Synthesis and characterization of polyhydroxylated polybutadiene binding 2,2′‐thiobis(4‐methyl‐6‐tert‐butylphenol) with isophorone diisocyanate

Abstract

A macromolecular hindered phenol antioxidant, polyhydroxylated polybutadiene containing thioether binding 2,2′‐thiobis(4‐methyl‐6‐tert‐butylphenol) (PHPBT‐b‐TPH), was synthesized via a two‐step nucleophilic addition reaction using isophorone diisocyanate (IPDI) as linkage. First, the OH groups of PHPBT reacted with secondary NCO groups of IPDI to form the adduct PHPBT‐NCO, then the PHPBT‐b‐TPH was obtained by one phenolic OH of 2,2′‐thiobis(4‐methyl‐6‐tert‐butylphenol) (TPH) reacting with the PHPBT‐NCO. The PHPBT‐b‐TPH was characterized by Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance (1H‐NMR), 13C‐NMR, and thermogravimetric analysis, and its antioxidant activity in natural rubber was studied by an accelerated aging test. Influences of reaction conditions on the two nucleophilic reactions between OH group and NCO group were investigated. In addition, catalytic mechanism for the reaction between PHPBT‐NCO and TPH was discussed. The results showed that the adduct PHPBT‐NCO could be obtained by using dibutyltin dilaurate (DBTDL) as catalyst, and the suitable temperature and DBTDL amount were 35°C and 3 wt %, respectively. However, triethylamine (TEA) was more efficient than DBTDL to catalyze the reaction between PHPBT‐NCO and TPH because of steric hindrance effect. In addition, it was found that the thermal stability and antioxidant activity of PHPBT‐b‐TPH were higher than those of the low molecular weight antioxidant TPH. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40942.

Thermo-oxidative aging resistance and mechanism of a macromolecular hindered phenol antioxidant for natural rubber

“…In our work, a novel macromolecular hindered phenol antioxidant, polyhydroxylated polybutadiene containing thioether binding 2,2 0 -thiobis(4-methyl-6-tert-butylphenol) (PHPBT-b-TPH), as shown in Figure 1, was successfully synthesized by the combination of a thiol-ene click reaction and a two-step nucleophilic addition reaction. 24,36 We found that the PHPBT-b-TPH exhibited excellent extraction resistance in NR matrix and revealed that the reasons for the excellent extraction resistance are mainly attributed to its higher molecular weight and better compatibility with NR than that of TPH. Additionally, the co-vulcanization between PHPBT-b-TPH and NR matrix was also the important factor for the improvement of extraction resistance.…”

“…Polyhydroxylated polybutadiene containing thioether (PHPBT) 37 and PHPBT-b-TPH 36 were obtained according to our reported method, as shown in Figure 1. Hydroxyl-terminated polybutadiene (HTPB, Figure 1) and polybutadiene (PB, under the trademark Ricon 157) were supplied by Cray Valley Co., USA.…”

Extraction resistance and mechanism of a macromolecular hindered phenol antioxidant in natural rubber

“…Polyhydroxylated polybutadiene containing thioether binding 2,2′‐thiobis (4‐methyl‐6‐ tert ‐butylphenol) (PHPBT‐ b ‐TPH) was synthesized in our lab . 2,2′‐Thiobis (4‐methyl‐6‐ tert ‐butylphenol) (TPH) was supplied by Zibo Debaiyi Industral & Trading Co. Ltd., China.…”

“…In order to minimize such drawbacks, increasing the molecular weight of hindered phenols by functionalization of polymer has attracted much attention in recent years . The polymer include natural rubber, polyolefin, polybutadiene, and others . Podesva et al .…”

“…2,2′‐Thiobis (4‐methyl‐6‐ tert ‐butylphenol) (TPH) is an important sterically hindered phenol antioxidant. In our previous work, the polyhydroxylated polybutadiene containing thioether binding 2,2′‐thiobis(4‐methyl‐6‐ tert ‐butylphenol) (PHPBT‐ b ‐TPH), was synthesized by polyhydroxylated polybutadiene and 2,2′‐thiobis (4‐methyl‐6‐ tert ‐butylphenol) via a two‐step nucleophilic addition reaction using isophorone diisocyanate (IPDI) as linkage . Compared with the TPH, the PHPBT‐ b ‐TPH had superior antioxidant activity.…”