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Acrylic acid characteristics

In September 1964 the Du Pont company announced materials that had characteristics of both thermoplastics and thermosetting materials. These materials, known as ionomers, are prepared by copolymerising ethylene with a small amount (1-10 % in the basic patent) of an unsaturated carboxylic acid such as acrylic acid using the high-pressure process. Such copolymers are then treated... [Pg.277]

Much like the oxidation of propylene, which produces acrolein and acrylic acid, the direct oxidation of isobutylene produces methacrolein and methacrylic acid. The catalyzed oxidation reaction occurs in two steps due to the different oxidation characteristics of isobutylene (an olefin) and methacrolein (an unsaturated aldehyde). In the first step, isobutylene is oxidized to methacrolein over a molybdenum oxide-based catalyst in a temperature range of 350-400°C. Pressures are a little above atmospheric ... [Pg.250]

CA 63,17781 (1965) Proplnt failure characteristics were measured in uniaxial and biaxial stress states for poly butadiene acrylic acid and Nitroplastisol proplnts, and failure conditions were examined over a wide range of temps. The observed failure conditions were compared for various failure criteria, and it was found that a... [Pg.946]

The two procedures give rise to different results. In both cases acrylic acid, present in the form of acrylate, readily reacts with ammonia at r.t. forming a species characterized by an intense band at 1535 cm i indicating the formation of an amide. With increasing reaction temperature (100°C), however, in the case of procedure A the band at 1535 cm shifts to 1495 cm-i and a weak band forms at 1720 cm h The latter band is characteristic of undissociated and weakly coordinated acrylic acid. This indicates that at 100°C amide dissociates with formation of the free acid. When ammonia is instead present in the gas phase (procedure B), the amide species undergoes transformation to acrylonitrile with a maximum in the intensity Fig. 6 IR spectra of 1 torr acrylic of the vcn band at 2220 cm- at an evacuation acid in contact (5 min) with Sb V=l temperature of about 300°C. and evacuation at r.t (a), and fol- Coordinated acrylic acid and ammonia thus lowing evacuations at 100 (b) and react faster at r.t. to form acrylamide, but in 200°C (c). absence of ammonia which inhibits the re-... [Pg.284]

A mixture of sulfonated styrene-maleic anhydride copolymer and polymers prepared from acrylic acid or acrylamide and their derivatives [759] are dispersants for drilling fluids. The rheologic characteristics of aqueous well drilling fluids are enhanced by incorporating into the fluids small amounts of sulfonated styrene-itaconic acid copolymers [761] and an acrylic acid or acrylamide polymer [755]. [Pg.311]

Figure 4. Effect of polymerization conditions on the release characteristics of the insulin/poly(acrylic acid) resin system. Figure 4. Effect of polymerization conditions on the release characteristics of the insulin/poly(acrylic acid) resin system.
Acrylic acid, CH2=CHCOOH, has the characteristic acid signature group. Acrylic acid can be made from propylene or from acrylonitrile and is generally used to make acrylates. [Pg.291]

The acrylates (for example, ethyl acrylate, CH2=CH-COOCH2CH3) are esters of acrylic acid, so they end.in the suffix -ate and have the characteristic signature -COOR. [Pg.291]

An interesting feature of current commercial products is that the polymer vehicles available for formulation have been limited to nonionic and anionic materials. The delivery vehicles available included off-the-shelf polymers such as carboxymethylcellulose, soluble starch, hydroxyethyl-cellulose, polyvinyl alcohol, poly(acrylic acid), and polyvinylpyrrolidone, or mixtures thereof. The choice of available polymeric delivery system primarily depends on component compatibility, aesthetics, and efficacy. However, by reliance upon available (off-the-shelf) systems, limitations on bioadhesion, drug bioavailability, contraceptive efficacy, and end-use characteristics has been limited. [Pg.217]

Monomer and initiator must be soluble in the liquid and the solvent must have the desired chain-transfer characteristics, boiling point (above the temperature necessary to carry out the polymerization and low enough to allow for ready removal if the polymer is recovered by solvent evaporation). The presence of the solvent assists in heat removal and control (as it also does for suspension and emulsion polymerization systems). Polymer yield per reaction volume is lower than for bulk reactions. Also, solvent recovery and removal (from the polymer) is necessary. Many free radical and ionic polymerizations are carried out utilizing solution polymerization including water-soluble polymers prepared in aqueous solution (namely poly(acrylic acid), polyacrylamide, and poly(A-vinylpyrrolidinone). Polystyrene, poly(methyl methacrylate), poly(vinyl chloride), and polybutadiene are prepared from organic solution polymerizations. [Pg.186]

