Crystalline Plastics
Crystalline structures are generally very ordered, which is what gives them strength and rigidity. A crystalline polymer, where the molecular chains are largely locked in place against one another, is similar. Apply a load and it will break rather than bend.
Features: Have a Sharp Melting Point, Opaque, Higher Shrinkage, Good Chemical Resistance, Higher Mechanical Properties.
Amorphous Plastics
Rather than being rigid, the random molecular jumble lets the chains move across each other when the polymer is pushed or pulled. In short, amorphous polymers have flexibility and elasticity.
Features: Do not have a Sharp Melting Point, Transparent, Lower Shrinkage, Poor Chemical Resistance, Lower Mechanical Properties