Styrene-butadiene rubber vulcanisation

Romero-Sanchez M.D. and Martfn-Martfnez J.M., 2003, Treatment of vulcanised styrene-butadiene rubber (SBR) with mixtures of trichloroisocyanuric acid and fumaric acid, J. Adhes., 79, 1111-1133. 

Processing aid-80, a masterbatch in the form of pressed crumb consisting of an 80 20 blend of crosslinked to ordinary natural rubber. The correct proportions of vulcanised latex and field latex are blended, coagulated and the resulting crumb pressed into 100 lb bales. The use of PA 80 confers Superior Processing properties on any natural or styrene-butadiene rubber with which it may be mixed. See Superior Processing Rubber. 

As a result of its saturated polymer backbone, EPDM is more resistant to oxygen, ozone, UV and heat than the low-cost commodity polydiene rubbers, such as natural rubber (NR), polybutadiene rubber (BR) and styrene-butadiene rubber (SBR). Therefore, the main use of EPD(M) is in outdoor applications, such as automotive sealing systems, window seals and roof sheeting, and in under-the-hood applications, such as coolant hoses. The main drawback of EPDM is its poor resistance to swelling in apolar fluids such as oil, making it inferior to high-performance elastomers, such as fluoro, acrylate and silicone elastomers in that respect. Over the last decade thermoplastic vulcanisates, produced via dynamic vulcanisation of blends of polypropylene (PP) and EPDM, have been commercialised, combining thermoplastic processability with rubber elasticity [8, 9]. 

High cis- 1,4-poly butadiene is manufactured on a large industrial scale and occupies a well-defined position in the elastomers market. It is employed mainly in the tyre industry, where it is blended with natural rubber and/or with styrene-butadiene rubber and applied in either sidewalls, threads or rims of tyres. It should be noted in this connection that natural rubber, in contrast to its synthetic counterpart, displays some physical properties that appear to be useful in the manufacture of tyres for heavy-duty machines. The fact is that some non-hydrocarbon substances appearing in natural rubber in small amounts (such as polypeptides) protect the high-dimensional tyre formed against collapsing prior to the vulcanisation process and thus enable a high-quality product to be obtained. 

Rudewicz and Munson [45] used this technique for the direct determination of additives in PP. The technique has also been used to determine oligomers in polyacrylates, PEG, siloxanes and polycarbonates [87], polyglycols [88] and adhesion promoters, primers and additives in the surface of PET film [89], volatile antioxidants in styrene-butadiene rubbers [34, 50], mercaptobenzothiazole sulfenamide accelerator in rubber vulcanisates [90] and divinyl benzene in styrene-divinyl benzene copolymer [91]. 

Altenau and co-workers [26,27] used MS to identify quantitatively volatile antioxidants in 0.02-0.03 inch thick samples of synthetic styrene-butadiene rubbers and rubber-type vulcanisates. They extracted the polymer with acetone in a Soxhlet apparatus, removed excess solvent, and dissolved the residue in benzene. Substances identified and determined by this procedure include N-phenyl-P-napthylamine, 6-dodecyl-2,2,4-trimethyl-l,2-dihydroquinolines, trisnonylphenylphosphate, isobutylene-bisphenol, 2-mercaptobenzothiazole sulfenamide (accelerator), N-cyclohexyl-2-benzothiazole... 

The family consists of, in order of market volume, polybutadiene (or butadiene rubber, BR), solution styrene butadiene rubber (SSBR) and styrenic block copolymers (SBC). A further subdivision may be made into those polymers that require vulcanisation (BR, SSBR) and those that do not (SBC). The latter are also known as thermoplastic rubbers as they have rubbery properties below a certain temperature when they soften and may be processed like thermoplastics. 

Meuzelaar et al. [453] have reported experiments with non-vulcanised styrene-butadiene rubber (SBR) in the presence of various catalysts and co-processing runs of coal and lower grade postconsumer polymers (coloured PE and PS, waste rubber tyres, commingled plastic mixture) in a high pressure TG-GC-MS system at a hydrogen pressure of 900 psi. This system is essentially designed for applied rather than analytical TG-GC-MS work. 

ISO 9924-1, Determination of the composition of vulcanisates and uncured compounds by thermogravimetry. Part 1 Butadiene, ethylene-propylene copolymer and terpolymer, isobutene-isoprene, isoprene and styrene-butadiene rubbers. International Organisation for Standardization, Geneva (1993). 

Specifically in phenol-formaldehyde resins [100]. Polymers have been separated using pyrolysis-GC. This approach, which yields an identifiable pyro-gram suitable of being further characterised by mass spectrometry, has been successful in the separation of acrylic plastics [101], phenol-formaldehyde polycondensate [102], vulcanised elastomers [103], silane coupling agents [104], polyquinones [105], polyester, polyamide and polyethylene fibres [106], styrene-butadiene rubbers [107] and in the classification of PVC tape [108]. 

Romero-Sanchez MD, Martin-Martinez JM (2004) Effects of overhalogenation of synthetic vulcanised styrene-butadiene rubber sole on its adhesion behaviour. J Adhes Sci Technol... 

