet or film with hundreds
or thousands of alternating layers of two or more polymers.
With this technology, we have created engineered
microstructures with unique electrical, mechanical and
barrier properties. With E. Baer, the hierarchical
structure-function relationships in collagenous tissues have
been explored. Numerous levels of organization are found
with highly specific interconnectivity designed to produce
the particular spectrum of properties for each oriented
composite system. A further area of interest with J. M.
Anderson is in understanding mechanisms of biocompatibility
and biodegradation of biomaterials with a view to enhancing
their biostability.
Current Activity
Recent research activities focussed on basic and applied
aspects of structure-property-processing relationships of
polymers. Many are the result of close collaboration with
colleagues in the industrial research and development
community through CAPRI, the Center for Applied Polymer
Research. Recent highlights include new insights into
structure-property relationships of homogeneous ethylene-octene
and ethylene-styrene copolymers; mechanisms of slow crack
growth in polyethylene and PVC; barrier properties of
poly(ethylene terephthalate) and related polyesters;
miscibility of ethylene copolymers; hot tack of ethylene
copolymers; and biostability of polyurethanes for
cardiovascular applications . Leadership in the processing,
analysis and characterization of microlayered polymers is
provided with the processing capability to microlayer 2 or 3
polymers into sheet or film with hundreds or thousands of
alternating layers. With this flexible facility, a wide
variety of microlayered concepts are scouted on an
experimental scale. Fundamental aspects of polymer
interdiffusion and adhesion have been addressed. Engineered
microstructures with unique electrical, mechanical, barrier
and optical properties have been created.
Recent Publications
“Buckling in elstomer/Plase/Elastomr 3-Layer Films,” by Y.
Hu, A. Hiltner; and E. Baer, Polymer composites, 25,
653-661 (2004).
“Surface Chemistry Mediates Adhesive Structure, Cytoskeletal
Organization, and Fusion of Macrophages,” by M. Dadsetan,
J. A. Jones, A. Hiltner, and J. M. Anderson, J. Biomed.
Mater. Res., 71A, 439-448 (2004).
“Micromechanical Processes in PET/PC Multilayered Tapes:
High Voltage Electron Microscopy Investigations,” by E. M.
Ivan’kova, G. H. Michler, A. Hiltner, and E. Baer, Macromol.
Mater. Eng., 289, 787-792 (2004).
“Biostability and Macrophage-Mediated Foreign Body Reactions
of Silicone-Modified Polyurethanes,” with E. M.
Christenson, M. Dadsetan, A. Hiltner, and J. M.
Anderson, J. Biomed. Mater. Res.,74A ,141-155 (2005).
“Relationship between Nanoscale Deformation Processes and
Elastic Behavior of Polyurethane Elastomers,” by E. M.
Christenson, J. M. Anderson, A. Hiltner, and E. Baer,
Polymer, 46, 11744-11754 (2005).
“Conductivity of Polyolefins Filled with High-Structure
Carbon Black,” by J. Yu, L. Q. Zhang, M. Rogunova, J.
Summers, A. Hiltner, and E. Baer, J. Appl. Polym. Sci.,
98. 1799-1805 (2005).
“Nanostructure Development in Multilayered Polymer Systems
as Revealed by X-ray Scattering Methods,” by F. J. Baltá
Calleja, F. Ania, I. P. Orench, A. Hiltner, E. Baer, T.
Bernal, and S. S. Funari, Prog. Colloid Polym. Sci.,
130, 140-148 (2005).
“Improving Oxygen Barrier Properties of PET by Incorporating
Isophthalate: II. Effect of Crystallization,” by Y. S. Hu
A. Hiltner, and E. Baer, J. Appl. Polym. Sci., 98,
1629-1642 (2005).
“Improving Oxygen Barrier Properties of PET by Incorporating
Isophthalate: I. Effect of Orientation,” by R. Y. F. Liu,
Y. S. Hu, M. R. Hibbs, D. M. Collard, D. A.
Schiraldi, A. Hiltner, and E. Baer, J. Appl. Polym. Sci.,
98, 1615-1628 (2005).
