Car tires

Tire disposal costs are 0.10—3.00 per tire. Cost for incineration without heat recovery is 0.35—0.70 per tire. Transportation of discarded tires can cost 0.04/kg, and size reduction can cost 0.20—0.60/kg. Distribution of passenger car tires is landfill, 85% retreaded, 10% and reclaimed, burned for fuel, and spht, 5%. 

Component Parts. Desired properties ia the components of a radial steel belted passeager car tire (PCT) are as follows. 

The pneumatic tire has the geometry of a thin-wallcd toroidal shell. It consists of as many as fifty different materials, including natural rubber and a variety ot synthetic elastomers, plus carbon black of various types, tire cord, bead wire, and many chemical compounding ingredients, such as sulfur and zinc oxide. These constituent materials are combined in different proportions to form the key components of the composite tire structure. The compliant tread of a passenger car tire, for example, provides road grip the sidewall protects the internal cords from curb abrasion in turn, the cords, prestressed by inflation pressure, reinforce the rubber matrix and carry the majority of applied loads finally, the two circumferential bundles of bead wire anchor the pressnrized torus securely to the rim of the wheel. 

Truck tires are operated at about four times the inflation pressure of passenger car tires, which principally accounts for truck tires lower rolling resistance coefficients. 

An NR-rich undertread layer can enhance the adhesion between belt or cap-ply and tread whilst a thicker subtread compound may be included to offer some additional benefits of low hysteresis for car tires and low heat generation for truck tires within the bulk of a thick section. The cure system needs better flexibility and low heat generation. Typically the cure system will be based on CV/SEV. Tread base is generally having a composition as depicted in Table 14.40. 

Cap-plies are more commonly used on high-performance car tires. Having a circumferential cord direction they provide an additional contractive force. They are also found more often now in normal-performance tires where they can act as a barrier layer between the tread and the casing to restrict migration of the chemicals from the tread into the belt. ... 

FIGURE 26.76 Measured distribution of (a) cornering and (b) fore and aft accelerations in a controlled road wear test for passenger car tires. 

FIGURE 26.77 Speed distribution in a controlled road test for passenger car tires also shown a distribution made up of two superposed normal ones. 

Design products to only release benign materials into the environment. This is not easy. For example, both brake pad dust and material from car tires is highly eco-toxic. Design the product for containment or destruction before end of life of any hazardous materials. 

Ensaco A process for making carbon black by the incomplete combustion of used car tires. Developed and commercialized by IMM, Belgium. 

Covalent polymer networks or (Class II) crosslinked macromolecular architecture polymers rank among the largest molecules known. Their molecular weight is given by the macroscopic size of the object for instance, a car tire made of vulcanized rubber or a crosslinked layer of protective coating can be considered one crosslinked molecule. Such networks are usually called macronetworks. On the other hand, micronetworks have dimensions of several nanometers to several micrometers (e.g. siloxane cages or microgels). 

Butadienes two double bonds make it very reactive. It readily forms polymers, reacting with itself to form polybutadiene. Its also used as a comonomer to make styrene-butadiene rubber (SBR), polychloroprene, and nitrile rubber. These are all forms of synthetic rubber and account for about 75% of the butadiene consumed. The largest share of them is on highway vehicles—truck and car tires, hoses, gaskets, and seals. 

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