Tetramethylthiuram disulphide

By reduction in the degree of polymerisation. To produce processable rubbers the original polymers are masticated with substances such as benzothiazole disulphide and tetramethylthiuram disulphide. The more severe degradation techniques to produce liquid polysulphides are mentioned below. 

An accelerator similar in properties to tetramethylthiuram disulphide, except that it cannot be used without added sulphur. 

Tetramethylthiuram disulphide (TMTD) has proved to be a useful reagent for the thiocarbamoylation of amine containing compounds. Thus, reaction of a series of hydrazones of aromatic aldehydes with TMTD in a 1 1 ratio gave amongst other products, 4,4-dimethylthiosemicarbazide 86 and 5-dimethylamino-l,3,4-thiadiazole-2-thiol 85. It was confirmed that 86 was an intermediate in the synthesis of 85 as treatment of 86 with TMTD gave 85 in 85% yield <00RCB344>. 

The authors describe experiments on six NR compounds commonly used for latex gloves to determine the potential hazards of skin contact with reference to curing compounds and accelerators, including mercaptobenzthiazole and zinc dialkyldithiocarbamates. Simulation methods and the influence of a common hand disinfectant were investigated. In the case of tetramethylthiuram disulphide, it was discovered that decomposition products could be formed on the skin which are not present in the original rubber. 6 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. Accession no.849747... 

The extent of formation of these NOC depends upon the presence of nitrogen oxides present in the atmosphere during the manufacturing cycle. The major contaminants are NDMA, A-nitrosodiethylamine (NDEA), A-nitrosopyrrolidine (NPYR), NMOR, A-nitrosodiphenylamine (NDPhA), A-nitrosopiperidine (NPIP) and A-nitrosodibutylamine (NDBA)68. NMOR was found in the hot process areas NDMA occurred in tube production areas in which NDPhA was being used as retarder and tetramethylthiuram disulphide as an accelerator. Figure 12 shows a proposed reaction scheme of formation of NOC in the rubber industry and subsequent exposure67. 

Bis-(dimethylthiocarbamyl)disulphide (tetramethylthiuram disulphide) [137-26-8] M 240.4, m 155-156°. Crystd from CHCI3, by addition of EtOH. 

Synonym Aapirol, Aatiram, Accel TMT, Accelerator T, Aceto TETD, Arasan, Atiram, Cyuram, Delsan, Ekagom TB, ENT-987, Falitiram, Fermide, Fernacol, Fernasan, Fernide, Thiuram, TMTD Chemical Name tetramethylthiuram disulphide bis(dimethylthiocarbomoyl) disulfide CAS Registry No 137-26-8 Uses fungicide and also as seed disinfectant. 

Kodama and co-workers [58] have reported TG-DSC curves for the analysis of the interaction between vulcanisation accelerators (tetramethylthiuram disulphide, dibenzothiazolyl disulphide, diphenylguanidine and N-cyclohexyl-2-benzothiazolyl-sulphenamide) and fillers (carbon black, white carbon, hard clay and CaC03). The initial melting point (MP) of the accelerators was largely influenced by the fillers. The higher the surface activity of the filler is, the lower and wider the melting range becomes. 

A particular example of replacement technology that is associated with natural rubber involves the substitution of the use of tetramethylthiuram disulphide (TMTD) in field latex as a preservative with newly developed bacterial chemicals. As previously mentioned, TMTD is also commonly used as an accelerator and produces nitrosatable substances. The resulting latex can then be used to produce food contact products such as gloves and meat netting thread. 

One of the earliest descriptions of this toxic interaction was made in 1937 by Dr EE Williams who noted it amongst workers in the rubber industry who were handling tetramethylthiuram disulphide ... 

PS-jQy) in the oxidation reaction. The solution of PS Qy in toluene was bubbled with oxygen at elevated temperature T = 353 K. The reaction of addition of 2,2 -azo-bisisobutyronitrile (AZBN) was initiated by UV irradiation. Polystyrene containing organosulphide groups was obtained by polymerization of styrene in the presence of tetramethylthiuram disulphide, or tetramethylthiuram disulphide and sulphur in the light of a UV lamp. The reaction temperature was... 

We have tried to increase the reactivity of modified polystyrene by introducing sulphur bonds with small dissociation energy into its macromolecules. For that purpose we carried out styrene polymerization with tetramethylthiuram disulphide in the presence of sulfur as an initiator. The chemical composition of modified polystyrene was as follows 83.02% C, 7.28% H, 1.07% N, 7.91% S (Table 1). As acconsequence of the addition of sulfur to the reaction medium the sulfur/nitrogen mole ratio increased from 2 1 to above 3 1. The average molecula weight of po lystyrene modified by thiuram and sulfur was low, Mv = 2030 and = 2080. 

Free acid very unstable. Rapidly oxidised to tetramethylthiuram disulphide. The salts are employed as rubber vulcanisation accelerators. Na salt, 2 HaO anhydrous at 130°. 

TMTD = tetramethylthiuram disulphide DTM = 4,4 -dithiomorpholine MBTS = dibenzothiazyl disulphide... 

Fig. 12.5. Dependence of tensile strength (Ts) on cross-link density (vt) and cross-link structure for (a) EPDM (Royalene 301) and (b) EPM (Dutral). Tested using dumbell type 3 at 250mm/min elongation rate at 20 C. Cure systems (a) EPDM (1) tetramethylthiuram disulphide, bis (benzothiazolyl) disulphide (2) dicumyl peroxide, 1 phr sulphur (3) dicumyl peroxide, 0 3 phr sulphur (4) mercaptobenzothiazole (5) dicumyl peroxide (b) EPM (1) dicumyl peroxide, 1 phr sulphur (2) dicumyl peroxide, 0-3 phr sulphur (3) dicumyl peroxide. (From Imoto et al, 1%8.)...

Tetramethylthiuram disulphide (3.40), which is used to check the growth of fungi in seeds and turf, acts by reduction to dimethyldithiocarbamic acid (3.41), which is a widely used chelating fimgicide (see Section 11.7c). 

For further reading on the dimethyldithiocarbamates, see Thom and Ludwig (1962). Some agriculturalists prefer to use the zinc and iron complexes of DMDC, principally because of the excellent adhesion to plants which enables the complexes to resist long periods of rain. Others prefer tetramethylthiuram disulphide, which is the disulphide obtained by oxidizing DMDC, and which is slowly reduced to DMDC imder field conditions. 

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