Showing papers on "Acrylic acid published in 1998"

Method for recovering acrylic acid

Abstract: An improved method which enables stable and effective recovery of acrylic acid over a prolonged period is provided, said method comprising contacting an acrylic acid-containing gas obtained upon gas-phase catalytic oxidation of propylene and/or acrolein, with water, whereby collecting the acrylic acid in form of an aqueous solution, introducing said aqueous solution into an azeotropic separation column and distilling it in the presence of an azeotropic solvent to isolate and recover the acrylic acid, in which polymerization of the acrylic acid in the azeotropic separation column is prevented. Said method is characterized by using as the azeotropic solvent either a mixed solvent composed of solvent A (eg., ethyl acrylate, methyl methacrylate, etc.) and solvent B (eg., toluene, heptane, etc.) (first embodiment) or the solvent A alone (second embodiment).

Synthesis of a new class of double-hydrophilic block copolymers with calcium binding capacity as builders and for biomimetic structure control of minerals.

Abstract: Small block copolymers consisting of a hydrophilic poly(ethylene glycol) block and a second, also hydrophilic, moiety which strongly interacts with alkaline earth ions were synthesized by diverse reaction sequences based on poly(ethylene glycol) monomethyl ethers (MW = 2000 and 5000 g/mol, respectively). These starting blocks were transferred to the poly(ethylene glycol) monomethyl monoglycidyl ether or to poly(ethylene glycols) with one terminal acid chloride group. Both intermediates were subsequently reacted with poly(ethyleneimine) (MW = 700 g/mol) and bromoacetic acid to yield poly(ethylene glycol)-block-poly[(N-carboxymethyl)ethyleneimine] (PEG-b-PEIPA, average MW = 3800 resp. 6800 g/mol) as a polymeric analog of EDTA. The terminal epoxy group is also convenient for the connection of simple peptide sequences. For the desired purpose of ion binding, poly(aspartic acid) (PAsp) was applied, resulting in the block copolymer PEO-b-PAsp. A simple testing procedure concerning the inhibition of calcium carbonate precipitation was applied for the prepared structures. A comparison with commercial builders for water treatment such as poly[(acrylic acid)-co-(maleic anhydride)] or poly(aspartic acid) stresses the superb calcium carbonate crystallization inhibition efficiency (up to the 20 fold) of the double hydrophilic block copolymer stabilizers.

The chemistry of deposits formed from acrylic acid plasmas

Abstract: SIMS and XPS were used to characterise the chemistry of thin plasma polymerised acrylic acid films (ppAAc), and to determine how this was influenced by plasma power. Quartz microbalance weight measurements were used to monitor the effect of power on the deposition rate and identify the uptake of water vapour by the films upon exposure to the atmosphere. Functional group derivatisation and XPS were used to quantify the proportion of carboxylic acid and ester functionalities. Derivatisation revealed that the level of retention in the deposit could be controlled by the plasma deposition power (P) up to a maximum of 66% at P=2 W. TOF SIMS analysis identified the presence of linear structures with up to five monomer units in the high retention deposit. The role of such structures in functional retention is discussed with reference to mass spectrometry data in the literature.

Metabolic routing towards polyhydroxyalkanoic acid synthesis in recombinant Escherichia coli (fadR): inhibition of fatty acid β‐oxidation by acrylic acid

Abstract: Heterologous expression of the phaC1 gene from Pseudomonas aeruginosa, which encodes one of the polyhydroxyalkanoic acid synthases, in Escherichia coli impaired in fatty acid β-oxidation results in polyhydroxyalkanoic acid accumulation when cells were cultivated on fatty acids. We evaluated the application of the fatty acid β-oxidation inhibitor acrylic acid as a tool to channel intermediates of β-oxidation to polyhydroxyalkanoic acid synthesis. Various E. coli strains affected in fatty acid metabolism and the wild-type strain harboring plasmid pBHR71 were analyzed with respect to polyhydroxyalkanoic acid accumulation in the presence of acrylic acid. The E. coli fadR mutant RS3097 revealed the strongest polyhydroxyalkanoic acid accumulation. The optimum inhibitory concentration of acrylic acid was 0.24 mg ml−1 and caused efficient channeling of intermediates of β-oxidation to polyhydroxyalkanoic acid synthesis. Under these conditions and grown on decanoate E. coli RS3097 harboring plasmid pBHR71 revealed a polyhydroxyalkanoic acid accumulation contributing to about 60% of cellular dry weight.

