Absorbed hydrocarbon polymers

Polynorbomene the oldest polyalkenamer is manufactured by a method developed by CDF Chimie156 157 since 1976. Tungsten or rhodium catalysts are used to yield a highly trans polymer. This is capable of rapidly absorbing hydrocarbon oils and can be crosslinked to produce a very soft rubber. 

There is ample energy in 29Unm radiation to break most bonds in hydrocarbon polymers, but both the absorbance rates and quantum yields are low. Photoreactions begin with the electronic excitation of a molecule. The excited cies, A, may inmedlately emit its excess energy in the form of radiation... 

Toluene Swelling. All samples swell substantially when immersed in toluene. It is assumed that toluene, a good solvent for polybutadiene, with a low dielectric constant (e—2.38 at 25°C) is absorbed preferentially in the hydrocarbon polymer phase and excluded from the ionic domains. Swelling is then equivalent to changing the distance between domains. 

One completely unexpected property of the polymer derived from monomer 8 R = H ( jco-Gly) was its ability to absorb hydrocarbons (Table 2). This property is independent of the CIS / trans alkene content of the polymer and of the molecular weight of the polymer provided M > 17,000. The reason why this polymer (and only this polymer) absorbs hydrocarbons is not yet clear, but the hydrocarbon is released only at temperatures above the glass transition temperature of the polymer. 

Hydrolysis can occur only if the polymer has functional groups capable of reaction with water and if the water can gain access. Hydrocarbon polymers are very resistant to hydrolysis because they are not wetted by water and contain no hydrolyzable groups. In the polyolefins, water access is also restricted by the semicrystalline nature of the polymers. In complete contrast, many natural polymers, especially the polysaccharides (cellulose, starch, etc), are quite readily hydrolyzed at appropriate pH, because they are water absorbing and contain readily hydrolyzable links. 

Hydrocarbon polymers containing polar groups have high water uptakes over a wide temperature range, and the absorbed water is restricted to the polar groups of polymer chains. 

Numerous works by other authors and our own research group describe the syntheses of new proton exchange membranes based on hydrocarbon polymers. The characteristics of these new materials, which determine their potential applications, are discussed in detail. A review of electrochemical properties, water uptake, and thermal stability makes possible a comprehensive understanding of the proton conduction mechanism and physical state of absorbed water in these systems. 

Quenchers are light-stabilizing additives able to take over the energy of photons already absorbed by a suitable chromophore (Chr) of the polymer (see Scheme 9). Carbonyl groups, hydroperoxides, and singlet molecular oxygen (or its precursors) are chromophores commonly believed to be involved in the photodegradative mechanisms for numerous hydrocarbon polymers. ... 

Torlon-type polymers are unaffected by aliphatic, aromatic, chlorinated and fluorinated hydrocarbons, dilute acids, aldehydes, ketones, ethers and esters. Resistance to alkalis is poor. They have excellent resistance to radiation. If a total of 10 Mrad is absorbed at a radiation dosage of 1 Mrad/h the tensile strength decreases by only 5%. 

Manufacture of highly water-absorbent polymers with uniform particle size and good flowability can be carried out by reverse phase suspension polymerization of (meth)acrylic acid monomers in a hydrocarbon solvent containing crosslinker and radical initiator. Phosphoric acid monoester or diester of alka-nole or ethoxylated alkanole is used as surfactant. A polymer with water-absorbent capacity of 78 g/g polymer can be obtained [240]. 

The BP Chemicals polymer cracking process is based at Grangemouth in Scotland and uses mixed plastics as the raw material. The reactor uses a fluidised bed which operates at 500 °C in the absence of air, and under these conditions the plastics crack thermally to yield hydrocarbons. These vaporize and are carried away from the bed with the fluidising gas. Solid impurities such as metals from PVC stabilisers accumulate in the bed or are carried away in the hot gas to be captured by a cyclone further along in the plant. PVC decomposes to HCl and this is neutralized on a solid lime absorbent to yield CaCl2 which is disposed of in landfill. The purified gas is cooled to condense most of the hydrocarbon which can be employed as commercially useful distillate feedstock. The light hydrocarbons which are less easy to condense are compressed, reheated and recycled as fluidising gas. 

Polymers used in medicine fall into two main categories those that are sufficiently inert to fulfill a long-term structural function as biomaterials or membranes, and those that are sufficiently hydrolytically unstable to function as bioeradible materials, either in the form of sutures or as absorbable matrices for the controlled release of drugs. For the synthetic organic polymers widely used in biomedicine this often translates to a distinction between polymers that have a completely hydrocarbon backbone and those that have sites in the backbone that are hydrolytically sensitive. Ester, anhydride, amide, or urethane linkages in the backbone usually serve this function. 

H. J. Delhommer and C. O. Walker. Method for controlling lost circulation of drilling fluids with hydrocarbon absorbent polymers. Patent US 4633950,1987. 

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