Viscoelastic creep characteristics of neat thermosets and thermosets reinforced with E-glass

The long-term creep behavior of vinyl esters and polyesters have been studied as a function of curing conditions using flexural creep tests at ambient temperature (23C). Vinyl esters that have been cured at room temperature had a greater creep exponent (n 0.20) for power law creep (tn) than vinyl esters that were postcured to crosslink completion at 93C (n 0.12). Reinforcements using woven glass fabric in the room temperature cured vinyl ester and the vinyl ester postcured at 93C gave much lower compliances, but with approximately the same time exponents (n 0.20 and 0.13, respectively). The vinylester without reinforcement was tested in creep after a variety of curing conditions: one day, one week, one month at room temperature; 49C for 4 h, 71C for 4 h, and 93C for 4 h. The total creep compliance as well as the time exponent n decreased systematically with increasing cure condition and time, with a creep compliance for room temperature cure for one day that is 250% more than that for a neat vinyl ester cured for 4 h at 93C.

Viscoelastic creep characteristics of neat thermosets and thermosets reinforced with E-glass Academic Article