Polyamide 6 pellets with and without glass fibers
Measuring Cell: TGA50
Pan: Alumina, 70 μl no lid
Sample preparation: Disk cut from pellet
TGA measurement: Heating from 25 to 700°C at 10 K/min
Atmosphere: Nitrogen, 50 cm3/min
Above 500 °C, the residues, R, are as follows,
PA6, base material, RPA6: 1.76%
PA6, fiber-reinforced, RGFRP: 27.40%
The glass fiber content αGF can be estimated from the difference of the two residues (indirect analysis):
αGF = [(RGFRP-RPA6)/(100-RPA6)]⋅100%. i.e. 26.1 %
Both samples exhibit two weight loss steps. The first is caused by the elimination of moisture - the samples have been kept in ambient air. The glass-fiber reinforced sample had absored less water because its polymer content was lower.
Compositional analysis by TGA can determine the moisture, polymer and glass fiber content in a PA6 sample. The inflection point in the TGA polymer pyrolysis curve can be used for identification purposes.
Determination of Glass Fiber Content | Thermal Analysis Handbook No.HB227 | Application published in METTLER TOLEDO TA Application Handbook Thermoplastics