Editing Polymer (section)

====Crystallization and melting====
[[File:Thermal transitions in amorphous and semicrystalline polymers.tif|thumb|300x300px|Thermal transitions in '''(A)''' amorphous and '''(B)''' semicrystalline polymers, represented as traces from [[differential scanning calorimetry]]. As the temperature increases, both amorphous and semicrystalline polymers go through the [[glass transition]] (''T''<sub>g</sub>). Amorphous polymers '''(A)''' do not exhibit other phase transitions, though semicrystalline polymers '''(B)''' undergo crystallization and melting (at temperatures ''T''<sub>c</sub> and ''T''<sub>m</sub>, respectively).]]
Depending on their chemical structures, polymers may be either semi-crystalline or amorphous. Semi-crystalline polymers can undergo [[crystallization of polymers|crystallization and melting transitions]], whereas amorphous polymers do not. In polymers, crystallization and melting do not suggest solid-liquid phase transitions, as in the case of water or other molecular fluids. Instead, crystallization and melting refer to the phase transitions between two solid states (''i.e.'', semi-crystalline and amorphous). Crystallization occurs above the glass-transition temperature (''T''<sub>g</sub>) and below the melting temperature (''T''<sub>m</sub>).