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polyacrylamide thermal stability introductions

  • Thermal stability of polyacrylamide solutions: effect of ...

    We have investigated the effect of temperature on the chemical (hydrolysis) and thermal (molecular weight) stability of purified polyacrylamide solution.From viscosity and light scattering data we show that no polymer degradation due to oxygen contamination results from heating polymer solutions although higher temperature is responsible for hydrolysis of amide groups.

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  • The thermal degradation of polyacrylamide with

    2000-2-1 · In this study, we examined the thermal stability of polyacrylamide stabilized, by the introduction of metal additives. Moreover, we investigated the effect of three adsorbed metal ions on the thermal degradation of polyacrylamide by using Flynn's analytical model. 2. Experimental

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  • Thermal stability of high-molecular-weight

    The above reported data show that temperature affects the stability of commercial polyacrylamide solutions in two different ways: The first process that increases the anionic character of polymers is responsible for the viscosity loss in the presence of monovalent salts and for eventual precipitation in the presence of divalent salts even if the molecular weight is not changed.Such a process will be …

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  • Polyacrylamide beads: Polymer entrapment increases

    2018-2-1 · Silva et al. [ 18] reported that the thermal stability of polyacrylamide might be due to the presence of strong interaction of the hydrogen bonds present within this matrix. This also reduces the mobility of the polymer chain and therefore, increase the thermal strength.

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  • The Two-Stages Thermal Degradation of

    1998-5-1 · The thermal degradation of polyacrylamide has been studied by using thermogravimetry. The experiments were carried out over the temperature range 100–900 at four heating rates of 5, 10, 20 and 40°C /min and in a nitrogen atmosphere.

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  • Theoretical studies of hydrolysis and stability of ...

    2015-11-1 · Thermal stability of PAM/HPAM under HT/HS environments is one of the most important factors preventing widespread oilfield applications of PAM chemicals in harsh reservoir conditions. Structural modifications of PAM to form substituted and/or associated polymers have shown potentials to improve their thermal stability , , , .

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  • Stability of Partially Hydrolyzed Polyacrylamides at ...

    2009-6-29 · stability of the polymer that was injected before the leak developed or the polymer that is injected after the leak is fixed. Of course, the polymer that is injected while the leak is active will be susceptible to oxidative degradation. Maintaining dissolved oxygen at undetectable levels is necessary to maximize polymer stability.

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  • Investigation of the degradation and stability of ...

    2016-12-1 · In order to observe the stability of acrylamide-based polymers in acid, the above four types of prepared polymers were assembled into eight polymer solutions (two replications of each polymer type), with viscosity ranging from 10 to 30 cp. Hydrochloric acid was then added to the eight polymer solutions to comprise 1 wt% HCl and 10 wt% HCl solutions for each polymer solution.

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  • Hydrolysis and thermal stability of partially hydrolyzed ...

    2019-4-8 · Partially hydrolyzed polyacrylamide (HPAM) is the water-soluble polymer most often used in flooding applications in the petroleum industry. However, in aqueous solutions at high temperatures, HPAM undergoes hydrolysis of the lateral amide groups, and the presence of salts in the solution can lead to precipitation of this polymer.

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  • Polyacrylamide crosslinked by bis-vinylimidazolium

    2019-9-3 · A series of ionic compounds 1,n-dialkyl-3,3′-bis-l-vinylimidazolium bromide (CnVIM) are prepared and employed to crosslink acrylamide for polyacrylamide (PAAM) hydrogel preparation via in situ solution polymerization. The swelling behavior, mechanical properties and thermal stability of the prepared CnVIM crosslink

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  • thermal stability and solubility of polyacrylamide

    Thermal stability of polyacrylamide Compared with other polyelectrolytes, polyacrylamide has high thermal stability. But when heated to above 100 C, the crosslinking is often caused by imines. Heating at high temperature for a long time will cause polymer degradation. In the absence of oxygen, when heated to 210 degrees, the weight loss is

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  • thermal stability of montmorillonite polyacrylamide ...

