As for compounds with i-PPD, it can be seen from Fig. 16 that the large amount of i-PPD decreases the compound elasticity.
In other word, the total crosslink
density is reduced by the addition of i-PPD because of
the cure retarding effect of amine functionality in i-PPD
as discussed earlier. The damping factor shown in Fig.
17 increases markedly with increasing i-PPD concentration,
implying a rise in viscous response due to a
decrease in crosslink density.