NASA Scientific and Technical Aerospace Reports

20040073722 Engineering Research and Consulting, Inc., Edwards AFB, CA
Developments in Nanoscience: Polyhedral Oligomeric Silsesquioxane (POSS) -Polymers
Phillips, Shawn H.; Haddad, Timothy S.; Tomczak, Sandra J.; Mar. 8, 2004; 38 pp.; In English; Original contains color
illustrations
Contract(s)/Grant(s): F04611-99-C-0025; Proj-2303
Report No.(s): AD-A422636; No Copyright; Avail: CASI; A03, Hardcopy
This review is intended to cover the more recent advances in both structure-property relationships of polymers
incorporating Polyhedral Oligomeric Silsesquioxane(s) (POSS) nanostructured chemicals as well as space-survivability testing
of POSS-polymers. The strategy employed for using POSS as building blocks is discussed in addition to current models and
predictions pertaining to the ideal crystallite/aggregate size of the nanocomposite within the polymer matrix to provide
maximum mechanical improvements. The oxidation and rapid formation of SiO2 during atomic oxygen testing leads to a
passivating layer and conclusive proof of these phenomena is presented. Also a brief history of POSS is outlined to help
readers understand how they relate to the recent boom in nanotechnology and their position in nanomaterials R&D.
DTIC
Nanocomposites; Nanocrystalline Materials; Polymers; Silicon Dioxide
20040073755 Engineering Research and Consulting, Inc., Huntsville, AL
Gas Phase Structural Characterization of Polyhedral Oligomeric Silsesquioxanes (POSS) with Styryl and Epoxy
Phenyl Capping Agents
Baker, Erin S.; Gidden, Jennifer; Anderson, Stanley E.; Haddad, Timothy S.; Bowers, Michael T.; Feb. 23, 2004; 27 pp.; In
English
Contract(s)/Grant(s): F04611-99-C-0025; Proj-2303
Report No.(s): AD-A422679; AFRL-PR-ED-TP-2004-045; No Copyright; Avail: CASI; A03, Hardcopy
This document is a report of the Gas Phase Structural Characterization of Polyhedral Oligomeric Silsesquioxanes (POSS)
with Styryl and Epoxy Phenyl Capping Agents.
DTIC
Epoxy Resins; Phenyls; Synthesis (Chemistry); Vapor Phases
20040074181 Pennsylvania State Univ., State College, PA, USA
Shearography for Non-Destructive Evaluation with Applications to BAT Mask Tile Adhesive Bonding and Specular
Surface Honeycomb Panels
Lysak, Daniel B.; December 2003; 24 pp.; In English
Contract(s)/Grant(s): NCC5-508
Report No.(s): NASA/CR-2003-212231; No Copyright; Avail: CASI; A03, Hardcopy
In this report we examine the applicability of shearography techniques for nondestructive inspection and evaluation in two
unique application areas. In the first application, shearography is used to evaluate the quality of adhesive bonds holding lead
tiles to the BAT gamma ray mask for the NASA Swift program. By exciting the mask with a vibration, the more poorly bonded
tiles can be distinguished by their greater displacement response, which is readily identifiable in the shearography image. A
quantitative analysis is presented that compares the shearography results with a destructive pull test measuring the force at
bond failure. Generally speaking, the results show good agreement. Further investigation would be useful to optimize certain
test parameters such as vibration frequency and amplitude. The second application is to evaluate the bonding between the skin
and core of a honeycomb structure with a specular (mirror-like) surface. In standard shearography techniques, the object under
test must have a diffuse surface to generate the speckle patterns in laser light, which are then sheared. A novel configuration
using the specular surface as a mirror to image speckles from a diffuser is presented, opening up the use of shearography to
a new class of objects that could not have been examined with the traditional approach. This new technique readily identifies
large scale bond failures in the panel, demonstrating the validity of this approach. For the particular panel examined here, some
scaling issues should be examined further to resolve the measurement scale down to the very small size of the core cells. In
addition, further development should be undertaken to determine the general applicability of the new approach and to establish
a firm quantitative foundation.
Derived from text
Nondestructive Tests; Evaluation; Adhesion Tests; Bonding; Adhesive Bonding; Honeycomb Structures; Shearography
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