Thermogravimetric Analyzer for Plastics

What is the Thermogravimetric Analyzer for Plastics?

A plastics thermogravimetric analyzer records specimen mass against temperature in a controlled atmosphere, quantifying decomposition, filler, carbon black, moisture and volatile content. It is used for composition checks and thermal stability ranking of compounds.

Overview

Specimens of 5 to 20 mg are suspended from a sensitive balance inside a furnace covering ambient to at least 1000 °C, and the mass curve with its derivative is recorded. A typical plastics programme decomposes the polymer in nitrogen, then switches to air or oxygen to burn off carbon, leaving the inorganic filler or ash as residue. Moisture and residual solvents appear as low-temperature steps, and their mass fraction can be quoted if the specimen is conditioned and the programme starts below 150 °C. Balance resolution of 0.1 µg allows small volatile fractions to be resolved, while the crucible material matters, because platinum catalyses some oxidation reactions and aluminium cannot be used at high temperature.

How does it work?

Each thermal analysis technique monitors a different physical property as temperature changes. Differential scanning calorimetry records heat flow and reveals glass transition, melting, crystallisation and cure. Thermogravimetry records mass and reveals decomposition and filler content. Thermomechanical analysis records dimensional change under a defined probe and load, giving the coefficient of linear thermal expansion and softening behaviour. Dynamic mechanical analysis applies an oscillating deformation and records storage modulus, loss modulus and damping, which are the most sensitive indicators of glass transition in composites. Heat deflection and Vicat instruments apply a defined load with a standard indenter and record the temperature at which a specified deflection is reached. Thermal conductivity methods measure steady-state or transient heat flow through the specimen.

What are the key features?

• Balance resolution of 0.1 µg
• Furnace to at least 1000 °C with programmable ramps
• Nitrogen to oxygen switching during a run
• Derivative curve for step resolution
• Alumina, platinum and quartz crucibles
• Residual mass and filler content reporting

What are the technical specifications?

A typical thermogravimetric analyzer for plastics configuration offers temperature range of Ambient to 1200 °C, heating rate of 0.1–100 °C/min, balance resolution of 0.1 µg, weighing accuracy of ±0.1%, typical sample mass of 5–20 mg and atmosphere control of Nitrogen, air and oxygen with switching. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Thermogravimetric Analyzer for Plastics is used in filler and glass fibre content of compounds, carbon black content in crosslinked plastics, moisture and volatile content measurement and decomposition temperature for process limits. Across the wider Thermal Analysis class, laboratories also deploy it for glass transition and melting point determination, heat deflection and Vicat softening temperature testing and thermal expansion and coefficient of linear expansion.

Which standards and certifications apply?

Relevant standards and methods include ISO 11357-1, ISO 11358-1, ISO 11359-1, ISO 6721-1, ISO 306, ISO 75-1, ASTM D648, ASTM D1525, ASTM D4065 and IEC 61010-1. Certification candidates for this model are CE and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Calibrate the temperature and the property scale with certified standards at the start of a series, and record heating and cooling rates because thermal history changes crystallinity and transitions for every technique. Condition specimens according to the product standard, usually 23 °C and 50% relative humidity, since absorbed moisture shifts results in polyamides and other hygroscopic plastics. Use specimens with parallel faces and uniform thickness, and avoid machining damage on the measuring surfaces. Purge gas protects against oxidation in calorimetry and thermogravimetry, while heat deflection and Vicat tests need a stable silicone oil bath and correct indenter geometry. Keep calibration certificates, raw curves and instrument logs for traceability.

How do I select the right Thermogravimetric Analyzer for Plastics?

Specify this technique when composition or thermal stability must be quantified rather than inferred. Confirm the maximum temperature from the fillers present, since mineral fillers and carbon fibre may need 900 °C or more for complete burn-off, and check whether mid-run atmosphere switching is required. Crucible material and blank runs should be agreed as part of the method.

How does it compare with other Thermal Analysis variants?

Start from the property the specification names. If the requirement is a glass transition or a melting point, differential scanning calorimetry is the usual method, while thermomechanical analysis is preferred when the transition must be expressed as a dimensional change or when the coefficient of thermal expansion is also needed. For composites, filled compounds and damping behaviour, dynamic mechanical analysis gives the clearest glass transition and is the standard reference for automotive and structural applications. Decomposition temperature, filler content and thermal stability require thermogravimetry. Heat deflection and Vicat temperatures are short-term, load-dependent indicators widely used in material specifications. Thermal conductivity is measured separately by transient or steady-state methods, and the technique chosen must match the conductivity range and specimen form.