Compounded rubber

Rubber compounds Rubber content Rubber latex... 

Carbon black dominates as black pigment. It is a petrochemical made from natural gas or petroleum residues by incomplete combustion - cooking to split the hydrocarbon into hydrogen and carbon. Its primary use is in compounding rubber for making tires of which an average passenger... 

Ethylene-Propylene-Diene Monomer (EPDM) Compounding Rubber Process Analyzer-Fourier Transform (RPA-FT) Results at 100°C Total Torque Harmonic Content (TTHC) versus Strain Fit Parameters of Equation 30.4... 

S. Bandyopadhyay, N. Mandal, S. Dasgupta, R. Mukhopadhyay, A.S. Deuri, and S.C. Ameta, Effect of recycled dust stop luhricating oil in rubber compounds. Rubber World, 233(6), 20, 2006. 

Rouse, M.W., Development and application of superfine tire powders for compounding, Rubber World, 206, 25, 1992. 

Osborn, B.D., Reclaimed tire rubber in TPE compounds. Rubber World, 212, 34, 1995. 

The compounded rubber is therefore a highly complex chemical system, difficult to analyse (cf. Section 2.2). 

Table 2.4) or proprietary test methods. Forrest [38] has listed 94 international rubber analysis standards (ISO) and 20 ISO standards in preparation referring to latices, carbon-black-filled compositions, raw and compounded rubbers. 

In principle, any type of sample can be analysed by SEC provided that it can be solubilised and that there are no enthalpic interactions between sample and packing material. By definition then, this technique cannot be carried out on vulcanisates and even unvulcanised fully compounded rubber samples can present problems due to filler-rubber interactions. The primary use of SEC is to determine the whole MWD of polymers and the various averages (number, viscosity, weight, z-average) based on a calibration curve and to allow qualitative comparisons of different samples. Many commercial polymers have a broad MWD leading to strong peak overlap in the chromatography of complex multicomponent systems. 

The thermal conductivity of compounded rubber is an additive property of the rubber and the compounding ingredients, and may be calculated from the mix formula and the individual thermal conductivities. 

Uses. Manufacture of vinyl chloride antiknock agent fumigant, insecticide degreaser compounds rubber cements... 

Blay, N.J., and Pembridge, E.F. (1972) Compatibility of Compounded Rubbers Containing Anti-oxidants Octamine and Flectol H with High Explosives and Propellants. US Nat. Tech. Inform. Serv. AD Report No. 752351. 

The substances listed in Table 28 correspond to the basic structure of elastomeric closures. The other components in rubber formulations are curing or vulcanizing agents, accelerators, activators, antidegradants, plasticizers, fillers, and pigments. The most common additives used to compound rubber for the pharmaceutical industry are listed in Table 29. The amount of each component may vary from rubber to rubber, and, depending on the component, the amount can reach more than 50% of the total mass of a formulation. While accelerators are used in amounts of around 1%, fillers may make up more than 50% of the formulation mass. 

TABLE 29 Ingredients Other Than Elastomers Used to Compound Rubbers for Pharmaceutical Industry... 

The most common method of measurement is to run the compound in the mooney viscometer until the viscosity shows a 5 point rise above the minimum. The viscosity of the compounded rubber at the processing temperatures can also be obtained from the minimum of the curve. The values normally taken from the cure curve are ... 

The classical means for following vulcanization by physical methods is to vulcanize a series of sheets for increasing time intervals and then measure the stress strain properties of each and plot the results as a function of vulcanization time. A modification of this test generally called a rapid modulus test is widely used in the industry as a production control test. A single sample taken from a production batch of compounded rubber is vulcanized at a high temperature and its tensile modulus is measured. Temperatures as high as 380°F are used to reduce the vulcanization test time to only a few minutes. Any modulus value deviating from a predetermined acceptance limit indicates that the batch is defective and is to be rejected. 

The saturated rubbers such as butyl or EPDM cannot be cross linked by sulphur and accelerators. Organic peroxides are necessary for the vulcanization of these rubbers. When the peroxides decompose, free radicals are formed on the polymer chains and these chains can then combine to form cross links of the type where only carbon-carbon bonds are formed, unlike in sulphur vulcanization. These carbon-carbon bonds are quite stable ones. Such bonds are also formed by vulcanization using gamma or x-ray radiation of compounded rubbers. Some rubbers can be vulcanized by the use of certain bisfunctional compounds which form bridge type cross... 

Laboratory measurement of curing characteristics was revolutionised by the introduction of so-called curemeters in the middle of the last century, which quite rapidly became almost universally used for the routine control of fully compounded rubbers. These instruments were so successful that the use of the Mooney to measure scorch and the need for routine measurement of physical tests on moulded test pieces has been much reduced. 

These techniques are useful for the separation of complex mixtures. Quantitative analyses have been reported on malathion pesticide in vegetable matter, limonin in grapefruit peel, and additives in compound rubber by means of SEC and RPC126>. SEC was performed with unstabilized THF and monitored at 215 nm. Working so near to the UV cut-off (210 nm) of THF was possible through the use of a detector with a flowing reference installed between the pump and the sample valve. Then the eluent passed the column and finally the analytical cell. Since the column back pressure never exceeded 10 MPa, this eluent line caused no problems. 

Molar mass strongly influences the performance of raw (unvulcanized) rubbers during the preparation of rubber compounds, e.g. addition of fillers and other ingredients. Also the processing characteristics of the compounded rubbers as well as the physical properties of the vulcanized rubbers significantly depend on the molar mass of the unvulcanized rubbers. In order to better meet various requirements, there is not only one BR grade available but... 

Mechanism of Carbon-Black Formation in Relation to Compounded-Rubber Properties... 

Progress is achieved through change which is understood. So, in this instance, scientific knowledge must surpass the art, and a knowledge of the Mechanism of Carbon Black Formation in Relation to Compounded Rubber Properties prevails. 

The compounded rubber stock will be further processed for use. The process could be injection or transfer molding into a hot mold where it is cured. Tire curing bladders are made in this fashion. Extrusion of the rubber stock is used to make hose or tire treads and sidewalls. Another common process is calendaring, in which a fabric is passed through rolls where rubber is squeezed into the fabric to make fabric-reinforced rubber sheets for roofing membranes or body plies for tires. The actual construction of the final product can be quite complex. For example, a tire contains many different rubber components some of which are cord or fabric reinforced. All of... 

Laboratory batches of compounded rubber samples were obtained from either Smithers Laboratories of Akron, Ohio, or Mare Island Naval Shipyard. Proper cure conditions were determined for each compound as per ASTM D 20845-79 through the use of a Monsanto lOOS oscillating disk rheometer. Samples used for experimental purposes were cured to 90% of optimum cure. Density was determined by Archimedes method. 

Modifiers for Compounded Rubbers Based on Fluoro- and Phenylsiloxane Rubbers... 

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