Perkin-Elmer DMA

Gelatin sheets were analyzed by means of a dynamic-mechanical analyzer from Perkin-Elmer DMA-7. Three point bending scan were performed using a static-to-dynamic stress ratio of 110% at 1 Hz frequency and a heating rate of 5 °C/min. Samples were maintained in a conditioned room, 50% relative hiunidity and 23 °C, for 10 days before testing. 

The Perkin Elmer DMA system is shown schematically in Figure 17.78 and applies the load in 3-point bending to high modulus materials via a linear foree motor and ean determine measurements up to 1000°C. 

The major practical difficulty in running photocures in the DMA is the current lack of a commercially available photocuring accessory, comparable to the photocalorimeters on the market. One normally has to adapt a commercial DMA to run these experiments. The Perkin-Elmer DMA-7e has been successfully adapted... 

Perkin-Elmer DMA 8000 -190-600°C 10,0.002 10 nm 52 mm Fluid bath (-196-150°C), humidity generator, reactive gas capability, vertical and horizontal operation, additional probes compression, shear, single/dual cantilever, parallel plate, powder pocket... 

Perkin-Elmer DMA 8000 This is a low-cost, compact dynamic mechanical analyzer originally designed by Triton Technologies. It is recommended for both research and routine quality testing for various types of samples such as polymers, composites, pharmaceuticals, and foods. 

Dynamic mechanical analysis (DMA) was performed to determine the influence of the polymer constitution on tensile modulus and mechanical relaxation behavior. For this purpose, a Perkin Elmer DMA-7 was run in tensile mode at an oscillation frequency of 1 Hz with a static stress level of 5 x lO Pa and a superposed oscillatory stress of 4 x 10 Pa. With this stress controlled instrument, the strain and phase difference between stress and strain are the measured outputs. Typically, the resulting strain levels ranged from 0.05% to 0.2% when the sample dimensions were 8 mm x 2 mm x 0.1 mm. A gaseous helium purge and a heating rate of 3°C min" were employed. The temperature scale was calibrated with indium, and the force and compliance calibrations were performed according to conventional methods. 

Dynamic mechanical analysis (DMA) was carried out on a Perkin Elmer (DMA 7e) instrument in the three-point bending mode and storage modulus, loss modulus, tan delta of the samples were determined. The test was performed in the temperature sweep mode from 20 C 150°C under a helium atmosphere at a frequency of IHz and at a heating rate of 5 C/min. Two samples were tested for each formulation. 

Dynamic mechanical anlaysis (DMA) measurements were done on a Rheometrics RDS-7700 rheometer in torsional rectangular geometry mode using 60 x 12 x 3 mm samples at 0.05% strain and 1 Hz. Differential scanning calorimetry (DSC), thermomechanical analysis (TMA), and thermogravimetric analysis (TGA) were performed on a Perkin-Elmer 7000 thermal analysis system. 

For T measurements, calorimetry (DSC-990 Du-Pont), linear and volume cubic thermal expansion (TMS-2 Perkin-Elmer), thermo-stimulated discharge (TSD) technique, dynamic mechanical Young modulus and damping (DMA-981 DuPont) and dielectric (102-105 Hz) measurements have been used as experimental techniques. All methods gave very well correlated values of T 19). 

See, for example, the product literature for Perkin Elmer s Diamond TMA and PYRIS software. The TMA and the DMA can both be used for running simple mechanical tests like stress-strain curves, creep-recovery, heat set and stress relaxation. Other vendors have similar packages. 

Input to the model requires a knowledge of Young s modulus of the resin as a function of temperature. This was obtained using a DuPont DMA 980 dynamic mechanical analyzer and Is presented in Figure 1. TCE of the resin as a function of temperature was obtained on the Perkin Elmer TMS-2 and Is presented in Table I along with TCEs for the fibers as obtained from the supplier s literature. 

Thermal analysis is a technique for characterizing materials by measuring changes in physical or chemical properties resulting from controlled changes in temperature. Systems include DSC, TGA, DMA, TMA and DTA. Companies like Du Pont, Mettler and Perkin Elmer have developed systems, each of which can be used with its own modular control system switching to the thermal analysis system in use, but of course only the system selected can be controlled at any one time. 

Figure 17.79 DMA performance of polyphenylene sulphide using the Perkin Elmer DMA7 system. Source Reprinted from Perkin Elmer technical literature.

Dynamic mechanical analyzer n. An instrument that can test in an oscillating-flexural mode over a range of temperature and frequency to provide estimates of the real , i.e., in-phase, and imaginary , i.e., out-of-phase parts of the complex modulus. The real part is the elastic component, the imaginary part is the loss component. The square root of the sum of their squares is the complex modulus. With polymers, the components and the modulus are usually dependent on both temperature and frequency. ASTM D 4065 spells out the standard practice for reporting dynamic mechanical properties of plastics. An example of a DMA thermogram of different Perkin-Elmer Inc., manufactures the Diamond DMA instrument. Polymer films is shown. Sepe MP (1998) Dynamic mechanical analysis. Plastics Design Library, Norwich, New York. 

Fig. 8. Effect of frequency on transitions the dependence of the Tg in polycarbonate on frequency. Data generated on a Perkin-Elmer Diamond DMA by the author.

Frequently asked questions dynamic mechanical analysis (DMA), a beginner s guide, booklet fiom Perkin Elmer. http //www.perkinelmer.com/CMSResources/ Images/44-74546GDE IntroductionToDMA.pdf... 

Dynamic mechanical analyzers can be divided into resonant and d ined frequency instruments. The torsion pendulum just described is, for example, a resonant instrument The schematic of a defined-frequency instrument is shown at the bottom of Fig. 6.18. The basic elements are the force generator and the strain meter. Signals of both are collected by the module CPU (central processing unit) and transmitted to the computer for data evaluation. This diagram is drawn after a modern, commercial DMA produced by Seiko. For the address of this company see Ref. 18 of Chapter 5. Several of the other thermal analysis manufacturers also produce DMA equipment (for example Du Pont, PL Thermal Sciences, Netzsch, and more recently also Perkin-Elmer). 

The dynamic mechanical behaviour of the protein films was measured with a Perkin-Elmer Pyris Diamond DMA (sinusoidal oscillation of rectangular specimens in tension). The sheet samples were cut into rectangular bars (20 mm by 8 mm) with the longitudinal direction of the bar being parallel to the flow direction from the extruded sheet. The samples were thinly coated in silicone oil to minimise the evaporation of the plasticisers. The protein samples were scanned from —100 to 130 C at 2 C/min. The glass transition temperature was determined by the maximum in tan at 1 Hz in the dynamic mechanical... 

Dynamic mechanical relaxation was measured with a Perkin Elmer model 7e DMA working in the bending mode with an oscillatory strain. The complex modulus, E = E + iE , of each sample was determined over a temperature range from 173 to 423 K at a constant frequency of 1 Hz. Dielectric measurements in the temperature range from -223 to 403 K at a constant fi equency of 100 Hz were performed using a DEA 2970 high-performance dielectric spectrometer of TA Instruments. Temperature sweeps were performed at constant frequency with thermal stability better than 0.2 K. Measurements were performed under nitrogen atmosphere to avoid water absorption. 

The dynamic mechanical properties of UDPNCs and FGPNCs were measured under a multiwave dynamic bending mode at the frequencies of 100 and 10 Hz on Pyris Diamond DMA, Perkin Elmer Instruments, U.S.A. The dimensions of the specimens were about 35 x 15 x 3 mm. 

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