Extrusion & Post
9 Aufrufe
PEOX heat-sensitive degradation causes unstable extrusion
Problembeschreibung
When polyethylene oxide PEOX is extruded at 60-100°C, the material viscosity continuously decreases, melt strength is lost, bubbles appear in the product and the color changes from white to yellow-brown, making it impossible to obtain continuous products.
Ursachenanalyse
PEOX is extremely sensitive to heat, and thermal-oxidative degradation with main chain scission begins above 60°C; insufficient temperature control accuracy of the processing equipment with actual temperature 5-10°C higher accelerates degradation; sufficient antioxidant and thermal stabilization protection is not added; water contained in the material accelerates hydrolytic degradation.
Lösung
Use precision temperature control equipment (±1°C) to strictly control within the PEOX recommended processing temperature window; add composite antioxidant BHT+phosphite 0.5-1% to delay degradation; fully dry the material to water content <0.1% before use; use a low-shear screw to reduce shear heat generation; use nitrogen to protect the processing environment.
Wichtigste Erkenntnis
The core of PEOX processing is precise temperature control and sufficient anti-oxidation protection; any overheating will cause irreversible degradation.
War das hilfreich?
0 Personen fanden dies hilfreich
Vielen Dank für Ihr Feedback!