Composite loss modulus

Figure 18.50 Effect of polymer processing on loss modulus by dynamic mechanical analysis. Effect of cooling rate of polyether ether ketone (PEEK) composite loss modulus at Tg. Source TA Instruments, New Castle, DE, USA)...

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. 

Fig. 4 Temperature dependence of the dynamic storage modulus E and loss modulus E" for CELL/PACMO composites. (Reproduced from [72])...

The dynamic mechanical properties of four 2,6-T-2P samples containing from 19 to 43 wt% hard segments are summarized in Figure 10. A low temperature s relaxation is apparent at about — 70°C for all compositions examined. The transition temperatures of these loss maxima and the associated activation energies are given in Table III. A second process, the c relaxation, can be noted as a shoulder on the high temperature side of the 8-loss maximum. The conclusion of this relaxation is marked by a change in slope of the loss modulus vs. temperature plots... 

Figure 8 presents the storage and loss-modulus master curves obtained on all five samples of interest. The dashed lines indicate extensions of the master curves, using appropriately reduced data from the Rheovibron experiments in tension. Storage-modulus data in the rubbery plateau region vary systematically with composition, i.e., the... 

Penetration temperature, expansion coefficient Elastic modulus, loss modulus Composition, weight loss as a function of temperature... 

Comparison of the loss modulus data for three blend compositions of the two polybutadiene samples in Fig. 9.23 at 30 C with the predictions of... 

Aqueous viscoelastic surfactant solutions for hair and skin care are disclosed in U.S. Patent 5,965,502. Rheology conditions are specified for optimum flow behavior, in terms of the shear modulus as a function of temperature and pH. A representative graph of the storage and loss modulus as a function of angular frequency is presented in the patent and this is shown in Figure 4.8. Cited compositions contain anionic, betainic, and nonionic surfactants, electrolytes, and a water-soluble polymer. A nonionic gel personal cleanser is specified in U.S. Patent... 

Fig. 31 Loss modulus E" as a function of the temperature for injection-molded PPE/PS blends as determined by DMA. The low-temperature shoulder at around 90 °C exhibited by the blends is indicated. The weight compositions refer to the ratio of PPE/PS [45]. Reprinted by permission of Elsevier Ltd...

Table 17.24 shows data for a series of regrinds all derived from the same composition, that is, HDPE (MFI 0.5) filled with rice hulls and Biodac , 29% of each filler. The storage and loss moduli were plotted against the frequency in double logarithmic coordinates, and the respective slopes are shown in Table 17.24. In all cases the storage modulus and the loss modulus increased with frequency. The same data were analyzed earlier, in Table 17.12, in terms of their zero-shear viscosity.

TABLE 17.25 Storage and loss modulus (parallel-plate rheometer, 177°C) of composite deck board material as a function of frequency... 

The dynamic mechanical analysis of virgin PP, untreated sisal/PP composites and MAPP treated sisal PP composites revealed an increase in the storage modulus (E ) in the PP matrix with the addition of fibers and MAPP (Figure 9.5a) [71]. The loss modulus displayed three relaxation peaks at -80°C (y), 8°C (P), and 100°C (a), respectively. The temperature of P relaxation maximum corresponds to the Tg of the matrix, while the a relaxation peak is related to the slip mechanism in the crystallites. The y relaxation peak is due to the... 

Figure 9.5 Variation of (a) storage modulus (b) loss modulus of virgin PP and untreated and treated sisal-PP composites as a function of temperature [71],...

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