Hydrocarbon macromolecule

Preparation of Cyclopropane Hydrocarbon Macromolecules. The preparation of cyclopropane type macromolecules C was contemplated with interest since this structure actually possesses similarities to those of polyenes A in the matter of local rigidity of the chains either with respect to the cyclopropane or to the double bond. Furthermore, several... 

Tewari, Y. B. Schreiber, H. P., "Thermodynamic Interactions in Polymer Systems by Gas-Liquid Chromatography. II. Rubber-Hydrocarbons," Macromolecules, 5, 329 (1972). 

In concluaon, the classes of polymers described in this work offer interesting posribilities for modifying hydrocarbon macromolecules through specific reactions... 

Ungar G (1986) From plastic-crystal paraffins to liquid-crystal polyethylene Continuity of the mesoi se in hydrocarbons. Macromolecules, 19 1317... 

An early, and widely used, commercial example of side-chain functionalities inducing interactions between polymer chains are ionomers, hydrocarbon macromolecules bearing, for example, carboxylic acid groups [e.g., poly(ethylene-co-methacrylic acid)], which are partially or fuUy neutralized with metal or quaternary ammonium ions. These ionomers are thermoplastic ionic polymers boasting unique physical properties such as enhanced impact strength, toughness, and thermal reversibility. They were developed and commercialized by DuPont, and have recently attracted attention due to their self-healing properties. ... 

Kobayashi H, Bell AT, Shen M. Plasma polymerization of saturated and unsaturated hydrocarbons. Macromolecules. 1974 7 277 83. 

Polyethylene Is a hydrocarbon macromolecule that Is inert to most chemicals we use in day-to-day life. 

After the heavy oil has been separated from the sand, the bitumen cannot be processed in a normal oil refinery. It must be treated in an upgrader, where the hydrocarbon macromolecules are broken into smaller fragments. There are two processes commonly used. Petroleum coke can be produced, where any sulfur components remain. The more common process involves hydrogen cracking, which produces synthetic crude oil, which is then further refined in traditional oil refineries. The sulfur trapped in the organic matrix of the oil is converted into hydrogen sulfide. A traditional Claus process can then be used to produce sulfur. 

This chapter examines why fluoropolymers exhibit extreme properties. It focuses on the reasons that replacement of hydrogen with fluorine in hydrocarbon macromolecules improves their thermal stability, chemical resistance, electrical properties, and coefficient of friction. Understanding the role of fluorine in determining the properties of a polymer will contribute to a more in depth appreciation of some of the other information in this book. It will also allow the readers to make more informed judgments about fluoropolymers and their applications. 

Preusting H, Nijenhuis A and Witholt B, Physical characteristics of poly(3-hydroxy-alkanoates) and poly(3-hydroxyalkenoates) produced by Pseudomonas oleovorans grown on aliphatic hydrocarbons. Macromolecules. 1990, 23 4220-4224. 

Most LB-forming amphiphiles have hydrophobic tails, leaving a very hydrophobic surface. In order to introduce polarity to the final surface, one needs to incorporate bipolar components that would not normally form LB films on their own. Berg and co-workers have partly surmounted this problem with two- and three-component mixtures of fatty acids, amines, and bipolar alcohols [175, 176]. Interestingly, the type of deposition depends on the contact angle of the substrate, and, thus, when relatively polar monolayers are formed, they are deposited as Z-type multilayers. Phase-separated LB films of hydrocarbon-fluorocarbon mixtures provide selective adsorption sites for macromolecules, due to the formation of a step site at the domain boundary [177]. 

At best, van der Waals interactions are weak and individually contribute 0.4 to 4.0 kj/mol of stabilization energy. ITowever, the sum of many such interactions within a macromolecule or between macromolecules can be substantial. For example, model studies of heats of sublimation show that each methylene group in a crystalline hydrocarbon accounts for 8 k[, and each C—IT group in a benzene crystal contributes 7 k[ of van der Waals energy per mole. Calculations indicate that the attractive van der Waals energy between the enzyme lysozyme and a sugar substrate that it binds is about 60 k[/mol. 

Fig. 3.5 Representation of a scheme of an experiment (upper set of drawings) and the obtained experimental results presented as AFM images (middle part) and cross-sectional profiles (bottom) that provides evidence of silica nucleation and shell formation on biopolymer macromolecules. Scheme of experiment. This includes the following main steps. 1. Protection of the mica surface against silica precipitation. It was covered with a fatty (ara-chidic) acid monolayer transferred from a water substrate with the Langmuir-Blodgett technique. This made the mica surface hydrophobic because of the orientation of the acid molecules with their hydrocarbon chains pointing outwards. 2. Adsorption of carbohydrate macromolecules. Hydrophobically modified cationic hydroxyethylcellulose was adsorbed from an aqueous solution. Hydrocarbon chains of polysaccharide served as anchors to fix the biomacromolecules firmly onto the acid monolayer. 3. Surface treatment by silica precursor. The mica covered with an acid mono-...

Macromolecules have also been specifically designed and synthesized for use as emulsifiers for lipophilic materials and as stabilizers in the colloidal dispersion of lipophilic, hydrocarbon polymers in C02. We have demonstrated the amphiphilicity of fluorinated acrylate homopolymers, such as PFOA, which contain a lipophilic, acrylate like backbone and C02-philic, fluorinated side chains (see Fig. 3) [103]. It has been demonstrated that a homopolymer which physically adsorbs to the surface of a polymer colloid prevents agglomeration by the presence of loops and tails (see Fig. 4) [113]. The synthesis of this type of... 

Covalent binding of chemical carcinogens to cellular macromolecules, DNA, RNA and protein, is wel1-accepted to be the first step in the tumor initiation process ( 1, 2). Most carcinogens, including polycyclic aromatic hydrocarbons (PAH), require metabolic activation to produce the ultimate electrophilic species which react with cellular macromolecules. Understanding the mechanisms of activation and the enzymes which catalyze them is critical to elucidating the tumor initiation process. 

In studies of the fate of hydrocarbons in terrestrial animals, considerable attention is directed toward relations between aromatic hydrocarbon metabolism, interactions of metabolites with macromolecules (e.g., DNA), and the formation of neoplastic lesions (] ). A broad perspective exists in studies with marine organisms. In the aquatic forms, exposure to pollutants that are rich in aromatic hydrocarbons, such as petroleum, leads to a wide variety of acute and chronic effects (2J. Attempts to delineate these effects require an understanding of the accumulation of the xenobiotics in tissues and an assessment of metabolite formation and retention. The important additional problem of the interaction of metabolites with genetic materials has not been studied to an appreciable degree in marine life. 

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