Addition of e–aq, H· and ·OH to acrylamide in aqueous solution and reactions of the adducts

The polymerization of acrylamide in aqueous surfactant solutions, initiated by potassium persulfate, has been investigated, dilatometry being used to follow the conversion. It has been shown that below the critical micellar concentration (CMC), cationic, anionic and non‐ionic surfactants have no effect, while above the CMC only cationic soaps have an effect, lowering both the rate of polymerization and the molecular weight of the resultant polymer.

Adiabatic polymerization of acrylamide in aqueous solutions in the presence of hydrolyzing agent

Adhesion of plasma‐pretreated polytetrafluoroethylene (PTFE) films to glass foils silanized with 3‐aminopropyltriethoxysilane (APS) was demonstrated via thermally induced surface graft polymerization with concurrent lamination. The simultaneous thermal grafting and lamination process was carried out under atmospheric conditions in the presence of pure acrylic acid (AAc) or aqueous solutions of acrylamide (AAm) and in the absence of polymerization initiator. The chemical composition and microstructure of the modified PTFE films and glass foils were characterized by XPS. The effects of the plasma pretreatment time for the substrates, thermal grafting/lamination temperature and time and graft monomers on the adhesion strength of the PTFE/APS‐glass junction were studied. The adhesion strengths of PTFE/APS‐glass assemblies were significantly improved in the presence of AAc or AAm. The 180° peel adhesion strength of the PTFE/AAc/APS‐glass and the PTFE/AAm/APS‐glass assemblies can reach about 11.2 and 4.6 N cm −1 , respectively. Analysis of the mechanically delaminated surfaces by XPS suggests that the failure modes of both assemblies involve mainly the cohesive failure in the PTFE substrate and some very small adhesion failure in the graft layer. Copyright © 2004 John Wiley & Sons, Ltd.

The swelling behaviors of poly(acrylamide) (PAAm)/clay nanocomposite hydrogels (hereinafter abbreviated as NC gels) in acrylamide (AAm) aqueous solution have been investigated. As‐prepared PAAm/clay hydrogels (S‐M gels) were posttreated by immersing them in AAm aqueous solution. It was found that the swelling ratio of the NC gels increased greatly when the concentration of the solution is below a critical concentration (c*), whereas the gels were disintegrated in the solution when the concentration of the solution is above the c*. Some disc‐like particles were found in the AAm solution accompanying with the unusual swelling behaviors. This unusual swelling behavior is resulted from the change of network structure of the NC gels in AAm aqueous solution, which was further convinced by transmission electron microscopy and element analyses. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Pulse radiolysis of (a) aqueous de-aerated solutions of acrylamide, methacrylamide, N-t-butyl acrylamide, acrylic acid and acrylonitrile and (b) styrene and α-methyl styrene in de-aerated cyclohexane, dioxane, tetrahydrofuran and benzene results in intense transient absorption spectra. Those for system (a) are assigned to monomer radical anions, m–1˙, and the products of reaction of a radical with the monomer. Their decay is second order and values of the extinction coefficients and bimolecular rate constants have been determined. Absolute rate constants( M–1 sec–1) were obtained for the reaction of acrylamide with (a) hydrated electrons, (2.1 ± 0.4)× 1010, (b) OH radicals, (2.0 ± 0.5)× 109 and for the reaction of the product of the reaction of the radical and monomer with oxygen and ferricyanide ion, (1.9 ± 0.3 )× 109 and (6.8 ± 0.4)× 106 respectively. For system (b) the absorptions and decay kinetics observed are not completely understood. At least two distinct species are formed, one of which can be ascribed to a radical but neither to a radical anion.

Novel interpenetrating networks (IPNs) hydrogels responsive to temperature were prepared in situ by liquid‐phase photopolymerization. The first network of the IPNs (poly isopropyl acrylamide) were formed with a special kind of hectorite (Laponite XLS) modified by tetrasodium pyrophosphate as cross‐linker and 2‐oxogultaric acid as photoinitiator. The samples were subsequently immersed in an acrylamide (AAm) aqueous solution for at least one day for preparing IPNs hydrogels, in which acrylamide aqueous solution containing N,N′‐Dimetyl acrylamide (MBAA) as cross‐linker and 2‐oxogultaric acid as photoinitiator. Then the second networks were in situ formed by introducing ultraviolet light irradiated PNIPAAm gels. The swelling/deswelling behaviors of IPNs hydrogels were measured. Compared with the corresponding nanocomposite PNIPAAm hydroges(NC hydrogels), chemically cross‐linked PNIPAAm and PAAm IPNs hydrogels, the results indicate that the new IPN hydrogel has a faster deswelling rate above its LCST (≈32 °C). The effect was explained as being an additional contribution of the PAAm chains in IPN hydrogels, which may act as a water‐releasing channel when the hydrophobic aggregation of PNIPA takes place.

