ATR/FTIR – Library match of spectrum indicates it is Polyamide (Nylon 6 or Nylon 66).

Desnity (ASTM D 792, 23 C) – 1.188 g/cc- This is higher than of Nylon 6 (1.13) and Nylon 66 (1.15). It could be either filled Nylon 6 or Nylon 66.

TGA (30-650 C, 20 C/ minute) scan shows melt transition at 260 C which is melting point of Nylon 66 The inorganic residue left is 9.2% .

Conclusion: Molded fitting is made of 10% filled Nylon 66.

Customer wanted to determine materail  competition product was made of.

Burning in air: Sample burns continuously with yellow flame, flaming drips, heavy black smoke, soot and with some frothing.   This indicates material to be acetate or Butyrate, stryrenic (PS, ABS) or an ester (PET, PETG, PBT) and not crosslinked polyolefin.

Density: The calculated and measured density is 1.23 g/cc.  This is less than density 1.31 g/cc of unfilled PET or PBT and similar to 1.27 g/cc of PETG.

DSC: (23 C to 290 C, 20 C minute heating rate, 5 C/ minute cool)

In second heating cycle, DSC scan exhibits two melt transitions, the first at 68 C and second around 123 C. Absence of melting point at 240 C indicates it not to be PET or PBT.  This DSC scan is similar to that of reference DSC of PET-G (shown below).

ATR : ATR scan matches with PET or PET-G. However, absence of clear meting peak at 240 C in DSC eliminate possibility that this is unfilled PET. It could be possibly PET-g.

Conclusion:  The tube is made of unfilled PET-G.