Tensile mechanical properties measurement

Velasco Santos et al. (27) measured both the dynamic mechanical behavior and tensile mechanical properties of MWCNT-PMMA composites. They observed 1135% increase in storage modulus at 90°C and increase in glass transition temperature by 40°C over neat PMMA with only 1 wt% functionalized nanotubes. The tensile... 

With regard to the mechanical reactirai of a polymer network to a stress applied, it is important that loose ends of macromolecules in a network structure are as shmrt as possible and/or their concentration is low. As these ends mostly extend out of the lamellas of crystallites then, while crossUnking is taking place in an amorphous phase and with the simultaneous presence of crystallites, a network with small loose ends should be formed. The crosslink junctions stabilize the natural molecular network (entanglements and crystallites), and every chain in the system is potentially elastically operative and can contribute to the stress in a tensile experiment [33]. The stabilization effect of chemical crosslinks on entanglements and crystallites may be the direct cause of observed differences in the determination of the amount of chemical crosslinks from mechanical property measurements and sol-gel analysis of the cross-linked polymer. 

The superdrawn filaments were very resistant to heat shrinkage, as seen in Figure 3.63. Mechanical property measurements on these filaments after the heat shrinkage showed a 16% loss in modulus and a 10% loss in tensile strength. The fibers began to melt at 155°C, and the peak maximum occurred at 161°C. 

Hot-Air Test Tiibe Aging. In this method (ASTM D 865), specimens are heated in air but confined within individual test tubes. This prevents cross-contamination of compounds due to transfer of volatile materials (e.g., antioxidants, curatives, plasticizers, degradation products, and so on) from one sample to another. Thus, this test is free of some of the complications that can occur when numerous compounds are aged in the same enclosure. As before, hardness and tensile mechanical properties are measured before and after aging. 

Mechanical properties measurements The dynamic relaxation behavior was investigated with DDV-II Rheovibron as a frequency of 110 Hz and a heating rate of 0.3 C/min over a temperature range of -20 to 200 C. Tensile properties were measured on a Tensilon UTM-II-20 (Toyo-Baldwin Co.) using dog-bone samples of 1.0 x 0.4 cm with thickness of 30 to 50 pm. All the samples were tested under an elongation rate of 40 % per minute at 25 C. 

All specimens for the mechanical properly measurement were preheated at 60 C for 24 hours in order to prevent reverse reaction (hydrolysis) from the moisture during the processing, and compression molded to a sheet having 1mm thickness and 5 mm width at the temperature of 30°C above its T. Tensile tests were performed using universal testing machine (UTM, Lloyd LR 50K), and dumbbell type specimens according to ASTM D-638 were used with a crosshead speed of 100 mm/min. For dynamic mechanical property measurements, dynamic mechanical thermal analyzer (DMTA, Rheometric Scientific, Mark IV) was employed and specimen with 1mm thickness and 5 mm width sheet was used. All tests were conducted at a 3°C/min heating rate and 1.1 Hz. 

Most of the research on metallic multilayer nanocomposites has focused on immiscible model alloy systems such as Cu/Nb, CuA, Al/Nb, and Zr/Nb alloys. These materials are generally not commercially available, and overall the property characterization has been relatively limited. Mechanical property measurements have largely been confined to room temperature hardness and a limited amount of compression and tensile tests... 

In the smdy of mechanical properties of particulate filled polymers, numerous models were developed to predict the effect of the particles on tensile or shear modulus. Most of these were derived from rheological models such as Einstein s, Eilers and Mooney s equations. A strong relationship exists between rheology and mechanical properties measurements and such correlations were studied by Gahleitner et al [66], as well as by Pukansky and Tudos [67]. There seems to have a direct relation between viscosity and shear modulus [59]. However, compensation has to be taken for matrix s Poisson ratio which is lower than 0.5 as shown by Nielsen and Landel [59]. Nevertheless, these equations on modulus predictions can be broadly classified under two groups. 

The latter figure shows the mechanical properties, measured at room temperature, of as-spun poly(l,4-phenylene terephthalamide) fibers plotted against the polymer concentration of the solutions from which the fibers were produced. The draw-down ratio, or spin-stretch factor (wind-up speed/ extrusion rate) was adjusted for each concentration to maintain a constant fiber diameter. Remarkably, these reported results display no discontinuity in the fiber tensile strength or stiffness at the onset of the formation of the anisotropic phase. 

Maj sztrik PW, Bocaisly AB, Benzigerv JB (2007) An instrument for environmental control of vapor pressure and temperature for tensile creep and other mechanical property measurements. Rev Sci Instrum 78(10) 103904... 

A breakthrough occurred in the mid 1960s when Du Pont introduced copoly(ethylene/meth-acrylic acid) under the tradename Surlyn these copolymers were partially neutralized with sodium and zinc cations. These modified polyethylenes possess remarkable clarity and tensile properties superior to those of conventional polyethylene. The development of Surlyn was an important factor in stimulating research in ionomers. The Surlyn systems emphasized the versatility of ionomer structures and the unique properties available from the modification of the polyethylene backbone. Many of the features which are peculiar to ionomers were recognized at this time notably, the idea that multi-ion clusters would be formed due to the low dielectric constant of the hydrocarbon matrix. It was only with more detailed X-ray diffraction studies and mechanical property measurements that the morphology of these materials was gradually revealed. 

If the film can be separated from the substrate, the mechanical properties can be measured by microtensile techniques. By opening a hole through the substrate to the bottom of the film, a bulge technique can be used to measure the tensile properties of the film. By measuring the deformation, the mechanical properties of the film can be determined. For example, films of Al-l%Si have been removed from an oxidized silicon substrate and the mechanical properties measured,... 

The highest mechanical properties measured on a corrunercial sample of CNS-V were 883 MPa (128 ksi) ultimate tensile strength, 800 MPa (116 ksi) yield strength at 0.2% offset and 29.0 HRC. The measured elongation of this sample is 7.5% and its electrical conductivity is 18 MS/m(31%IACS). 

Four modes of characterization are of interest chemical analyses, ie, quaUtative and quantitative analyses of all components mechanical characterization, ie, tensile and impact testing morphology of the mbber phase and rheology at a range of shear rates. Other properties measured are stress crack resistance, heat distortion temperatures, flammabiUty, creep, etc, depending on the particular appHcation (239). 

The most important displacive transformation is the one that happens in carbon steels. If you take a piece of 0.8% carbon steel "off the shelf" and measure its mechanical properties you will find, roughly, the values of hardness, tensile strength and ductility given in Table 8.1. But if you test a piece that has been heated to red heat and then quenched into cold water, you will find a dramatic increase in hardness (4 times or more), and a big decrease in ductility (it is practically zero) (Table 8.1). 

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