Aliphatic oil

Whilst exhibiting the excellent low-temperature flexibility (with a Tg of about -80°C) and very good heat resistance (up to 200°C) typical of a silicone rubber, the fluorosilicones also exhibit good aliphatic oil resistance and excellent aging resistance. However, for some applications they have recently encountered a challenge from the polyphosphazenes (see Section 13.10). 

It has been suggested that the explanation of pulmonary disease among powder workers in other countries may lie in the duration of exposure, the size of the particles, the density of the dust, and especially the fact that all reported cases have been associated with exposure to a submicron-sized aluminum pyrotechnic flake (powder), which has been lubricated with a nonpolar aliphatic oil rather than the usually employed stearic acid 7... 

The HLB temperature was found to be the most important factor in the formation of stable emulsions. In each case, w/o HIPEs [9,11,80] would only form at temperatures above the HLB temperature of the systems, while o/w HIPEs [14] formed below the PIT. The nature of the oil phase was also found to be of importance to the formation of stable w/o HIPEs [11] aromatic liquids, for example, did not produce highly concentrated emulsions. With aliphatic oils, the stability was observed to vary with chemical nature. This was due to the different HLB temperatures for each liquid. 

It is believed that the conflicting study results are due to differences in the lubricant used to retard surface oxidation during milling (Dinman 1987). Stearic acid is the most commonly used lubricant in the aluminum industry the stearic acid combines with the aluminum to form aluminum stearate. Exposure to the aluminum stearate does not appear to be fibrogenic to workers (Crombie et al. 1944 Meiklejohn and Posner 1957 Posner and Kennedy 1967). In contrast, the previous and now discontinued use of a nonpolar aliphatic oil lubricant, such as mineral oil, has been associated with fibrosis (Edling 1961 McLaughlin et al. 1962 Mitchell etal. 1961 Ueda etal. 1958). 

Ueda et al. 1958). The pulmonary fibrosis has only been associated with pyropowders utilizing nonpolar aliphatic oil lubricants, such as mineral oil exposure to pyropowder which used stearic acid as a lubricant does not result in fibrosis (Crombie et al. 1944 Meiklejohn and Posner 1957 Posner and Kennedy 1967). 

The resulting TPE can either be used alone or blended with aliphatic oil and polypropylene. In the former case a higher tensile strength and elongation at break are obtained in comparison with the commercially available styrene-hydrogenated butadiene-styrene block copolymers, especially at high temperatures. 

Fig. 32. (a) Two-dimensional small-angle X-ray scattering pattern of an SBS block copolymer with 33% aliphatic oil content and stretched to a draw ratio X = 4. (b) Long period L in SBS Meek copolymers as a function of the draw ratio X (pure SBS and SBS with different oil contents), (c) height of the polystyrene cylinders h in SBS block copolymers as a function of the draw ratio X (pure SBS and SBS with different oil contents), (d) diameter of the polystyrene cylinders 2r in SBS block copolymers as a function of the draw ratio X (pure SBS and SBS with different oil contents)... 

Slightly soluble in H3O soluble in ethyl alcohol, benzene, ether, and essential and aliphatic oils. 

Numerous aromatic and aliphatic oils have been tested and reported in the literature. The oils most commonly used commercially are deodorized kerosenes (Exxcxi Goip.), as for example Isc iar M, AMSCO OMS and IX)PS (low odour paraffin solvent). 

It is found that the AG for the tran.sfer of an EO group from water to heptane decreases from 0.6 to 0,4 calorie as temperature increases from 25°C to 50 C. It means that it is easier to transfer an EO group from water to oil at higher temperature. Oil phase nature also seems to be quite imponant in this energetic barrier. Recent evidence indicates that with aromatic oil phases, the AG (EOgropp may be much smaller than with aliphatic oils, may be zero with pure benzene. This corroborates the trends found on the PIT some 40 years ago. 

Acids Bases Aromatics Aliphatics Oil in water Water in oil... 

In most of the experiments, an aliphatic oil (Soltrol-130) was used as the wetting phase and air was the nonwetting phase. This choice of fluids ensured that the contact angle was zero through the oil phase for all experiments. The Soltrol had a viscosity of 1.42 cp, density of 0.7484 gm/cm, and surface tension of 23.19 dynes/cm. All measurements were made at room temperature (23 0.5 C). 

Three different resin-rubber blend systems were examined by frequency scan at room temperature. First, we examined blends of natural rubber with a compatible aliphatic oil. Figure 44 shows G vs. frequency at various loadings of oil to natural rubber. As we add oil, the modulus curve as a function of frequency is depressed. This is to be expected as the oil softens the composition which, in turn, causes the reduction of the modulus. In other words, oil does not change the tan 8 peak (7g) temperature of natural rubber it only reduces the room-temperature modulus value of natural rubber. Consequently, it does not function as an effective tackifying resin. 

All fats, aliphatic oils, and waxes belong to the ester class of compounds, and on hydrolysis liberate alcohol and acids. Hence, in studying the lipides it is convenient to start with a survey of these aliphatic or lipide acids. 

When a compatible oil is added to an elastomer such as natural rubber, it acts as a plasticizer. The storage modulus (G ) of a natural rubber/aliphatic oil adhesive decreased at all frequencies with the increasing amount of plasticizing oil as shown in O Fig. 13.6 (Satas 1999). 

Effect of plasticizing oil on the storage modulus (G ] of natural rubber/aliphatic oil as function of frequency at 25°C (Satas 1999)... 

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