scholarly journals Synthesis of Lignosulfonate-Based Dispersants for Application in Concrete Formulations

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7388
Author(s):  
Sandra Magina ◽  
Ana Barros-Timmons ◽  
Dmitry V. Evtuguin
Keyword(s):  
Chain Transfer ◽  
Raft Polymerization ◽  
Poly Ethylene Glycol ◽  
Polymeric Surfactants ◽  
Cement Pastes ◽  
Reversible Addition ◽  
Poly Ethylene ◽  
Poly Propylene ◽  
Derivatives Of ◽  
Ionizable Groups

Lignosulfonates (LS) are products from the sulfite pulping process that could be applied as renewable environmentally-friendly polymeric surfactants. Being widely used as plasticizers and water-reducing admixtures in concrete formulations LS compete in the market with petroleum-based superplasticizers, such as naphthalene sulfonate formaldehyde polycondensate (NSF) and copolymer polycarboxylate ethers (PCE). In this work, different chemical modification strategies were used to improve LS performance as dispersants for concrete formulations. One strategy consisted in increasing the molecular weight of LS through different approaches, such as laccase and polyoxometalate-mediated polymerization, glyoxalation, and reversible addition-fragmentation chain transfer (RAFT) polymerization. The other strategy consisted of preparing LS-based non-ionic polymeric dispersants using two different epoxidized oligomer derivatives of poly(ethylene glycol) (PEG) and poly(propylene glycol) (PPG). Modified LS were used to prepare cement pastes, which were examined for their fluidity. Results revealed that the most promising products are PPG-modified LS due to the introduction of PPG chains by reaction with phenolic moieties in LS. The enhanced dispersant efficiency of the ensuing products is probably related not only to electrostatic repulsion caused by the sulfonic ionizable groups in LS but also to steric hindrance phenomena due to the grafted bulky PPG chains.

Development of Core-Crosslinked Micelles for Drug Delivery System

2012 ◽  
Vol 486 ◽  
pp. 449-454 ◽  
Author(s):  
Yue Zhao ◽  
Ming Tao Liang ◽  
Yoseop Kim ◽  
Xin Tan ◽  
Ling Zhang ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Drug Delivery System ◽  
Delivery System ◽  
Raft Polymerization ◽  
Poly Ethylene Glycol ◽  
Reversible Addition ◽  
Self Assembled ◽  
Poly Ethylene ◽  
Crosslinked Micelles ◽  
Glycol Methyl Ether

A polymer drug delivery system was developed using crosslinked self-assembled micelles, which form stable coreshell particles. The block copolymer, composed of poly [poly (ethylene glycol) methyl ether methacrylat-block-[poly (methyl methacrylate-p-nitrophenyl acrylate)] [P(PEGMEMA)-b-P(MMA-NPA)], was synthesized via reversible addition fragmentation chain transfer (RAFT) polymerization. The self-assembled micelles were stabilized by core crosslinking through the reaction of p-nitrophenyl acrylate with 1,8-octandiamine forming stable coreshell particles.

Preparation of a Self-Crosslinking Resin System at Ambient Temperature

2011 ◽  
Vol 380 ◽  
pp. 331-334
Author(s):  
Tang Wei Wang ◽  
Zhong Xiao Li ◽  
Hua Sheng Lu ◽  
Jia Ling Pu
Keyword(s):  
Chain Transfer ◽  
Amphiphilic Polymer ◽  
The Self ◽  
Resin System ◽  
Poly Ethylene Glycol ◽  
Water Solvent ◽  
Reversible Addition ◽  
Raft Agent ◽  
Poly Ethylene ◽  
Glycol Methyl Ether

A reversible addition fragmentation chain transfer (RAFT) agent, 2-(dodecylthiocarbonothioylthio)propanoic acid (RAFT-1), was synthesized and characterized. Diacetone acrylamide and poly(ethylene glycol)methyl ether methacrylate were polymerized in the presence of RAFT-1 to give an amphiphilic polymer(RAFT-2). A very stable and narrowly-distributed emulsion was obtained by the micellization of the amphiphilic polymer in water. The self-crosslinking resin system was prepared by adding a crosslinker (adipic dihydrazide) to the prepared emulsion. Upon the evaporation of water of the emulsion, a tough and transparent crosslinked film was prepared, which had good water/solvent resistance and certain adhesiveness.

