Polyethylene terephthalate photo-oxidation

Cruz-Pinto JJC, Carvalho MBS, Ferreira JEA (1994) The kinetics and mechanism of polyethylene photo-oxidation. Angew Makromol Chem 216 113—133 Darwin PRK, Abdefilah A, Elise D, Josefina LC, Sebastian MG (2003) Synthesis, characterization, and properties of poly(ethylene terephthalate)/poly(l, 4-butylene succinate) block copolymers. Polymer 44 1321—1330... 

Polybutylene terephthalate and polyethylene terephthalate, even without the addition of stabilizers, exhibit good weathering resistance, which can be improved by carbon black. Figure 5.89. During photo-oxidative degradation, mostly chain cleavage, but no crosslinking occur. The main photo-oxidation products are CO, COj, and carbonic acids. 

When polybutylene terephthalate and polyethylene terephthalate degrade under the influence of light, photo-induced reactions are observed such as Norrish type I and type II (see Figure 5.12) and photo-oxidative processes. Figure 5.88. The formation of m-biphenyl structures can also be detected [38]. 

Several examples have been presented, for example, the thermo-oxidative degradation of PEGs, PAs, polycarbonates (PCs), polyetherimides (PEIs), and polyethylene terephthalates (PBTs) monitored by MALDI-TOF MS. Valirable stmctural information on the photo-oxidized PEIs (ULTEM) species can be extracted from the MALDI spectra. Hie data revealed that this particular way of degradation involves several simultaneous reactions. The ultrasonic degradation of PMMA and PEG was shown to be useful for the MALDI-TOF MS... 

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