Research Interests
Processing of polymers and composite materials; structural
analysis of surfaces and interfaces; molecular spectroscopy
of synthetic polymers.
Overview of Research
Our group's research interests can be divided into three
areas: they are molecular characterization; rheology and
processing of composites and blends; and development of new
materials. Molecular characterization activity makes use of
many instruments such as FTIR, Raman, NMR, GC-MS, SEC, and
HPLC, and are used for the study of surface and interface
characterization of composite materials. Rheological study
uses dynamic mechanical analysis and has been quite useful
in understanding the processing of composite materials, and
the interaction of fibers and fillers with polymer matrices.
Development of materials is a multi-task area involving
synthesis, characterization of molecular, physical, thermal
and mechanical properties, reaction kinetics, and
application studies. Recently, we have focused our major
research activity on the development of a new class of
phenolic materials, polybenzoxazines. Of particular interest
is the analysis of thermal properties using techniques such
as TGA, modulated DSC, high pressure DSC, and laser flash
photometry as these polymers are thermally stable. Unlike
traditional phenolic resins, these polymers polymerize via
ring opening polymerization with volumetric expansion (or
near-zero shrinkage). Because of this new rout to synthesize
phenolic polymers, historically encountered problems have
been mostly solved. Low viscosity of the monomers offer
excellent epoxy-like processability. In addition, several
unusual properties that have rarely been found with other
polymers have been discovered. Rich molecular design
flexibility allows properties to be tailored. These polymers
are comparable or better than advanced epoxies, phenolics,
bismaleimides, and even polyimides. For application of these
new polymers, we have focused our attention to the
development of electronic packaging materials beyond the
year 2000, where we have developed the highest thermal
conductivity material for protecting computer chips. New
materials for the future interior of airplanes have also
been investigated. Our materials are now considered by FAA
as one of the most flame resistant among all processable
polymers. With the formation of an industrial consortium,
the commercialization effort is well underway. Our long
continuing research interest is the molecular understanding
of surfaces and interfaces in composite materials. We are
especially interested in the studies of silane coupling
agents that are used to improve adhesion between glass
fibers (or fillers) and polymer matrices. Our activity also
extends to high performance composite materials such as the
polymers reinforced by carbon fibers and ultra-high modulus
organic fibers. Other surface, interface, and thin film
analyses have also been a long interest of this laboratory.
Unlike atomic techniques, we utilize vibrational
spectroscopy to achieve very sensitive analysis with rich
molecular information. To aid in this task, we are
interested in theoretical simulation using exact optical
theory. Combination of theory and experimental verification
allows development of many new surface characterization
techniques.
Current Activity
A large family of ring-opening phenolic resins called
polybenzoxazines have been developed and commercialized.
Polybenzoxazines have superb balance of mechanical and
physical properties, expands upon polymerization, absorbs
little water, have one of the highest char yield, and show
superb processibility. Potential application areas include:
electronic packaging materials, printed circuit boards,
coatings, frictional materials, catalysis, ion entrapment
materials, and airplane bodies. Mechanical properties
favorably compare with epoxies, phenolics, bismaleimides and
polyimides. Advancement in the knowledge of initiators and
catalysts led the development of both thermosetting and
thermoplastic polybenzoxazines from the same benzoxazine
monomer. Ultrafast magic angle spinning, solid-state proton
NMR with double quantum technique allowed determination of
the detailed structure of hydrogen bonds, which is the key
to the appearance of many unusual polybenzoxazine
properties, in structurally controlled model polybenzoxazine
oligomers. The position of hydrogen in hydrogen bonded
systems has been determined for the first time. Fourier
transform infrared spectroscopic study complemented the
fundamental NMR study and was in excellent agreement. One
type of commercializable nano-technology under study is
clay-based nanocomposites. By simple addition of a few
percent of clay, dramatic improvement in mechanical and
physical properties of polymers can be expected using
ordinary processing techniques. However, to date, only a
limited number of polymers could be used for this purpose.
We have developed a universal approach to prepare
nanocomposites from virtually any polymer, ranging from very
hydrophobic polymers like Teflon, polyolefins, rubbers, to
more polar polymers such as poly(vinyl alcohol) and nylon.
More industrially attractive nanocomposite preparation
method, charge-dipole interaction, has been studied in
detail so that nanocomposite can be prepared without
multiple steps.
Recent Publications
“Identification
of Volatile Products and Determination of Thermal
Degradation Mechanisms of Polybenzoxazine Model Oligomers by
GC-MS,” K. Hemvichian, H.D. Kim and H. Ishida,
Polym. Degrad. Stabil., 87, 213 (2005).
“Synthesis and characterization of maleimide and norbornene
functionalized benzoxazines,” H. Ishida and S. Ohba,
Polymer, 46, 5588 (2005).
“Surface Study of Hexagonal Boron Nitride Powder by Diffuse
Reflectance Fourier Transform Infrared Spectroscopy,” M.
T. Huang and Hatsuo Ishida, Surf. Interface Anal.,
37, 621 (2005).
Awards
2006 Named
Society of Plastics' Engineers (SPE) Fellow 2003 International Scientist of the Year, The International
Biographical Centre of Cambridge, England
2001 The PEL Associates Award in Pure Polymer Chemistry, PEL
Associates
2001 Award for Excellence in Adhesion Science, The Adhesion
Society, Williamsburg, VA
2001 Outstanding Conference Paper Award, Society of
Advancement for Materials and Process Engineering (SAMPE),
Longbeach, California
2000 SAMPE Fellow, Society for Advancement of Materials and
Process Engineering
1999 Alexander von Humboldt Award for Senior Scientist,
Humboldt Foundation, Germany
1998 Edwin P. Plueddeman Award for Excellence in Composite
Interface Research
1998 Best Paper Award in Research, Society for Plastic
Industries (SPI) 1998 Modern Plastic Magazine Award, SPI
Editor-in-Chief, Composite Interfaces
Associate Editor, Polymers and Polymer Composites
Advisory Board: Journal of Adhesion and Journal of Materials
Science and Eng. A
US Coordinator: US-Thai Cooperative Program
Eminent Scientist, Institute for Physical and Chemical
Research (RIKEN), Japan
|
