Hottest tire rubber dynamic mechanical analyzer

2022-10-01
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Tire rubber dynamic mechanical analyzer

dynamic mechanical analysis (DMA) is a powerful tool in characterizing and studying rubber products (such as tires, gaskets, wiper blades, etc.). Using dma8000 correctly can better understand the material behavior in a wide temperature range and a wide frequency range. This paper describes how to use dynamic mechanical analysis technology to characterize the export of more than 100 million tons of tire rubber

characterizing automobile tire rubber shows a common problem. Samples taken from different parts of the same single automobile tire show different glass transition temperatures, and the glass transition temperature depends on the part of the tire from which the material is taken. The modulus and damping properties of rubber will change dramatically from solid state to rubber state. Different parts of the tire correspond to different properties, which shows that the materials used in each part of the tire are different. It also shows that some places use mixtures of materials. In addition, the frequency scanning test of dynamic mechanical analyzer can produce the master curve of the sample

dynamic mechanical analyzer is an instrument most suitable for characterizing the relaxation behavior of five components such as microcomputer control system. When the sample to be tested is in the rubber state at room temperature, it is a challenge for the tester to clamp the sample and the hardness of the material tested by the instrument from the glass state to the rubber state. Rubber samples are usually tested in shear or bending mode. Here we will show the test results of the sample in single cantilever mode

the working principle of the dynamic mechanical analyzer is to apply a vibrating force to the sample, and then test the resulting displacement of the sample. In this way, the hardness can be defined and the loss factor tan delta can be calculated. Tan delta is the ratio of the loss part to the storage part. By measuring the phase lag of the displacement relative to the applied force, the damping performance of the material can be determined. Tan delta plots the temperature. Because the sample will absorb energy when passing through the glass transition region, the observed peak is the glass transition temperature

most automobile tires are mainly composed of polybutadiene, but different parts of the whole tire may be composed of different fractions and mixtures. PE's dynamic mechanical analyzer can be used to display the areas where different grades are located and the obvious overlapping parts of materials. The sample is obtained from the cross section of a single tire. Then cut into different samples from the tread, the bottom of the tread and the tread near the sidewall. Figure 1 shows the test results of dynamic mechanical analyzer 8000. Because the glass transition temperature of rubber is lower than 0 ℃, we need to start from low temperature. The dynamic mechanical analyzer 8000 can reach a low temperature of -190 ℃ by using a common furnace, and -150 ℃ is enough for these materials. It can be seen from here that the two sides near the tread are composed of two different rubbers, one of which is very different from other rubbers. The material of the tread and the bottom of the tread is a single component, and slightly different glass transition temperatures can be seen. In order to confirm whether these events really represent the glass transition, we need to carry out scanning tests at different frequencies, and calculate the activation energy based on the relatively stable material properties

we can also do a wide range of frequency scanning to generate the master curve. The master curve is usually used to predict the material properties in special cases. It can be used in 300 ℃ pressurized hot water or steam. In these cases, the material is generally not easy to measure. This idea comes from the WLF equation, which puts forward a theory that the behavior of rubber at low temperature is similar to that at long time. If we use a dynamic mechanical analyzer to scan the frequency of one of the rubber samples, we can get the modulus or tan delta change with frequency and temperature. Figure 2 shows two representations of these data

from the data in Figure 2, we can use one of the curves as a reference. In this case, we choose the temperature point closest to the glass transition temperature, and the other curves translate around it. This produces the master curve, as shown in Figure 3. The frequency range of dynamic mechanical analyzer 8000 is 0.001 to 300 Hz, while the frequency range covered by the master curve is 1e-12 to 1e16 Hz. It spans 28 orders of magnitude, far wider than the range we can test. This technique is based on some assumptions, and wicket curve can be used to quickly check these results, as shown in Figure 3. If these curves are not arc-shaped or wicket shaped, the data does not conform to the assumption of superposition. This is applicable to most rubbers, in which case we can generally get a reasonable fit

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