Dynamics of Water in a Polymer Matrix Studied by a Microwave Dielectric Measurement

Abstract: Dielectric measurements on water mixtures of polymers such as poly(vinylpyrrolidone) (PVP), poly(ethylene glycol) (PEG), poly(vinyl methyl ether) (PVME), poly(vinyl alcohol) (PVA), poly(acrylic acid) (PAA), poly(ethylenimine) (PEI), and poly(allylamine) (PAlA) were performed over a frequency range from 300 MHz to 15 GHz at 25 °C. Dielectric dispersion and absorption curves related to the orientational motion of water can be described well by the Cole−Cole equation. The distribution of the relaxation time is interpreted by the variation of the water structure. The logarithmic plot of the relaxation time against the parameter for the distribution of the relaxation time suggests two groups of polymers. One group contains nonelectrolyte polymers and another contains electrolyte polymers and PVA. This result implies that water structures in the mixtures of the former group are more uniform and stable than that in the mixtures of the latter group.

Solid Phase Synthesis of beta-Peptoids: N-Substituted beta-Aminopropionic Acid Oligomers.

Abstract: A solid-phase organic synthesis method has been developed for the preparation of N-substituted-β-aminopropionic acid oligomers or β-peptoids 1. Treatment of polymer-bound 4-(benzyloxy)benzyl acrylate 2 with primary amines afforded N-substituted β-alanines 3. Polymer loadings and product conversions were determined by direct cleavage of resin-bound materials and measurement by 1H NMR with an internal standard. The NMR method was used to establish loading of all resin-bound intermediates including acrylic acid. Acylation with acryloyl chloride followed by Michael addition of primary amines to the acrylamide allowed preparation of di-β-peptoids. By a linear set of seven reactions, trimeric N-benzyl-β-aminopropionic acid was prepared in 67% overall yield. Single-bead FT-IR microspectroscopy was used to acquire spectra of the resin bound mono-β-peptoids, di-β-peptoids, and acrylamide intermediates. A combinatorial library of defined mixtures of tri-β-peptoids was prepared by mixing equimolar amounts of the mon...

Polymer Micelles from Poly(acrylic acid)-graft-polystyrene

Abstract: Micelles have been prepared from poly(acrylic acid)-graft-polystyrene by direct injection of a dioxane solution of the polymer into water containing various concentrations of NaCl. The size of the ...

Novel Family of Thermogelling Materials via C−C Bonding between Poly(acrylic acid) and Poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide)

Abstract: Pluronic poly(ethylene oxide)−poly(propylene oxide)−poly(ethylene oxide) (PEO−PPO−PEO) block copolymers are copolymerized with poly(acrylic acid) (PAA) by a one-step free-radical polymerization of acrylic acid with the chain transfer to the Pluronic dissolved in the acrylic acid. Exponential increase of branching and cross-linking in the resulting Pluronic−PAA copolymers is observed at high degrees of conversion of acrylic acid. The solutions show reversible gelation within a narrow temperature range, with a gelled state resembling that of permanently cross-linked gels. Onset of thermogelation in Pluronic−PAA solution coincides with augmentation of light-scattering intensity of large scatterers and approaches the critical micellization temperature of the parent Pluronic. Effects of the overall PEO content and the length of the PPO segment in the parent Pluronic on the properties of copolymers are revealed.

Volume Phase Transition of Polyelectrolyte Gels with Different Charge Distributions

Abstract: Four polyelectrolyte gels consisting of acrylic acid (AA) and N-isopropylacrylamide (NIPA) were prepared using the following methods: (i) the usual redox polymerization of an aqueous solution containing NIPA, AA, and N,N‘-methylenebis(acrylamide) (cross-linker) which was initiated by a pair of ammonium persulfate and N,N,N‘,N‘-tetramethylethylenediamine; (ii) the same method as employed in (i) except for the use of poly(acrylic acid) (PAA) instead of the AA monomer; (iii) the gelation of an aqueous solution containing the polymer of NIPA (PNIPA) and PAA with γ-ray irradiation from 60Co; (iv) the same method as used in (iii) except for the use of an AA/NIPA copolymer instead of the PAA/PNIPA mixture. The gels prepared by (i) and (iv) contain the AA residues randomly distributed within the network, while the AA residues in the gels prepared by (ii) and (iii) are localized along the PAA chain within the network. This difference in the AA distribution between the former and latter gels was found to result in...

