The melting of amorphous polymers is not like traditional liquids such as water. There is no specific temperature here the material tuns from solid form to liquid form since there is always some amount of polymer chain entanglement and inter-molecular attraction present to provide strength.

Question: What is different between melting amorphous and semi-crystalline polymers during recovery.

note: I will address this in two blog posts.

Amorphous Polymers: All polymers have polymer chain entanglement and some amount of inter-molecular attraction. When heated, the polymer chain mobility increases and the inter-molecular attraction will decrease, causing the polymer to ‘soften’. In amorphous polymers, a constant shearing and heating of the polymer chains works best to prepare the polymer for processing. Screws designed for melting amorphous polymers tend to have a short feed zone with long gradual transition zone to provide consistent shear to help melt the polymer.

-Andy