Polymer modification acetone

In an acetone extract from a neoprene/SBR hose compound, Lattimer et al. [92] distinguished dioctylph-thalate (m/z 390), di(r-octyl)diphenylamine (m/z 393), 1,3,5-tris(3,5-di-f-butyl-4-hydroxybenzyl)-isocyanurate m/z 783), hydrocarbon oil and a paraffin wax (numerous molecular ions in the m/z range of 200-500) by means of FD-MS. Since cross-linked rubbers are insoluble, more complex extraction procedures must be carried out (Chapter 2). The method of Dinsmore and Smith [257], or a modification thereof, is normally used. Mass spectrometry (and other analytical techniques) is then used to characterise the various rubber fractions. The mass-spectral identification of numerous antioxidants (hindered phenols and aromatic amines, e.g. phenyl-/ -naphthyl-amine, 6-dodecyl-2,2,4-trimethyl-l,2-dihydroquinoline, butylated bisphenol-A, HPPD, poly-TMDQ, di-(t-octyl)diphenylamine) in rubber extracts by means of direct probe EI-MS with programmed heating, has been reported [252]. The main problem reported consisted of the numerous ions arising from hydrocarbon oil in the recipe. In older work, mass spectrometry has been used to qualitatively identify volatile AOs in sheet samples of SBR and rubber-type vulcanisates after extraction of the polymer with acetone [51,246]. 

A series of novel styrene- and siloxane-based silanol polymers and copolymers were synthesized by a selective oxidation of the Si—H bond with a dimethyldioxirane solution in acetone from corresponding precursor polymers. The conversion of the Si—H to Si—OH in the polymer modification proceeded rapidly and selectively. The silanol polymers obtained in situ showed no tendency for self-condensation to form siloxane crosslinks in solution. Moreover, stable silanol polymers in the solid states were obtained by placing bulky substitute groups bonded directly to the silicon atom. It was found that the properties of these novel silanol polymers and copolymers depended largely on substituents bonded directly to the silicon atom and silanol composition in the copolymers as well. 

Polymer modification is of particular interest when the desired polymer is not readily available from its corresponding monomer by conventional polymerization methods. The primary challenge of polymer modification is to achieve a high conversion and selective modification of the appropriate functional group. In this paper, we describe a new convenient polymer modification to prepare novel silanol polymers by a rapid and selective oxidation of the Si—H bond with a dimethyldioxirane solution in acetone from their corresponding precursor polymers. 

A new convenient polymer modification has been developed to synthesize a series of novel silanol-containing polymers by a selective oxidation of Si—containing precursor polymers with a dimethyldioxirane solution in acetone. The silanol hydrogen bonding interactions in polymer blends as well as the silanol self-condensation to form siloxane semi-interpenetrating polymer networks in miscible polymer blends and organic-inorganic polymeric hybrids are discussed. 

Polymer Modification of the sSi—Containing Precursor Polymers with a Dimethyldioxirane solution in acetone. To a methyl ethyl ketone solution of sSi—H containing precursor polymers or copolymers, a cold solution (ca. -10 °C) of dimethyldioxirane in acetone was quickly added and reacted for 30 min at 0 °C. The mole ratio of dioxirane to polymer was ca. 1.2 1.3. The resulting silanol polymers or copolymers were obtained either in solution and used as is or precipitated into hexane followed by vacuum drying at 40 °C for 24 h. 

A new convenient polymer modification for synthesis of silanol-containing polymer was developed by the selective oxidation of the Si—H bond with a dimethyldioxirane solution in acetone. The oxyfunctionalization of the silane precursor polymers can be utilized to synthesize a wide variety of silanol-containing polymers. Control over the properties of these silanol polymers, such as stability and self-association of silanols, was realized through the placement of different substitute groups bonded directly to the silicon atom. The miscibility in either polymer blends or polymeric hybrids was achieved by the formation of strong inter-polymer hydrogen bonds between the... 

Photoreactions of MA with 1,2-polybutadiene, 1,4-polybutadiene, poly(styrene-co-butadiene), poly(styrene-co-isoprene), polystyrene, and poly(styrene-co-methyl methacrylate) have been studied in air. " In homogeneous solutions, MA addition to the polymers proceeds efficiently by a chain mechanism, where the quantum yield of the photoaddition was greater than unity under irradiation at A >310 nm. From the effects of solvent and photosensitizers and spectroscopic data, a radical chain mechanism was proposed to account for addition and crosslinking of the polymers by MA molecules. The photoaddition reaction was applied to the surface of polymer films. The photoreactions were conducted at the interphase between solid polymer and acetone solution of anhydride and also at the interphase between solid polymer and gaseous anhydride. Irradiation with a 300-W high-pressure lamp brought about considerable surface modification, as shown by wettability and dyeability properties. 

As an example, bulk modification by the organic reaction of unsaturated PHA with sodium permanganate resulted in the incorporation of dihydroxyl or carboxyl functional groups [106]. Due to the steric hindrance of the isotactic pendant chains, complete conversion could not be obtained. However, the solubility of the modified polymers was altered in such a way that they were now completely soluble in acetone/water and water/bicarbonate mixtures, respectively [106]. Solubility can play an important role in certain applications, for instance in hydrogels. Considering the biosynthetic pathways, the dihydroxyl or carboxyl functional groups are very difficult to incorporate by microbial synthesis and therefore organic chemistry actually has an added value to biochemistry. 

