Dynamic Thermal Mechanical Analyzer

Dynamic Mechanical Thermal Analyzer (DMTA) c 10-" -2 X 10" 10 -10" Rheometric Scientific, Inc., Piscataway, N.J. 

The dynamic mechanical properties were studied via a Polymer Laboratories Dynamic Mechanical Thermal Analyzer (DMTA) used with ... 

The glass transition (Ta) and melting (Tm) temperature of the pure component polymers and their blends were determined on a Perkin-Elmer (DSC-4) differential scanning calorimeter and Thermal Analysis Data Station (TADS). All materials were analyzed at a heating and cooling rate of 20°C min-1 under a purge of dry nitrogen. Dynamic mechanical properties were determined with a Polymer Laboratories, Inc. dynamic mechanical thermal analyzer interfaced to a Hewlett-Packard microcomputer. The... 

The dynamic mechanical thermal analyzer (DMTA) is an important tool for studying the structure-property relationships in polymer nanocomposites. DMTA essentially probes the relaxations in polymers, thereby providing a method to understand the mechanical behavior and the molecular structure of these materials under various conditions of stress and temperature. The dynamics of polymer chain relaxation or molecular mobility of polymer main chains and side chains is one of the factors that determine the viscoelastic properties of polymeric macromolecules. The temperature dependence of molecular mobility is characterized by different transitions in which a certain mode of chain motion occurs. A reduction of the tan 8 peak height, a shift of the peak position to higher temperatures, an extra hump or peak in the tan 8 curve above the glass transition temperature (Tg), and a relatively high value of the storage modulus often are reported in support of the dispersion process of the layered silicate. 

The variation of the damping factor (tan 5) with temperature was measured using a Polymer Laboratories Dynamic Mechanical Thermal Analyzer (DMTA). The measurements were performed on the siloxanfe-modified epoxies over a temperature range of — 150° to 200 °C at a heating rate of 5 °C per minute and a frequency of 1 Hz. The sample dimensions were the same as those used for flexural modulus test specimens. 

Recently, Hon and San Luis [23] studied the thermal properties of cyanoethylated wood by DSC and dynamic mechanical thermal analyzer (DMTA). Depending upon the N content, the cyanoethylated wood exhibited a softening temperature ranging from 162°C to 177°C and melting temperature ranging from 240°C to 270 C. The DMTA measurements suggest that wood materials are susceptible to degradation upon cyanoethylation. 

Dynamic Mechanical Thermal Analyzer MKII Polymer Laboratory... 

Various methods (1-1) have used to determine the dynamic mechanical properties of polymers. Many of the instruments described are well known and are widely used (torsional pendulum, rheovibron, vibrating reed, and Oberst beam ASTM D4065-82). Newer instruments like the torqued cylinder apparatus (4), resonant bar apparatus (5) and Polymer Laboratories Dynamic Mechanical Thermal Analyzer (6) are becoming more popular in recent times. 

BENDING OF A BEAM. The complex dynamic Young s modulus can be determined from the forced, non-resonant oscillations of a single or double cantilever beam. The apparatus considered in this paper is the Dynamic Mechanical Thermal Analyzer (DMTA) (6), manufactured by Polymer Laboratories, Inc. Figure 3 shows the experimental setup for the single cantilever measurement. A thin sample is clamped at both ends. One end is attached to a calibrated shaker through a drive shaft. 

Figure 3. Dynamic mechanical thermal analyzer (DMTA) apparatus.

The dynamic mechanical property data for Groups 1,2,and 3 materials were obtained from a Polymer Laboratory Model 983 Dynamic Mechanical Thermal Analyzer (DMTA), and include log tan S (loss factor), log E (storage modulus), and log E (loss modulus). Frequency was held constant at 10 Hz for all samples. The superposed results are shown for each group in Figures 2-10. 

Glass transition temperature, Tg, and storage modulus, E , were measured to explore how the pigment dispersion affects the material (i.e. cross-link density) and mechanical properties. Both Tg and E were determined from dynamic mechanical analysis method using a dynamic mechanical thermal analyzer (DMTA, TA Instruments RSA III) equipped with transient testing capability. A minimum of 3 to 4 specimens were analyzed from each sample. The estimated uncertainties of data are one-standard deviation. 

The thermal properties (DSC second cycle), melt viscosities, and properties of test bars injected into unheated molds in a 1-oz Watson-Stillman injection-molding machine were determined as described earlier for the SDA copolyesters <2. 7. 81. The glass transition temperatures (Tg s) were determined on 1/16-in. thick injection-molded bars at 4°C/min and a frequency of 0.3 Hz with a Mark IV Dynamic Mechanical Thermal Analyzer from Polymer laboratories, Inc. 

Dynamic mechanical properties were determined with a Polymer Laboratories Dynamic Mechanical Thermal Analyzer (DMTA) using the tensile mode. The fiber length was in all cases 20 mm at an initial 0.5% elongation. The heating rate was set to 5°C/min. Break tenacities were measured on an Instron tensile tester model 1130 using a sample length of 25.4 mm and a strain rate of 0.508 mm/min (0.02 in./min). All reported break-tenacities and moduli are the mean values of four measurements. 

There is a growing tendency to incorporate nanofillers into polymer blends. When the two polymers differ significantly in rigidity, their behavior resembles that of TPE. For example, a blend of PA-6 with PP (PA-6/PP = 70/30) compatibilized with EPR-MA was melt-compounded with 4 phr of MMT-ODA [Chow et al., 2005]. The CPNC had a high degree of clay dispersion and distribution. The dynamic mechanical thermal analyzer (DMTA) data (at 10 Hz) showed a tendency opposite to that observed for TPE The largest enhancement of E was obtained for non-compatibilized CPNC at the lowest temperature of -100°C (by about 25%) the addition of EPR-MA reduced this effect by one-half, up to - -100°C. However, for these systems the tensile moduli measured in steady state and dynamic mode at 23°C were comparable (i.e.. 

STA Simultaneous Thermal Analyzer (TGA/DSC or TGA/DTA) DMTA Dynamic Mechanical Thermal Analyzer TMA Theimomechanical Analyzer DETA Dielectric Thermal Analyzer... 

The instrument for determination of shear moduli was a Rheometric Scientific dynamic mechanical thermal analyzer, model DMTA V. Round shear sandwich geometry was used. The instrument was inverted so that the sandwich fixtures and sample were in water. A water-jacketed 1000 mL Pyrex cylinder supplied by Rheometric Scientific allowed control of temperature with a circulating temperature bath. A sinusoidal linear shear was applied by moving a flat plate between two identical disk-shaped samples over a specified range of frequencies. The two identical disk-shaped samples were sandwiched between the moving plate and two 12 mm diameter plates (called studs) fastened to a frame. The dynamic frequency sweeps to obtain the loss shear modulus, G", from 0.16 Hz to 318 Hz were reported in log scale. For our purposes the applied initial static force was 0.05 N. Sample size was 12 mm diameter and 0.7 mm thickness. The sample was equilibrated at 40°C for 12 hours prior to starting the series of measurements. Shear moduli were measured from high to low temperature with an equilibration time of 2 hours at each temperature. The sequence of measurements was 40°C, 30°C, 25°C, and 15°C. 

Thermal stability properties are measured by two complementary methods, i.e. tensile-type measurements at elevated temperatures using a hot-air environmental chamber and also the Dynamic Mechanical Thermal Analyzer (DMTA) method. In the DMT A test a small rectangular strip (40 mm X 10 mm x 2 mm) is subjected to constant cyclic deformation over a changing temperature range and the storage modulus ( ) recorded and used to relate change of stiffness with temperature. 

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