Subject hydrocarbon polymers

Before fluorination, the dielectric constant ofpoly(bisbenzocyclobutene) was 2.8, and this value was reduced to 2.1 after plasma treatment. No data were reported in the paper on characterization of structure or properties, except for the dielectric constant of the modified poly(bisbenzocyclobutene). The authors did report that the thermal stability offluorinatedpoly(vinylidenefluoride) was inferior to the original poly(vinylidenefluoride) when treated in a similar way. One of the probable reasons for the low thermal stability is that the NF3 plasma degraded the polymer. According to their results, the thickness of fluorinated poly(bisbenzo-cyclobutene) was reduced by 30%. The same phenomenon was observed for other hydrocarbon polymers subjected to the NF3 plasma process. A remaining question is whether plasma treatment can modify more than a thin surface layer of the cured polymer Additionally, one of the side products generated was hydrogen fluoride, which is a serious drawback to this approach. 

In the development of polymer electrolyte membrane fuel cells (PEMFC), the durability of the membrane is one of the most important issues. For automotive utilization of PEMFCs, high-temperature operations between 110 and 120°C and low-humidity conditions are required. Fot the membranes of PEMFCs, perfluOTOsulfonic acid (PFSA) polymers are extensively used owing to their considerably higher chemical stability over hydrocarbon polymers. However, conventional PFSA polymers have glass-transition temperatures around 80°C, and are subject to critical breakdown of the membrane at high tanperatures. Additionally, conventional PFSA polymers suffer from degradation under low-humidity conditions even at 80°C. 

The WAG process has been used extensively in the field, particularly in supercritical CO2 injection, with considerable success (22,157,158). However, a method to further reduce the viscosity of injected gas or supercritical fluid is desired. One means of increasing the viscosity of CO2 is through the use of supercritical C02-soluble polymers and other additives (159). The use of surfactants to form low mobihty foams or supercritical CO2 dispersions within the formation has received more attention (160—162). Foam has also been used to reduce mobihty of hydrocarbon gases and nitrogen. The behavior of foam in porous media has been the subject of extensive study (4). X-ray computerized tomographic analysis of core floods indicate that addition of 500 ppm of an alcohol ethoxyglycerylsulfonate increased volumetric sweep efficiency substantially over that obtained in a WAG process (156). 

Performance of plastics , W. Brostow Hanser Gardner Pubis (1999) ISBN 1569902771. Comprehensively covers the behavior of the most important polymer materials. Subject areas range from Computer Simulations of Mechanical Behavior to Reliability and Durability of aircraft structures made of fiber-reinforced hydrocarbons. 

The nitration of aromatic hydrocarbons is one of the most widely studied and well-documented reactions in organic chemistry. Aromatic nitro compounds are of huge industrial importance in the synthesis of pharmaceutical drugs, agrochemicals, polymers, solvents and perfumes, and for the synthesis of other industrially important chemicals containing amine and isocyanate functionality. However, early research into aromatic nitration was fuelled exclusively by their use as explosives and intermediates in the synthesis of dyestuffs. The former is the subject of this chapter. 

One line of attack, which is the subject of this paper, is to convert the sulfuric acid in the used catalyst to dialkyl sulfates, which are soluble in hydrocarbons, and then extract the dialkyl sulfates from the conjunct polymers and water. Considerable background information was available prior to the late 1950 s when a study was started with the specific objective of developing such a recovery process. When it is considered that sulfuric acid had a net cost of not over about one cent per pound, or 20.00 per ton, and a net cost in alkylation of about... 

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