Modifications of monodisperse colloidal silica, of 10 or 500 nm in diameter, were carried out using trialkoxysilane-terminated polymer in a low polar solvent, such as acetone or 1,2-dimethoxyethane. without coagulation during the coupling reaction (35,37-42). In this modification, the hydrophobic polymer can be efficiently bound to hydrophilic colloidal silica surface. The reaction mechanism of the binding... 

If the surface of a metal or carbon electrode is covered with a layer of some functional material, the electrode often shows characteristics that are completely different from those of the bare electrode. Electrodes of this sort are generally called modified electrodes [9] and various types have been developed. Some have a mono-molecular layer that is prepared by chemical bonding (chemical modification). Some have a polymer coat that is prepared either by dipping the bare electrode in a solution of the polymer, by evaporating the solvent (ethanol, acetone, etc.) of the polymer solution placed on the electrode surface, or by electrolytic polymerization of the monomer in solution. The polymers of the polymer-modified electrodes are either conducting polymers, redox polymers, or ion-exchange polymers, and can perform various functions. The applications of modified electrodes are really limit-... 

Polymer-protected bimetallic clusters were also formed using a modified polyol process. The modification included addition of other solvents and sodium hydroxide. In the synthesis of Co-Ni with average diameters between 150 and 500 nm, PVP and ethylene glycol were mixed with either cobalt or nickel acetate with PVP. The glycol and organic solvents were removed from solution by acetone or filtration. The PVP-covered particles were stable in air for extended periods of time (months). 

Attenuated total reflectance infrared spectroscopy was employed to determine the possible chemical modification of the PVC specimen exposed to t-butyl alcohol and methyl t-butyl ether. Infrared spectroscopy has been used to study solvent absorption (17), oxidation (18) and other degradation reactions of polymers (19). In the studies of the hostile effects of methyl t-butyl ether and acetone, the solvent was concentrated and examined using conventional infrared techniques. 

Tanaka and his coworkers have used Flory s formula with several modifications to understand a discrete phase transition in ionic gels. First, the term Vo IV in Eq. 3 was replaced by the term

volume fraction of the network on condition that the constituent polymer chains have random-walk configurations [5]. Flory assumed that the dry gel (in other words, the network formed by cross-linking of the unswollen polymer at volume V0) satisfies the condition of no polymer interactions i.e., covalently cross-linked PAAm gels in an acetone-water mixture therefore he claimed that the elastic term is generally not a function simply of V0/V (=[Pg.594]

Therefore it is necessary to use the different finely dispersed suspension for the modification of enumerated materials. The series of suspensions consist the suspensions on the basis of following liquids water, ethanol, acetone, benzene, toluene, dichlorethane, methylene chloride, oleic acid, polyethylene polyamine, isomethyl tetra hydrophtalic anhydrite, water solutions surface-active substances or plasticizers. In some cases the solutions of correspondent polymers are applied for the making of the stable finely dispersed suspensions. The estimation of suspensions stability is given as the change of optical density during the definite time (Figure 8.26)... 

In Germany, a different method was used for the modification of the solubility of PVC, and an acetone-soluble polymer was obtained by the chlorination of PVC. A fiber of this type of polymer was produced for the first time in 1934 and was called the Pe-Ce fiber [145]. 

Inagaki, N., Tasaka, S., Takami, Y, 1990. Durable and hydrophobic surface modification by plasma polymers deposited from acetone/hexafluoroacetone, ethylene/hexafluoroacetone, and ethane/hexafluoroacetone mixture. J. Appl. Polym. Sci. 41, 965-973. 

In this section, the blocking of the amine end groups of PA-6 with liquid diketene (the dimer of ketene) and the diketene acetone adduct (Fig. 13.8) in supercritical CO2 is discussed. Ketene itself is an extremely reactive, unstable, and very toxic gas. Diketene and the diketene acetone adduct have frequently been used in industry since they are reactive toward a large variety of functional groups such as amines, alcohols, and carboxylic adds [83-85], but are not reactive toward the amide groups in the PA-6 chain without a catalyst, whereas ketene is. This makes them useful for the modification of polymer partides in supercritical CO2 under very mild reaction conditions, thereby avoiding side reactions. 

The baseline resistance of the sensors also depends on the posttreatment. There are various explanations for the mechanism behind the response behavior modification due to the posttreatment. The lower baseline resistance and the faster response transients after the acetone treatment could be caused by dissolving some of the acrylic matrix during this posttreatment. Dissolving the matrix can result in a closer contact between the conducting polymer grains and enhanced diffusion due to a smaller path length through the composite layer. 

The extent of modification depends on the conditions and the swelling of the polymer in the fluids. At 40-60 °C and 135 - 340 bar over 24 hours the modification is only about 2% for PVA (due to its high crystallinity) but 70 % for PHMPA. Extend of modifications is improved with addition of acetone as cosolvent to carbon dioxide - this improves the solubility of the reactants. 

Random copolymers of acrylamide with N,N-dimethylacrylamide and with N,N-diethylacrylamide were prepared as illustrated in reactions (7) and (8). The respective copol3nners, PAMDMAM and PAMDEAM, have been synthesized to elucidate more fully the role of hydrogen-bonding and N-substitution on viscosity modification. These polymers were synthesized using potassium persulfate initiators in water or 30% methanol/water solutions. Reaction conditions and monomer feed ratios are given in Table 2. The resulting copolymers were purified by precipitation into acetone followed by vacuum drying at 50 C for 60 hours. 

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