Effect of water spray on degradation of styrene-butadiene-rubber during accelerated weathering tests

Kano, Makiko; Ohtake, Yoshito; Yamanobe, Takeshi; Uehara, Hiroki

doi:10.1016/j.polymdegradstab.2020.109379

Cited by 3 publications

(3 citation statements)

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“…43 A direct result of weathering in both materials is the occurrence of a carbonyl band at about 1713 cm -1 (see * in Figure 5) after 168 h of weathering and is prominently present in the skin at 504 h, but disappears in the core. 44 In NR, the asymmetric =C−H stretching band at 3035 cm -1 (i) decreases from 0 h to 504 h, 45 while the skin shows its complete loss at 504 h. Likewise, the asymmetric −CH3 stretching (2959 cm -1 , ii) and asymmetric −CH2− stretching (2918 cm -1 , iii) bands also reduce with weathering.…”

Section: Chemical Modifications Due To Weathering As Studied By Ftir ...mentioning

confidence: 99%

“…This is in line with the gas chromatography that the relative amount of butadiene with respect to the pristine sample completely disappeared after 100 h of accelerated weathering. 44 From these observations, it can be appreciated that the reactions caused by weathering, mainly involving oxygen, lead to chemical modifications that affect the surface preferentially.…”

Section: Chemical Modifications Due To Weathering As Studied By Ftir ...mentioning

confidence: 99%

“…For up to 100 h of weathering of SBR Kano et al observed a 0.5 % volume change due to temperature increase during photo irradiation and temperature decrease during water sprays. 44 This periodic thermal treatment leads to differential expansion and contraction of the skin and the core. In the present study, the long-term weathering of SBR for 504 h and 988 h caused a visual caving-in of the specimen towards the irradiated surface due to contraction and stretching of the rear surface due to expansion.…”

Section: Indentation Depth [Nm]mentioning

confidence: 99%

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Effects of artificial weathering in NR/SBR elastomer blends

Karekar

Schicktanz

Tariq

et al. 2022

Preprint

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Degradation of polymer blends occurs by the constituent phases undergoing distinct chemical changes that depend on their unique chemical structures. This makes predicting and establishing a structure-property relationship for each phase necessary as well as challenging. In this work, the molecular and physical changes occurring in sulfur-cross-linked natural rubber (NR), styrene-butadiene rubber (SBR), and their 50/50 blend subjected to accelerated weathering are analyzed by 1H nuclear magnetic resonance (NMR) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, atomic-force microscopy (AFM), and dynamic mechanical thermal analysis (DMTA). NMR transverse relaxation time (T2) studies suggest the formation of rigid components due to weathering. FTIR and AFM reveal that this is related to the formation of a stiff surface due to chemical modifications, which shows up as an additional thermal transition in the DMTA curves. Low-field double-quantum (DQ) NMR studies of the cross-link density, by the residual dipolar coupling constant (Dres), of SBR show a continuous increase in its cross-link density over the weathering duration (988 h). In contrast, NR exhibits dominant chain scission reactions resulting in defects, with both materials demonstrating the formation of different chain lengths. During the first 168 h, NR also undergoes modification of sulfur bond lengths, which is also observed in the blend. The blend largely follows an intermediate trend of cross-link densities compared to the two polymers but shows signs of lesser chain modifications than a weighted average of the two polymers. This is confirmed by phase-resolved DQ magic-angle spinning (MAS) NMR experiments whereby the peak-specific Dres of the blend was measured to be lesser than that of the individual vulcanizates, thus proving that the blend is more resistant to weathering than its constituent elastomers.

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Section: Chemical Modifications Due To Weathering As Studied By Ftir ...mentioning

confidence: 99%

Section: Chemical Modifications Due To Weathering As Studied By Ftir ...mentioning

confidence: 99%

Section: Indentation Depth [Nm]mentioning

confidence: 99%

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