scholarly journals Covalently Crosslinked Nanogels: An NMR Study of the Effect of Monomer Reactivity on Composition and Structure

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 353 ◽  
Author(s):  
Pengfei Liu ◽  
Charles M. Pearce ◽  
Rozalia-Maria Anastasiadi ◽  
Marina Resmini ◽  
Ana M. Castilla
Keyword(s):  
Chemical Structure ◽  
Monomer Concentration ◽  
Careful Study ◽  
Functional Monomers ◽  
Nmr Study ◽  
Composition And Structure ◽  
Experimental Parameters ◽  
Total Monomer Concentration ◽  
Final Composition ◽  
Random Nature

Covalently crosslinked nanogels are widely explored as drug delivery systems and sensors. Radical polymerization provides a simple, inexpensive, and broadly applicable approach for their preparation, although the random nature of the reaction requires careful study of the final chemical composition. We demonstrate how the different reactivities of the monomers influence the total degree of incorporation into the polymer matrix and the role played by the experimental parameters in maximizing polymerization efficiency. Nanogels based on N-isopropylacrylamide, N-n-propylacrylamide, and acrylamide crosslinked with N,N’-methylenebisacrylamide were included in this study, in combination with functional monomers N-acryloyl-l-proline, 2-acrylamido-2-methyl-1-propanesulfonic acid, and 4-vinyl-1H-imidazole. Total monomer concentration and initiator quantities are determining parameters for maximizing monomer conversions and chemical yields. The results show that the introduction of functional monomers, changes in the chemical structure of the polymerizable unit, and the addition of templating molecules can all have an effect on the polymerization kinetics. This can significantly impact the final composition of the matrices and their chemical structure, which in turn influence the morphology and properties of the nanogels.

Study on Superabsorbent Material in Thermal Infrared Camouflage

2014 ◽  
Vol 941-944 ◽  
pp. 370-373
Author(s):  
Nai Yan Zhang ◽  
Jiang Yu ◽  
Juan Zhang
Keyword(s):  
Chemical Structure ◽  
Monomer Concentration ◽  
Thermal Infrared ◽  
Molar Ratio ◽  
Object Temperature ◽  
Different Temperatures ◽  
Total Monomer Concentration ◽  
Equilibrium Swelling Ratio ◽  
Composition Ratios ◽  
Infrared Camouflage

Objectives, which is motional on the batter field, such as vehicles, tanks, planes, warships, firing cannons, etc. They are all active objects. On the surface of these objects there have very higher temperatures than around background, they have special pictures, and are easy found by thermal infrared reconnaissance systems. In this study, itaconic acid (IA) was co-polymerized with N, N-diethylacrylamide (DEA) monomer to improve the swelling behavior and the total absorbing water. These copolymer materials were prepared by changing the initial DEA/IA molar ratio and total monomer concentration. The chemical structure of materials was characterized by fourier transform infrared (FTIR) spectroscopy. In comparison with the PDEA hydrogel, the equilibrium swelling ratio (ESR) of the materials increase with the increase of IA content in the feed and the swelling dynamics behaviors of the different composition ratios of the P(DEA-co-IA) materials on the different temperatures was investigated in detail. Using the big hot-inertia of water, the superabsorbent material of the object surface is propitious to debase the object temperature, which suggests that these materials have potential application as thermal infrared camouflage materials.

scholarly journals Preparation and Characterization of High-Efficiency Magnetic Heavy Metal Capture Flocculants

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1732
Author(s):  
Yuanyuan Yu ◽  
Yongjun Sun ◽  
Jun Zhou ◽  
Aowen Chen ◽  
Kinjal J. Shah
Keyword(s):  
Heavy Metal ◽  
Reaction Time ◽  
High Efficiency ◽  
Removal Rate ◽  
Low Cost ◽  
Monomer Concentration ◽  
Synthesis Process ◽  
Response Surface Optimization ◽  
Metal Capture ◽  
Total Monomer Concentration

In this study, a high-efficiency magnetic heavy metal flocculant MF@AA was prepared based on carboxymethyl chitosan and magnetic Fe3O4. It was characterized by SEM, FTIR, XPS, XRD and VSM, and the Cu(II) removal rate was used as the evaluation basis for the preparation process. The effects of AMPS content, total monomer concentration, photoinitiator concentration and reaction time on the performance of MF@AA flocculation to remove Cu(II) were studied. The characterization results show that MF@AA has been successfully prepared and exhibits good magnetic induction characteristics. The synthesis results show that under the conditions of 10% AMPS content, 35% total monomer concentration, 0.04% photoinitiator concentration, and 1.5 h reaction time, the best yield of MF@AA is 77.69%. The best removal rate is 87.65%. In addition, the response surface optimization of the synthesis process of MF@AA was performed. The optimal synthesis ratio was finally determined as iron content 6.5%, CMFS: 29.5%, AM: 53.9%, AMPS: 10.1%. High-efficiency magnetic heavy metal flocculant MF@AA shows excellent flocculation performance in removing Cu(II). This research provides guidance and ideas for the development of efficient and low-cost flocculation technology to remove Cu(II) in wastewater.

