Behavior of Hydrogel Microparticles Based on Acrylamide and 2-HEMA Obtained By Inverse Emulsion

2015 ◽  
Vol 1767 ◽  
pp. 43-48
Author(s):  
Raymundo Sanchez-Orozco ◽  
Salomon R. Vasquez-Garcia ◽  
Nelly Flores-Ramirez ◽  
Lada Domratcheva
Keyword(s):  
Spherical Shape ◽  
Continuous Phase ◽  
Radical Copolymerization ◽  
Absorption Capacity ◽  
Solution Temperature ◽  
Hydroxyethyl Methacrylate ◽  
Particle Size Reduction ◽  
Free Radical Copolymerization ◽  
Inverse Emulsion ◽  
Hydrogel Microparticles

ABSTRACTPoly(acrylamide-co-2-hydroxyethyl methacrylate), hydrogel microparticles were prepared by free radical copolymerization of acrylamide (AAm) and 2-hydroxyethyl methacrylate (2-HEMA) using an inverse emulsion polymerization technique, employing ethylene glycol dimethylacrylate (EGDMA) as crosslinker in the presence of w/o emulsifiers span-80 and span-85 (sorbitol mono-oleate) above the lower critical solution temperature. Water absorption capacity and characteristics of the hydrogel microparticles were analyzed by Optical Microscopy (OM), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetric Analysis (TGA). Thus, microparticles were submitted to a gravimetric study on their ability to absorb and to retain distilled water at 25°C. One gram of microparticles absorbed at least 15 g of water. By varying the relative ratio between the continuous phase (hexane and emulsifiers) and the dispersed phase (monomers, initiator and crosslinker), non-agglomerated dispersed particles with nearly spherical shape were obtained having a narrow size distribution in the range from 10 to 20 µm. At a constant value of the emulsifier, and as a result of increasing the stirring rate, a particle size reduction was observed from 13 to 7 µm. The PAAm and PHEMA structures of synthesized hydrogel were confirmed using FTIR analysis. Additionally, through thermal analysis the P(AAm-HEMA) hydrogel showed an increase of water retention and thermal stability due to PAAm addition.

A novel high temperature retarder applied to a long cementing interval

RSC Advances ◽  
2016 ◽  
Vol 6 (17) ◽  
pp. 14421-14426 ◽  
Author(s):  
Ya Lu ◽  
Ming Li ◽  
Zihan Guo ◽  
Xiaoyang Guo
Keyword(s):  
High Temperature ◽  
Free Radical ◽  
Itaconic Acid ◽  
Radical Copolymerization ◽  
Hydroxyethyl Methacrylate ◽  
Free Radical Copolymerization ◽  
Styrene Sulfonate ◽  
Sodium Styrene Sulfonate

A retarder comprised of sodium styrene sulfonate, itaconic acid and hydroxyethyl methacrylate was synthesized by aqueous free radical copolymerization, which can be applied to a long cementing interval.

scholarly journals EXTRACTION AND REEXTRACTION OF HISTIDINE AND RIBOFLAVIN BY N-VINYLCAPROLACTAME COPOLYMERS WITH 1-VINYL- AND 1-METHACRYLOYL-3,5-DIMETHYLPYROZOLE

2018 ◽  
Vol 59 (7) ◽  
pp. 55
Author(s):  
Maria S. Lavlinskaya ◽  
Gennadiy V. Shatalov ◽  
Nadezhda Ya. Mokshina ◽  
Oksana A. Pakhomova ◽  
Vyacheslav A. Kuznetsov
Keyword(s):  
Free Radical ◽  
Uv Spectroscopy ◽  
Aqueous Media ◽  
Radical Copolymerization ◽  
Water Soluble ◽  
Solution Temperature ◽  
Free Radical Copolymerization ◽  
Critical Solution Temperature ◽  
Two Phases ◽  
Degree Of Extraction

