scholarly journals PREPARATION AND STUDY OF THE PROPERTIES OF THE COPOLYMER OF CYCLIC UNSATURATED BISMALEIMIDE WITH STYRENE

2021 ◽  
Vol 0 (4) ◽  
pp. 25-29
Author(s):  
A.I. Alikhanova ◽  
◽  
R.Sh. Rasulzade ◽  
Keyword(s):  
Molecular Weight ◽  
Reaction Rate ◽  
Chain Transfer ◽  
Radical Copolymerization ◽  
Active Participation ◽  
Reaction Yield ◽  
Monomer Mixture ◽  
Initial Monomer ◽  
Initial Monomer Mixture ◽  
Copolymerization Reaction

The paper is devoted to the study of regularities of radical copolymerization reactions of unsaturated cyclic N,N'-bisimides (M1) with styrene (M2), the study of dependence of copolymerization reaction rate, composition of obtained copolymers, composition and estimated molecular weight on the composition of the initial monomer mixture. With the increase of bismaleimide amount in the initial monomer mixture a decrease of copolymerization reaction yield and molecular weight of the obtained copolymers was observed. This fact can be explained by active participation of bismaleimide in chain transfer in radical copolymerization reaction. The composition of the obtained copolymers in all cases is rich in styrene links

Kinetics of the radical copolymerization of styrene and 2-methoxyethyl methacrylate

1983 ◽  
Vol 48 (9) ◽  
pp. 2656-2665 ◽  
Author(s):  
Jaroslav Stejskal ◽  
Dagmar Straková ◽  
Ondřej Procházka ◽  
Pavel Kratochvíl
Keyword(s):  
Experimental Data ◽  
Molecular Weight ◽  
Kinetic Data ◽  
Radical Copolymerization ◽  
Copolymer Composition ◽  
Monomer Mixture ◽  
Diffusion Controlled ◽  
Kinetics Of ◽  
Best Fit ◽  
Copolymerization Kinetics

Twenty low-conversion statistical copolymers of styrene and 2-methoxyethyl methacrylate with various composition were prepared. The dependence of the copolymer composition, molecular weight, initiation efficiency and other parameters on the composition of the monomer mixture is discussed. Kinetic data are correlated by means of various models of the copolymerization kinetics. The best fit with experimental data is provided by a diffusion-controlled termination model, especially its dyad variant suggested in this study.

scholarly journals Radical polymerization by a supramolecular catalyst: cyclodextrin with a RAFT reagent

2016 ◽  
Vol 12 ◽  
pp. 2495-2502 ◽  
Author(s):  
Kohei Koyanagi ◽  
Yoshinori Takashima ◽  
Takashi Nakamura ◽  
Hiroyasu Yamaguchi ◽  
Akira Harada
Keyword(s):  
Aqueous Solution ◽  
Molecular Weight ◽  
Complex Formation ◽  
Radical Polymerization ◽  
Chain Transfer ◽  
Reaction Yield ◽  
Host Molecule ◽  
Narrow Molecular Weight Distribution ◽  
X Ray ◽  
A Chain

Supramolecular catalysts have received a great deal of attention because they improve the selectivity and efficiency of reactions. Catalysts with host molecules exhibit specific reaction properties and recognize substrates via host–guest interactions. Here, we examined radical polymerization reactions with a chain transfer agent (CTA) that has α-cyclodextrin (α-CD) as a host molecule (α-CD-CTA). Prior to the polymerization of N,N-dimethylacrylamide (DMA), we investigated the complex formation of α-CD with DMA. Single X-ray analysis demonstrated that α-CD includes DMA inside its cavity. When DMA was polymerized in the presence of α-CD-CTA using 2,2'-azobis[2-(2-imidazolin-2-yl)propane dihydrochloride (VA-044) as an initiator in an aqueous solution, poly(DMA) was obtained in good yield and with narrow molecular weight distribution. In contrast, the polymerization of DMA without α-CD-CTA produced more widely distributed polymers. In the presence of 1,6-hexanediol (C6 diol) which works as a competitive molecule by being included in the α-CD cavity, the reaction yield was lower than that without C6 diol.

Determining chemospecificity in reactions with chain transfer agent and corresponding radical via evaluation of molecular weight dependency of apparent comonomer reactivity ratios: free-radical copolymerization of vinyl acetate and dibutyl maleate

RSC Advances ◽  
2016 ◽  
Vol 6 (111) ◽  
pp. 109759-109768 ◽  
Author(s):  
Seyed Saeid Rahdar ◽  
Mahdi Abdollahi ◽  
Ebrahim Ahmadi ◽  
Abbas Biglari
Keyword(s):  
Molecular Weight ◽  
Free Radical ◽  
Chain Transfer ◽  
Radical Copolymerization ◽  
Reactivity Ratios ◽  
Free Radical Copolymerization ◽  
Molecular Weights ◽  
Radical Reactivity ◽  
Dibutyl Maleate ◽  
Trichloromethyl Radical

Performing copolymerization with two different conditions leading to different molecular weights allows us to determine trichloromethyl radical reactivity towards comonomers.

