Graduate
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The Department of
Mechanical Engineering – Engineering Mechanics
Proudly Presents
Gregory B. McKenna, Ph.D.
Professor of Chemical Engineering, Paul Whitfield Horn Professor and The John R. Bradford Endowed Chair in Engineering
Texas Tech University
Dr. Gregory B. McKenna has a reputation as a pioneering researcher in four areas of
polymer and plastics science and technology: Physical Aging and Structural Recovery of
Polymer Glasses, Solid Mechanics and Nonlinear Viscoelasticity of Polymers,
Thermodynamics and Mechanics of Elastomers and Gels, Molecular Rheology.
He received his Bachelor’s in Engineering Mechanics at the U.S. Air Force Academy,
and his MS in the area of composite materials from MIT. He entered active duty as a test
and evaluation engineer at Hill Air Force Base in Ogden, Utah. In 1976 he received his
Ph.D. in Materials Science and Engineering at the University of Utah. Dr. McKenna
started at the National Bureau of Standards (now called NIST) as a National Research
Council Postdoc and accepted a permanent position as a staff scientist in 1977. He served
as the head of the Structure and Mechanics Group in the Polymers Division at NIST from 1992-99. In 1989 Dr.
McKenna became a Fellow of the American Physical Society and was the recipient of the NIST E.U. Condon
Award for excellence in technical exposition for his classic review article “Glass Formation and Glassy Behavior.”
In 1998, he was elected a Fellow of the Society of Plastics Engineers.
After NIST, he joined Texas Tech University as a Professor in the Department of Chemical Engineering and the
John R. Bradford Endowed Chair in Engineering. In 2005 he became a Paul Whitfield Horn Professor at TTU.
He is the 2009 recipient of the Bingham Medal of the Society of Rheology, has received the International Award of
the Society of Plastics Engineers, and the Mettler Toledo Award from the North American Thermal Analysis
Society. He served on the Governing Board of the American Institute of Physics, the Executive Committees of the
Society of Rheology and The Division of High Polymer Physics (DHPP) of the American Physical Society. He was
the Chairman of the DHPP, the Society of Engineering Science, and the Polymer Analysis Division of the Society of
Plastics Engineers. Currently he is vice-president of the Society of Rheology.
Thursday, Mar. 22, 2012
4:00 – 5:00 p.m.
Room 112, ME-EM Bldg.
Using Mechanics to Interrogate the Physics of Soft Matter:
From the Glassy to the Rubbery States and from the Macro-scale to the Nano-scale
M e c h a n ic a l m e a s u re m en ts offe r a u n iq u e m e a ns of in te rrog a ting th e p hys ic s o f a m orp h o u s
g la s s -fo rm ers a n d ru b be ry p o lym e rs . H e re w e p re s e n t s e ve ra l vig n e ttes to d e m o n strate th e
a b ility o f b o th c la s s ic a l a n d n o ve l rh e o lo g ic a l e xp e rim e n ts to re s o lve im p o rta n t q u e stio n s in
c o n d e n s e d m atter p h ys ic s . F irs t, re s u lts from torq u e a n d n o rm a l forc e m e a s u re m e nts a im e d at
u n d e rs ta n d ing th e th erm o d yn a m ic s a n d m e c h a n ic s of p o lym e r n etw o rk s in b o th d ry a n d s w o lle n
s ta te s a re p re s e nte d . In p a rtic u la r, w e e xa m in e th e va lid ity o f th e F re nk e l-F lo ry-R e h n e r th e o ry of
ru b b e r n e tw o rk s w e llin g . T ors io n a n d n o rm a l fo rc e m e a s ure m e nts a re a ls o d e s c rib e d fo r a
s e rie s of p o lym e ric g la ss e s th at e xh ib it s im ila r s h e a r m o d u li b u t, s u rpris in g ly, ve ry d iffere n t
n o rm a l forc e re s p o n s e s, w ith o n e s e t of m ateria ls s h o w in g e xtre m e d e via tio n s from n e o H o o k e a n b e h a vio r a n d th e o th e r b e in g c lo s e to n e o -H o ok e a n . W e th e n d e s c rib e th e u s e of a
n o ve l to rs io n a l d ila to m e te r, w h ic h a llo w s s im u lta n e o u s m e a s u rem e n t of m e c h a n ic a l p ro p e rties
a n d vo lu m e re c o ve ry, to in ve s tig a te th e ag ing a n d re ju ve n a tio n b e h a vio rs of g la s s y p o lym e rs .
T h e te m p era ture d e p e nd e n c e of d yn a m ic s is pro b e d in g la s s y p o lym e rs th a t h a ve b e e n a g e d
in to e q u ilib riu m b e lo w th e n o m in a l g la s s tra ns itio n te m p era ture a n d e vid e n c e is p re s e nte d that
tim e -sc a le d ive rg e n c e m a y n o t b e a tru e s ig na tu re of th e g la s s tra n sitio n its e lf. F in a lly, w e
d e s c rib e a re d u c tio n in s c a le o f th e c la s s ic a l m e m b ra n e infla tio n te st to a llo w m e a s u re m e n t of
th e b ia xia l c re e p c o m p lia n c e o f n a n o m ete r th ic k p o lym e ric film s us in g a n atom ic forc e
m ic ro s c o p e. In e a c h in s ta n c e e m p h a s is is p la c ed o n h o w th e m e a s u rem e n ts a re d e s ig n e d to
in te rrog ate th e p h ys ic s of in tere s t in th e m a teria ls in ve s tig a te d.
Funding for the ME-EM Graduate Seminar Series is provided by Professional Plating, Inc. of Anoka, MN www.proplate.com
and the Department of Mechanical Engineering – Engineering Mechanics www.me.mtu.edu/seminar