Copolymers of N-vinylcaprolactam (VC) with 1-vinyl-3,5-dimethylpyrazole (VDMP) and 1-methacryloyl-3,5-dimethylpyrazole (MDMP) were synthesized by free radical copolymerization  in dioxane with azodiisobutironitrole as initiator. Both water-soluble and water-insoluble copolymers were obtained. The copolymers compositions were determined by FTIR and UV-spectroscopy. The copolymerization constants were calculated and they were: for VC (М1)–VDMP, r1 = 0.65 ± 0.03, r2 = 0.43 ± 0.03; for VC (М1)–MDMP, r1 = 0.79 ± 0.04, r2 = 0.21 ± 0.02. These values show that VC (М1) exhibits somewhat higher activity compared to М2 and that the tendency toward alternation of comonomer units is more pronounced in VC–MDMP copolymers (r1r2 = 0.17) compared to VC–VDMP copolymers (r1r2 = 0.27). It was found that VC–VDMP copolymers are water-soluble at VC content higher than 75 mol %, and VC–MDMP copolymers at VC content higher than 88 mol %. The water-soluble copolymers based on VC have lower critical solution temperature. Their values are in range of 54-69 °C. Two-phases water-salts systems based on synthesized water-soludle thermoresponsive copolymers are proposed for histidine and riboflavin (re)extraction in aqueous media. It was found that extraction systems based on VC-VDMP copolymers are more efficient then VC-MDMP systems. Degree of extraction for both substances in a case of VC-VDMP copolymers achieved 96%. Reextraction carried out by thermoprecipitation of VC (co)polymers. It was shown that reextraction is more efficient at pH 7.6 and its degree achieved 61.7 % for histidine.

An Investigation of Free-Radical Copolymerization Propagation Kinetics of Styrene and 2-Hydroxyethyl Methacrylate

2009 ◽  
Vol 42 (20) ◽  
pp. 7736-7744 ◽  
Author(s):  
Kun Liang ◽  
Marco Dossi ◽  
Davide Moscatelli ◽  
Robin A. Hutchinson
Keyword(s):  
Free Radical ◽  
Radical Copolymerization ◽  
Hydroxyethyl Methacrylate ◽  
Free Radical Copolymerization ◽  
Kinetics Of

pH-Responsive 2-hydroxyethyl methacrylate/citraconic anhydride–modified collagen hydrogels as ciprofloxacin carriers for wound dressings

2017 ◽  
Vol 32 (4) ◽  
pp. 355-381 ◽  
Author(s):  
Daniela Pamfil ◽  
Cornelia Vasile ◽  
Liliana Tarţău ◽  
Liliana Vereştiuc ◽  
Antoniea Poiată
Keyword(s):  
Wound Care ◽  
Ammonium Persulfate ◽  
Radical Copolymerization ◽  
Wound Dressings ◽  
Hydroxyethyl Methacrylate ◽  
Free Radical Copolymerization ◽  
Citraconic Anhydride ◽  
Living Tissues

pH-Sensitive hydrogels of 2-hydroxyethyl methacrylate/citraconic anhydride–modified collagen were obtained by free radical copolymerization/crosslinking in the presence of ammonium persulfate/ N,N,N′, N′-tetramethylethylenediamine redox initiator system. Their pH-responsiveness was demonstrated by swelling behavior and ciprofloxacin release tests. Both unloaded and loaded hydrogels were characterized by Fourier transform infrared, scanning electron microscopy, and biocompatibility tests. The enzymatic degradation in the presence of Clostridium histolyticum mainly depends on initiator content. In vivo biocompatibility tests involving intraperitoneal hydrogels’ implantation in rats following the analysis by the granuloma test, leukocyte formula, immune parameters, and hepatic transaminases demonstrated their non-toxicity and biocompatibility with living tissues. The in vitro antimicrobial activity, in vivo biocompatibility, and in vitro biodegradability tests attest the possibility to use these new polymeric hydrogels with tailored properties as matrices for bioactive products in medical and pharmaceutical applications as wound care and targeting drug delivery systems. The ciprofloxacin release studies proved their potential as materials for wound dressings.

scholarly journals Thermoresponsive Poly(N,N-diethylacrylamide-co-glycidyl methacrylate) Copolymers and Its Catalytically Active α-Chymotrypsin Bioconjugate with Enhanced Enzyme Stability

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 987
Author(s):  
György Kasza ◽  
Tímea Stumphauser ◽  
Márk Bisztrán ◽  
Györgyi Szarka ◽  
Imre Hegedüs ◽  
...  
Keyword(s):  
Glycidyl Methacrylate ◽  
Enzyme Stability ◽  
Radical Copolymerization ◽  
Solution Temperature ◽  
Free Radical Copolymerization ◽  
Methacrylate Copolymers ◽  
Catalytically Active ◽  
One Step ◽  
Copolymer Poly ◽  
Average Size

