Dynamic mechanical analysis applications

DYNAMIC MECHANICAL ANALYSIS APPLICATION TO DYNAMIC THEPMOMECHANOMETRY... 

A number of analytical techniques such as FTIR spectroscopy,65-66 13C NMR,67,68 solid-state 13 C NMR,69 GPC or size exclusion chromatography (SEC),67-72 HPLC,73 mass spectrometric analysis,74 differential scanning calorimetry (DSC),67 75 76 and dynamic mechanical analysis (DMA)77 78 have been utilized to characterize resole syntheses and crosslinking reactions. Packed-column supercritical fluid chromatography with a negative-ion atmospheric pressure chemical ionization mass spectrometric detector has also been used to separate and characterize resoles resins.79 This section provides some examples of how these techniques are used in practical applications. 

Mechanical properties. See also Dynamic mechanical analysis (DMA) of polyamides, 138 of polyester LCPs, 52 of polyurethanes, 242-244 of semicrystalline aromatic-aliphatic polyesters, 45 Mechanical recycling, 208 Medical applications, for polyurethanes, 207... 

The epoxy resin formed by tetraglycidyl 4,4 -diamino diphenyl methane and 4,4 -diamino diphenyl sulfone was characterized by dynamic mechanical analysis. Epoxy specimens were exposed to varying dose levels of ionizing radiation (0.5 MeV electrons) up to 10,000 Hrads to assess their endurance in long-term space applications. Ionizing radiation has a limited effect on the mechanical properties of the epoxy. The most notable difference was a decrease of approximately 40°C in Tg after an absorbed dose of 10,000 Mrads. Sorption/desorption studies revealed that plasticization by degradation products was responsible for a portion of the decrease in Tg. 

Dimethacrylate monomers were polymerized by free radical chain reactions to yield crosslinked networks which have dental applications. These networks may resemble ones formed by stepwise polymerization reactions, in having a microstructure in which crosslinked particles are embedded in a much more lightly crosslinked matrix. Consistently, polydimethacrylates were found to have very low values of Tg by reference to changes in modulus of elasticity determined by dynamic mechanical analysis. 

Lu El, Obeng Y, Richardson KA. Applicability of dynamic mechanical analysis for CMP polyurethane pad studies. Mater Charact 2002 49(2) 177. 

The recoverable deformation of the pellets was quantifled from the linear portion of the load/deformation profile obtained when measuring the strength of pellets by Aulton et al. (88). Alternatively, the elastic properties as a storage modulus" can be measured by the application of dynamic mechanical analysis (DMA) (89). The values obtained by this method for a series of pellet formulations were found to be considerably greater than those obtained by application of the former method (81). which must therefore be considered as an estimate of the real value. It did rank the pellet formulations in the same order as the DMA. 

Bashatwoldu AB. Podczeck F, Newton JM. Application of dynamic mechanical analysis (DMA) to determine the mechanical properties of pellets. Int J Pharm 2004 269 329-42. 

Many processes in pharmaceutics are related to transport, and the appHcations of the outlined theory are therefore numerous. Notwithstanding their practical importance, the special instances of the general transport equation (11) listed in Table 2 are assumed to be relatively familiar, and will therefore not be discussed further in this chapter. Instead, we focus our attention on applications of hereditary integrals and linear response theory, in particular on dynamic mechanical analysis (DMA) and impedance spectroscopy. 

Whereas there have been several applications of dynamic mechanical analysis for the characterization of the viscoelastic and mechanical properties of biomedical polymers, the characterization of pharmaceutical polymers has not received similar attention. One possible reason for this disparity has been the relative unavailability of appropriate sample geometries for pharmaceutical systems. However, the availability of newer geometries should address this problem. In spite of these difficulties, several studies have successfully employed dynamic mechanical analysis for the characterization of pharmaceutical systems and some of these are described in the following paragraph. 

The book opens with the first three chapters devoted to differential scanning calorimetry (DSC), the most commonly used thermal method. These chapters cover the principles, optimal use, and pharmaceutical applications of the method. Subsequent chapters explore modulated temperature DSC, thermogravimetric analysis, thermal microscopy, microcalorimetry, high sensitivity DSC, dynamic mechanical analysis, and thermally stimulated current, all of which have attracted great interest within the pharmaceutical field. Each chapter includes theoretical background, measurement optimization, and pharmaceutical applications. 

K. P. Menard, Dynamic Mechanical Analysis A Practical Introduction to Techniques and Applications, CRC Press, Boca Raton, FL, 1999. 

Mathematical modeling of the cure process coupled with the automation of various thermal analytical instruments and Fourier Transform Infrared Spectroscopy (FT-IR) have made possible the determination of quantitative cure and chemical reaction kinetics from a single dynamic scan of the reaction process. This paper describes the application of FT-IR, differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) in determining cure and reaction kinetics in some model organic coatings systems. 

Dynamic mechanical behaviors of CNTs are of importance in various applications, such as high frequency oscillators and sensors [56]. By adding CNTs to polymer the fundamental frequencies of CNT reinforced polymer can be improved remarkably without significant change in the mass density of material [57]. It is importance indicate that the dynamic mechanical analysis confirms strong influence of CNTs on the composite damping properties [58]. 

The glass-transition temperature, melting point, heat distortion temperature, thermal degradation temperature, ete. are important parameters affecting the application and processing of semicrystalline polymer materials. These thermal parameters can be obtained via differential scanning calorimetry, dynamic mechanical analysis, thermogravimetric analysis, etc. 

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