I'm not an expert on composites, but the way I see it, Duroplast was a smarter choice than fiberglass, yet Trabants were the only cars made out of this cotton-based plastic while fiberglass went widestream with the Corvette.
If you've ever came across an old fiberglass-bodied car that spent too much time outside, you know that this strong and relatively light composite is hardly as resistant to sunlight than the early adverts suggested. On the other hand, the body panels of Trabants stood the test of time, even if nothing else did.
The benefit of Duroplast was that unlike fiberglass, this cotton or wool re-enforced resin plastic was pressable just like steel panels. The AWZ P70 "Zwickau" was the first East-German car to enjoy the benefits of that.
Using recycled cotton waste and phenol resins, Zwickau built more than 3 million Duroplast cars in the next decades, while the material also made its way into the suitcase industry.
After the Berlin Wall fell and junkyards started to fill up with Trabant 601s, the Zwickau plant (now backed by Volkswagen) started to work on the question of disposal. While some were experimenting with bacteria that would eat up the body of a Trabant in just a few weeks time, a more down-to-earth solution was to shred it all down and used as an aggregate in cement blocks, as CBS' Scientific American Frontiers reported in January, 1994.
No Duroplast car was made after production of the four-stroke Trabant 1.1 finished in 1991.
Photo credit: Fortepan