Photostabilization of Polymers

Photogeneration of carbon dioxide from polypropylene film stabilized by hindered amines

“…3 and listed in Table 1 show clearly that the quasi-linear rate of CO 2 photogeneration during UV exposure of PP in humidified oxygen was reduced by 25-50% by the addition of any one of the three HALS, and that this reduction varied with the HALS type. These observations mirror the well-known benefits associated with the use of HALS to stabilize propylene polymers [13,14,16,21,22]. The reduction of 25-50% in the rate of CO 2 photogeneration is of the same order as the reduction in the rate of O 2 uptake, w50%, or CO 2 generation, w33%, observed over a period of 1000 h by Gijsman and Dozeman [13] following the addition of 0.076% HALS to PP.…”

Photogeneration of carbon dioxide from polypropylene film stabilized by hindered amines

“…3 and listed in Table 1 show clearly that the quasi-linear rate of CO 2 photogeneration during UV exposure of PP in humidified oxygen was reduced by 25-50% by the addition of any one of the three HALS, and that this reduction varied with the HALS type. These observations mirror the well-known benefits associated with the use of HALS to stabilize propylene polymers [13,14,16,21,22]. The reduction of 25-50% in the rate of CO 2 photogeneration is of the same order as the reduction in the rate of O 2 uptake, w50%, or CO 2 generation, w33%, observed over a period of 1000 h by Gijsman and Dozeman [13] following the addition of 0.076% HALS to PP.…”

Investigations on Polymeric and Monomeric Intramolecularly Hydrogen-Bridged UV Absorbers of the Benzotriazole and Triazine Class

“…(Hydroxyphenyl)triazines such as MA-TZ 1 bearing appropriate substituents, e.g., methacrylic or vinyl groups, undergo radical copolymerization without detriment to the intramolecular hydrogen bond which is essential for the photostabilizing potential of these compounds. The same has been observed with polymerizable benzotriazoles like MA-TIN 1 (this paper) and other comparable structures. − Both as monomers, and chemically bonded to a polymer backbone, these stabilizers exhibit a weak fluorescence from the proton-transferred state S 1 ‘ ( φ f ∼ 10 -4 at room temperature). The quantum yield for the proton-transferred fluorescence of the (hydroxyphenyl)triazines appears strongly affected by the electron-donating capacity of further substituents on the triazine ring (electron density or energy aspect 27 ), as well as by additional alkyl and particularly aryl moieties attached to the triazine ring.…”

Effect of Composition on the Physicochemical Properties of Cross-Linked Poly(sodium acrylate)/Sodium Silicate Hydrogels

“…It can be assumed that increasing the share of polymer additive causes the gelation point to shift to higher time values. For the samples with a 15 wt.% aqueous solution of sodium acrylate, a cross-over point was observed in each case (starting from the samples with the highest polymer content, this parameter was as follows: 80 s, 150 s, 210 s, 110 s, 315 s, and it was shifted in time compared to the corresponding samples with a 20 wt.% aqueous solution of sodium acrylate, which confirms the fact that the more diluted the solution of the starting monomer, the later polymerization occurs [32,33].…”

Photogeneration of carbon dioxide from polypropylene film stabilized by hindered amines

“…3 and listed in Table 1 show clearly that the quasi-linear rate of CO 2 photogeneration during UV exposure of PP in humidified oxygen was reduced by 25-50% by the addition of any one of the three HALS, and that this reduction varied with the HALS type. These observations mirror the well-known benefits associated with the use of HALS to stabilize propylene polymers [13,14,16,21,22]. The reduction of 25-50% in the rate of CO 2 photogeneration is of the same order as the reduction in the rate of O 2 uptake, w50%, or CO 2 generation, w33%, observed over a period of 1000 h by Gijsman and Dozeman [13] following the addition of 0.076% HALS to PP.…”

Investigations on Polymeric and Monomeric Intramolecularly Hydrogen-Bridged UV Absorbers of the Benzotriazole and Triazine Class

