Byproduct Measurement
The concentration of an ether-diol byproduct in polyester resin determines the polymer’s thermal and mechanical properties. High diethylene glycol content in polyethylene terephthalate reduces the melting point of the fibre. This compound is formed during the esterification step of polyester synthesis.
Its presence must be carefully controlled to prevent yarn inconsistencies.
Structural Degradation
Excessive amounts of this byproduct introduce ether linkages into the polyester chain, which increases polymer flexibility but decreases thermal stability. Yarn spun from polymer with elevated diethylene glycol content exhibits higher dye affinity but lower tensile strength. This makes the yarn prone to breaking during high-speed texturizing.
Fabric made from such yarn may display uneven dyeing or stripe defects, which decreases product quality.
Laboratory Evaluation
Gas chromatography of hydrolyzed polymer samples provides the exact measurement of this byproduct. The polyester must be depolymerized using methanol or potassium hydroxide before injection into the chromatograph. Accurate monitoring ensures that each batch of resin meets the specifications required for high-speed melt spinning.
This test is a standard quality check for resin suppliers.
Spinning Performance
The melting behavior of the polyester chips depends heavily on polymer purity. Consistent glycol levels prevent pressure fluctuations in the spinneret pack. This consistency reduces filament breakages during extrusion.