Radiation induced polymerization and crosslinking behavior of N-hydroxy methyl acrylamide in aqueous solutions

The radical polymerization of methacrylic acid, acrylic acid and acrylamide in aqueous solution has been investigated. Detailed kinetic models for both acrylic acid, AA, and methacrylic acid, MAA, have been developed applying the program PREDICI. Good representation of experimental conversion vs. time profiles and molar mass distributions as well as, in case of AA, the branching level could be achieved. The polymerization of MAA has been studied at 35 and 50 °C with focus on the influence of 2-mercaptoethanol, ME, as chain transfer agent, CTA, on reaction kinetics. The rate coefficient of transfer to CTA, ktr,CTA was measured for different monomer levels by the Mayo and the chain length distribution procedure. The ratio of ktr,CTA to the propagation rate coefficient, kp , is independent of monomer to water ratio while both rate coefficients increase by approximately one order of magnitude in passing from bulk to dilute aqueous solution. It was found that addition of CTA reduces the rate of MAA polymerization by two effects on kt. At negligible monomer conversion, kt increases towards higher content of CTA, because average chain length is reduced by the CTA. Chain-length dependent termination may be represented by adopting the composite model, which is a well-established theory to describe chain-length dependency of termination of macroradicals of identical size. The composite model could be applied to average chain length. The reduction of kt towards higher degrees of monomer conversion (Norrish–Trommsdorff or gel effect) becomes weaker towards higher levels of CTA, which could be described by correlating the intensity of the gel effect to molar mass of polymer in solution. The polymerization of non-ionized AA in aqueous solution has been studied between 35 and 80 °C with and without ME as CTA. Chain-length dependent termination was taken into account for modeling as for MAA. During AA polymerization a 1,5-hydrogen shift (backbiting) takes place transforming the secondary propagating radical, SPR, into a tertiary midchain radical, MCR, the kinetics of which were included into the model. The backbiting reaction was quantified via 13C-NMR the other MCR reactions were estimated from conversion vs. time profiles. By measuring the MCR fraction during butyl acrylate, BA, polymerization via electron paramagnetic resonance, EPR, it could be shown that the transfer of MCRs to CTA is not an important reaction path. BA can be used as AA model compound so that the same finding should also apply for AA polymerizations in aqueous phase. Chain transfer of SPRs of AA was measured by the Mayo method. The model was extended towards high-temperature polymerization of AA between 90 and 170 °C, where beta-scission and propagation of macromonomers need to be considered. Moreover, a model for the polymerization of ionized AA was developed, which takes numerous dependencies of rate coefficients on ionization and ionic strength into account, e.g., propagation is reduced by ionization of monomer, but to a higher extent for lower monomer concentration. Moreover, propagation of ionized monomer augments towards higher ionic strength. MCRs were found during acrylamide polymerization via EPR revealing the backbiting reaction to apply for this monomer as well. Thus, the kinetic scheme is the same as for AA polymerization.

Investigation of the kinetics of the polymerization of acrylamide in aqueous solutions of sulphuric and acetic acids, initiated by trivalent cobalt ions

A kinetic model for the radical homopolymerization of acrylamide in aqueous solution is developed, incorporating propagation and termination rate coefficients as functions of monomer concentration and including the formation and reaction of midchain radicals based on the insights and measured rate coefficients from recent pulsed‐laser studies. The model successfully represents the batch conversion profiles measured using an in situ NMR technique between 40 and 70 °C with initial monomer concentrations of 5 to 40 wt%, as well as the associated polymer molar mass distributions. In particular, the model captures the decreased rate that occurs at lowered monomer concentrations as a result of the formation of less‐active midchain radicals by backbiting. Previous literature data are also well represented by the model. image

Download options Please wait... Article information DOI https://doi.org/10.1039/TF9575300489 Article type Paper Download Citation Trans. Faraday Soc., 1957,53, 489-498 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions The polymerization of acrylamide in aqueous solution. Part 2.—The effect of ferric perchlorate on the X- and γ-ray initiated reaction E. Collinson, F. S. Dainton and G. S. McNaughton, Trans. Faraday Soc., 1957, 53, 489 DOI: 10.1039/TF9575300489 To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Search articles by author E. Collinson F. S. Dainton G. S. McNaughton

The “special” nature of processes of copolymerisation of sodium N-(meth)acryloylaminoalkyl carboxylates with acrylonitrile and acrylamide in aqueous solutions is shown. The effects of the influence of the initial concentration of monomers and initiators on the composition of the products of copolymerisation of sodium salt of N-acryloylaminoacetic acid with acrylonitrile are found and explained.

Copolymerization of sulfuric acid salt of N,N-dimethylaminoethyl methacrylate with acrylonitrile and acrylamide in aqueous solution was studied.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOne-electron redox reactions of water-soluble vitamins. 4. Thiamin (vitamin B1), biotin and pantothenic acidP. N. Moorthy and E. HayonCite this: J. Org. Chem. 1977, 42, 5, 879–885Publication Date (Print):March 1, 1977Publication History Published online1 May 2002Published inissue 1 March 1977https://pubs.acs.org/doi/10.1021/jo00425a026https://doi.org/10.1021/jo00425a026research-articleACS PublicationsRequest reuse permissionsArticle Views364Altmetric-Citations33LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

Adiabatic polymerization of acrylamide in aqueous solutions initiated by the system K 2S 2O 8Na 2S 2O 5