In a related application, polyelectrolyte microgels based on crosslinked cationic poly(allyl amine) and anionic polyfmethacrylic acid-co-epoxypropyl methacrylate) were studied by potentiometry, conductometry and turbidimetry [349]. In their neutralized (salt) form, the microgels fully complexed with linear polyelectrolytes (poly(acrylic acid), poly(acrylic acid-co-acrylamide), and polystyrene sulfonate)) as if the gels were themselves linear. However, if an acid/base reaction occurs between the linear polymers and the gels, it appears that only the surfaces of the gels form complexes. Previous work has addressed the fundamental characteristics of these complexes [350, 351] and has shown preferential complexation of cationic polyelectrolytes with crosslinked car-boxymethyl cellulose versus linear CMC [350], The departure from the 1 1 stoichiometry with the non-neutralized microgels may be due to the collapsed nature of these networks which prevents penetration of water soluble polyelectrolyte. [Pg.29]

The bioadhesive characteristics of tablets for oral use made from modified starch, poly(acrylic acid), polyethylene glycol) and sodium carboxymethyl cellulose were recently investigated [406]. In this work, the force and energy adhesion were determined in vitro, and maximum adhesion times were evaluated in vivo in humans [406], In the in vitro, studies, the poly(acrylic add) gave the best performance, however in vivo bioadhesion was not strongly correletated with... [Pg.34]

Industrial needs for brighter phosphors in the form of well-dispersed finer particles are ever increasing, for display with higher resolution. This became realistic after the reports of Bhargava et al. (12,13). In the authors laboratory, ZnS Mn was modified by acrylic acid (AA) to increase the photoluminescence (PL) intensity (14-18). In this section, methods and characteristic features of such nanocomposites are reproduced in detail. The mechanism of increasing PL intensity is also elucidated from various angles. [Pg.687]

Poly(acrylic acid) (PAA), a MIP film candidate, has been shown to bind to the bare CdSe surface from methanol solution with considerable affinity [13]. Placement of drops of a PAA-methanol solution on the surface of CdSe and evaporation of the solvent leaves a PAA film on the semiconductor surface. Once coated with this PAA film, CdSe shows no change in PL intensity in the presence of amines. Despite the lack of a PL change, the deprotonation of the carboxylic acid could be observed by the shifting of the infrared (IR) carboxylic acid peak to lower frequencies characteristic of the carboxylate anion upon amine binding, as shown in Fig. 5. The reaction chemistry is ... [Pg.351]

A hydrogel placed in an excess of water will absorb the liquid until it reaches a maximum. This ability is typically reported as the percent water in a fully swollen gel. The hydrophilicity of the polymer and the degree of cross-linking determine the degree to which the gel will absorb. Some hydrogels contain as much as 99% water. An acrylic acid gel will have a higher equilibrium moisture than a polyvinyl alcohol gel. This characteristic is not unlike the hydrodynamic volume factor described above. [Pg.178]

Low density poly(ethylene) (LDPE) may have unsatisfactory heat seal properties, as they often do not provide sufficient adhesion between the sealing layers to result in a good adhesive seal for a package. Efforts to improve the heat seal characteristics of LDPE by blending them with other materials, such as ethylene copolymers with methacrylic acid or acrylic acid, have not had universal success. [Pg.146]

Acrylic acid can be used simultaneously as a monomer and as the solvent, the polyamide solution being frozen at dry ice temperature and ground in a vibration mill. The graft copolymer is said to be formed by mechanosynthesis and was confirmed by nitrogen analysis and solubility as well as swelling characteristics (5). [Pg.98]

Carbon Chain Backbone Polymers. These polymers may be represented by (4) and considered derivatives of polyethylene, where n is the degree of polymerization and R is (an alkyl group or) a functional group hydrogen (polyethylene), methyl (polypropylene), carboxyl (poly(acrylic acid)), chlorine (poly(vinyl chloride)), phenyl (polystyrene) hydroxyl (poly(vinyl alcohol)), ester (poly(vinyl acetate)), nitrile (polyacrylonitrile), vinyl (polybutadiene), etc. The functional groups and the molecular weight of the polymers, control their properties which vary in hydrophobicity, solubility characteristics, glass-transition temperature, and crystallinity. [Pg.478]

ACROLEIN AND DERIVATIVES. Acrolein (2-propenal), C3H4O, is the simplest unsaturated aldehyde (CH2=CHCHO). The primary characteristic of acrolein is its high reactivity due to conjugation of the carbonyl group with a vinyl group. More than 80% of the refined acrolein that is produced today goes into the synthesis of methionine. Much larger quantities of crude acrolein are produced as an intermediate in the production of acrylic acid. More than 85% of the acrylic acid produced worldwide is by the captive oxidation of acrolein. [Pg.14]


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See also in sourсe #XX -- [ Pg.314 ]




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