Improving thermal oxidative aging resistance and anti‐reversion property of natural rubber by adding a crosslinking agent

2021 ◽  
pp. 51882
Author(s):  
Yang Jiang ◽  
Yong Zhang
2013 ◽  
Vol 706-708 ◽  
pp. 266-269
Author(s):  
Yong Zhou Wang ◽  
Fu Quan Zhang ◽  
Mao Fang Huang ◽  
Mei Chen ◽  
Hong Xing Gui ◽  
...  

In this work, thermogravimetry (TG) and Wallace plastometer were used to study the thermal-oxidative aging resistance properties of natural rubber (NR) dried by microwave and hot-air. Showed from the results, thermal degradation temperature, primary thermal-oxidative degradation temperature, the value of P0, PRI and VR for NR dried by microwave were higher than those of NR dried by hot-air; the thermal-oxidative aging resistance properties of NR vulcanizes dried by microwave improved significantly, and the rate of change for elongation at break (-26.76%) and tensile strength (-38.6%) of NR vulcanizes dried by microwave before and after aging were apparently higher than those of NR vulcanizes dried by hot-air, which were (-60.29%) and (-82.11), respectively.


2012 ◽  
Vol 550-553 ◽  
pp. 1755-1758
Author(s):  
Guang Lu ◽  
He Ping Yu

Abstract. The natural rubber latex (NRL) concentrate was mixed with 10~50 parts per hundred rubber (phr) of methyl methacrylate-grafted-natural rubber latex having a methyl methacrylate content of 49% (MGL49), prevulcanized, and then cast to obtain prevulcanized NRL/MGL49 films. The leached films of prevulcanized NRL/MGL49 were aged in an hot-air oven for comparison of the mechanical properties before and after aging, whereas the thermal decomposition of these films in an atmosphere of air was carried out in a thermo-gravimetric analyzer, and the films were also immersed into water to obtain water absorption. Results showed that the incorporation of MGL49 improved the thermal-oxidative aging resistance of natural rubber latex film when the MGL49 content was less than 50 phr, the water absorption increased with the increment of MGL49 content, and the NRL/MGL49 film containing 10phr of MGL 49 has a best thermal-oxidative stability and highest water absorption also.


2017 ◽  
Vol 46 (6) ◽  
pp. 251-257
Author(s):  
Hongqiang Li ◽  
Yong Zhong ◽  
Lin Zhang ◽  
Wenjian Wu ◽  
Xuejun Lai ◽  
...  

2017 ◽  
Vol 31 (3) ◽  
pp. 376-391 ◽  
Author(s):  
Aman I Khalaf ◽  
Azza A Ward ◽  
Nehad N Rozik

The main aim is to investigate the effect of adding of 5% hydrolyzed poly (ethylene-co-vinyl acetate) (EVAOH), itaconic anhydride (naturally obtained during fermentation of sugars (It.anhydride)), and mercapto-modified ethylene-co-vinyl acetate (EVASH) as compatibilizers on the mechanical properties before and after thermal oxidative aging at 90°C for different time periods up to 7 days, electrical properties, and morphology of ethylene propylene diene monomer/ethylene vinyl acetate (EPDM/EVA) blends of different compositions (75/25, 60/40, 50/50, and 25/75, respectively). Stress at yield, tensile strength, and elongation at break of EPDM/EVA were improved markedly by the addition of 5% compatibilizers (EVAOH, It.anhydride, and EVASH). The micrographs of fractured surfaces obtained from the scanning electron microscope demonstrated further the enhancement of compatibility between EPDM and EVA by the addition of reactive compatibilizers. Further, the blends permittivity ε′ and dielectric loss ε″ have been measured at specific temperatures. The dielectric properties revealed that It.anhydride and EVASH/EPDM/EVA compositions are promising materials for insulation purposes. Finally, aging resistance was improved by the use of compatibilizers.


2017 ◽  
Vol 50 (4) ◽  
pp. 372-387
Author(s):  
Wenjian Wu ◽  
Hongqiang Li ◽  
Shuyan Yang ◽  
Xuejun Lai ◽  
Hongbo Fan ◽  
...  

Macromolecular antioxidant due to its low physical loss, high thermal stability, and good compatibility has been considered to be a promising candidate to inhibit polymer aging. In this study, thermo-oxidative aging resistance and antioxidative mechanism of a macromolecular hindered phenol antioxidant, namely, polyhydroxylated polybutadiene containing thioether binding 2, 2′-thiobis (4-methyl-6-tert-butylphenol) (PHPBT-b-TPH) for natural rubber (NR) vulcanizate was studied in detail by oxidation induction time and accelerated thermal aging tests. The results showed that the antioxidative efficiency of PHPBT-b-TPH was very high. When the amount of PHPBT-b-TPH was only 1 phr, the NR vulcanizate could exhibit excellent thermo-oxidative aging resistance, obviously higher than that of NR vulcanizate with low-molecular-weight antioxidant TPH. After aged at 100°C for 168 h, the retentions of tensile strength and elongation at break of NR vulcanizate with PHPBT-b-TPH were 43.6% and 58.6%, respectively. However, those of NR vulcanizate with TPH were 35.6% and 54.5%. In addition, it was found that both thioether and urethane groups in PHPBT-b-TPH had antioxidative ability and had synergistic effect with hindered phenol. Through our findings, new strategy to design and synthesize the macromolecular antioxidant with multi-antioxidative groups for rubber materials and other polymer materials could be developed.


2014 ◽  
Vol 599 ◽  
pp. 203-207
Author(s):  
Song Xu ◽  
Wei Dan ◽  
Wen Zu Li ◽  
Jian Ying Yu

Layered double hydroxides (LDHs)/SBS modified bitumens used for waterproofing membrane were prepared by melt blending using various contents of SBS and LDHs. Effects of the LDHs on physical properties and thermal oxidative aging performance of modified bitumen were investigated. The results show that softening point and low temperature flexibility of LDHs/SBS modified bitumen are increased simultaneously with the rise of SBS content, while they are little affected by the change of LDHs content. The thermal oxidative aging resistance of SBS modified bitumen is gradually improved with increasing LDHs content. In addition, the aging rate of SBS modified bitumen with LDHs are evidently lower than that without LDHs over time, which indicates that LDHs improve the ability of SBS modified bitumen to resist the thermal oxidative aging effectively.


2021 ◽  
Vol 22 (19) ◽  
pp. 10894
Author(s):  
Anna Masek ◽  
Olga Olejnik

This research focuses on revealing the double role of quercetin accompanied by silica in epoxidized natural rubber. A crosslinking ability with antioxidative properties exists and reveals the dependence of these functions on quercetin content. Here, the aging resistance of self-healable biocomposites was analyzed. The self-healing properties were presented in our previous work. The stabilizing effect of quercetin applied as a crosslinking agent has been studied in epoxidized natural rubber with a 50 mol% of epoxidation (ENR-50). Some of five -OH moiety groups existing in the quercetin structure are able to react with epoxy rings of ENR-50 and cure this elastomer, whereas other free hydroxyl groups can donate the hydrogen molecule to a radical molecule, stabilizing it. The aging resistance of prepared composites was estimated by mechanical tests conducted before and after different types of aging, as well as by differences in color and surface energy between aged and un-aged samples. Changes within the oxygen function, which occurred as a result of the aging process, were observed using FT-IR absorbance spectroscopy. Furthermore, the impact of quercetin content on composites’ thermal stability was investigated by thermogravimetry (TGA). According to the results, a proper dose of quercetin can act as a crosslinker and antioxidant in ENR-50 at the same time.


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