PolyPEGylation of Protein using Semitelechelic and Mid-functional Poly(PEGMA)s synthesized by RAFT polymerization

2011 ◽  
Vol 64 (12) ◽  
pp. 1602 ◽  
Author(s):  
Yingkai Liu ◽  
Mei Li ◽  
Dengxu Wang ◽  
Jinshui Yao ◽  
Jianxing Shen ◽  
...  
Keyword(s):  
Steric Hindrance ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Polymer Chains ◽  
High Yield ◽  
Protein Surface ◽  
Molecular Weights ◽  
Pharmaceutical Protein ◽  
Reversible Addition ◽  
Poly Ethylene

A series of well defined semitelechelic and mid-functionalized poly(poly(ethylene glycol) methyl ether methacrylate)s (poly(PEGMA)s) were synthesized through reversible addition-fragmentation chain transfer (RAFT) polymerization using thiazolidine-2-thione-functionalized chain transfer agents (CTAs). The thiazolidine-2-thione group was located either at the end or in the middle of polymer chains depending on the different structural CTAs. All polymers were fully analyzed by 1H NMR spectroscopy and GPC, confirming their well-defined structures, such as predesigned molecular weights, narrow polydispersity indices, and high yield chain-end or chain-middle functionalization. The thiazolidine-2-thione functionality located at the end of or at the middle of the polymer chains can react with amine residues on protein surfaces, forming protein-polymer conjugates via amide linkages. The bioactivity of protein conjugates were subsequently tested using micrococcus lysodeikticus cell as substitute. The protein conjugations from the mid-functionalized polymer remained much more protein bioactivity comparing to their semitelechelic counterpart with similar molecular weights, indicating the steric hindrance of the mid-functionalized poly(PEGMA)s lead to the better selective conjugation to protein. The number of polymer chains on the protein surface was additionally evaluated by TNBS analysis, exhibiting that there are less mid-functionalized poly(PEGMA)s linked on the protein surface than the semitelechelic polymers, also supporting the hypothesis that the steric hindrance from branch-structural polymers results in the better reaction selectivity. This synthetic methodology is suitable for universal proteins, seeking a balance between the protein bioactivity and the protein protection by the covalent linkage with polymer, and exhibits promising potential for pharmaceutical protein conjugation.

scholarly journals Construction of NIR Light Controlled Micelles with Photothermal Conversion Property: Poly(poly(ethylene glycol)methyl ether methacrylate) (PPEGMA) as Hydrophilic Block and Ketocyanine Dye as NIR Photothermal Conversion Agent

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1181
Author(s):  
Lan Yao ◽  
Haihui Li ◽  
Kai Tu ◽  
Lifen Zhang ◽  
Zhenping Cheng ◽  
...  
Keyword(s):  
Ethylene Glycol ◽  
Methyl Ether ◽  
Raft Polymerization ◽  
Poly Ethylene Glycol ◽  
Photothermal Conversion ◽  
Nir Light ◽  
Reversible Addition ◽  
Poly Ethylene ◽  
Post Modification ◽  
Glycol Methyl Ether