scholarly journals Effect of chemical structure and linear density charge of sulfonate-containing aromatic polyamides on interaction with polycations in organic and water-organic media

2019 ◽  
Vol 60 (11) ◽  
pp. 40-47
Author(s):  
Natalya N. Smirnova ◽  
Keyword(s):  
Chemical Structure ◽  
Phase State ◽  
Linear Charge ◽  
Linear Charge Density ◽  
Sodium Sulfonate ◽  
Interpolyelectrolyte Complexes ◽  
Composition And Structure ◽  
Average Size ◽  
Organic Solutions ◽  
Acrylonitrile Copolymers

The interaction of sulfonate-containing aromatic poly- and copolyamides with acrylonitrile copolymers with N,N-dimethyl-N,N-diallylammonium chloride (DMDAAC) and N,N-diethylaminoethylmethacrylate (DEAEM) in organic and water-organic solutions was studied. It was shown that as a result of macromolecular reactions interpolyelectrolyte complexes (IPEC) forms. They are stabilized mainly by electrostatic forces. To characterize the interpolyelectrolyte complexes composition the φ parameter was used, that defines as the ratio of corresponding functional groups molar concentrations of interacting polyelectrolytes. The transformation degree in interpolymer reactions θ was calculated as the ratio of the salt bonds number between polyions to their maximum possible number. It was shown that the main factors determining the composition and structure of forming interpolyelectrolyte complexes are linear charge density of polyelectrolytes, the nature and composition of the solvent in which interpolymer reactions occurs. It is possible to obtain IPEC, the composition of which for the same polycation will vary from φ = 2.5 to φ = 1.0, changing these factors. It was found that at the complexation process is not accompanied by a change in the phase state of the interpolymer system, when the concentration of units with sulfonate groups in the macromolecular polyamide chain 5 mol.%. It was found that the introduction of polycation leads to the formation of IPEC structures in the form of particles with an average size of ~217.7 nm for poly-4,4'-(2-sodium sulfonate) – diphenylaminisophthalamide and ~248.1 nm in the case of poly-4,4'-(2-sodium sulfonate) -diphenylaminterephthalamide. It was shown that the decrease in the polymer content of units with sulfonate groups is accompanied by a decrease in the transformation degree from 0.65-0.66 to 0.18. It was found that the studied complexes can be transferred to the solution by increasing its ionic strength. The result obtained during this work can serve as a base for the development of for the manufacturing technology of film and membrane materials based on sulfonate-containing aromatic poly- and copolyamides.

Orthogonal Test Design for Optimization of Dispersive Type Cement Slurry Fluid Loss Control Additive Used in Petroleum Drilling

2011 ◽  
Vol 361-363 ◽  
pp. 487-492
Author(s):  
Sheng Lai Guo ◽  
Yu Huan Bu
Keyword(s):  
Ph Value ◽  
Orthogonal Experiment ◽  
Monomer Concentration ◽  
Ammonium Persulfate ◽  
Fluid Loss ◽  
Oil Well ◽  
Cement Slurry ◽  
Orthogonal Test Design ◽  
Total Monomer Concentration ◽  
Loss Control

The fluid loss control additive plays a key role in reducing reservoir damage and improving the cementing quality of an oil well. Aiming at good fluid loss control ability and excellent dispersibility, a new dispersive type fluid loss control additive was synthesized through orthogonal experiment with 2-acrylamido-2- methyl propane sulfonic acid, acrylamide, N, N-dimethylacrylamide and maleic anhydride. The orthogonal experiment result shows that the influence on the properties of FLCA decreases in the order: PH value > monomer concentration > monomer mole ratio > initiator concentration > temperature. The result indicates that the optimal conditions for FLCA were 4/2.5/2.5/1 of mole ratio of AMPS/AM /NNDMA/MA, 32.5% total monomer concentration in deionized water, 1.0% (by weight of monomer) ammonium persulfate/sodium bisulfite, 4 of PH value, 40°Cof temperature. The synthesized copolymer was identified by FTIR analysis. The results show the dispersive type fluid loss control additive has excellent dispersibility, fluid loss control ability, thermal resistant and salt tolerant ability. As the temperature increases, the thickening time of the slurry containing the synthesized additive reduces. The copolymer is expected to be a good fluid loss control additive.