    2021-5-15 · Thermal stability of high-molecular-weight polyacrylamide . The above reported data show that temperature affects the stability of commercial polyacrylamide solutions in two different ways: The first process that increases the anionic character of polymers is responsible for the viscosity loss in the presence of monovalent salts and for eventual precipitation in the presence of divalent salts ...

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  • thermal stability and solubility of polyacrylamide by ...

    Thermal stability of high-molecular-weight polyacrylamide. The above reported data show that temperature affects the stability of commercial polyacrylamide solutions in two different ways: The first process that increases the anionic character of polymers is responsible for the viscosity loss in the presence of monovalent salts and for eventual precipitation in the presence of divalent salts ...

    Get Price
  • Mechanical and Thermal Stability of Polyacrylamide

    In a previous work (Zaitoun, et al., 2012), a study of the shear stability of different EOR polymers was reported. Shear stability was found to directly correlate to chain flexibility. Thus, for a flexible coil such as polyacrylamide, the presence of large monomer groups (e.g. ATBS, NVP) leads to an increase of its rigidity, hence enhancing its shear stability.

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  • Polyacrylamide - Stability | Technology Trends

    Stability. In dilute aqueous solution, such as is commonly used for Enhanced Oil Recovery applications, polyacrylamide polymers are susceptible to chemical, thermal, and mechanical degradation.Chemical degradation occurs when the labile amine moiety hydrolyzes at elevated temperature or pH, resulting in the evolution of ammonia and a remaining carboxyl group.

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  • thermal stability and solubility of polyacrylamide ...

    Solubility and thermal stability at different protein concentrations (1%, 2.5%, 5%, and 7%) in a black tea beverage were also measured. Alcalase-hydrolyzed SPI was chosen for the sensory . Solubility study of polyacrylamide in polar solvents | Request PDF. Agarose/PAAm nanofiber sheet was showing thermal stability close to the pure polyacrylamide.

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  • Thermal stability of polyacrylamide solution prepared

    2021-6-15 · Cite this article: KONG Bailing. Thermal stability of polyacrylamide solution prepared by oilfield produced water[J]. , 2001, 28(1): 2-0. URL:

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  • polyacrylamide mechanical degradation stability |

    Polyacrylamide Mechanical Degradation and Stability in the ... Thermal stability of polyacrylamide solutions: effect of residual impurities in the molecular-weight-degradation process upon heating. Polym. Bull. 5, 39–45. doi: 10.1007/BF00255085. Free Inquiry

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  • Polyacrylamide beads: Polymer entrapment increases the ...

    Polyacrylamide Thermal stability Recycling efficiency a b s t r a c t Immobilization is a unique method for the improvement of product yield. During solid phase catalysis, the chemistry of the synthetic matrix plays an essential role in the performance of the biocatalyst. In the

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  • Significant improvement of thermal stability of

    2013-12-10 · The thermal stability of these mutants was roughly evaluated by incubating the purified enzymes at 60 °C for 10 min. As expected, all mutants had improved in thermal stability to varying degrees, especially for mutants DS24, DS27, DS28, DS30 and DS255, which still retained 85%, 140%, 75%, 98% and 82% activity of each initial value .

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  • Thermodynamic stability of polyacrylamide and

    Thermodynamic stability of polyacrylamide and poly(N,N‐dimethyl acrylamide) ... Thermal degradation to form a radical would require the cleavage of carbon–carbon bonds in the polymer chain; the energy needed for this cleavage was found to depend on the structure of the repeat unit which ranged from low of 72.5 kcal for a rare head‐to ...

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  • Hydrolysis and thermal stability of partially hydrolyzed ...

    Partially hydrolyzed polyacrylamide (HPAM) is the water‐soluble polymer most often used in flooding applications in the petroleum industry. However, in aqueous solutions at high temperatures, HPAM undergoes hydrolysis of the lateral amide groups, and the presence of salts in the solution can lead to precipitation of this polymer.

    Get Price
  • Thermal Stability of r-Amylase from Aspergillus oryzae ...

