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<title>Simultaneous Measurements of Effective Chemical Shrinkage and Modulus Evolution During Polymerization
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<center><i>Proceedings of the 2008 58th Electronic Components and Technology Conference, Orlando, FL, May 27 – 30, 2008</i>

<br><h2>Simultaneous Measurements of Effective Chemical Shrinkage and Modulus Evolution During Polymerization</h2>
<br><br><b>Yong Wang</b><br><b>Bongtae Han</b><br><b>Avram Bar-Cohen</b><br>
Department of Mechanical Engineering<br>
University of Maryland, College Park, MD 20742<br>


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<b>Abstract:</b>

<p>An integrated measurement technique is proposed to measure
the effective chemical shrinkage and the modulus of
polymeric materials simultaneously, as a function of time,
during polymerization (evolution history). The method is
based on a fiber Bragg grating (FBG) sensor. A polymer is
cured around a glass FBG and the Bragg wavelength (BW)
shift is continuously documented while polymerization
progresses at the curing temperature. Based on the theoretical
relationship between the BW shift and the stress field in the
FBG, the measured BW shift is used to determine the
evolving effective chemical shrinkage and the modulus. The
results can be employed to predict curing-induced residual
stresses in geometrically-complex packaged assemblies. The
proposed method is implemented on a high temperature
curing epoxy.
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<p><a href="../../fulltext/2008/ECTC2008_FBG.pdf">Complete article</a> is available to CALCE Consortium Members.</p>


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