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Thermogravimetric Analysis (TGA) is an analytical technique that measures the change in a substance's mass as a function of temperature or time under a controlled program. This method detects physical phenomena (such as melting, sublimation, and adsorption) and chemical reactions (including dehydration, decomposition, oxidation, and reduction) by recording mass loss events on a Thermogravimetric (TG) curve. On this curve, mass is plotted on the vertical axis (decreasing downwards) against temperature or time on the horizontal axis. TGA instruments typically consist of a precision balance, a furnace, a temperature control system, and a data recorder. The core measurement mechanisms rely on either the deflection method, which records beam inclination directly, or the null-point method, which uses an electromagnetic coil to counterbalance mass changes, converting the required restoring current into a precise mass-loss profile.

The Rubber Carbon Black Dispersion Tester is a specialized instrument designed in accordance with standard GB-6030 and international standard ISO-11345. Its testing principle is as follows: When rubber (vulcanized rubber or masterbatch) is cut, the undispersed carbon black aggregates, which possess higher hardness relative to the surrounding rubber matrix, cause deviations in the cutting path. This results in a rough and uneven cut surface. Furthermore, the larger the undispersed carbon black aggregates, the greater the surface roughness. Light is projected onto the cut surface at a specific angle. The surface conditions are magnified, directly displayed on the screen, and recorded as digital images. These digital images are processed by a computer. Based on the size and frequency of the protruding clusters on the cut surface, the system automatically evaluates the dispersion rating (Automatic Grading Function) in accordance with relevant standards to characterize the degree of carbon black dispersion in the rubber. Alternatively, the images can be directly compared with standard images stored in the instrument or with user-defined standards (Image Comparison Function).

The accuracy of Thermogravimetric Analysis (TGA) is governed by five critical experimental parameters. First, sample preparation requires small masses (2–5 mg) and fine particle sizes to minimize temperature gradients and mass transfer resistance, while the crucible material must be chemically inert to prevent reactions with the sample or atmosphere (e.g., avoiding silica crucibles for alkaline samples). Second, the heating rate significantly impacts resolution; faster rates cause thermal lag and shift decomposition temperatures higher, potentially obscuring intermediate steps. Third, the atmosphere composition and flow rate dictate reaction kinetics, where reactive gases (like oxygen) or product gases (like CO₂) can alter decomposition temperatures and oxidation behaviors. Fourth, volatile condensation on cooler parts of the apparatus can lead to erroneous weight measurements, necessitating sufficient gas flow to sweep away evolved gases. Finally, buoyancy effects caused by gas expansion during heating create an apparent weight gain, which must be corrected via blank baseline runs. Careful optimization of these factors is essential for obtaining reliable and reproducible TGA data.

The Differential Scanning Calorimeter (DSC) is the core instrument for conducting Oxidation Induction Time (OIT) tests. This method evaluates the oxidative stability and thermal stability of materials—especially plastics and lubricants—by precisely controlling temperature and gaseous atmospheres.