Synthesis and Characterization of Poly(N-Isopropylacrylamide)-Modified Zinc Oxide Nanoparticles

2013 ◽  
Vol 771 ◽  
pp. 141-146 ◽  
Author(s):  
Ping Zhang ◽  
Shan Shan Wu
Keyword(s):  
Zinc Oxide ◽  
Zno Nanoparticles ◽  
Chain Transfer ◽  
Size Structure ◽  
Random Coil ◽  
Reversible Addition ◽  
Structure Morphology ◽  
Raft Agent ◽  
Effect Of Surface

This paper reports a surface functional polymer- poly(N-isopropylacrylamide) (PNIPAM) was grafted on the surface of zinc oxide (ZnO) nanoparticles. It has been demonstrated that Reversible addition fragmentation chain-transfer (RAFT) agent was successfully grafted onto the surface of ZnO. PNIPAM chains were successfully grafted from the surface of ZnO via RAFT process by using RAFT agent immobilized on ZnO. The effect of surface modification on the size, structure, morphology, and properties of ZnO nanoparticles was investigated. The thickness of a PNIPAM monolayer bound to the ZnO core is somewhat larger than the size of the random coil of the corresponding free PNIPAM in aqueous solution, which suggests that the conformation of a PNIPAM chain bound to the ZnO core is extended.

Reversible addition fragmentation chain transfer (RAFT) polymerization of styrene in fluid CO2

e-Polymers ◽  
2004 ◽  
Vol 4 (1) ◽  
Author(s):  
Toshihiko Arita ◽  
Sabine Beuermann ◽  
Michael Buback ◽  
Philipp Vana
Keyword(s):  
Chain Transfer ◽  
Raft Polymerization ◽  
Molecular Weights ◽  
Reversible Addition ◽  
Significant Difference ◽  
Raft Agent ◽  
Successful Control ◽  
A Minor ◽  
Peak Widths

Abstract Reversible addition fragmentation chain transfer (RAFT) polymerizations of styrene in fluid CO2 have been carried out at 80°C and 300 bar using cumyl dithiobenzoate as the controlling agent in the concentration range of 3.5·10-3 to 2.1·10-2 mol/L. This is the first report on RAFT polymerization in fluid CO2. The polymerization rates were retarded depending on the employed RAFT agent concentration with no significant difference between the RAFT polymerization performed in fluid CO2 and in toluene. Full chain length distributions were analyzed with respect to peak molecular weights, indicating the successful control of radical polymerization in fluid CO2. A characterization of the peak widths may suggest a minor influence of fluid CO2 on the addition reaction of macroradicals on the dithiobenzoate group.

scholarly journals Synthesis and Characterization of NBR´s by RAFT Technique and their use as Rubber Precursor in ABS Type Resins

2017 ◽  
Vol 58 (2) ◽  
Author(s):  
Francisco Javier Enríquez-Medrano ◽  
Florentino Soriano-Corral ◽  
Pablo Acuña-Vázquez ◽  
Edgar N. Cabrera-Álvarez ◽  
Hened Saade-Caballero ◽  
...  
Keyword(s):  
Chain Transfer ◽  
Dynamic Mechanical Properties ◽  
Bulk Polymerization ◽  
Reversible Addition ◽  
Raft Agent ◽  
Rubber Component ◽  
Distribution Composition ◽  
Chain Transfer Polymerization

<p>Different rubbers based on polybutadiene were synthesized in solution by the reversible addition-fragmentation chain-transfer polymerization (RAFT) technique using 4-cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl] entanoic acid as RAFT agent and 1,1’-azobiscyclohexanecarbonitrile (Vazo-88) as initiator. The results obtained in the polymerization of polybutadiene and poly(butadiene-<em>co</em>-acrylonitrile) (NBR) are discussed in terms of molecular weight distribution, composition and microstructure. Composition of polybutadiene in NBR´s was kept constant along the copolymerization, and the vinyl, <em>cis</em> and <em>trans</em> isomers are shown in values of around 12, 26 and 62% in all cases. Resulting rubbers were used to synthesize acrylonitrilebutadiene-styrene (ABS) type resins through an <em>in situ</em> bulk polymerization. Dynamic-mechanical properties and the morphology were analyzed in all the different ABS resins. In DMA analyses, the rubber component presented two transitions as well as an increase in the magnitude of the transition located around -75 °C, which is explained by the significant amount of SAN occlusions in the morphology, analyzed by TEM.</p>

scholarly journals Nano-Assemblies from Amphiphilic PnBA-b-POEGA Copolymers as Drug Nanocarriers

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1164
Author(s):  
Angeliki Chroni ◽  
Thomas Mavromoustakos ◽  
Stergios Pispas
Keyword(s):  
Molecular Weight ◽  
Chain Transfer ◽  
Raft Polymerization ◽  
Polymeric Nanocarriers ◽  
Reversible Addition ◽  
2D Noesy ◽  
Drug Nanocarriers ◽  
Glycol Methyl Ether ◽  
Different Molecular Weight