The accelerated sulfur vulcanisation of general purpose diene rubbers (e.g., natural rubber (NR), Styrene butadiene rubber (SBR), and butadiene rubber (BR)) in the presence of organic accelerators and other rubbers, which are vulcanised by closely related technology (e.g., ethylene-propylene-diene terpolymer (EPDM) rubber, butyl rubber (HR), halobutyl rubber (XIIR), nitrile rubber (NBR)) comprises more than 90% of all vulcanisations. 

STYRENE-BUTADIENE RUBBER/EPOXIDISED NATURAL RUBBER BLENDS THE EFFECT OF VULCANISATION SYSTEM ON BLENDS PROPERTIES... 

Studies on the vulcanisation of a black and oil filled styrene-butadiene rubber compound accelerated by a number of different sulphenamide and sulphenimide compounds were made using a conventional curemeter operated to normal ASTM standards. The vulcanisation reactions were also studied using different modelling software, CODESSA software for deriving quantitative structure-property relationships and MOPAC software for semiempirical molecular orbital calculations which together yielded excellent correlation to onset of cure and maximum cure... 

The cure and tensile properties of sulphur vulcanised styrene-butadiene rubber filled with a conventional furnace black or a fluorinated black have been determined. Compositions with the fluorinated black and normal curative levels exhibit retarded cure compared to corresponding ones with the furnace black. This is due to a reaction between the sulphenatnide accelerator and the fluorinated black. Notwithstanding, a fluoro-filled composition with no curatives substantially crosslinks when moulded at 150 deg.C. Thus, fluoro-black filled specimens have competing effects toward crosslinking. On the one hand, crosslinking is inhibited by reaction with the accelerator, while on the other, the fluoro-black itself can cause crosslinking. 2 refs. 

Phenolic antioxidants in rubber extracts were determined indirectly photometrically after reaction with Fe(III) salts which form a red Fe(II)-dipyridyl compound. The method was applicable to Vulkanox BKF and Vulkanox KB [52]. Similarly, aromatic amines (Vulkanox PBN, 4020, DDA, 4010 NA) were determined photometrically after coupling with Echtrotsalz GG (4-nitrobenzdiazonium fluoroborate). For qualitative analysis of vulcanisation accelerators in extracts of rubbers and elastomers colour reactions with dithio-carbamates (for Vulkacit P, ZP, L, LDA, LDB, WL), thiuram derivatives (for Vulkacit I), zinc 2-mercaptobenzthiazol (for Vulkacit ZM, DM, F, AZ, CZ, MOZ, DZ) and hexamethylene tetramine (for Vulkacit H30), were mentioned as well as PC and TLC analyses (according to DIN 53622) followed by IR identification [52]. 8-Hydroquinoline extraction of interference ions and alizarin-La3+ complexation were utilised for the spectrophotometric determination of fluorine in silica used as an antistatic agent in PE [74], Also Polygard (trisnonylphenylphosphite) in styrene-butadienes has been determined by colorimetric methods [75,76], Most procedures are fairly dated for more detailed descriptions see references [25,42,44],... 

Aryl naphthylamine derivatives are good general antioxidants with moderate volatility and negligible effect on cure. These give a small degree of fatigue protection in natural and polyisoprene rubbers, but little in styrene-butadiene and butadiene vulcanisates. 

Synthetic rubbers, CR(chloroprene), SBR (styrene-butadiene) Involve carcinogenic substances in the work environment of production and processing (vulcanisation). CR may generate hydrogen chloride and dioxins when incinerated or burned. 

As few experimental TVA set-ups have been built, the method has found restricted application, mainly for identification of rubbers, vulcanisation of natural rubber, determination of total and non-condensable volatiles in polymers and degradation studies. TVA has proved useful for testing a wide range of polymers (including PS, poly-a-methylstyrene, styrene-butadiene copolymers, PVC, polyisobutene, butyl and chlorobutyl rubber) on the presence of trapped solvents, monomers, etc. 

An in-line moulding press interfaced to a GC-MS has been used to analyse the effluent from the vulcanisation of rubber formulations for the purpose of identifying and quantifying organic compounds present in the vulcanisation fumes [42]. Analyses were performed on natural, ethylene-propylene-diene monomer, styrene-butadiene, nitrile, chloroprene, silicone, and polyfluorocarbon rubbers. Degradation mechanisms were proposed based on the volatiles observed. 

Buna 85 is polybutadiene (the number represents Mooney viscosity), molecular weight -80,000. Hard rubber has high softening point and excellent chemical resistance. The coefficient of vulcanisation to the ebonite stage is 39.3. The coefficient of vulcanisation is the number of unit weight of sulfur combined with 100 units by weight of unsaturated hydrocarbons. Buna S is a butadiene styrene copolymer with 70/30 to 68/32 ratio. Buna SS contains a high proportion of styrene. Perbunan are nitrile rubbers... 

Figure 3.406. Dependence of strain, e, by the deformation rate at 294 K 1) poly(butadiene-co-styrene) vulcanised rubber without filler 2) idem, containing 30 %vol. black carbon 3) idem, containing 60 %vol. black carbon.

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