Attachment of human keratinocytes to plasma co-polymers of acrylic acid/octa-1,7-diene and allyl amine/octa-1,7-diene

Abstract: Plasma co-polymers (PCPs) of acrylic acid/octa-1,7-diene and allyl amine/octa-1,7-diene have been prepared and characterised using X-ray photoelectron spectroscopy (XPS). The use of a hydrocarbon diluent in the monomer feed allowed the deposition of films with controlled concentrations of carboxylic acid and nitrogen-containing functional groups. Human keratinocytes were cultured on these PCP surfaces, tissue culture poly(styrene) (TCPS) and collagen I. The level of keratinocyte attachment over 24 h was measured. PCP surfaces containing low concentrations of carboxylic acid groups (2.3%) were found to promote keratinocyte attachment. The performance of these PCPs was similar to collagen I, a well established substratum for attachment. Nitrogen-containing PCP surfaces were found to promote attachment at higher functional group concentrations, although the attachment did not attain the level achieved on the acid functionalised PCP surfaces.

Interfacial interactions of plasma‐polymerized acrylic acid and an oxidized aluminium surface investigated using XPS, FTIR and poly(acrylic acid) as a model compound

Abstract: X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) are used to characterize the interface between poly(acrylic acid) (PAA) and an aluminium oxyhydroxide (AlOOH) surface. Reaction of the PAA carboxylic acid functionality with hydroxyl groups at the surface of the oxide to form a monodentate carboxylate complex C(O)OAl was identified by FTIR. The degree of conversion of the acid to the salt at the interface was estimated to be 40% from the XPS analysis of PAA overlayers of varying thickness. An equivalent reaction was identified at the interface between AlOOH and a monolayer of strongly bonded plasma-polymerized acrylic acid (ppAAc) that remained after solvent washing. The resistance of the monolayer of ppAAc to solvent washing was attributed to the formation of interfacial carboxylate complexes with the AlOOH surface. © 1998 John Wiley & Sons, Ltd.

Polyether-Modified Poly(acrylic acid): Synthesis and Applications

Abstract: Poly(acrylic acid) (PAA) copolymers modified with block-copolymers of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) are inherently attractive for medicinal applications as their components are considered pharmaceutically safe. The laboratory-scale synthesis of poly(acrylic acid) bonded onto a PEO−PPO−PEO triblock (Pluronic) backbone via dispersion polymerization is reported. Initial optimization of the synthesis defines appropriate levels of initial loading of acrylic acid and Pluronic, with a mixture of 2,2‘-azobis(2,4-dimethylpentanenitrile) and lauroyl peroxide as an initiator system. The synthesis results in a copolymer with low residual monomer content and a very high degree of bonding between Pluronic and PAA. Diluted aqueous solutions of Pluronic-g-PAA exhibit rapid thermogelation. Rheological parameters of the copolymers urge on their ophthalmic applications.

Three-Layer Micelles of an ABC Block Copolymer: NMR, SANS, and LS Study of a Poly(2−ethylhexyl acrylate)-block-poly(methyl methacrylate)-block-poly(acrylic acid) Copolymer in D2O

Abstract: A poly(2-ethylhexyl acrylate)-block-poly(methyl methacrylate)-block-poly(acrylic acid) (PEHA−PMMA−PAAc) triblock copolymer was prepared by group transfer polymerization (GTP) and subsequent acidolysis. When transferred from a molecular solution into water or D2O, the copolymer is shown, by static light scattering (SLS) and dynamic light scattering (DLS), to form spherical micelles of a narrow size distribution. According to NMR line shape and signal intensity analysis, and SANS measurements using contrast variation by a selective swelling of PEHA blocks with cyclohexane-d12, the three block types are mostly segregated in a micelle, PEHA forming the inner and PMMA the outer layer of the core. Both methods indicate an existence of mixed layers in which the blocks PEHA−PMMA (in the core) and PMMA−PAAc (at the outer rim of the core) are entangled. NMR data point to the temperature-dependent conflict of the influence between the PEHA compression resistance and the core−shell interface tension. Solvents general...

Synthesis and Characterization of Thermally Degradable Polymer Networks

Abstract: Diacrylate and dimethacrylate monomers containing thermally cleavable tertiary ester linkages with different spacer lengths were synthesized and studied. The photopolymerization rates of diacrylates were much higher than those of dimethacrylates. Glass transition temperatures of the prepared networks increased from 55 to 180 °C with decreasing spacer length for diacrylate networks and from 135 to 185 °C for dimethacrylate networks. Isothermal thermogravimetric analyses revealed that the networks were thermally stable up to 150 °C and decomposed smoothly between 180 and 200 °C to form partially dehydrated linear poly(acrylic acid) or poly(methacrylic acid). It was observed that decomposition reactions were dominated by an autoacceleration mechanism. The rate of weight loss was dependent on temperature and spacer length. Although the resulting decomposition products were insoluble in dimethylformamide, methanol, and water due to the presence of intermolecular acid anhydride groups, they were completely solu...

