Thiophosphoryl disulfides as crosslinking agents for chloroprene rubber

Carbon black (CB)‐filled chloroprene rubber (CR) compounds and vulcanizates containing naphthenic oil (NO), soybean oil (SO), and two different levels of norbornyl modified soybean oil (MSO) were prepared and investigated. The MSO was prepared through the reaction of SO and dicyclopentadiene (DCPD) at different ratios. Various properties including gel fraction, crosslink density, bound rubber fraction, curing behavior, thermal, mechanical, and aging properties of CB‐filled CR containing different oils were compared. It was observed that the addition of SO and MSO could benefit the dispersion of the filler, lower the glass transition temperature, and increase the thermal stability of the CB‐filled CR/MSO compounds and vulcanizates, and also slightly decrease the crosslink density of the CB‐filled CR/MSO vulcanizates compared to that of the CR/NO vulcanizate. With the increase of the modification level of the MSO, the curing time of the CB‐filled CR/MSO compounds was found to be decreased, the tensile property, tear strength, abrasion resistance, and aging resistance of the CB‐filled CR/MSO vulcanizates were improved compared with those of the CB‐filled CR/NO vulcanizate. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43809.

Section: Introductionmentioning

confidence: 99%

Effect of norbornyl modified soybean oil on CB‐filled chloroprene rubber

Isayev

Xue-ping

et al. 2016

“…Metal oxide‐, thiuram‐, and thiourea‐based curing agents, particularly ethylene thiourea (ETU), are widely used to cure CR 7. Recently, newer curing agents, include thiophosphoryl disulfides, dimethyl l‐cystine, and cetyltrimethylammonium maleate, have been reported 8–10. Although there are many published works on various curing agents for CR, the most practical curing agents are still metal oxides due to the superior mechanical properties of the cured products.…”

Section: Introductionmentioning

confidence: 99%

MgO and ZnO as reinforcing fillers in cured polychloroprene rubber

Chokanandsombat

Sirisinha

2012

Polychloroprene rubber (CR) is generally cured in a manner different from that of other diene rubbers. Compounding formulations based on metal oxides have been used satisfactorily for the crosslinking of CR, especially magnesium oxide (MgO) and zinc oxide (ZnO) at loadings of 4 and 5 phr, respectively. In this work, the total loading of MgO and ZnO was varied while the MgO : ZnO loading ratio of 4 : 5 (equivalent to MgO and ZnO volume fractions of 0.013 and 0.009, respectively) that usually used with CR was kept constant. Cure and mechanical properties of CR compounds and cured specimens were investigated. The obtained results could resolve the separate increments in hardness, tensile strength, abrasion resistance, and modulus associated with the increases in crosslink density and total loading of metal oxides. Furthermore, poor compression set and increased heat build-up of cured CR specimens, particularly at high total loading of metal oxides, were believed to be the result of a post-curing effect and of molecular restriction by the increased crosslink density, respectively.

“…Again, it has been reported24, 25 that during the crosslinking of CR in the presence of ZnO and MgO, diene, triene, and intramolecular cyclic structures are formed by dehydrohalogenation and molecular rearrangement. However, these diene and triene structures are supposed to provide crosslinking sites for sulfur vulcanization at the curing temperature 26…”

Section: Resultsmentioning

confidence: 99%

Naturally occurring amino acid: Novel curatives for chloroprene rubber

Das

Naskar

Datta

et al. 2006

Polychloroprene is a diene rubber, but unlike other diene rubbers, its compounding with various additives and curing mechanisms is different. A derivative of thiourea, ethylene thiourea (ETU), is widely used to vulcanize chloroprene rubber (CR), and the vulcanizates thus obtained exhibit excellent mechanical properties, good aging resistance, and very good sealing properties. However, the problem is that ETU is reported to be a potent carcinogenic compound, and hence, the effective substitution for ETU has been extensively explored. In this study, we used a naturally occurring amino acid derivative, dimethyl l-cystine, as an ecofriendly compound for the vulcanization of CR. It had a significant influence on the curing characteristics and mechanical properties, such as modulus, tensile strength, elongation at break, and hardness values. The concentration of this novel crosslinking agent and also the curing temperature were optimized. In the presence of dimethyl l-cystine, the amount and activity of magnesium oxide also exhibited significant influences on the crosslinking characteristics.