Polymeric nanomaterials made from amphiphilic block copolymers are increasingly used in the treatment of tumor tissues. In this work, we firstly synthesized the amphiphilic block copolymer PBnMA-b-P(BAPMA-co-PEGMA) via reversible addition-fragmentation chain transfer (RAFT) polymerization using benzyl methacrylate (BnMA), poly (ethylene glycol) methyl ether methacrylate (PEGMA), and 3-((tert-butoxycarbonyl)amino)propyl methacrylate (BAPMA) as the monomers. Subsequently, PBnMA-b-P(APMA-co-PEGMA)@NIR 800 with photothermal conversion property was obtained by deprotection of the tert-butoxycarbonyl (BOC) groups of PBAPMA chains with trifluoroacetic acid (TFA) and post-modification with carboxyl functionalized ketocyanine dye (NIR 800), and it could self-assemble into micelles in CH3OH/water mixed solvent. The NIR photothermal conversion property of the post-modified micelles were investigated. Under irradiation with NIR light (λmax = 810 nm, 0.028 W/cm2) for 1 h, the temperature of the modified micelles aqueous solution increased to 53 °C from 20 °C, which showed the excellent NIR photothermal conversion property.

Trehalose-functionalized block copolymers form serum-stable micelles

2014 ◽  
Vol 5 (17) ◽  
pp. 5160-5167 ◽  
Author(s):  
Swapnil R. Tale ◽  
Ligeng Yin ◽  
Theresa M. Reineke
Keyword(s):  
Block Copolymers ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Chain Transfer Agent ◽  
Macromolecular Chain ◽  
Reversible Addition ◽  
Poly Ethylene

Well-defined amphiphilic diblock terpolymers of poly(ethylene-alt-propylene)–poly[(N,N′-dimethylacrylamide)-grad-poly(6-deoxy-6-methacrylamido trehalose)] (denoted as PEP–poly(DMA-grad-MAT) or PT) have been synthesized using a PEP macromolecular chain transfer agent by reversible addition–fragmentation chain transfer (RAFT) polymerization.

Preparation of Biocompatible Micelles as Drug Delivery via RAFT Polymerization

2011 ◽  
Vol 322 ◽  
pp. 219-223
Author(s):  
Lian Lai Cui ◽  
Tao Yu ◽  
Xin Tan ◽  
Yue Zhao ◽  
Jian Ping Li ◽  
...  
Keyword(s):  
Self Assembly ◽  
Ring Opening ◽  
Raft Polymerization ◽  
Aqueous Environment ◽  
Poly Ethylene Glycol ◽  
Block Polymers ◽  
Reversible Addition ◽  
Raft Agent ◽  
Poly Ethylene ◽  
Glycol Methyl Ether

Block copolymers D,L-Polylactide-b-poly(poly(ethylene glycol) methyl ether acrylate) (D,L- P(LA)-b-P(PEGMA)) were prepared via ring-opening polymerization and reversible addition fragmentation chain transfer (RAFT) polymerization. The block polymers generated in the reaction reveal the living behavior with the molecular weight increasing with time. The copolymer D,L-P(LA)200-b-P(PEGMA)225 was synthesized successfully with D,L-P(LA) macro-RAFT agent, and was self-assembled in an aqueous environment, leading to the formation of self-assembly micelles. A distinct critical micelle concentration (CMC) was observed of the self-assembly system. The size of it was characterized by both DLS and TEM.

Self-Healing Hydrophobic POSS-functionalized Fluorinated Copolymer via RAFT Polymerization and dynamic Diels-Alder Reaction

2021 ◽  
Author(s):  
Siva Ponnupandian ◽  
Prantik Mondal ◽  
Thomas Becker ◽  
Richard Hoogenboom ◽  
Andrew B Lowe ◽  
...  
Keyword(s):  
Chain Transfer ◽  
Raft Polymerization ◽  
Alder Reaction ◽  
Diels Alder ◽  
Self Healing ◽  
Diels Alder Reaction ◽  
Reversible Addition

This investigation reports the preparation of a tailor-made copolymer of furfuryl methacrylate (FMA) and trifluoroethyl methacrylate (TFEMA) via reversible addition-fragmentation chain transfer (RAFT) polymerization. The furfuryl groups of the copolymer...

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