scholarly journals Correction: Determining chemospecificity in reactions with chain transfer agent and corresponding radical via evaluation of molecular weight dependency of apparent comonomer reactivity ratios: free-radical copolymerization of vinyl acetate and dibutyl maleate

RSC Advances ◽  
2016 ◽  
Vol 6 (114) ◽  
pp. 112949-112949
Author(s):  
Seyed Saeid Rahdar ◽  
Mahdi Abdollahi ◽  
Ebrahim Ahmadi ◽  
Abbas Biglari
Keyword(s):  
Molecular Weight ◽  
Free Radical ◽  
Vinyl Acetate ◽  
Chain Transfer ◽  
Radical Copolymerization ◽  
Chain Transfer Agent ◽  
Reactivity Ratios ◽  
Free Radical Copolymerization ◽  
Dibutyl Maleate

Correction for ‘Determining chemospecificity in reactions with chain transfer agent and corresponding radical via evaluation of molecular weight dependency of apparent comonomer reactivity ratios: free-radical copolymerization of vinyl acetate and dibutyl maleate’ by Seyed Saeid Rahdar et al., RSC Adv., 2016, 6, 109759–109768.

scholarly journals Kinetics and Mechanism of Synthesis of Carboxyl-Containing N-Vinyl-2-Pyrrolidone Telehelics for Pharmacological Use

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2569
Author(s):  
Andrey N. Kuskov ◽  
Anna L. Luss ◽  
Inessa A. Gritskova ◽  
Mikhail I. Shtilman ◽  
Mikhail V. Motyakin ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Temperature ◽  
Kinetic Model ◽  
Aqueous Solutions ◽  
Radical Polymerization ◽  
Anticancer Drug ◽  
Reaction Rate ◽  
Chain Transfer ◽  
Thiolate Anions ◽  
First Time

It was found that sulfanylethanoic and 3-sulfanylpropanoic acids are effective regulators of molecular weight with chain transfer constants of 0.441 and 0.317, respectively, and show an unexpected acceleration effect on the radical polymerization of N-vinyl-2-pyrrolidone, initiated by 2,2’-azobisisobutyronitrile. It was determined for the first time that the thiolate anions of mercapto acids form a high-temperature redox initiating system with 2,2’-azobisisobutyronitrile during the radical polymerization of N-vinyl-2-pyrrolidone in 1,4-dioxane. Considering the peculiarities of initiation, a kinetic model of the polymerization of N-vinyl-2-pyrrolidone is proposed, and it is shown that the theoretical orders of the reaction rate, with respect to the monomer, initiator, and chain transfer agent, are 1, 0.75, 0.25, and are close to their experimentally determined values. Carboxyl-containing techelics of N-vinyl-2-pyrrolidone were synthesized so that it can slow down the release of the anticancer drug, doxorubicin, from aqueous solutions, which can find its application in the pharmacological field.

Effect of Resin Formulation on Thermoset Viscoelasticity

2006 ◽  
Vol 128 (4) ◽  
pp. 478-483 ◽  
Author(s):  
K. M. B. Jansen
Keyword(s):  
Crosslink Density ◽  
Relaxation Curve ◽  
Shift Factor ◽  
Mixing Ratio ◽  
Monomer Mixture ◽  
Thermoset Resins ◽  
Initial Monomer ◽  
Initial Monomer Mixture ◽  
Conversion Level ◽  
Relaxation Curves

Viscoelastic relaxation curves of thermoset resins may change considerably for relatively small changes in properties of the initial monomer mixture or final conversion level. In order to be able to predict the effect of such changes, a model is proposed which relates the properties of the initial monomer mixture such as the functionality, mixing ratio, and conversion level to changes in the relaxation curves. It basically consists of two parts. Firstly, the crosslink density is calculated based on the exact composition of the monomer mixture and, secondly, the effect of this crosslink density on the position of the glass transition and the rubbery modulus was calculated. The model was tested with a series of Novolac epoxies in which the functionality, mixing ratio, and conversion level were varied systematically. It turned out that changes in the relaxation curves due to variations in conversion level could be predicted quite accurately from the shape and shift factor of the fully cured mastercurve. The agreement between relaxation curve predictions for the series with changing functionality and mixing ratio was only moderate, which was ascribed to errors in the prediction of correct values for the crosslink density.

Monitoring Polymer-Assisted Mechanochemical Cocrystallisation Through in Situ X-Ray Powder Diffraction

2020 ◽  
Author(s):  
Luzia S. Germann ◽  
Sebastian T. Emmerling ◽  
Manuel Wilke ◽  
Robert E. Dinnebier ◽  
Mariarosa Moneghini ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Powder Diffraction ◽  
Reaction Rate ◽  
Polymer Additives ◽  
Time Resolved ◽  
X Ray

Time-resolved mechanochemical cocrystallisation studies have so-far focused solely on neat and liquid-assisted grinding. Here, we report the monitoring of polymer-assisted grinding reactions using <i>in situ</i> X-ray powder diffraction, revealing that reaction rate is almost double compared to neat grinding and independent of the molecular weight and amount of used polymer additives.<br>

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.

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