Photodegradation and stabilization of styrene-butadiene-styrene rubber

Abstract

Photooxidative degradation and stabilization of a polystyrene-block-polybutadiene-block-polystyrene thermoplastic elastomer using a polychromatic UV light in air at 60°C has been studied by monitoring the appearance of the hydroxyl and carbonyl groups in Fourier transform infrared spectroscopy. The extent of photooxidative degradation in different samples has been compared. The rate of photooxidation was also estimated in the presence of different concentrations of 2,6-di-tert-butyl-4-methylphenol [BHT], 2-(2Ј-hydroxy-5Ј-methylphenyl)benzotriazole [Tinuvin P] and tris(nonylphenyl) phosphite [Irgafos TNPP], and 1,2,2,6,6-pentamethyl piperidinyl-4-acrylate was grafted onto the surface of the SBS film. The kinetic evolution of the oxidative reaction was determined. The morphological changes upon irradiation in the solution cast SBS films were studied by scanning electron microscopy. Based on the experimental data a suitable photooxidative degradation mechanism also has been proposed.

Correlation between artificial and natural weathering tests on polystyrene‐block‐polybutadiene‐block‐polystyrene block copolymer

“…The surface of the samples turned to yellowish in the initial stage of the weathering tests. With the aging process proceeding, the surface of the sample turned to be more yellow, which was caused by the degradation of the SBS copolymer 12…”

Improvement of the photo-stability of polystyrene-block-polybutadiene-block-polystyrene through carbon nanotubes

“…In styrene-butadiene copolymer, styrene units seems to not play a significant role in photo-oxidation; in fact, there is no change of phenyl ring during irradiation and no "yellowing" was observed. Differently, Allen et al [29,30] found that, in SEBS copolymer, both styrenic and olefinic phases undergo degradation; photo-oxidation of the polystyrene phase leads to the formation of acetophenone chromophores due to end-chain oxidation and scission. Degradation in the styrene phase also yielded the formation of stilbene-type, which can contribute significantly to the strong yellowing observed in the irradiated SEBS.…”

“…It is generally admitted that the photo-degradation of SB occurs by two simultaneous events: formation of oxidized species, mainly in the polystyrene units, and crosslinking process taking place in the polybutadiene phase. It was reported that the use of a suitable stabilization system, such as piperidinyl-based stabilizer, can prevent the crosslinking process and can, therefore, protect successfully the SB copolymer against photo-degradative phenomena [30]. In this work, the photo-oxidative behavior of polystyrene-blockpolybutadiene-block-polystyrene (SBS) based nanocomposites, particularly SBS/CNTs and SBS/CNTs-COOH nanocomposites was investigated and compared to that of pristine SBS copolymer, in order to probe the effectiveness of CNTs in the protection against UVB induced degradation.…”

Intercalation of p-methycinnamic acid anion into Zn-Al layered double hydroxide to improve UV aging resistance of asphalt

“…This may be due to the formation of hydrogen peroxide, alcohol, hydroxyl, acidic, carboxyl and ketonic functional groups during the UV aging process, which increased the polarity of the fragments of the SBS molecular chain. 24 UV aging causes chemical reactions to occur and changes the molecular structure of asphalt. For example, the degradation caused by oxidation reactions between methylene and unsaturated chains leads to the formation of ketones and carboxylic acids.…”