Extrusion & Thermal Properties: Not Just for the Lab Guys

摘要

Solid and melt density are particularly important in screw design and extruder sizing. Some polymers have a modest change in density as they soften or melt, while others change significantly. Typically, crystalline polymers have a much larger change in densiry during processing than amorphous polymers. HDPE (crystalline) density changes 18% from 0.95 to 0.78 g/cc when melted, while HIPS (amorphous) changes only 15% from 1.04 to 0.88 g/cc when raised to the processing temperature.