There's South Carolina Gold in Them Thar Rockets

Jul 2, 2019

Forgive yourself if you can’t pronounce “polybenzimidizole,” much less know what it’s used for. But if you ever went to the moon, you were sure glad to have it on your skin.  

Familiarly, polybenzimidizole goes by the much more vocally friendly name of PBI. It’s a twill-like material made by, fittingly, PBI Performance Products in Rock Hill. The company makes polymers, solutions, and films for industrial purposes, but the Rock Hill plant is the only place in the world that manufactures the company’s most visible product, PBI staple fiber.

It’s a long and complicated process to make this fiber; something that goes through numerous stages on multiple floors, all to come away with what ultimately looks like a luxuriant, satiny rope made of actual gold.

Scott Groshans, vice president of operations at PBI Performance Products in Rock Hill, and a pot of (rather literal) gold, in the form of PBI staple fiber.
Credit Scott Morgan / South Carolina Public Radio

“PBI Gold” is the fiber’s natural color, which, says the company’s vice president of operations, Scott Groshans, makes the fabric tough to dye. But it’s also why the old photos you see of NASA’s moon mission years feature an astronaut in a golden suit. It wasn’t designed that way, but it certainly proved a vivid image of America’s dominance in the moon race.

The irony is, the material wasn’t designed with anything particular in mind. In fact, says Groshans, when it was developed at Celanese Corp. in New Jersey, decades before the moon missions, nobody really knew what to use it for.

“It sat on the shelf for years,” he says.

It took catastrophe to really ramp up production of the staple fiber for a practical application. In 1967, three astronauts died in a rocket fire during a test run of the Apollo 1 craft.

“After that tragedy,” Groshans says, “NASA embarked on a program to acquire flame-resistant materials to use in their program.”

NASA approached Celanese and asked the company to develop PBI-based space suits to be used in the Apollo program. That’s because PBI staple fiber has an immense tolerance for high heat – certainly an asset wherever astronauts sit atop hundreds of thousands of gallons of fuel.

The company contributed to astronaut suits in the 1960s and 70s, from the moon missions through Skylab. Celanese built the Rock Hill site in 1982 and soon had its PBI-making operations running here, but the company stopped contributing to suits after Skylab because “there just aren’t that many space suits being made,” Groshans says.

Celanese eventually sold the PBI-making business. While the plant still operates in Rock Hill, it is now part of InterTech Group.

A closeup look at PBI staple fiber.
Credit Scott Morgan / South Carolina Public Radio

Clothingwise, PBI’s largest market today is firefighters, Groshans says. It also makes materials for tactical military clothing and some industrial applications.

But the company’s NASA ties are still strong. Though PBI Products stopped contributing to astronaut clothing, it did contribute staple fiber to rocket linings – called a “blade of insulation” -- during the Space Shuttle program.

“That vehicle used solid-rocket booster motors,” Groshans says. “Those types of motors have to be lined with an insulating product to protect them from being burned when the fuel inside them burns.”

And even though the Space Shuttle program is no more, PBI still has an in with NASA as the space agency develops the next wave of otherworldy flight.

“We are specked in for the next generation of solid-rocket booster motor vehicles that they’re building,” Groshans says. “When they get ready to move forward with their test flights and so on, they’ll be using our product – a blade of insulation containing PBI short-cut fibers.”

This story is part of South Carolina Public Radio’s coverage of the 50th anniversary of the first lunar landing in 1969, looking into many the roles the Palmetto State played in the race to the moon.