Novel Phase Formation in Polymeric Biomaterials and Its Impact on Performance



August Dinner Lecture & Other Announcements


"Novel Phase Formation in Polymeric Biomaterials
and Its Impact on Performance"

Michael Jaffe
Department of Biomedical Engineering
New Jersey Institute of Technology

Novel mesogenic phases, similar to the Condis Crystals described by Wunderlich have been found in melt spun fibers of the bioerodable polyesteramides based on a desaminotyrosyl bisphenol monomer. The characterization of these phases and the impact on biorelevant polymer performance will be discussed.

Polymeric biomaterials are synthetically derived or
modified biological polymers designed for in-vivo use
or for use in the proximity of biological fluids (for
example, blood bags). As is common in the polymer
industry, these polymers are produced as powders and
then spun into fibers for a variety of projected in-vivo
uses. Characterization of polymeric biomaterials as
powders and fibers has two purposes: 1. Development of parameters for processing, and 2. Determination of end- use performance characteristics.

The polyarylate combinatorial library, produced by Prof.
J. Kohn of Rutgers University, has been spun into fibers
to determine the range of mechanical properties and
dimensional stability available as a function of spinning conditions and backbone chemistry. In general, all of the library polymers show systematic changes in tensile modulus, tensile strength and shrinkage at the glass transition with increasing molecular chain orientation as expected from a series of amorphous polymer fibers of varying Tg. Two unexpected results of these studies were the high shrinkage and tensile property loss exhibited by the DTE adipate and DTE succinate fibers in water at 37 C (dry Tg's, 60 and 80 C, respectively) and the mechanical property retention of the low Tg variants, poly DTD do- decanate and DTO sebacate fibers at room temperature or in water at 37 C (dry Tgs ~12 C).

While at temperatures significantly higher than 37 C,
proteins denature and direct biological relevance may
be lost, the plasticizing and anti-plasticizing effects
of the biological environment on fiber properties may
offer routes other than temperature alone to accelerate/ understand in-vivo phenomena of interest. It is shown that the compositions with short diacids and side chains are highly plasticized by water, leading to the observed lack of dimensional stability. Mechanical property retention of the long diacid, long sidechain variants is shown to be a function of ordered phase formation. In both cases TA techniques play a vital role in understanding the phenomena involved,

These results illustrate the importance of understanding
the impact of the total processing history of a polymeric biomaterial fiber on its properties and how TA provides a convenient tool for monitoring structural and performance variables.



DATE: Tuesday, August 13

Location: Michael's at Shoreline Park, Mountain View

Timing: 6 PM social hour
7 PM dinner
8 PM lecture

Cost: $30
half price students, retired, unemployed
free for just the lecture at 8PM
(but please let us know for headcount)

Deadline for registration: 5 PM, Friday, Aug. 9

Please register on the web site
Otherwise, register by contacting
Nayan Ashar

You should receive confirmation of your registration; if not, please contact us again.


Dinner choices:
broiled salmon
chicken stuffed with mushrooms
vegetarian Napoleon (polenta, eggplant, vegetables)

Note that we must request that you be liable for your registration fee if you register and do not attend; cancellation is allowed up to the registration deadline.


From 101 in Mountain View, take the Shoreline Boulevard
Exit, turning toward the bay. Drive past the Shoreline Amphitheater and go straight ahead, entering into Shoreline Park. After a mile or so inside the park, a sign for Michael's will direct you to turn left into the parking lot for Michael's.
Address: 2960 N Shoreline Blvd.
Restaurant phone: 650-962-1014
(do not call restaurant for reservations)


Upcoming GGPF Dinner Lectures:

Sept.12, Mountain View (Michael's)
James Bennett of Symyx Technologies, Inc.
"Rapid Thermal Analysis."


OTHER EVENTS of possible interest to the
GGPF audience:


July 30, South San Francisco
BAMS dinner meeting
"LC/MS/MS Approaches for Differential Expression
Proteomics and in vivo Phosphorylation Site
Identification", Karl Clauser, Millennium


Sept. 18, location tbd
BAMS annual Corporate Sponsor night

Sept. 18-20, Berkeley
"Integrated Nanosystems 2002: Design, Synthesis
& Applications"

Sept. 26, Santa Clara
ACS Santa Clara Valley Section dinner lecture
"Carbon Nanotubes for Nanoscale Science and
Technology", Prof. Hongjie Dai, Stanford


Oct. 10, San Jose
"Chemical Mechanical Planarization 2002:
7th Annual International Conference" (click on 'CMPUG")


Nov. 3-6, San Francisco
"SYSTEOMICS 2002: Integrating Proteomics, Genomics and Metabonomics"

Nov. 13-16, Sonoma
ACS POLY Division Workshop,
"Polymers in Medicine and Biology: 2002"

Nov. 17-20, Sonoma
ACS POLY Division Workshop,
"2002 POLY Biennial: Polymeric Nanomaterials"


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or by replying to this announcement with your name and preferred email address.

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mentioned in these announcements to

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