Note: All the above should be checked by analysing the evolved gases and residual solids. Above
400 °C further decomposition occurs with loss of SO 2 and SO 3 to give copper oxide.(2) (a) Since the loss to 110°C was small, it is probable that this sample contains very little moisture or
residual solvents. The silanizing would tend to make it hydrophobic.
(b) The coating is stable to about 150°C but is then lost in two stages. This could be due either to
two different silanizing coatings (see p. 97) or to the coating of two different sites on the packing.Since the total loss is 45.5 mg from 400 mg and the loss below 110°C is small, there is 11.4% by
weight of coating on the packing.(3) (a) In this example, 1 mm ≈ 2.5% by weight. The loss by 100°C is about 1.5 mm corresponding to
about 4% moisture content.
(b) The residue above 800°C is about 5 mm or 12%. This is a thermally stable filler, such as
titanium dioxide. Note that some fillers, e.g. CaCO 3 , may decompose at high temperatures. A very
small char residue is assumed.(c) The mass of the dry, filler-free polymer present corresponds to 84%. Since the degradation is in
two stages, it is unlikely to be a polyolefin, or poly(methyl methacrylate).The first loss between 100°C and 400°C is 50% of the total or about 60% of the polymer. This
suggests poly(vinyl chloride):Calculated loss 58.4%