The composition and structure of polyvinyl butyral furfural: NMR study

2014 ◽  
Vol 56 (1) ◽  
pp. 40-47 ◽  
Author(s):  
Yu. A. Kurskii ◽  
N. K. Kobyakova ◽  
E. P. Pashkina ◽  
A. G. Rodionov ◽  
M. Yu. Ryabinina ◽  
...  
Keyword(s):  
Polyvinyl Butyral ◽  
Nmr Study ◽  
Composition And Structure

Preparation and Swelling Dynamics Characterization of Poly(N, N-Diethylacrylamide-Co-Itaconic Acid) Intelligent Hydrogels

2012 ◽  
Vol 490-495 ◽  
pp. 3382-3386
Author(s):  
Xiao Qi Li ◽  
Nai Yan Zhang ◽  
Jun Hai Zhang
Keyword(s):  
Itaconic Acid ◽  
Monomer Concentration ◽  
Molar Ratio ◽  
Solution Temperature ◽  
Temperature Changes ◽  
Different Temperatures ◽  
Total Monomer Concentration ◽  
Equilibrium Swelling Ratio ◽  
Composition Ratios ◽  
Response To Temperature

Poly(N,N-diethylacrylamide) (PDEA) hydrogel is known for their intelligent reversible swelling/deswelling behavior in response to temperature changes across a lower critical solution temperature (LCST) at around 31oC. In this study, itaconic acid (IA) was co-polymerized with N, N-diethylacrylamide (DEA) monomer to improve the swelling behavior and the total absorbing water. These copolymer hydrogels were prepared by changing the initial DEA/IA molar ratio and total monomer concentration. The chemical structure of hydrogels was characterized by fourier transform infrared (FTIR) spectroscopy. In comparison with the PDEA hydrogel, the equilibrium swelling ratio (ESR) of the hydrogels increase with the increase of IA content in the feed and the swelling dynamics behaviors of the different composition ratios of the P(DEA-co-IA) hydrogels on the different temperatures was investigated in detail.

Influence of the Chemical Structure of Functional Monomers on Their Adhesive Performance

2008 ◽  
Vol 87 (8) ◽  
pp. 757-761 ◽  
Author(s):  
K.L. Van Landuyt ◽  
Y. Yoshida ◽  
I. Hirata ◽  
J. Snauwaert ◽  
J. De Munck ◽  
...  
Keyword(s):  
Bond Strength ◽  
Dissolution Rate ◽  
Chemical Bonding ◽  
Chemical Structure ◽  
Calcium Salt ◽  
Atomic Absorption Spectrophotometry ◽  
Functional Monomer ◽  
Functional Monomers ◽  
Chemical Structures ◽  
Adhesive Performance

Functional monomers in adhesive systems can improve bonding by enhancing wetting and demineralization, and by chemical bonding to calcium. This study tested the hypothesis that small changes in the chemical structure of functional monomers may improve their bonding effectiveness. Three experimental phosphonate monomers (HAEPA, EAEPA, and MAEPA), with slightly different chemical structures, and 10-MDP (control) were evaluated. Adhesive performance was determined in terms of microtensile bond strength of 4 cements that differed only for the functional monomer. Based on the Adhesion-Decalcification concept, the chemical bonding potential was assessed by atomic absorption spectrophotometry of the dissolution rate of the calcium salt of the functional monomers. High bond strength of the adhesive cement corresponded to low dissolution rate of the calcium salt of the respective functional monomer. The latter is according to the Adhesion-Decalcification concept, suggestive of a high chemical bonding capacity. We conclude that the adhesive performance of an adhesive material depends on the chemical structure of the functional monomer.

Preparation and Characterization of Thermosensitive Submicron Particles for Gene Delivery

2006 ◽  
Vol 6 (9) ◽  
pp. 2804-2810 ◽  
Author(s):  
Nalan Özdemir ◽  
Ali Tuncel ◽  
Myungchan Kang ◽  
Emir Baki Denkbş
Keyword(s):  
Gene Delivery ◽  
Plasmid Dna ◽  
Aqueous Media ◽  
Monomer Concentration ◽  
Mouse Fibroblast ◽  
Submicron Particles ◽  
Dna Adsorption ◽  
Different Temperatures ◽  
Total Monomer Concentration

In this study, a new thermosensitive material was proposed as a carrier for gene delivery. The thermosensitive submicron particles were synthesized by the dispersion copolymerization of N-isopropylacylamide (NIPA) with a relatively new, cationic comonomer, N-3-dimethylamino-propylmethacrylamide (DMAPM) with higher ionization ability with respect to the commonly used cationic comonomers. To achieve particle sizes smaller than 1 μm, suitable for gene delivery, the total monomer concentration in the dispersion copolymerization was kept at a sufficiently low level. The size of poly(NIPA-co-DMAPM) particles was determined as 454 nm, by AFM in dry state. The poly(NIPA-co-DMAPM) particles showed both temperature and pH sensitivity in the aqueous media. The plasmid DNA adsorption onto the thermosensitive cationic particles was investigated at different temperatures and pHs. The adsorbed amount of plasmid DNA onto the particles was significantly increased by the introduction of cationic comonomer. The equilibrium plasmid DNA adsorptions up to 13 mg/g dry particles were achieved at physiological pH. Approximately 36% w/w of adsorbed plasmid could be desorbed from the cationic nanolatex. The results of biocompatibility studies performed with mouse fibroblast cells showed the suitability of thermosensitive cationic particles for intended application.

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