Plastics exist in huge variety, however several types of commodity polymer dominate global production: polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyethylene terephthalate (PET, PETE), polystyrene (PS), polycarbonate (PC), and poly(methyl methacrylate) (PMMA). The degradation of these materials is of primary importance as they account for most plastic waste.
These plastics are all thermoplastics and are more susceptible to degradation than equivalent thermosets, as those are more thoroughly cross-linked. The majority (PP, PE, PVC, PS and PMMA) are addition polymers with all-carbon backbones that are more resistant to most types of degradation. PET and PC are condensation polymers which contain carbonyl groups more susceptible to hydrolysis and UV-attack.