The use of fillers in rubber products is nearly as old as the use of rubber itself. In time, the fillers which were likely first used for their color, zinc oxide and carbon black, became recognized for their reinforcement potential. In the early years of the 20th century, prior to World War I, zinc oxide was the most widely used reinforcing filler in rubber; the abrasion resistance it provided made it the preferred filler in tire treads. It was also during this
period that zinc oxide was discovered to be the activator for the newly emerging organic accelerators. The reinforcing effect of carbon black was quantified during the first decade of this century, but remained unexploited for about ten years.Carbon Black – Carbon black is essentially elemental carbon in the form of fine amorphous particles. Each particle is composed of randomly oriented microcrystalline layered arrays of condensed carbon rings. Because of their random orientation, many arrays expose open layer edges with unsatisfied carbon bonds at the particle surface. This in turn provides the sites for chemical activity. Individual round carbon black particles do not exist as discrete entities but form aggregates, which may be clumps or chains of various sizes and configurations. The functional carbon black “particle”, therefore, is actually the aggregate. Average particle size and aggregate configuration (structure) are the major determinants of the utility of a given carbon black in a specific rubber compound. The major differences among commercial grades result from control of these averages.
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .
الرجوع الى لوحة التحكم
|