Nitroxides bearing an α‐hydrogen decompose upon heating in a bimolecular reaction. A new mechanism is proposed for the decomposition of t‐butylisopropylphenyl nitroxide (TIPNO) involving the formation of a head‐to‐tail dimer, single electron transfer to form an oxammonium salt, epimerization to the corresponding nitrone, and elimination to form a conjugated oxime. This mechanism may provide insights into designing new nitroxides for use in controlled polymerization. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 697–717, 2006

Polyvinyl Chloride (PVC) is among the most abundant plastics worldwide. Phthalates and other plasticizers—small molecules added to PVC to impart flexibility—have raised numerous health concerns due to their tendency to migrate out of PVC, where they can be ingested or contaminate the environment. Internal plasticization, in which a plasticizer is covalently bound to the PVC backbone, offers a solution to the problem of plasticizer migration. This comprehensive review covers the preparation of internally plasticized PVC in the literature. Strategies fall into three main categories: nucleophilic substitution of chlorine atoms on PVC; graft polymerization using plasticizing monomers, usually from defect sites in the PVC backbone; and copolymerization of vinyl chloride with monomers bearing plasticizing species. Minimizing cost and number of synthetic steps are important considerations when designing plasticizers for this large-scale commodity plastic.

Branched and linear nonmigratory internal plasticizers attached to PVC by a pendant triazole linkage were synthesized and investigated. Copper‐free azide‐alkyne thermal cycloaddition was employed to covalently bind triazole‐based phthalate mimics to PVC. To systematically investigate the effect of plasticizer structure on glass transition temperature, several architectural motifs were explored. Free volume theory was considered when designing many of these internal plasticizers: hexyl‐tethers were utilized to generate additional space between the triazole‐phthalate mimic and the polymer backbone. Miscibility of these triazole‐plasticizers in PVC is important: variation of the ester moieties on the triazole possessing alkyl and/or poly(ethylene oxide) chains produced a wide range of glass transition temperatures (T_g): from anti‐plasticizing 96 °C, to highly efficient plasticized materials exhibiting T_g values as low as −42 °C. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 2397–2411