Tyres, additives

Sheldon, J. C., and S. Y. Tyree Addition Compounds of Metal Halides with POX3 Compounds. J. Amer. chem. Soc. 80, 4775 (1958). 

If braking action is now externally applied to the tyre, additional energy losses are caused near the tread/road boundary, and these can be conveniently expressed as the adhesional and the hysteretic components of an interfacial friction force. We must emphasize that energy loss is the fundamental factor in both the internal and external friction mechanisms, and the concept of a frictional force is a convenient means of expressing such energy loss only in the vicinity of a sliding interface. 

The bulk properties of a polymer ean often be altered considerably by the incorporation of additives. Probably the most well-known examples of this occur in rubber technology where variations in the choice of additives can produce such widely differing products as tyres, battery boxes, latex foam upholstery, elastic bands and erasers. It is also possible to achieve variations as extensive as this amongst plastics materials, in particular with PVC from which rigid rainwater piping, baby pants, conveyor belting, footballs and domestic insulating flex may all be prepared. 

GC-MS and GC-AED techniques were used for the direct analysis of used tyre vacuum pyrolysis oil [255]. Antioxidants and antiwear additives (0.25-5 wt% DODPA, a-NPA, TCPs, TPP, IPPs) in lubricating synthetic oils, essentially esters of branched-chain alcohols such as pentaerythritol, neopentylglycol and trimethylolpropane, were determined by means of GC-SIM-MS using diphenylamine (DPA) as an internal standard [256] similarly, TCPs, TPP, IPPs, DPs and I2P were quantitatively analysed by GC-FPD using triethylphosphate (TEP) as an internal standard. RSD values of 3-6% were reported for GC-SIM-MS, and 7-9 % for GC-FPD. 

Furthermore, concentrates may also be used as conventional additives in the same polymer or in different polymers. In this way a substantive antioxidant (or modifier) system can be produced with very high effectiveness especially under aggressive environments. In comparison, under such demanding conditions, conventional antioxidants will not only lead to premature failure of the polymer but also to dangerous situations such as in the case in food contact application (packaging), medical uses of polymers (artificial joints), and failure of aircraft tyres where human lifes are at risk. 

Resin cures utilise phenol-formaldehyde resins with reactive methylene groups and a small added amount of either a chlorinated rubber, e.g., polychloroprene, or stannous chloride. If halogenated phenolic resins are used the additional source of a halogen may not be required. Resin cures give butyl compounds excellent heat stability and are used to good effect where this is required, e.g., in tyre curing bags which have to resist service at 150 °C in a steam atmosphere. 

Until the 1970s in Europe and the 1980s elsewhere tyres were built in cross-ply (diagonal ply) construction, with the reinforcement layer running at a bias to the direction of tyre rotation. Now the vast majority are radial ply with the carcass reinforcement layer placed radially, or at 90° to the direction of rotation. There is always an even number of plies or reinforcement layers - generally car tyres have two and trucks around 6 or 8 plies. In addition, there are tread reinforcing (bracing) layers called belts, which run around the circumference under the tread. 

A bicycle tyre gets quite hot during its inflation. The work of inflating the tyre explains in part why the temperature increases, but careful calculations (e.g. see pp. 86 and 89) show that additional factors are responsible for the rise in temperature. 

This chapter will present a short overview of worn tyre management practices, with data for the USA, followed by a discussion of the effects of energy recovery through tyre combustion on both solid waste products and atmospheric emissions. In addition to reviewing... 

A larger-scale tyre combustion experiment was performed by Lemieux Ryan (1993) in order to collect emission data from a simulated open waste tyre fire. In addition to identifying a large number of organic compounds, including... 

In addition to collection and transportation costs, there are major expenses associated with the preparation of the tyres for combustion or with modifications to the fuel feeding systems of power plants (e.g., Goddard 1992 Lamarre... 

Although all the coins analyzed are presumed to be minted in Tyre, the results of analysis will be given for both hoards separately as well as combined. In addition, the dates covered by each hoard overlap one another with the Qumran hoard dating from 138 B.C.E. to 1 B.C.E. while the Isfiya hoard dates from 34 B.C.E. to 53 C.E. This common mint context, with coins from two... 

The introduction of steel cord into the manufacture of automobile tyres led to the need to find additives which would promote the adhesion of steel to rubber. A cobalt complex known commercially as Manobond C-16 has been used for this purpose.70,71 Manobond C-16 is a borate complex with the composition (RC02CoO)3B. The R groups are described as having an average of 21 carbon atoms, five of which are methyl groups. 2 No further structural details seem to be available. 

Rubber industries produce various types of complicated products like tyre, cable, belt, seal, bearings, engine mounts, etc. The products are composed of rubber, plastics, fibre, metal, fillers and many other additives like antioxidants, accelerators, etc. Reverse engineering is a technique by which a rubber technologist can reconstruct the composition of the products based on thermal analysis. Dormagen [178] and Baranwal [179] reconstructed the formulation of a tyre, based on analyses of FTIR, spectra, thermal analysis and high performance liquid chromatography. 

Where one or both of the contacting surfaces becomes permanently deformed during sliding, the energy required to produce the deformation represents an additional component of the friction force. For engineering surfaces the amount of permanent deformation which can be tolerated is very limited so that the deformation friction is small in comparison with the adhesive friction. Elastic deformation only makes a significant contribution to the total friction when there is a high level of hysteresis in the elastic recovery, such as in vehicle tyres, and this is not normally a consideration when molybdenum disulphide is used. For practical purposes it can therefore be assumed that adhesive friction is the only type of friction which needs to be considered. 

Rubber tyres are by far the most visible of rubber products. Identification is trivial and collection is well organized. Recycling and disposal, however, are less evident. A major route for tyres is their use as a supplemental fuel in cement kilns. Major compounds in tyres are styrene-butadiene rubber (SBR), synthetic and natural polyisoprene rubber, steel cord, carbon black, zinc oxide, sulphur and vulcanization-controlling chemicals. Tyres can be retreaded, which is economic for large sizes (truck tyres), or ground to crumb or powder (cryogenic grinding). Such materials have some limited market potential as an additive in asphalt, and in surfaces for tennis courts or athletics. 

The isoalkene structure of the majority of the oil components confirms the good gasoline quality of pyrolytic fuel from NR. Nevertheless, from tyre waste other components are also evolved related to the vulcanizing agent and additives. 

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