Meaning
Thermal analysis of polymer samples sequentially elevates the temperature to release different volatile compounds at distinct heat levels. Employing stepped temperature desorption allows laboratories to distinguish between surface water, bound moisture, and additives. The differentiation is necessary for understanding the total volatile profile of raw polymer resins before processing.
Volatile Separation
An oven heats the material in predetermined increments while a continuous gas flow transfers the desorbed gases to a detection system. Under stepped temperature desorption, each thermal plateau isolates specific components based on their boiling points or diffusion rates. The method separates low-temperature moisture from high-temperature polymer breakdown products.
Material Selection
Moulders use these desorption data to select resins that will not outgas during high-temperature moulding or end-use. For materials like nylon or polycarbonate, knowing the temperatures where moisture is released prevents surface blemishes. The analytical trace guides the setup of drying parameters for each resin grade.
Process Calibration
Establishing correct drying temperatures depends on understanding when volatiles escape. By analyzing the output of stepped temperature desorption, process engineers calibrate their dehumidifying dryers to run at the lowest effective temperature. Such calibration prevents thermal degradation of the polymer granules while ensuring complete removal of troublesome volatile compounds that cause voids or splay in the finished product.
Having these tailored drying profiles reduces the cycle time in the dryer and lowers overall factory energy costs.
