- Programmed Degradation of Hydrogels with a Double-Locked Domain
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The ability to control the degradation of a material is critical to various applications. The purpose of this study was to demonstrate a concept of controlling degradation by using a double-locked domain (DLD). DLDs are molecular structures with two functional units that work cooperatively under environmental stimulation. One unit is triggered to transform without cleavage in the presence of the first stimulus, but this transformation enables the activation of the other unit for cleavage in the presence of the second stimulus. A DLD is presented that is activated to transform through intramolecular reconfiguration when exposed to light. After this transformation, the light-triggered DLD can undergo rapid cleavage under acid treatment. When this DLD is used as the crosslinkers of hydrogels, hydrogels undergo rapid degradation after sequential exposure to light irradiation and acid treatment. Reversing the order of light irradiation and acid treatment or only using individual stimulation does not lead to comparable degradation. Thus, this study has successfully demonstrated the great potential of using DLDs to achieve programmable degradation of materials.
- Lai, Jinping,Abune, Lidya,Zhao, Nan,Wang, Yong
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Read Online
- Runge-Kutta analysis for optimizing the Zn-catalyzed transesterification conditions of MA and MMA with diols to maximize monoesterified products
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Terminal hydroxylated acrylates and methacrylates were prepared by catalytic transesterification of acrylates and methacrylates with diols catalyzed by a system of a tetranuclear zinc alkoxide, [Zn(tmhd)(OMe)(MeOH)]4 (1a), with 4 equiv. of 2,2′-bipyridine (L1). The reaction time to reach the equilibrium state was analyzed by kinetic studies and a curve-fitting analysis based on the Runge-Kutta method for optimizing the best reaction conditions for mono-esterification. In addition to these kinetic analyses, DFT calculations estimated a proposed mechanism of the catalytic transesterification. This journal is
- Kato, Taito,Akebi, Shin-Ya,Nagae, Haruki,Yonehara, Koji,Oku, Tomoharu,Mashima, Kazushi
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p. 6975 - 6986
(2021/11/17)
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- Predicting Monomers for Use in Polymerization-Induced Self-Assembly
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We report an in silico method to predict monomers suitable for use in polymerization-induced self-assembly (PISA). By calculating the dependence of LogPoct /surface area (SA) on the length of the growing polymer chain, the change in hydrophobicity during polymerization was determined. This allowed for evaluation of the capability of a monomer to polymerize to form self-assembled structures during chain extension. Using this method, we identified five new monomers for use in aqueous PISA via reversible addition-fragmentation chain transfer (RAFT) polymerization, and confirmed that these all successfully underwent PISA to produce nanostructures of various morphologies. The results obtained using this method correlated well with and predicted the differences in morphology obtained from the PISA of block copolymers of similar molecular weight but different chemical structures. Thus, we propose this method can be utilized for the discovery of new monomers for PISA and also the prediction of their self-assembly behavior.
- Foster, Jeffrey C.,Varlas, Spyridon,Couturaud, Benoit,Jones, Joseph R.,Keogh, Robert,Mathers, Robert T.,O'Reilly, Rachel K.
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supporting information
p. 15733 - 15737
(2018/11/23)
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- DENTAL CURABLE COMPOSITION
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PROBLEM TO BE SOLVED: To provide a dental curable composition that comprises a polymerizable monomer, a cured product of which has excellent mechanical strength, and which has low viscosity and excellent handleability even in room temperature environment, and further has excellent operability. SOLUTION: A dental curable composition comprises (A) polymerizable monomer represented by formula (1), (B) polymerization initiator, and (C) organic-inorganic composite filler, where X is a divalent group; Ar1 and Ar2 each are an aromatic; L1 and L2 each are a hydrocarbon with the main chain consisting of 2-60 atoms; R1 and R2 independently represent H or methyl; m1, m2, n1 and n2 independently an integer of 1-3]. SELECTED DRAWING: None COPYRIGHT: (C)2017,JPO&INPIT
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Paragraph 0193
(2017/10/13)
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- DENTAL CURABLE COMPOSITION
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PROBLEM TO BE SOLVED: To provide a dental curable composition that promptly completes polymerization upon light irradiation. SOLUTION: A dental curable composition comprises: (A) a polymerizable monomer represented by general formula (1); and (B) a photoinitiator containing B1) an α-diketone compound, B2) a photoacid generator and B3) an aromatic amine compound. [X is -O-; Ar1 and Ar2 are divalent to tetravalent aromatic groups; L1 and L2 are divalent to tetravalent C2-60 hydrocarbon groups; R1 and R2 are hydrogen or methyl groups; and m1, m2, n1 and n2 are integers from 1 to 3.] SELECTED DRAWING: None COPYRIGHT: (C)2017,JPOandINPIT
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Paragraph 0191
(2017/11/01)
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- Hydroxy functional acrylate and methacrylate monomers prepared via lipase-catalyzed transacylation reactions
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Candida antarctica lipase B (CAL-B, Novozyme 435) catalyzes the transacylation of methyl acrylate and methyl methacrylate with diols and triols in 2-methyl-2-butanol at 50 °C. Under the experimental conditions, up to 70 mol% of the acyl donor methyl acrylate was converted. Methyl methacrylate is the less efficient acyl donor (up to 60 mol%) due to the higher sterical hindrance in the enzymatic transacylation. Under the reaction conditions high yields of the mono-acylated products are obtained, which contain minor amounts of bis(meth)acrylates. In addition it was observed that Novozyme 435 catalyzes regioselectively the acylation of the primary hydroxyl groups. In comparison with the chemical catalyzed route no selectivity was observed for unsubstituted diols. For substituted diols more mono-acylated product was formed in the lipase-catalyzed reaction than in the chemical catalyzed reaction.
