Project Title:

Ultra-High Stiffness Net-Shape Tubular Space Structures

04.05-3200A
Ultra-High Stiffness Net-Shape Tubular Space
	Structures
Foster-Miller, Inc.
350 Second Avenue
Waltham, MA 02254
Ted E. Kirchner  (617-890-3200)
JSC -- NAS9-17940

Abstract:

	 Net-shaped tubular extrusions of solution-processed, ordered (liquid crystal) polymers
can be combined with inter-penetrating networks (IPNs) to produce tubular space structures
having ultra stiffness (40 Msi), near zero (less than 1 ppm/deg.C) coefficient of
thermal expansion (CTE), and low weight (1.56 gm/cc). The approach taken was to co-extrude
biaxially oriented (microfibrillar network), thin-walled poly p-phenyline benzolbisthiazole
(PBZT) tubing and, then, introduce a polyimide IPN, Thermid AL-600. The goals were
to achieve high axial stiffness through a nearly axial orientation of the PBZT molecules
in the inner tube and a low CTE through the combined effects of the more biaxial
orientation of the outer tube and the polyimide IPN. These materials would have superior
performance to aluminum and would be cheaper to fabricate than graphite-reinforced,
metal-matrix tubes.
	The project was successful in extruding PBZT tubing with controlled orientation
and volume fractions of polyimide IPN. A zero CTE was bracketed but not achieved.
The bonding between the coaxial tubes during the post-cure processing was evident;
however, the high modulus was not reached for these tubes as had been demonstrated
for PBZT films and tubes in other projects. The difficulty in reaching a high modulus
is the result of processing problems.

Potential Commercial Application:

Potential Commercial Application: The primary application would be for space-based
structures fabricated from many tubular struts, truss members, and supports.