UV-Irradiation Effect on the Photodegradation of Plasticized Poly (Ortho, Meta, and Para-Fluorostyrene) Isomers in Solid Films

Abstract

The photostability of thin films of poly (Fluorostyrene) isomers was studied by irradiation with UV-light, in presence of air at room temperature. The irradiated polymer films were exposed to different intervals of time and the degradation process was investigated with absorption, fluorescence and FT-IR spectroscopic methods. The influence of phthalate and terephthalate plasticizers on photo-oxidative degradation was also investigated. Blending with these plasticizers was found to decrease the stability of the irradiated polymers. The same observation was noticed in the photodegradation of other substituted polystyrenes films. The intensity of absorption was also found to increase with time of irradiation and in the intensity of a new absorption band at longer wavelength. In addition the formation on new fluorescence band at longer wavelength for the irradiated film is an evidence of photodegradation of the irradiated polymer films. The FT-IR spectra of irradiated polymers and for blended polymer films with phthalates and terephthalate, showed an increase in the absorption bands of these isomers indicating the possibility of degradation. The mechanism of photodegradation of these isomers was found to be similar to that of polystyrene. The order of photostability of these isomers was found that poly (p-fluorostyrene) is the most stable isomer and, poly (o-fluorostyrene) is the lowest stable isomer towards irradiation effect.

Irradiation Effect on Photodegradation of Pure and Plasticized Poly (4-Methylstyrene) in Solid Films

“…It was also found that the photo-stability of SPS was reduced by blending with phthalates and terephthalates plasticizers [31]. Phthalate plasticizers were more efficient in the increase in the photodegradation of irradiated polymeric chromophores in solid films [11] [12].…”

“…On the other hand, polymeric additives were found to accelerate the radiation-induced degradation of polystyrene and substituted polystyrene films [6]- [12]. It was reported that the photo-stability of PS was reduced by the addition of bromine containing flame retardant, and appeared to depend upon the chemical structure of the polymeric additives [29].…”

“…Several studies have also been carried out for photodegradation of substituted polystyrene and were found to be of interest for both the theoretical aspects of photo stability and the preparation of new polymers [7]- [12]. During irradiation of polymeric chains in presence of air, excited chromophores are formed followed by other processes, such as chain scission, photooxidation and cross-linking take place [13]- [19].…”

Fourier‐transform infrared spectroscopic study of plasticization effects on the photodegradation of poly(fluorostyrene) isomers films

“…As can be seen from Fig. 6 and Tables 1, 2, and 3, modifications were also noticed in various absorption bands in the FTIR spectra in the region (2,000-1,000 cm 21 ) of blended p-PFS with 0.0%, 1.0%, 3.0%, and 5.0% DBP, upon irradiation for 3.0 h. It showed an increase in the intensity of the absorption band at (1,721 cm 21 ) with an increase of irradiation time [38], and with the increase in amount of added plasticizer. This may increase in the formation of carbonyl compounds that resulted from the photo-oxidation of polymeric chains in the presence of atmospheric oxygen.…”

“…In an earlier study, it was reported that the FTIR spectra of irradiated PFS isomers showed an increase in the absorbance in many bands associated with a clear shift of energy at (1,582-1,449 cm 21 ) for o-PFS, at (1,588-1,449 cm 21 ) for m-PFS, and at (1,506 cm 21 ) for p-PFS [38]. The shifts in these ranges were attributed either to C5O stretching vibration of aromatic ketones or to the stretching vibration of the substituted benzene ring [8].…”