Composite properties storage modulus

Fig. 3. Influence of silane coupling agent on dynamic viscoelastic properties of GF/PP composites (a) storage modulus as a function of angular frequency, (b) loss modulus as a function of angular frequency...

The viscoelastic and thermal properties of fully and partially cured DGEBA epoxy resin composites were smdied modified with montmorillonite nanoclay exposed to UV radiation. Samples were fabricated and cured to 80 % conversion (partially cured) based on isothermal cure kinetic smdies. Influence of 1-3 wt% loading of montmorillonite nanoclay on the cure behavior and development of physical properties of these composites were evaluated. Results of the smdy revealed that for optimization of modified epoxy composite properties, a different curing cycle was necessary due to interaction of different amounts of nanoclay and epoxy molecules. Addition of nanoclay increased the viscoelastic properties, storage modulus and activation energy of decomposition of partially cured samples evolved over exposure time, while fuUy cured samples degraded over the same period. 

Experiments with the /3-lg/Tween 20 system were performed at a macroscopic a/w interface at a /3-lg concentration of 0.2 mg/ml [40]. The data obtained relate to the properties of the interface 20 minutes after formation. Up to R = 1, the storage modulus (dilational elasticity) was large and relatively constant, whereas the loss modulus (dilational viscosity) increased with increasing R. As R was increased to higher values there was a marked decrease in the storage modulus (dilational elasticity) and a gradual increase in the loss modulus (dilational viscosity). In summary, the data show the presence of a transition in surface dilational behavior in this system at a solution composition of approximately R = 1. At this point, there is a transformation in the adsorbed layer properties from elastic to viscous. 

Velasco Santos et al. (27) measured both the dynamic mechanical behavior and tensile mechanical properties of MWCNT-PMMA composites. They observed 1135% increase in storage modulus at 90°C and increase in glass transition temperature by 40°C over neat PMMA with only 1 wt% functionalized nanotubes. The tensile... 

After drawing the torsional storage modulus of the blend of LCP60-80 with PPS is remarkably improved in comaprison with that of neat PPS film and its magnitude is comparable with that for the PPS/carbon fiber composite (Figure 19). On the other hand, for the blends of PPS with LCP80 there was no significant enhancement of the properties as the draw ratio was increased. This is due to the lack of fibrils in the latter case. 

DMA analysis substantiated the possible morphological features that could partially account for the trend in mechanical and fracture properties of the glass laminate composites [146]. The DMA, done at a frequency of 1 Hz, are given in Fig. 12, where the percentage retention of the room temperature storage modulus (E ) is plotted as a function of temperature to normalize the anomalies resulting from differences in resin content for different systems. EPOBAN-modified... 

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