Abstract

A great deal of interest has been given to extending the life of our fleet of solid rocket motors. Once poured, these motors are essentially stored, unused, and are therefore subject to various environmental conditions. Cycling between high and low temperatures causes thermal expansion and contraction of motor materials. This will eventually lead to cracks forming and propagating in the rocket motor, rendering it unreliable and thus must be re-poured at great expense. A common binder material used in these motors is hydroxy-terminated polybutadiene (HTPB), which when cured with a diisocyanate, creates the solid matrix to house the energetic materials of the motor. HTPB can be post-synthetically modified to incorporate mechanically reactive moieties (mechanophores) along the polymer chain that will react via the stress felt through environmentally induced cycling. These mechanophores will act to relieve the tension in the binder material vs. binder material failure. gem-Dichlorocyclopropanes were installed along the backbone of HTPB, and the functionalized HTPB was cured with the typical diisocyanate curative. The material was then subjected to quantitative tensile testing typically utilized to determine the mechanical properties of solid rocket motor materials. Once the material was tested to failure, the material was analyzed to determine if the g-DCC moieties were mechanically activated.

Disciplines

Polymer Science

Mentor

Capt Hope Klukovich

Lab site

Air Force Research Laboratory (AFRL)

Funding Acknowledgement

This material is based upon work supported by the S.D. Bechtel, Jr. Foundation and by the National Science Foundation under Grant No. 0952013 and Grant No. 0833353. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the S.D. Bechtel, Jr. Foundation or the National Science Foundation. This project has also been made possible with support of the National Marine Sanctuary Foundation. The STAR program is administered by the Cal Poly Center for Excellence in Science and Mathematics Education (CESaME) on behalf of the California State University (CSU)., This material is based upon work supported by the S.D. Bechtel, Jr. Foundation and by the National Science Foundation under Grant No. 0952013 and Grant No. 0934931. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the S.D. Bechtel, Jr. Foundation or the National Science Foundation. This project has also been made possible with support of the National Marine Sanctuary Foundation. The STAR program is administered by the Cal Poly Center for Excellence in Science and Mathematics Education (CESaME) on behalf of the California State University (CSU).

Share

COinS
 

URL: http://digitalcommons.calpoly.edu/star/162

 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.