Polymer and plastic material

In injection molding there are two major classifications: Thermosets – compounds that go through a chemical reaction when exposed to heat and crosslink into the molded part. The second classification is Thermoplastics – compounds that are only melted, injected and cooled into their new shape of the molded product. Thermoplastics come in two (sometime three) sub classifications: Amorphous – those polymers with no discrete molecular geometry, Crystalline – those with fixed polymer geometry, and Semi-Crystalline – polymers possessing both crystalline and amorphous properties.