GEO-COMPOSITE: fire resistant matrix

Excerpt from the technical press
Performance Materials,
February 5, 1996, page 5.

As Hot as You Like It

Mechanical Properties are Looking Good for French Inorganic Polymer that Doesn’t Burn.

Fire safety is a concern often voiced by those who are skeptical about the use of composite materials in the infrastructure. These fears may be put to rest by a revolutionary European matrix material that doesn’t burn at all (PM, July 31, 1995). “Fire is going to be the limiting criterion in a lot of infrastructure applications C says Rich Lyon of the Federal Aviation Administration (FAA) Tech Center in Atlantic City. But his ICCI ‘96 presentation about the new family of inorganic polymer composites was almost anticlimactic. “It’s a fairly boring story because there is no fire response,” Lyon said in Tucson.

FAA Is Interested, Too

The inorganic polymeric materials are cheap, at about $2-3 a pound. They cure at low temperatures.
And now there is evidence that the new material family, trade named Geopolymer (or, more precisely, Géopolymère), boasts mechanical properties comparable to those of organic-matrix composites. FAA-supported testing was conducted at Rutgers University in New Jersey.
“The initial results are very encouraging: Prof. P (Bala) Balaguru of Rutgers said at the Tucson infrastructure meeting. Carbon-matrix composites made with the Geopolymer matrix demonstrated a strength of approximately 327 MPa (about 225 ksi), he said, quite comparable to organic composites. “The same thing is true for flex and shear;’ Balaguru said. The Rutgers test coupons were made using 3K, polyacrylonitrile-based carbon fiber that was manually impregnated and vacuum-bagged for curing in an 80°C (176°F) heated press. The samples were post-cured in an 80°C oven for 24 hours.
Experimenters have thus far made samples only via hand layup, and have been able to achieve fiber loadings of only 50 % (the Rutgers tests were conducted on 45-percent material). At least 60 % is expected when fabrication processes are refined, says the FAA’s Lyon. Problems with voids are also expected to be solved when better fabrication techniques are applied.
“These materials are in their infancy) FAA Lyon says. Geopolymer inventor Joseph Davidovits spent much of his career as a textile chemist and began pursuing inorganic polymers in part, he says, behind a tragedy in France in which the deaths by fire of more than 100 young night club patrons were attributed to fast-burning polyester curtains. Davidovits cites three key Geopolymer attributes his company says “make them superior to ceramics, plastics, and organic composite materials:” (Performance Materials, February 5, 1996).

The First Non-flammable fabric laminate for Aircraft cabin and cargo interiors, Géopolymère Composite™ was introduced on November 18, 1998, in Atlantic City, NJ, USA, at the International Aircraft Fire and Cabin Safety Research Conference sponsored by the Federal Aviation Administration. More details in Press Release (see page 3)

Predicted time to flashover in ISO 9705 corner/room fire test with various structural composites as wall materials