- Popescu, Dragos,Hoogenboom, Richard,Keul, Helmut,Moeller, Martin
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experimental part
p. 80 - 89
(2010/08/20)
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- Synthesis of methacrylate-functionalized phosphonates and phosphates with long alkyl-chain spacers and their self-aggregation in aqueous solutions
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Polymerizable amphiphilic organophosphorous compounds were synthesized and their self-aggregation behavior was investigated. The studied molecules contain a hydrophilic phosphorus end group, an alkyl chain spacer with a variable length from 3 to 11 CH2 groups and a polymerizable methacrylic group at the other chain end. Thus, the molecules represent a class of polymerizable surfactants. Two different reaction methods were used; either unsaturated alcohols or bromine-containing alcohols were applied as starting compounds for the preparation of the organophosphorous surfactants. The self-aggregation and micelle formation of the prepared compounds were investigated in aqueous solution by dynamic light scattering measurements. The critical micelle concentration of the P-containing amphiphiles was in all cases smaller than 0.040 mol/l and strongly dependent on the polarity of the phorphorous head group and the chain length of the spacer. Graphical abstract: [Figure not available: see fulltext.] The synthesis of organophosphorous amphiphiles as surface active monomers for the modification of metal oxide surfaces is presented. The spacer between the phosphorous head group and the methacrylate group was varied with regard to their length and composition. The self-aggregation behavior of these methacrylate-functionalized phosphates and phosphonates surfactants was investigated.
- Francova, Denisa,Kickelbick, Guido
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experimental part
p. 413 - 422
(2010/06/14)
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- Novel monovinyl methacrylic monomers containing secondary functionality for ultrarapid polymerization: Steady-state evaluation
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Experimental investigations were made into the effects of monomer structure and functionality on free-radical polymerization kinetics. A more comprehensive understanding of how structural characteristics, monomer traits, and polymerization conditions influence the polymerization mechanisms and network evolution was desired. Variations in the nature of the monomers' secondary functionality and the terminal substitution were the primary variables examined. The three factors hypothesized as important to the advantageous polymerization characteristics observed are hydrogen bonding, hydrogen abstraction, and the electronic characteristics of the monomer. The experimental evaluations presented clearly demonstrate that each of these mechanisms contributes to the reactivity of these monomers and the networks that they form. The combination of these factors leads to cross-linked network formation and enhanced polymerization kinetics, i.e., monovinyl monomers with reactivities that rival those of commonly used divinyl monomers.
- Berchtold, Kathryn A.,Nie, Jun,Stansbury, Jeffrey W.,Hacioglu, Bilge,Beckel, Eric R.,Bowman, Christopher N.
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p. 3165 - 3179
(2007/10/03)
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- Process for synthesis of Di(meth)acrylic acid esters
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A process for the synthesis and recovery of di(meth)acrylic acid esters at a high degree of purity. Di(meth)acrylic acid esters are produced by transesterfication of (meth)acrylic acid esters of C1to C4alcohols with 1,n-diols (where n≧3) in the presence of a zirconium catalyst that comprises a chelate of zirconium with a 1,3-dicarbonyl compound. These catalysts can be readily separated or removed from the reaction mixture by precipitation with phosphoric acid, thus providing a convenient and inexpensive method of producing a di(meth)acrylic acid ester with a reduced level of zirconium.
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Page/Page column 5-6
(2008/06/13)
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- Improving the Strategy and Performance of Molecularly Imprinted Polymers Using Cross-Linking Functional Monomers
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A new strategy for monomer design has been investigated that combines interactive monomer functionality with a cross-linking format, giving as a result noncovalent molecularly imprinted polymers (MIPs) with improved performance. This strategy was explored under the premise that more functionality could be introduced without suffering performance losses due to reduced cross-linking. While this proved to be correct, equally important contributions to selectivity enhancement at the molecular level by conformation control and diastereomeric complexation were also discovered. Monomers derived from L-serine and L-aspartic acid were synthesized and used to prepare MIPs, with the best performance obtained for the MIP formulated with the serine-based cross-linker (N,O-bis-methacryloyl L-serine, 3), versus the aspartic-acid-based cross-linkers and the traditional methacrylic acid/ethylene glycol dimethacrylate (MAA/EGDMA) formulation. Quantitative structure selectivity relationship (QSSR) studies revealed that the improved performance of 3 was due to three key factors: (1) the cross-linking nature of this monomer; (2) control of conformational flexibility; (3) a strong influence of monomer chirality on enantioselectivity in MIPs.
- Sibrian-Vazquez, Martha,Spivak, David A.
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p. 9604 - 9611
(2007/10/03)
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- Regioselective Reductive Cleavage of Terminal Epoxides with Polymer-supported Chloroaluminium Tetrahydroborate
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Epoxides are reduced exclusively to the less substituted alcohols with regenerable polyvinylpyridine-supported chloroaluminium tetrahydroborate in high yields.
- Tamami, Bahman,Lakouraj, M. Mansour,Yeganeh, Hamid
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p. 330 - 331
(2007/10/03)
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- High solids acrylic coating systems
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High solids acrylic coating compositions are formulated by using as a reactive diluent, a low molecular weight hydroxyl-containing acrylic polymer. These polymers are prepared at about 15°-20° C. with anionic initiator concentrations greater than about 5 mole percent.
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