Question

I obtained an IR spectra of low denisty polyethylene (top spectra) and then i heated at 320 C for 40 min and obtained the bottom spectra. Can someone help me label those peaks? Why was there an emergence of a new peak when it was burned? There was also one peak that dissapeared. Can someone explain it to me?

here is the pic http://imgur.com/reHx5sP

Answer 1

Answer:

The signal identified as #2 belongs to a C=O possibly formed during heating of the sample by the presence of oxygen link .

The signal identified as #4 belongs to traces of C=C which are formed by heating and electronic incitement to momentarily lose a couple of hydrogen atoms, allowing for partial ethylenes .

In general, the IR spectra show new bands after heat the sample, bands define new peaks that reduce the transmittance and increased absorbance from infrared radiation .