| 초록 |
In this study, the time-temperature superposition principle (TTSP) is applied to obtain the master curves and predict the life time of materials. The material used in this study is polyurethane (PU) composites based on hydroxyl-terminated polybutadiene (HTPB) as a prepolymer, isophorone diisocyanate (IPDI) as a curing agent to prepare PU materials. Hollow glass microspheres (HGM) and hollow organic microspheres (HOM) are used as void particles for PU composites. Dynamic mechanical analyser (DMA) is used to evaluate the storage modulus, loss modulus, tan delta and glass transition temperature (Tg) for each PU composite samples to show time (frequency) and temperature dependent. The storage modulus of PU composites slightly decreases after the glass transition, instead of remaining constant at rubber plateau region. These phenomena are also investigated using Cole-Cole and Wicket plots in details. |
