Meaning
Direct heating methods applied to solid polymer samples volatilize organic compounds for rapid gas chromatography analysis without solvent extraction. Implementing thermal desorption screening allows moulding facilities to quickly check incoming resin batches for volatile impurities, residual monomers, or moisture. This technique provides a rapid profile of the volatile compounds that could outgas during high-temperature injection moulding.
Outgassing Analysis
The process involves placing a small polymer sample directly into a heating chamber where it is heated to a temperature below its decomposition point. This heat releases the volatile compounds, which are then swept by a carrier gas directly into the analyzer. In the automotive plastics sector, thermal desorption screening is used to measure the compounds that cause windshield fogging or unpleasant cabin odors.
It replaces tedious solvent-extraction steps, reducing the analysis time from hours to minutes.
Defect Prevention
This rapid test prevents the moulding of parts with surface defects like splay marks or blistering caused by excess volatiles. It allows operators to reject damp or contaminated resin before it enters the dryer.
Process Optimization
Analyzing the outgassing profile helps engineers optimize the barrel temperature and venting settings of the injection moulding machine. By knowing the temperature where volatile release begins, they can adjust the process to avoid outgassing while maintaining material flow. This optimization reduces scrap rates and improves the cosmetic quality of the finished plastic parts.
