Photodegradation of poly(vinylacetophenone). II. Short‐wave photolysis

Abstract

SynopsisThe photodegradation of films (2 x cm thick) of poly(viny1-acetophenone) [poly(4acetylstyrene)] exposed to 254 nm radiation under high vacuum at 25 & 1°C was studied. The principal gaseous product was H,, but CH,, C,H,, and smaller amounts of acetaldehyde and CO were also formed. The photochemistry more closely resembles that of other substituted styrene polymers than that occurring on the long wave ( A > 300 nm) irradiation of the polymer in that the principal initial processes involve fissions of bonds in the /?-position to the phenyl chromophores. Studies of a deuterated analogue (D3 acetyl) indicate that H-abstractions occur from the polymer and also that fission of C-H bonds in the acetyl group does not occur. The polymer undergoes rapid cross linking. Mechanisms of the various primary and secondary processes are discussed.

Synthesis, characterization, and biological activity of N‐(4‐acetylphenyl)maleimide and its oxime, carbazone, thiosemicarbazone derivatives and their polymers

“…All the experimental data indicate that photodegradation in the carbonyl region occurred and crosslinking followed. Some polymers with ketone side chains display photodegradation 47, 48. In addition, dichloromethane solutions of polymers were cast separately onto salt plates and dried.…”

Synthesis and characterization of two new aryl cyclobutyl ketoethyl methacrylate monomers and their polymers

“…All the experimental data indicate that photodegradation in the ketone carbonyl region occurred and crosslinking followed. It is known that some polymers with keto side chains show photodegradation 20–22. There is no evidence of scission of the cyclobutane ring due to ultraviolet irradiation at 254 nm.…”

Testing Methods of Weathered Specimen

“…IR spectrophotometry 48,83,101,102,[106][107][108][112][113][114][115] is the predominant method for analyzing the changes in weathered specimens. IR has been used to study acrylonitrile-butadiene-styrene copolymer, ABS, low density polyethylene, LDPE, high density polyethylene, HDPE, polypropylene, PP, acrylic/urethane, polyurethane, PU, polystyrene, PS, polycarbonate, PC, polyisobutylene, PIB, polyesters, polyamide, PA, acrylic resins, epoxy resins, EP copolymer, polyoxymethylene, POM, polyvinylchloride, PVC, cotton, coatings of 145-54, 2011.…”

“…However, when molecular weight 30,86,97,101,103,105,106,110,119,127,134,164,165,175,181,186,192,202,205,213,255,272,273,287,399,410, is used as an indicator of degradation, the interpretation of results is complicated by the fact that crosslinking and chain scission occur simultaneously. However, when molecular weight 30,86,97,101,103,105,106,110,119,127,134,164,165,175,181,186,192,202,205,213,255,272,273,…”

“…The Mark-Houwink constants of standards are used to calibrate a method for each polymer used. 101 This determination might be combined with the monitoring of low molecular weight substances by mass spectroscopy. In some cases, an internal marker is added to the solvent to monitor the rate of solvent flow which should be constant for the results to be valid.…”