“Nano and Microlayered Polymers: Structure and Properties,”
by T. E. Bernal-Lara, A. Ranade, A. Hiltner,
and E. Baer, in Mechanical Properties of Polymers Based
on Nanostructure and Morphology (G. H. Michler and F. J.
Baltá Calleja, eds.), Taylor & Francis, 2005, pp.629-681.
“Improving Transparency of Stretched PET/MXD6 Blends by
Modifying PET with Isophthalate,” by Y. S. Hu, V.
Prattipati, A. Hiltner, E. Baer, and S. Mehta, Polymer,
46, 5202-5210 (2005).
“Surface Modification of Poly(ether urethane urea) with
Modified Dehydroepiandrosterone for Improved In Vivo
Biostability,” by E. M. Christenson, M. J. Wiggins,
A. Hiltner, and J. M. Anderson, J. Biomed. Mater. Res.,
73A, 108-115 (2005).
“Polymer Interphase Materials by Forced Assembly,” by R.
Y. F. Liu, T. E. Bernal-Lara, A. Hiltner, and E.
Baer, Macromolecules, 38, 4819-4827 (2005).
“Effect of Compatibilization on Oxygen-Barrier Properties of
PET/MXD6 Blends,” by V. Prattipati, Y. S. Hu,
S. Bandi, D. A. Schiraldi, A. Hiltner, E. Baer, and
S. Mehta J. Appl. Polym. Sci., 97, 1361-1370 (2005).
“Effect of Water Sorption on Oxygen Barrier Properties of
Aromatic Polyamides,” by Y. S. Hu, S. Mehta, D. A.
Schiraldi, A. Hiltner, and E. Baer, J. Polym. Sci. Part B:
Polym. Phys., 43, 1365-1381 (2005).
“Structure and Thermal Stability of Polyethylene Nanolayers,”
by T. E. Bernal-Lara, R. Y. F. Liu, A. Hiltner,
and E. Baer, Polymer, 46, 3043-3055 (1005).
“Effect of Orientation on the Free Volume and Oxygen
Transport of a Polypropylene Copolymer,” by L. S. Somlai,
R. Y. F. Liu, L. M. Landoll, A. Hiltner, and E. Baer, J.
Polym. Sci. Part B: Polym. Phys., 43, 1230-1243
(2005).
“Improving Gas Barrier of PET by Blending with Aromatic
Polyamides,” by Y. S. Hu, V. Prattipati, S.
Mehta, D. A. Schiraldi, A. Hiltner, and E. Baer, Polymer,
46, 2685-2698 (2005).
“Oxygen Transport as a Solid State Structure Probe for
Polymeric Materials: A Review,” by A. Hiltner, R. F. Y.
Liu, Y. S. Hu, and E. Baer, J. Polym. Sci. Part
B: Polym. Phys., 43, 1047-1063 (2005).
“Structure and Properties of Homogeneous Copolymers of
Propylene and 1‑Hexene,” by B. Poon, M. Rogunova, S.
P. Chum, A. Hiltner, E. Baer, A. Galeski, and E. Piorkowska,
Macromolecules, 38, 1232-1243 (2005).
Recent Presentations
“Structural Design for Barrier in Polyester Systems,” 28th
Asilomar conference on Polymeric Materials, Pacific Grove,
CA, Feb. 13-16, 2005.
“Bio-Mimetic GRIN Lenses Using Polymeric Nanolayered Film
Systems,” E. Baer, A. Hiltner, Y. Jin, A. Ranade, H. Tai, J.
Shirk, M. Wiggins, and M. Sandrock, Invited Lecture for the
Herman Mark Award Symposium honoring Don Paul, ACS National
Meeting, Washington DC, Aug. 28 - Sept. 1, 2005.
Awards
2005
Spotlight Series Prize for Women’s Scholarship
sponsored by the Flora Stone Mather Center for Women Alumnae
Association.
2005 Outstanding Achievement Award from the Society
of Plastics’ Engineers (SPE)
2005 Named an ACS Polymeric Materials Science and
Engineering Division Fellow.
2001 ACS Cooperative Research Award in Polymer Science and
Engineering
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