Dynamic mechanical analyser

Thermal and Dynamic Mechanical Analyses. The thermal and mechanical properties of the new photocured films were evaluated by DMA and TGA. The initial DMA scan of the photocured polymer (prepared from a 3 1 blend of 4-allyloxystyrene DVE-3) to ensure crosslinking on UV exposure shows two transitions at 62°C and 232°C, as shown in Figure 4, scan a. The low temperature transi-... 

The authors acknowledge Drs James Scanlan and Peter Shang of Eastman Chemical Company for providing unpublished dynamic mechanical analyses data and DSC data, respectively... 

Becanse there are many factors involved in the dynamic mechanical compression of polyolefin foams, the Taguchi method was employed in a Perkin Elmer DM A7 dynamic mechanical analyser to establish a method to improve the measurement process. The signal-to-noise ratio was measured to determine how the variability could be improved. Control and noise factors were evaluated and levels chosen, with details being tabulated. Appendix A describes some of the factors. Tests were conducted on two closed cell foams. NA2006 foam is 48 kg/cu m LDPE and NEE3306 foam is 32 kg/cu m EVA. Different factors were shown to influence results for E and tan delta but an optimum combination is proposed for the simultaneous measurement of both properties. The results were less variable as frequency was increased. Small differences in the dynamic response of different materials should be measurable because of the low variability in the experimental results. 18 refs. 

Fig. 57 Dynamic mechanical analyses of EPDM-LDH and XNBR-LDH nanocomposites [104]...

Dynamic mechanical analysers, as discussed in chapter 9, can be constructed so that they can be used with unvulcanised materials and, hence, the in phase and out of phase components of modulus and the loss angle measured. The usual test piece geometries for cured rubbers are not convenient for the uncured materials where some form of oscillating shear is probably the best approach. This is the geometry used in cure meters discussed in the next section and such instruments have formed the basis for apparatus which measures dynamic properties from before and through the curing process. 

The excess heats of mixing experiments were performed using a modified McGlashan calorimeter. All the dynamic mechanical analyses were conducted using a Polymer Laboratories instrument at a frequency of 10 Hz and a heating rate of 2 C per minute. 

Judging from the results of dynamic mechanical analyses, IPNs showed more effective damping properties than commercial chloroprene rubber at elevated temperatures. In addition, filled IPNs prepared by adding platelet fillers showed even higher attenuation (logarithmic decrement). 

Hiltner, A., Anderson, J., Baer, E., Dynamic Mechanical Analyses of Poly-... 

Dynamic mechanical analyses were performed on an Orientec Rheovibron DDV-III-EP. The storage modulus spectra were obtained from -150 C to 250 Cat a heating rate of 2 C/min and a frequency of 110 Hz. 

FIGURE 10.10 Diagrammatic representation of the design of the dynamic mechanical analyzer 2980. (Adapted from Dynamic Mechanical Analyser 2980 Operator s Manual, TA Instruments, New Castle, DE, 1996.)... 

Dynamic Mechanical Analyser 2980 Operator s Manual, TA Instruments, New Castle,... 

Fire relstance,chemical composition by infrared (IR) and nuclear magnetic resonance (Mlffit) spectroscopy, thermal analyses, Clash-Berg moduli determination and dynamical mechanical analyses were determined. The fluorenone polyesters were spun as fibers from solution. They were blended with an acetylene terminated fluorenone monomer for plasticization and crosslinking at high temperatures to form an improved thermally stable product. 

Thermomechanical Analyses (TMA) were recorded on a DuPont thermal analyzer. Model 943 TMA fitted with a penetrating tip probe, at 2g load and 10°C/mln temperature rise. Vertical displacement and the first derivative of that displacement with respect to time were recorded as a function of temperature. Dynamic Mechanical Analyses (DMA) were obtained on a DuPont 981 DMA Instrument. 

The distinction between a thermomechanical analyser and a dynamic mechanical analyser is blurred nowadays since many instruments can perform TMA-type experiments. The configuration of a DMA is essentially the same as the TMA shown in Figure 5 with the addition of extra electronics to apply an oscillating load and the ability to resolve the resulting specimen deformation into in-phase and out-of-phase components so as to determine E, E" and tan S. The facility for sub-ambient... 

The effect of temperature on the mechanical properties of a liquid can be investigated using a special type of dynamic mechanical analyser called an oscillatory rheometer. In this instrument the sample is contained as a thin film between two parallel plates. One of the plates is fixed while the other rotates back and forth so as to subject the liquid to a shearing motion. It is possible to calculate the shear modulus from the amplitude of the rotation and the resistance of the sample to deformation. Because the test is performed in oscillation, it is possible to separate the shear modulus (G) into storage (G ) and loss modulus (G") by measuring the phase lag between the applied strain and measured stress. Other geometries such as concentric cylinders or cone and plate are often used depending on the viscosity of the sample. 

Using a dynamic mechanical analyser, it is possible to carry out experiments with the sample immersed in a liquid. For this type of measurement, the instrument is fitted with a metal liner which is inserted into the oven so that the sample and clamps can be immersed and the temperature of the bath programmed in the usual way. Results from testing acrylic fibres under different conditions are shown in Figure 22. 

Calibration of Dynamic Mechanical Analysers E 1868 (1997) Loss on Drying by TGA E 1877 (2000) Thermal Endurance from TGA Decomposition Data... 

Dynamic mechanical analysers, contract thermal analysis)... 

Other thermal analysis techniques such as dilatometry in Sect. 4.1 or thermo-mechanical analysis in Sect. 4.5 can also be used to study the time dependence of T. Especially suited for measurement of the frequency response are dynamic mechanic analyses in Sects. 4.5.4 and 4.5.5, and dielectric thermal analyses in Sect. 4.5.6. Although the different techniques respond to different external excitations, the obtained relaxation times are similar, as shown in Fig. 6.117. Over wider temperature... 

Dynamic mechanical analyser Instrument for measuring the behaviour of a sample subjected to an oscillating stress in response to a temperature programme. 

Dynamic mechanical analysis curve Graphical representation of the data collected by a dynamic mechanical analyser, where the dynamic loss modulus, dynamic storage modulus and tan 5 are plotted as a function of temperature (scanning mode) or time (isothermal mode). 

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