The focus of this study is the development of highly stable losartan potassium (LSR) polymeric nanocarriers. Two novel amphiphilic poly(n-butyl acrylate)-block-poly(oligo(ethylene glycol) methyl ether acrylate) (PnBA-b-POEGA) copolymers with different molecular weight (Mw) of PnBA are synthesized via reversible addition fragmentation chain transfer (RAFT) polymerization, followed by the encapsulation of LSR into both PnBA-b-POEGA micelles. Based on dynamic light scattering (DLS), the PnBA30-b-POEGA70 and PnBA27-b-POEGA73 (where the subscripts denote wt.% composition of the components) copolymers formed micelles of 10 nm and 24 nm in water. The LSR-loaded PnBA-b-POEGA nanocarriers presented increased size and greater mass nanostructures compared to empty micelles, implying the successful loading of LSR into the inner hydrophobic domains. A thorough NMR (nuclear magnetic resonance) characterization of the LSR-loaded PnBA-b-POEGA nanocarriers was conducted. Strong intermolecular interactions between the biphenyl ring and the butyl chain of LSR with the methylene signals of PnBA were evidenced by 2D-NOESY experiments. The highest hydrophobicity of the PnBA27-b-POEGA73 micelles contributed to an efficient encapsulation of LSR into the micelles exhibiting a greater value of %EE compared to PnBA30-b-POEGA70 + 50% LSR nanocarriers. Ultrasound release profiles of LSR signified that a great amount of the encapsulated LSR is strongly attached to both PnBA30-b-POEGA70 and PnBA27-b-POEGA73 micelles.

Synthesis and characterization of a naphthalimide–dye end-labeled copolymer by reversible addition–fragmentation chain transfer (RAFT) polymerization

2011 ◽  
Vol 89 (3) ◽  
pp. 317-325 ◽  
Author(s):  
Binxin Li ◽  
Daniel Majonis ◽  
Peng Liu ◽  
Mitchell A. Winnik
Keyword(s):  
Chain Transfer ◽  
Raft Polymerization ◽  
Polymer Composition ◽  
Cooh Group ◽  
Agent Based ◽  
Molecular Weights ◽  
Reversible Addition ◽  
Raft Agent ◽  
End Use ◽  
Naphthalimide Dye

We describe the synthesis of an end-functionalized copolymer of N-(2-hydroxypropyl)methacrylamide (HPMA) and N-hydroxysuccinimide methacrylate (NMS) by reversible addition–fragmentation chain transfer (RAFT) polymerization. To control the polymer composition, the faster reacting monomer (NMS) was added slowly to the reaction mixture beginning 30 min after initating the polymerization (ca. 16% HPMA conversion). One RAFT agent, based on azocyanopentanoic acid, introduced a –COOH group to the chain at one end. Use of a different RAFT agent containing a 4-amino-1,8-naphthalimide dye introduced a UV–vis absorbing and fluorescent group at this chain end. The polymers obtained had molecular weights of 30 000 and 20 000, respectively, and contained about 30 mol% NMS active ester groups.

Toughening of an epoxy thermoset with poly[styrene-alt-(maleic acid)]-block-polystyrene-block-poly(n-butyl acrylate) reactive core–shell particles

RSC Advances ◽  
2016 ◽  
Vol 6 (42) ◽  
pp. 35621-35627 ◽  
Author(s):  
Ren He ◽  
Xiaoli Zhan ◽  
Qinghua Zhang ◽  
Fengqiu Chen
Keyword(s):  
Emulsion Polymerization ◽  
Maleic Acid ◽  
Butyl Acrylate ◽  
Chain Transfer ◽  
Core Shell ◽  
Reversible Addition ◽  
Raft Agent ◽  
Shell Particles

Reactive core–shell particles for epoxy toughening were synthesized via reversible addition–fragmentation chain transfer emulsion polymerization mediated by an amphiphilic macro-RAFT agent followed by core-crosslinking to increase stability.

Light-responsive terpolymers based on polymerizable photoacids

2017 ◽  
Vol 8 (19) ◽  
pp. 2959-2971 ◽  
Author(s):  
Felix Wendler ◽  
Kilian R. A. Schneider ◽  
Benjamin Dietzek ◽  
Felix H. Schacher
Keyword(s):  
Radical Polymerization ◽  
Chain Transfer ◽  
Synthesis And Characterization ◽  
Reversible Addition

We present the synthesis and characterization of amphiphilic terpolymers containing photoacids based on 1-naphthol using reversible addition fragmentation chain transfer radical polymerization (RAFT).

Synthesis of Novel Triazole-Containing Phosphonate Polymers

2015 ◽  
Vol 68 (4) ◽  
pp. 680 ◽  
Author(s):  
Ciarán Dolan ◽  
Briar Naysmith ◽  
Simon F. R. Hinkley ◽  
Ian M. Sims ◽  
Margaret A. Brimble ◽  
...  
Keyword(s):  
Chain Transfer ◽  
Click Reaction ◽  
Raft Polymerization ◽  
Ethyl Acrylate ◽  
Polymer Chemistry ◽  
Synthesis And Characterization ◽  
Reversible Addition

The objective of this research was to develop novel phosphonate-containing polymers as they remain a relatively under researched area of polymer chemistry. Herein, we report the synthesis and characterization of 2-(1-(2-(diethoxyphosphoryl)ethyl)-1H-1,2,3-triazol-4-yl)ethyl acrylate (M1) and diethyl (2-(4-(2-acrylamidoethyl)-1H-1,2,3-triazol-1-yl)ethyl)phosphonate (M2) monomers using the copper-catalyzed azide–alkyne cycloaddition (CuAAC) ‘click’ reaction, and their subsequent polymerization via both uncontrolled and reversible addition–fragmentation chain transfer (RAFT) polymerization techniques yielding phosphonate polymers (P1–P4).

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