MELTING POINT OF POLYMER

1. Melting point

3. • Higher temperatures destroy the molecular
arrangement .
• Small crystals melt fast
• Sharp melting for uniform crystal size

4. General polyester structure:
[-O-R-O-CO- -CO-] n
Melting of Polyesters:
R Tp (C)
PET (-CH2-CH2-)n 265
PPT (-CH2-CH2-CH2-)n 228
PBT (-CH2-CH2-CH2-CH2-)n 225
(-CH2-CH-) Non crystalline
CH3
Structural Irregularities and Melting point

5. Nylon Type TmC
Nylon 3 330
Nylon 4 270
Nylon 5 265
Nylon 6 230
Nylon 7 230
Nylon 8 205
Nylon 9 210
Nylon10 185
Nylon11 195
Nylon12 180
Nylon13 185
Other nylons:
Nylon 6,6 270
Nylon 6T 370
Estimate the Tm range of Nylon 6 10 & nylon6 12
Influences of chain length of nylons on melting point

6. Melting temperature (Tm)
• The (Tm) when applied to polymers suggests
not a solid-liquid phase transition, but a
transition from a crystalline phase to a solid
amorphous phase. Crystalline melting is only
discussed with thermoplastics, as thermosets
will decompose at high temperatures rather
than melt.