Oil-Extended Rubber

Property ASTM method Paraffinic Naphthenic Aromatic 

Naphthenic Ethylene propylene copolymer (EPM) Sealants, Caulking 

Polyvinyl chloride (PVC) has peculiar material characteristics because of its high level of syndiotactic vinyl chloride units. The polymer as a result has a low to modest level of crystallinity (-10%). The uncrystaUized regions in PVC are subject to dissolution by polar solvents. The solutions formed have exothermic heats of mixing and negative deviations from ideality. Non-volatile polar liquids, which dissolve amorphous PVC, are called plasticizers . PVC now becomes an elastomeric mixture of small crystalline regions and a solution phase. These materials are called plasticized polyvinyl chloride. 

Non-volatile esters are widely used as plasticizers for PVC. The relationship between PVC and ester solvents is similar to chloroform and acetone. They are used as plasticizers because they soften the PVC. Effectively they reduce the glass transition temperature of the amorphous regions below room temperature. The most famous of these ester-based plasticizers are phthalates (e.g., dioctyl phthalate). Table 3.6 lists various ester-based and other plasticizers for polyvinyl chloride. 

Doty and Zable [76] have examined the swelling of crosslinked polyvinyl chloride and determined the Kparameter of Eq. 3.31. Smaller values of Kmean greater swelling and better 

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These data for typical properties of EP polymers are either as measured or as advertised by respective manufacturers. This table is not intended to be definitive either in terms of the total grade slate or the specific data reported for each producer. Note that the molecular weight distribution data are based on a qualitative comparison of GPC curves. Mooney viscosities are repotted for final product form (i.e.. in the case of oil-extended rubbers, the viscosity is that of the EP plus oil. 

Network Structure in Oil-Extended Rubbers - Effect of Chain Entanglements... 

Knowledge of the physical state of oil in oil-extended rubbers and their vulcanisates is of great importance, because the processing of oil-extended rubbers and the mechanical properties of such rubbers are strongly affected by the rubbers oil content and the type of oil concerned. 

Up to 400 K (127 °C), the fraction of the component with a long decay time was smaller than the concentration of oil hydrogen in the oil-extended rubber. Apparently, a small fraction of oil molecules shows a molecular mobility comparable with that of EPDM chains. The fraction of these physically trapped oil molecules decreased with an increasing temperature, and... 

The crosslinking kinetics and the final state of cure are commonly studied with the aid of rheometers. NMR relaxation experiments can offer several advantages for the characterisation of the crosslinking kinetics in complex materials because of high method selectivity with respect to the rubbery chains/phases in polymer blends, filled and oil extended rubbers. 

The time it takes for the temperature of a sample to stabilise in an NMR probe can also be determined in real-time XH NMR Tj relaxation experiments, because at vulcanisation temperatures Tj is only slightly affected by a moderate crosslink density [22, 180, 181]. The T2 data obtained in the aforementioned experiments were used for determining an increase in the density of chemical crosslinks upon vulcanisation time (Figure 10.18) [179]. The method can also be used in kinetic studies of the vulcanisation of filled and oil-extended rubbers. 

Rubbers are plasticized with petroleum oils, before vulcanization, to improve processability and adhesion of rubber layers to each other and to reduce the cost and increase the softness of the final product. Large quantities of these oil-extended rubbers are used in tire compounds and related products. The oil content is frequently about 50 wt% of the styrene-butadiene rubber. The chemical composition of the extender oil is important. Saturated hydrocarbons have limited compatibility with most rubbers and may sweat-out. Aromatic oils are more compatible and unsaturated straight chain and cyclic compounds are intermediate in solvent power. 

Oil is also often a component of the car tyre rubber compound. It is blended with the pure rubber forming the so-called oil-extended rubber phase. Usually an aromatic oil is used such an oil showed a Tg(onset)-value at 232K (-41°C). But also naphtenic oil with a Tg(onset)-value of 208 K (-65°C) is used. 

Figure 2.75 shows the constructions of a standard bias (diagonal) ply tire and a radial ply tire. The major components of a tire are bead, carcass, sidewall, and tread. In terms of material composition, a tire on an average contains nearly 50% of its weight in actual rubber for oil extended rubbers (typically containing 25 parts of aromatic or cycloparafiBnic oils to 75 parts of rubber), it is less. The remainder included carbon black, textile cord, and other compounding ingredients plus the beads. 

OER Oil-extended rubber (rubber filled with mineral oil)... 

EPDM XG 006 Ethylene-propylene oil extended rubber Polysar-Miles... 

Polymer solutions (i.e., polymers dissolved in low molecular weight solvents) are widely used in industrial compoimds of varying complexity. Synthetic hydrocarbon elastomers are often marketed as oil-extended rubber , which are solutions of the basic elastomer with hydrocarbon mineral oils. Polyvinyl chloride is often marketed in a plasticized form, which are solutions involving low molecular weight esters. Many additives dissolve in polymers forming polymer solutions. In this chapter, we consider the fundamental thermodynamics and rheology of polymer solutions as well as important applications. 

In Table 4.1, the solubility of various low molecular weight compounds in polymers is summarized. The situation is very different from oil-extended rubber (Section 3.10) or plasticized polyvinyl chloride (Section 3.11). The level of miscibility of polar additives in non-polar polyolefins is quite small. 

Using the mixing method described in the previous paper in this series, which produces reproducible data, the authors investigated each factor that affects the black incorporation time. Various carbon blacks, oil-extended rubber and oil were used as the materials in the tests. The mixing conditions used were the rotational speed, rotational ratio of the rotor, fill factor and ram pressure. The authors studied the effect of these factors on the black incorporation time by the new theory based on static electricity phenomena and rabber viscoelasticity. 7 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. 

Macrogel-containing rubber may be oil-extended to alleviate the milling problem. Sometimes oil-extended rubber has a superior strength as a vulcanisate compared with the gel-free, non-oil-extended counterpart. 

In comparing compounds 5 and 7, the oil-extended rubber, SBR 1712, shows a lower amplification. A smaller amount of rubber against the amount of carbon black may be the reason. 

It is inconceivable that within such a short time rubber molecules can diffuse into the tortuous passage of approximately 20 nm size (see Figure 9.5), and fill 95% of the void volume. Knowing that both SBR 1712 and BR 411 were oil extended rubbers, the oil could have filled the void. Along with the oil a small amount of rubber molecule could also have been carried into the void. 

The following abbreviations arc also used. ICR rubber from undiluted latex of natural rubbo- (initial eoncentration rubber) OER oil-extended rubber, RTV room temperature ... 

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