Tire products performance

NR adhesives perform adequately under peeling stresses. The peel strength can vary from a few N/m in PSA formulations to substrate tear in vulcanized compounds used in hose, belting and tire products. 

Reinforcing fillers used are carbon black and non-black fillers such as silica, clay, and calcium carbonate although the latter two are used more in lower cost industrial applications and not in tires. Protectant systems consist of antioxidants, antiozo-nants, and waxes. The vulcanization system essentially ensures that the optimum mechanical properties of the polymer system are achieved. Finally, the tire compound can contain various miscellaneous materials such as processing aids and resins. The materials scientist when designing a tire compound formulation has a range of objectives and restrictions within which to operate. Product performance objectives define the initial selection of materials. These materials must not raise environmental concerns, be processable in tire production plants, and be cost effective for the end user [4]. 

Composites. Various composite materials have evolved over the years as a significant class of high performance textile products. The prototype composite is carbon fiber with an epoxy resin matrix for stmctural akcraft components and other aerospace and military appHcations. Carbon fiber composites ate also used in various leisure and spotting items such as golf clubs, tennis rackets, and lightweight bicycle frames. However, other types of appHcations and composites ate also entering the marketplace. For example, short ceUulose fiber/mbbet composites ate used for hoses, belting, and pneumatic tire components. 

Economics and price of the final article often dictate a specific type of mbber that can be used. The expected usable life for the product is controlled by many factors including end customer awareness, competitive situation in the marketplace, safety, reUabiUty, and other factors. Rubber is almost always used as a functional part of another system. For example tires, hoses, belts, O-rings, and numerous mbber components are used in manufacturing automobiles and tmcks. The overall life of the vehicle as well as its performance level often control or direcdy relate to the service life or quaUty level of the mbber parts. 

Cost. Price is an important consideration for most commodity types of mbber products, eg, tires, hoses, and belts. Eor specialty items, eg, mbber products for medical appHcations, cost is not a primary factor performance is more important. 

Synthetic. The main types of elastomeric polymers commercially available in latex form from emulsion polymerization are butadiene—styrene, butadiene—acrylonitrile, and chloroprene (neoprene). There are also a number of specialty latices that contain polymers that are basically variations of the above polymers, eg, those to which a third monomer has been added to provide a polymer that performs a specific function. The most important of these are products that contain either a basic, eg, vinylpyridine, or an acidic monomer, eg, methacrylic acid. These latices are specifically designed for tire cord solutioning, papercoating, and carpet back-sizing. 

The performance properties of PEN present opportunities for replacement of rayon or polyamide in carcass construction. The use of PEN cord in these applications is currently being evaluated in both Asia and Europe. PEN has demonstrated acceptable flexural fatigue equivalent to polyethylene terephthalate (PET) and rayon. It has equivalent toughness to rayon, which is important for sidewall impact resistance. PEN s superior mechanical properties also afford opportunities to use less fiber in carcass construction enabling production of lighter-weight, more fuel-efficient tires. 

The most important experimental task in structural chemistry is the structure determination. Il is mainly performed by X-ray diffraction from single crystals further methods include X-ray diffraction from crystalline powders and neutron diffraction from single crystals and powders. Structure determination is the analytical aspect of structural chemistry the usual result is a static model. The elucidation of tire spatial rearrangements of atoms during a chemical reaction is much less accessible experimentally. Reaction mechanisms deal with tliis aspect of structural chemistry in the chemistry of molecules. Topotaxy is concerned witli chemical processes in solids, in which structural relations exist between the orientation of educts and products. Neither dynamic aspects of tliis kind are subjects of this book, nor tlie experimental methods for the preparation of solids, to grow crystals or to determine structures. 

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