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Dr. Benicewicz received his B.S. in Chemistry from Florida
Institute of Technology in 1976, and his Ph.D. in Polymer Chemistry
from the University of Connecticut in 1980. He held positions
as a research scientist at Celanese Research Company, as senior
scientist at Johnson & Johnson, and as a section leader
and deputy group leader at Los Alamos National Laboratory. He
joined the faculty of Rensselaer in 1997.
Liquid Crystalline Polymers
Liquid crystalline polymers are under intense investigation
due to the unique physical, mechanical, and electrical properties
imparted by the ordered phases of these materials. Synthetic
efforts are focused on the design and preparation of new polymers
with specific properties. Liquid crystalline thermosets are
being investigated as new high-performance crosslinked polymers
for structural applications. Benicewicz recently demonstrated
that magnetic field alignment of LCT’s produces large
increases in tensile modulus along the direction of orientation.
The use of these materials in nanocomposites is also being investigated.
Linear liquid crystalline polyamides and polyesters have been
commercialized as high-strength fibers and molded plastics.
Attempts to modify their properties with molecular kinks, swivels,
bends, and side groups have resulted in a trade-off between
increased processability and lower physical properties. Benicewicz
is preparing monomers and polymers using a new design concept
called main-chain asymmetry to maintain processability, while
exploring structures that could lead to higher physical properties.
New catalysts are also being tested to reduce polymerization
times and increase molecular weights.
Conducting Polymers
Benicewicz has shown that conducting polymers such as polyaniline
are effective at inhibiting corrosion on metal surfaces. An
active area of research is the understanding of the interrelationships
of electrical conductivity, redox behavior, and corrosion inhibition.
Also, new synthetic approaches to processable conducting polymers
are being explored. Acrylate and acrylamide monomers containing
short-chain aniline oligomers have been prepared and polymerized
by standard free radical polymerization techniques. These polymers
have shown redox behavior similar to that observed in high molecular
weight polyaniline, even though the oligoaniline units are 2-4
repeat units in length. Structure-property relationships of
this class of polymers are being investigated.
Biodegradable Polymers
Polymers designed to hydrolyze in the body to harmless by-products
can be used for surgical staples, devices, sutures, and controlled
release applications. A key focus in this area of research is
the ability to design polymer molecules with controlled degradation
rates for the various applications. These same design criteria
can also be used to synthesize new polymers for other industrial
applications where they may eventually end up in the environment.
Polymer Synthesis
New monomer and polymer synthesis is an underlying thrust for
all of our research programs. Benicewicz is interested in exploring
free radical, condensation, and ring opening polymerizations
for many applications. New findings could contribute to the
understanding of the fundamental aspects and new developments
in these areas. Benicewicz’s most recent work has focused
on the field of living radical polymerization using the RAFT
(reversible addition-fragmentation chain transfer polymerization)
technique. These polymerizations produce polymers with narrow
polydispersities and predictable molecular weights and rely
on specifically designed sulfur-based chain transfer agents
to provide a high degree of control. Benicewicz has developed
two new synthetic procedures for the synthesis of dithioesters
that eliminate many of the problems associated with their synthesis
and offer researchers in this field improved methods to prepare
dithioesters that contain a variety of substituents. Synthetic
methods have been expanded to easily prepare thiocarbamates
and xanthates that may also show utility for specific classes
of monomers. The preparation of various molecular architectures
(block, star, gradient) using living radical polymerization
is currently being pursued.
B.C. Benicewicz, S. Kanagasabapathy, A. Sudalai, “Montmorillonite
K 10 Catalyzed Regioselective Addition of Thiols and Thiobenzoic
Acids onto Olefins: An Efficient Synthesis of Dithiocarboxylic
Esters,” Tetrahedron Lett., 42,
3791-3794 (2001).
B.C. Benicewicz, S. Kanagasabapathy, A. Sudalai, “Phosphorus
Pentasulfide: A Mild and Versatile Catalyst/Reagent for the
Preparation of Dithiocarboxylic Esters,” Org. Lett.,
2(20), 3213-6 (2000).
B.C. Benicewicz and R. Chen, “Synthesis and Characterization
of Polymers with Oligoaniline Side Chains,” Polym.
Prepr., 41, 1733-1734 (2000).
B.C. Benicewicz, E.P. Douglas, R.S. Duran, J.D. Earls, R.D.
Priester, Jr., S.M. Setz, M.E. Smith, “Magnetic Field
Orientation of Liquid Crystalline Epoxy Thermosets,” Macromolecules,
31, 4730-4738 (1998).
B.C. Benicewicz, E.P. Douglas, J.D. Earls, R.D. Priester, Jr.,
M.E. Smith, “Novel Routes to High Strength, Light Weight
Materials: Magnetic Field Processing of Liquid Crystalline Thermosets,”
CHEMTECH, August, 1997.
B.C. Benicewicz, R.P. Hjelm, D.A. Langlois, M.E. Smith, E.P.
Douglas, “Properties of Liquid Crystal Thermosets and
Their Nanocomposites.” In Applications of High Temperature
Polymers. Boca Raton, FL: CRC Press, 1997, 79-96.
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