Linear-temperature programmed pyrolysis of thermoresistant polymers - mass and FTIR spectrometries I. Experimental; aromatic polyethers and polyetherketones
التفاصيل البيبلوغرافية
العنوان:
Linear-temperature programmed pyrolysis of thermoresistant polymers - mass and FTIR spectrometries I. Experimental; aromatic polyethers and polyetherketones
During thermal decomposition, most of the thermo-resistant polymers leave a considerable fraction of the original mass behind, consisting mainly of a carbonaceous material. The gases evolved are, to the largest part, low-molecular (H2O, CO2, CO, NH3, HCN, hydrocarbons); they are formed during polycondensation processes. The rate of heating strongly influences the degradation mechanism and thus the composition of the gaseous pyrolyzate. Rapid heating i.v. to the maximum temperature chosen frequently favors the formation of heavy fragments. These can be identified by field-ionization or low-voltage mass spectrometry; they usually allow conclusions on the composition of the original polymer. Slow, temperature-controlled heating allows rearrangement and polycondensation reactions in the polymer. A study of the processes going on in the residue during temperature-controlled heating is important with regard to the behavior of thermoresistant polymers under real conditions. An elegant method of continuous residue analysis is FTIR spectrometry. A heatable IR cell designed in our institute allows the study of both gaseous pyrolyzate and solid residue in separate experiments. The time needed for the measurement of one spectrum (from 20 scans) was 36 s. This, with a heating rate of 5 K/min, corresponds to a temperature resolution of 3 K/spectrum. Results are given for aromatic polyethers and polyetherketones.