TMTD

EPM/EPDMcompounding pLASTOTffiRS, SYNTTiETIC - ETTiYLENE-PROPYLENE-DIENE RUBBER] (Vol 8) Tetramethylthiuram disulfide (TMTD) [137-26-8]... 

Evaluations have been conducted using deer, a multiple-choice preference-testing apparatus, and tetramethylthiuram disulfide [137-26-8] (TMTD) (29) or the fungicide thiram as a standard repeUent for competitive tests with repeUent-treated food (78). 

Sulfur-containing chemicals such as dimorpholinyl disulfide (DTDM) and tetraethylthiuram disulfide (TMTD) are not only effective accelerators, but they can also be used as sulfur donors. As such, they are effective ia controlling sulfur cross-link length to form primarily moao- and disulfide cross-links. These short cross-links are more thermally stable than conventional sulfur curing and thereby provide better heat and set resistance. 

In contrast, the EV cure systems employ much lower levels of free sulfur (0.1—1.0 phr) or they use sulfur donors such as TMTD or DTDM combkied with higher accelerator levels. The short mono- and disulfide cross-links that form often do not exhibit the excellent physical properties of the conventional systems but they do retain thek properties much better after aging. 

MET, mercaptobenzothiazole TMTM, tetramethylthiuram mono sulfide TMTD, tetramethylthiuram disulfide and CBTS, Al-cyclohexyl-2-benzothiazole... 

Recipe, in parts by wt smoked sheets, 100.00 zinc oxide, 5.00 filler, as indicated nondiscoloring antioxidant, 1.00 MBTS, 1.00 TMTD, 0.10 sulfur, 2.75 stearic acid, 3.00. 

In addition to the 1 part of MBTS shown in recipe, the 20 vol HiSil 233 stock contains 0.25 parts TMTD and 0.5 parts triethan o1 amine the 30 vol stock contains 0.5 parts TMTD and 2 parts triethano1 amine and the 40 vol stock contains 0.5 parts TMTD and 3 parts triethano1 amine. 

The HiSd 233 stocks contain 2.3, 3.5, and 4.8 parts of diethylene glycol, respectively. The 30 vol stock contains 1.2 parts MBTS and 0.15 parts TMTD instead of the combination in the recipe the 20 and 40 vol stocks contain 1.5 parts MBTS and 0.1 parts TMTD. 

TBBS A/-t-ButyIbenzothiazole-2-su(phenamide MBTS Dibenzothiazole di.sulphide MBT 2-Mercaptobenzothiazole TMTD Telrainethythiutam disulphide... 

It was found that PP-EPDM blends [30] with a slow curing EPDM have a high-impact strength. Effect of tet-ramethyl thiuram disfulfide (TMTD) concentration on the Charpy notched impact strength of PP-EPDM blend is given in Table 8. 

Table 8 Effect of Composition of TMTD Curing System on the Charpy Notched Impact Strength (ai<) for 85/15 and 80/20 PP/EPDM Blends...

BR is incompatible with CR because of the large difference in polarity. Mingyi et al. have studied their compatibUization in the presence of a styrene-butadiene-styrene block (SBS) copolymer [30]. The blends were prepared by blending the two mbbers separately at approximately 75°C. The master batch of the BR compound contained 1 part of sulfur, 2 parts of copolymer, 1.5 parts of TMTD, 5 parts... 

Aside from the sulfur, the sulfur bearing compounds that can liberate sulfur at the vulcanization temperature can be used as vulcanizing agents. A few sulfur donors are given in Table 14.5, which include some compounds like dithiodimorpholine (DTDM), which can directly substitute sulfur. Others, like tetramethylthiuramdisulhde (TMTD), can act simultaneously as vulcanization accelerators. The amount of active sulfur, as shown in Table 14.5, is also different for each compound. Sulfur donors may be used when high amount of sulfur is not tolerated in the... 

A sulfur donor system in NR (DTDM, 1.5 CBS, 1.5 TMTD, 0.5) yields a stable network stmcture with a contribution of 80% mono- and disulfidic cross-links at the optimum cure at 143°C or 183°C curing [13]. 

CA-isoprene rubber cured with bis(dusopropyl)thiophosphoryl disulfide (DIPDIS) shows results at 160°C, producing a predominantly monosulfidic network structure [14]. Similar work on heat-resistant network structures has been carried out on other synthetic rubbers. For example, a sulfur-less system using 1 phr TBBS, 2.0 phr DTDM, and 0.4 phr TMTD in SBR gives the best aging resistance [15]. 

TMTD, TETD, TBzTD ZDMC, ZDBC, ZBEC... 

A = TBBS = Sulfenamide B = MBTS = Thiazole C = TMTD = Thiuram D = ZDMC= Dithiocarbamate E = DPG = Guanidine... 

Although ultra accelerators or sulfur donors can be used together with primary accelerator (such as sulfenamide, TBBS) to improve cure rate as well as the heat resistance [16-18], their use is restricted because of the associated nitrosamine issue [19]. Accelerators derived from secondary amines, for example, MBS, TMTD, TETD, TMTM, and OTOS fall into this category. The combination of sulfenamide, such as CBS or TBBS, and a thiuram, such as TMTD or TETD, shows high-cure rates but suffers from the adverse effects on scorch resistance and vulcanizate dynamic property [20]. Additionally as previously mentioned, the use of TMTD or Tetraethylthiuram disulhde (TETD) or A-oxidiethylene dithiocarbamyl-A -oxidiethylene sulfenamide (OTOS) or 4,4 -Dithiodimorpholine (DTDM) is undesirable [21] due to concerns over carcinogenic nature of the A-nitrosamines formed from the parent amines. The solution to this originated by introduction of nitrosamine safe ultra accelerator such as TBzTD [22,23]. 

Unlike TMTD, TBzTD is unique since use of small amount of TBzTD (0.1-0.2 phr) with sulfenamide system does not influence the processing characteristics while improving cure rate and dynamic properties. A comparative data are tabulated in Tables 14.6 through 14.10. Details are reported by Datta et al. [24]. 

Properties Control 0.1 phr TBzTD 0.2 phr TBzTD 0.1 phr TMTD 0.2 phr TMTD... 

Concentration Control TBzTD TBzTD TMTD TMTD... 

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