Cinnamylidene‐amine‐sensitized photodegradation of polyethylene

Abstract

synopsisThe activity of Schiffs bases of cinnamic aldehyde and aromatic amines in the controlled photodegradation of polyethylene (PE) was studied. N-cinnamylidene anilines containing different substituents in the amine ring (methyl group, halogen, or amine group) and N-cinnamylidene a-naphthyl amine were synthesized and introduced into the polyethylene films by compression molding or extrusion, and they were exposed to the filtered ultraviolet light produced by mercury lamp. The changes in molecular weight, tensile strength, and characteristic IR absorptions were followed during irradiation to control the processes undergoing in the polymer films. It was discovered that N-cinnamylidene anilines containing methyl or halogen substituents and N-cinnamylidene a-naphthyl amine accelerated the photodegradation of polyethylene. Their sensitizing activity increased when the mixtures of Schiffs bases and stannous laurate were introduced into the polymer. PE films containing these additives became brittle after 600 h exposure to the artificial UV light which was the equivalent of 1.5-2 years exposure to the natural sunlight in the medium geographic latitudes. The mechanism of the initial step of photodegradation is discussed.

Ethyl lactate as a tunable solvent for the synthesis of aryl aldimines

“…Cinnamylidene imines are useful intermediates in the preparation of b-lactam antibacterial compounds 16 and have been shown to greatly accelerate photodegradation of polyethylene, which could have favorable environmental consequences. 17 To demonstrate the versatility of this solvent tuning technique for generating aryl aldimines, a variety of aryl aldehydes and aryl amines containing both activating and deactivating substituents were examined (Table 1). We found no need for catalysts or external energy for the reactions except the example with p-nitrobenzaldehyde (a).…”

Photochemical Properties of Polyethylene Modified by Low-Molecular Organic Compounds

“…Thus, a number of studies deal with the mechanisms and kinetics of degradation as well as stabilisation of these polymers. [1][2][3][4][5][6][7][8][9][10] Recently, a new ecological problem connected with utilisation of plastic waste, appears. Most plastics based on polyolefins degrade very slowly under environmental conditions.…”