“…(Hydroxyphenyl)triazines such as MA-TZ 1 bearing appropriate substituents, e.g., methacrylic or vinyl groups, undergo radical copolymerization without detriment to the intramolecular hydrogen bond which is essential for the photostabilizing potential of these compounds. The same has been observed with polymerizable benzotriazoles like MA-TIN 1 (this paper) and other comparable structures. − Both as monomers, and chemically bonded to a polymer backbone, these stabilizers exhibit a weak fluorescence from the proton-transferred state S 1 ‘ ( φ f ∼ 10 -4 at room temperature). The quantum yield for the proton-transferred fluorescence of the (hydroxyphenyl)triazines appears strongly affected by the electron-donating capacity of further substituents on the triazine ring (electron density or energy aspect 27 ), as well as by additional alkyl and particularly aryl moieties attached to the triazine ring.…”

Effect of Composition on the Physicochemical Properties of Cross-Linked Poly(sodium acrylate)/Sodium Silicate Hydrogels

“…It can be assumed that increasing the share of polymer additive causes the gelation point to shift to higher time values. For the samples with a 15 wt.% aqueous solution of sodium acrylate, a cross-over point was observed in each case (starting from the samples with the highest polymer content, this parameter was as follows: 80 s, 150 s, 210 s, 110 s, 315 s, and it was shifted in time compared to the corresponding samples with a 20 wt.% aqueous solution of sodium acrylate, which confirms the fact that the more diluted the solution of the starting monomer, the later polymerization occurs [32,33].…”

Photogeneration of carbon dioxide from polypropylene film stabilized by hindered amines

“…3 and listed in Table 1 show clearly that the quasi-linear rate of CO 2 photogeneration during UV exposure of PP in humidified oxygen was reduced by 25-50% by the addition of any one of the three HALS, and that this reduction varied with the HALS type. These observations mirror the well-known benefits associated with the use of HALS to stabilize propylene polymers [13,14,16,21,22]. The reduction of 25-50% in the rate of CO 2 photogeneration is of the same order as the reduction in the rate of O 2 uptake, w50%, or CO 2 generation, w33%, observed over a period of 1000 h by Gijsman and Dozeman [13] following the addition of 0.076% HALS to PP.…”

Investigations on Polymeric and Monomeric Intramolecularly Hydrogen-Bridged UV Absorbers of the Benzotriazole and Triazine Class

“…(Hydroxyphenyl)triazines such as MA-TZ 1 bearing appropriate substituents, e.g., methacrylic or vinyl groups, undergo radical copolymerization without detriment to the intramolecular hydrogen bond which is essential for the photostabilizing potential of these compounds. The same has been observed with polymerizable benzotriazoles like MA-TIN 1 (this paper) and other comparable structures. − Both as monomers, and chemically bonded to a polymer backbone, these stabilizers exhibit a weak fluorescence from the proton-transferred state S 1 ‘ ( φ f ∼ 10 -4 at room temperature). The quantum yield for the proton-transferred fluorescence of the (hydroxyphenyl)triazines appears strongly affected by the electron-donating capacity of further substituents on the triazine ring (electron density or energy aspect 27 ), as well as by additional alkyl and particularly aryl moieties attached to the triazine ring.…”

Effect of Composition on the Physicochemical Properties of Cross-Linked Poly(sodium acrylate)/Sodium Silicate Hydrogels

“…It can be assumed that increasing the share of polymer additive causes the gelation point to shift to higher time values. For the samples with a 15 wt.% aqueous solution of sodium acrylate, a cross-over point was observed in each case (starting from the samples with the highest polymer content, this parameter was as follows: 80 s, 150 s, 210 s, 110 s, 315 s, and it was shifted in time compared to the corresponding samples with a 20 wt.% aqueous solution of sodium acrylate, which confirms the fact that the more diluted the solution of the starting monomer, the later polymerization occurs [32,33].…”