Responsive (smart, intelligent, adaptive) polymers have been widely explored for a variety of advanced applications in recent years. The thermoresponsive poly(N,N-diethylacrylamide) (PDEAAm), which has a better biocompatibility than the widely investigated poly(N,N-isopropylacrylamide), has gained increased interest in recent years. In this paper, the successful synthesis, characterization, and bioconjugation of a novel thermoresponsive copolymer, poly(N,N-diethylacrylamide-co-glycidyl methacrylate) (P(DEAAm-co-GMA)), obtained by free radical copolymerization with various comonomer contents and monomer/initiator ratios are reported. It was found that all the investigated copolymers possess LCST-type thermoresponsive behavior with small extent of hysteresis, and the critical solution temperatures (CST), i.e., the cloud and clearing points, decrease linearly with increasing GMA content of these copolymers. The P(DEAAm-co-GMA) copolymer with pendant epoxy groups was found to conjugate efficiently with α-chymotrypsin in a direct, one-step reaction, leading to enzyme–polymer nanoparticle (EPNP) with average size of 56.9 nm. This EPNP also shows reversible thermoresponsive behavior with somewhat higher critical solution temperature than that of the unreacted P(DEAAm-co-GMA). Although the catalytic activity of the enzyme–polymer nanoconjugate is lower than that of the native enzyme, the results of the enzyme activity investigations prove that the pH and thermal stability of the enzyme is significantly enhanced by conjugation the with P(DEAAm-co-GMA) copolymer.

Solvent effect on the free-radical copolymerization of 2-hydroxyethyl methacrylate witht-butyl acrylate

2001 ◽  
Vol 39 (12) ◽  
pp. 2043-2048 ◽  
Author(s):  
Carmen Fernández-Monreal ◽  
Gerardo Martínez ◽  
Manuel Sánchez-Chaves ◽  
Enrique López Madruga
Keyword(s):  
Free Radical ◽  
Solvent Effect ◽  
Butyl Acrylate ◽  
Radical Copolymerization ◽  
Hydroxyethyl Methacrylate ◽  
Free Radical Copolymerization

scholarly journals Influence of Cyclodextrins on Thermosensitive and Fluorescent Properties of Pyrenyl-Containing PDMAA

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1569 ◽  
Author(s):  
Dong ◽  
Sun ◽  
Chen ◽  
Yang ◽  
Li ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Emission Intensity ◽  
Solution Concentration ◽  
Radical Copolymerization ◽  
Ethanol Solution ◽  
Solution Temperature ◽  
Fluorescent Properties ◽  
High Concentration ◽  
Excimer Emission ◽  
Free Radical Copolymerization

A series of pyrenyl-containing PDMAA copolymers were prepared by free radical copolymerization of dimethylacrylamide (DMAA) with pyrenebutanoyloxy ethyl methacrylate (PyBEMA). The structure of as-prepared copolymers was characterized by UV, FT-IR and 1H NMR spectroscopy. The effect of cyclodextrins (α-CD, β-CD and γ-CD) on the thermosensitivity and fluorescence of the copolymers in aqueous solutions were investigated. It was found that the as-prepared copolymers exhibit lower critical solution temperature (LCST)-type thermosensitivity. Cloud point (Tcp) decreases with the increasing molar content of PyBEMA unit in the copolymers. Tcp of the copolymers increases after the CD is added from half molar to equivalent amount relative to pyrenyl moiety, and that further adding twice equivalent CD results in a slight decrease in Tcp. The copolymers exhibit a pyrene emission located at 377 nm and a broad excimer emission centered at 470 nm. The copolymers in water present a stronger excimer emission (Intensity IE) relative to monomer emission (Intensity IM) than that in ethanol. The IE/IM values decrease after the addition of equivalent α-CD, β-CD and γ-CD into the copolymers in aqueous solution, respectively. The IE/IM values abruptly increase as the copolymers’ concentration is over 0.2 mg/L whether in ethanol solution or aqueous solution with or without CD, from which can probably be inferred that intra-polymeric pyrene aggregates dominate for solution concentration below 0.2 mg/L and inter-polymeric pyrene aggregates dominate over 0.2 mg/L. Furthermore, the formation of the CD pseudopolyrotaxanes makes it possible to form pyrene aggregates. For high concentration of 5 g/L, the copolymers and their inclusion complexes completely exhibit an excimer emission. The IE values abruptly increased as the temperature went up to Tcp, which indicates that the IE values can be used to research phase separation of polymers.

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