Ultrathin Films of a Polyelectrolyte with Layered Architecture

Abstract: Posttransfer modification of preformed Langmuir-Blodgett films of poly(tert-butyl methacrylate) and poly(tert-butyl acrylate) by gaseous hydrochloric acid yields films with layered architecture of poly(methacrylic acid) and poly(acrylic acid), respectively. X-ray reflectivity and infrared spectroscopy confirm monolayer by monolayer transfer of the source polymers and their transformation to acid multilayer assemblies with retention of low surface roughnesses. The incorporation of cross-linking groups into the system offers the possibility for further chemical modification to produce ultrathin films of model networks desirable for bioadsorption studies and as hydrophilic spacing layers for tethered membranes.

Application of microcapsules as latent heat accumulators

Abstract: The invention relates to the application of microcapsules I with one or more lipophilic substances as core material. Said lipophilic substances have a solid/liquid phase transition at a temperature ranging from -20 to 120 °C and a polymer which is used as a shell and can be obtained by means of radical polymerization of a monomer mixture containing 30 to 100 wt.%, referring to the total weight of the monomers, one or more C1-C24-alkyl esters of the acrylic acid and/or methylacrylic acid (monomer I), 0 to 80 wt.%, referring to the total weight of the monomers, one bi- or polyfuntional monomer (monomer II) which is insoluble or poorly soluble in water, and 0 to 40 wt.%, referring to the total weight of the monomers, and other monomers (monomer III). The microcapsules can be used as latent heat accumulators. The invention also relates to novel microcapsules Ia, spray-dried microcapsules Ia', methods for the production thereof, and to shaped bodies and coating masses containing said microcapsules.

Antibacterial activities of acrylic acid‐grafted polypropylene fabric and its metallic salt

Abstract: Acrylic acid (AAc) was grafted onto polypropylene (PP) fabric by a preirradiation method using a 60Co gamma ray. The effects of the absorbed dose, the reaction temperature, reaction time, storage time, as well as the addition effect of ferrous ion and sulphuric acid on the degree of grafting, were determined. It was shown that the synergistic effect of a strong acid with ferrous sulfate can increase the grafting yield. Antibacterial activities on metallic complexes of acrylic acid-grafted polypropylene (AAc-g-PP) fabric were evaluated by a viable cell counting method. An Ag complexed fabric had strong biocidal effect for all bacteria. Fe, Cu, and Zn complexed fabrics had different antibacterial activities depending on each bacterium. However, AAc-g-PP fabric and Ni-complexed fabric did not have bactericidal effect. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 2213–2220, 1998

Toner compositions with acrylonitrile and processes

Abstract: A toner composition comprised of colorant, and an addition polymer resin of styrene, butadiene, acrylonitrile and acrylic acid.

Properties of Aqueous Solutions and Gels of Poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide)-g-poly(acrylic acid)

Abstract: Gelation in aqueous solutions of poly(acrylic acid) (PAA) grafted onto poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (Pluronic F127) has been studied. The gel point and onset of micellization are observed in Pluronic−PAA solutions at the same temperatures, confirming that the gelation occurs via formation of micelles that act as thermoreversible cross-links. The salt- and pH-dependent expansion or folding of the polyelectrolyte segments changes the gel elasticity. The increased polarity due to enhanced polymer ionization at higher pH or with salt addition causes the poly(propylene oxide) (PPO) segments to aggregate at lower temperatures. The weak dependence of the polymer concentration at the maximum reduced viscosity on the salt concentration is attributed to hydrophobic interactions among PPO segments.

Process for the production of 1,3-propanediol

Abstract: A process for the production of 1,3-propanediol by hydrating acrolein in the presence of an ion exchanger to form 3-hydroxypropionaldehyde includes reacting acrolein and water in a ratio by weight of 1:2 to 1:20 at 30° to 120° C. and a pressure in the range from 1 to 20 bar, in the presence of an ion exchange hydration catalyst. The ion exchanger and any unreacted acrolein are separated from the reaction mixture. The 3-hydroxypropionaldehyde is then catalytically hydrogenated in a liquid or gas phase using hydrogenation catalysts. The ion exchanger hydration catalyst includes polyamine/polycarboxylic acid resins produced by reacting polyamine resins based on a crosslinked polyacrylamide matrix with acrylic acid, acrylic acid derivatives or a salt of an ω-haloalkanoic acid. An ion exchanger includes reaction product of reacting a polyamine resin based on a crosslinked polyacrylamide matrix with acrylic acid, acrylic acid derivatives or ω-haloalkanoic acid salts.