Comparison
PET Fiber Grade vs PA66
A side-by-side comparison of Polyethylene Terephthalate for Fiber Applications and Polyamide 6,6 (Nylon).
Physical
Density
1.30-1.39 g/cm³
1.14 g/cm³
Water Absorption (24h)
0.1-0.5 %
1.2 %
Transparency
Can be opaque or clear (before spinning)
Opaque
Shrinkage
0.5-1.5 %
1.5 – 2.0 %
Mechanical
Young's Modulus
2.5-4.0 GPa
3.0 GPa (dry)
Tensile Strength
50-70 MPa
80 MPa
Elongation at Break
10-50 %
60 %
Impact Strength (Izod)
30-60 J/m
50 J/m
Flexural Strength
—
110 MPa
Thermal
Glass Transition Temperature
65-85 °C
70 °C
Melting Point
250-260 °C
255 – 265 °C
Continuous Service Temperature
Up to 150 °C (intermittent)
100 – 120 °C
Heat Deflection Temperature
60-70 °C
75 °C (unfilled)
Electrical
Dielectric Constant
3.0-3.2
4.0
Volume Resistivity
10¹²-10¹⁴ Ω⋅cm
10¹² Ω·cm
Dielectric Strength
15-25 kV/mm
—
Chemical resistance
Acids
Good resistance to dilute acids
Poor
Bases
Poor resistance to strong bases
Good
Solvents
Insoluble in most solvents, but can be attacked by strong acids, bases, and chlorinated hydrocarbons
—
UV Resistance
Fair (requires stabilization)
Fair
Alcohols
—
Good
Oils & Fuels
—
Excellent
Sustainability
Recyclability
Highly recyclable
Recyclable
Recycling Code
1 (PET)
7
Carbon Footprint
Moderate
~7.4 kg CO₂e / kg
Bio-based Content
—
0 – 100 % (bio grades)