Polymer Photochemistry

New Push–Pull Dyes Derived from Michler’s Ketone For Polymerization Reactions Upon Visible Lights.

“…A huge number of Type II BP derivatives have been synthesized and studied. They involved (i) compounds bearing somewhat usual substituents linked by a carbon atom (alkyl, phenyl, benzoyl, trimethylsilyl, acrylate, ...), an oxygen (alkoxy, phenoxy, ...), a sulfur (thioether...), or a nitrogen (4,4′-dimethylaminobenzophenone or Michler’s ketone MK, 4,4′-diethylaminobenzophenone EAB...), (ii) water-soluble derivatives, (iii) slightly modified skeletons, oligomeric or polymeric arrangements, and tailor-made two-photon absorbing compounds . Type I cleavable benzophenone derivatives (that can also behave as Type I PIs) have been developed; they contain, e.g., a sulfoxide, a thiobenzoate, a phenyl sulfide, a sulfonyl (BPSK), a tris(trimethylsilyl) silyloxy (BP–OSi), an alkoxylamine (BP–N(−X)–Y) or a N -phenylglycine moiety, several perester groups....…”

Photodegradation of some low‐density polyethylene–montmorillonite nanocomposites containing an oligomeric compatibilizer

“…This article is an extension to this earlier work, wherein the photo‐oxidation behavior of maleated LDPE–clay composites is investigated. A poly(ethylene‐ co ‐butylacrylate‐ co ‐maleic anhydride) (PEBAMA) compatibilizer was blended with the LDPE.…”

“…It is believed that some hydroperoxides and other photoactive species are formed in PEs by undesirable side reactions that occur during synthesis or processing of polyolefins, and that these act as the initiators for PE photo‐oxidation. The results of an enormous body of work and the methods adopted to minimize the effects of these photoactive species on the useful life times of PEs have been periodically reviewed …”

“…They assigned these components to a variety of ketones and aldehydes, carboxylic acids and esters, peracids and peresters, lactones, and unsaturated groups. Thus, the methods of initiation of oxidation of PEs in air and the photo‐oxidation products of polyolefin degradation have been well characterized, and reaction sequences have been formulated to account for byproduct formation …”