As previously mentioned, this cure system is one that had historically been used with GPO-58, the predecessor to GPCO T6000.
Overall, even considering the aforementioned concerns about DeMattia testing, the new GPCO T6000 polymer performed very well in resistance to flex fatigue.
When combining all tangent delta together in one plot and looking at log frequency response, the clear pattern is that the GPCO T6000 compounds with low sulfur and small particle size black (N330) had the highest damping characteristic, therefore, the most predisposition to have higher hysteresis.
As mentioned earlier, the new GPCO polymer did quite well with regard to flex fatigue resistance, except in the LS N330 compound.
GPCO attempted to make the audit, but Bender declined, on the grounds that this was a construction contract not requiring audit and that it was fixed-price lump sum by its terms.
Army argued that the contract was changed from lump sum to unit pricing by the terms of the modifications that called for GPCO audit and the presentation of disposal certificates.