Natural rubber basic compounding

Just as in the manufacture of sheet natural rubber and the asphaltic sheet linings, the basic material as the sheet lining manufacturer receives it from the plantation (rubber) or from the refiner or importer (asphalt), the manufacturer of the synthetic lining materials will receive his synthetic elastomer, thermoplastic or other basic resin from the company that produces it-and will have to blend it with fillers, stabilizers, plasticizers, and other materials to make a suitable compound which will-as a lining—perform its function satisfactorily under the anticipated conditions, and for an economical length of time. The actual amount of the basic resinous material in the compound may be as low as 70% of the total weight. 

Our analytical procedure consists of stepwise acetone extraction followed by cyclohexane. Subsequently, the acetone-soluble fraction is partioned between hexane/aqueous ethanol (12,15), and the soluble components are freed of solvents and determined gravimetrically. For lack of specific nomenclature, the botanochemicals isolated by this technique have been referred to as "whole plant oil," "polyphenol," and "polymeric hydrocarbon." Actually, components from these extracts need to be further characterized. However, petroleum refinery processes may be sufficiently insensitive to allow use of carbon-hydrogen rich compounds represented by a broad spectrum of structures. For example, consider the diverse chemicals ranging from methanol to natural rubber which have been converted to gasoline (16). Thus, chemical species may be important if chemical intermediates are being generated but may be nonconsequential for production of fuels, solvents, carbon black, and other basic chemicals. 

A common feature of tyre compounds is the presence of natural rubber (NR), the most important rubber for highly demanding dynamic applications, such as the ones in tyre, basically as a consequence of its matchless elasticity. 

The idea that, if a single available material cannot fulfill a set of desired properties, then a mixture or a compound of that material with another one might be satisfactory is likely as old as mankind. Adobe, likely the oldest building material, is made by blending sand, clay, water and some kind of fibrous material like straw or sticks, then molding the mixture into bricks and drying in the sun. It is surely one of the oldest examples of reinforcement of a "plastic" material, moist clay, with natural fibers that was already in use in the Late Bronze Age, nearly everywhere in the Middle East, North Africa, South Europe and southwestern North America. In a sense, the basic principle of reinforcement, i.e., to have a stiffer dispersed material to support the load transmitted by a softer matrix, is already in the adobe brick. Therefore, the "discovery" of natural rubber reinforcement by fine powdered materials, namely carbon black, in the dawn of the twentieth century surely proceeded from the same idea. 

The basic chemistry of crosslinking and reversion is discussed, and a new concept is proposed to counteract reversion, based on the use of l,3-bis(citraconimido-methyljbenzene (BCl-MX, tradename Perkalink 900). The effect of BCl-MX in natural rubber compounds with regard to suppression of reversion, hysteresis and dynamic properties is investigated. A theory on the mechanism of reversion prevention is proposed. 22 refs. Articles from this journal can be requested for translation by subscribers... 

Terpenoids are widely distributed in nature they mainly exist in plants, animals and microorganisms. Terpenoids are used extensively with a long history. The earliest application can be traced back to ancient Egypt, when people widely used this kind of compound in the manufacturing of spices, medicine, pigment and antiseptic. Many terpenoids have been proved to be the active components in Chinese medicinal herb. At the same time, terpenoids are essential basic raw materials in cosmetics and food industry. Even in the automobile and aircraft industry, terpenoids have found the applications such as terpenoids rubber and so on [9-11]. 

The most typical adhesive solvents are those based on elastomers, compounds characterized by the fact that they have a strong natural adhesiveness, especially in respect of themselves (the phenomenon of self-adhesion, the instantaneous adhesion of two films of glue after almost total evaporation of the solvent, is the basis for the composition of the contact glues especially neoprene-based (Fletcher 1971)). The basic chemical composition of neoprene synthetic rubber is polychloroprene (O Fig. 14.6). The polymer structure can be modified by copolymerizing chloroprene with, for example, 2,3-dichloro-1,3-butadiene to yield a family of materials with a broad range of chemical and physical properties. 

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