    2003-9-8 · the thermal stability (50-75 °C) of Aspergillus oryzaeR-amylase immobilized in polyacrylamide gel in phosphate buffer, mashed potatoes, and minced shrimp was examined. Changing the cross-linking agent concentration from 3.3 to 5.3% and adding 2% salt did not markedly affect the thermal stability of the immobilized R-amylase.

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  • Thermal degradation of polyacrylamide and

    Department of Chemistry, Trinity Western University, Langley, British Columbia, Canada V3A 4R9. Search for more papers by this author

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  • Mechanism of Polyacrylamide Hydrogel Instability on

    A gel system composed of acrylamide (AM), N,N'-methylenebisAM (BIS), and ammonium persulfate ((NH 4) 2 S 2 O 8) was developed and applied extensively in reservoirs to reduce water cut and increase oil production in mature fields.However, this gel system suffers from thermal stability loss and syneresis at high temperatures that reduces its ability to control water flow.

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  • Design and Study of a Novel Thermal-Resistant and

    In this study, we compared the thermal stabilities of AMV RT and MMLV RT by observing their irreversible thermal inactivation. The temperatures reducing initial activity by 50% in 10-min incubation, T(50), of AMV RT were 47 degrees C without the template-primer (T/P), poly(rA)-p(dT)(12-18), and 52 degrees C with the T/P (28 microM).

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  • Synthesis, characterization and evaluation of ...

    2021-5-12 · Shape-Stable Hydrated Salts/Polyacrylamide Phase-Change Organohydrogels for Smart Temperature ACS Applied Materials & Interfaces ( IF 9.229) Pub Date : 2021-04-27, DOI: 10.1021 Chenxiao Yin, Ji Lan, Xiangdong Wang, Yulin Zhang, Rong Ran, Ling-Ying Shi

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  • thermal stability and solubility of polyacrylamide

    Thermal stability of polyacrylamide Compared with other polyelectrolytes, polyacrylamide has high thermal stability. But when heated to above 100 C, the crosslinking is often caused by imines. Heating at high temperature for a long time will cause polymer degradation. In the absence of oxygen, when heated to 210 degrees, the weight loss is

    Get Price
  • Polyacrylamide - Stability | Technology Trends

    Stability. In dilute aqueous solution, such as is commonly used for Enhanced Oil Recovery applications, polyacrylamide polymers are susceptible to chemical, thermal, and mechanical degradation.Chemical degradation occurs when the labile amine moiety hydrolyzes at elevated temperature or pH, resulting in the evolution of ammonia and a remaining carboxyl group.

    Get Price
  • thermal stability of montmorillonite polyacrylamide ...

    2021-5-15 · Thermal stability of high-molecular-weight polyacrylamide . The above reported data show that temperature affects the stability of commercial polyacrylamide solutions in two different ways: The first process that increases the anionic character of polymers is responsible for the viscosity loss in the presence of monovalent salts and for eventual precipitation in the presence of divalent salts ...

    Get Price
  • Mechanical and Thermal Stability of Polyacrylamide

    In a previous work (Zaitoun, et al., 2012), a study of the shear stability of different EOR polymers was reported. Shear stability was found to directly correlate to chain flexibility. Thus, for a flexible coil such as polyacrylamide, the presence of large monomer groups (e.g. ATBS, NVP) leads to an increase of its rigidity, hence enhancing its shear stability.

    Get Price
  • thermal stability and solubility of polyacrylamide ...

    Solubility and thermal stability at different protein concentrations (1%, 2.5%, 5%, and 7%) in a black tea beverage were also measured. Alcalase-hydrolyzed SPI was chosen for the sensory . Solubility study of polyacrylamide in polar solvents | Request PDF. Agarose/PAAm nanofiber sheet was showing thermal stability close to the pure polyacrylamide.

    Get Price
  • Thermal Stability of r-Amylase from Aspergillus oryzae ...

    2003-9-8 · the thermal stability (50-75 °C) of Aspergillus oryzaeR-amylase immobilized in polyacrylamide gel in phosphate buffer, mashed potatoes, and minced shrimp was examined. Changing the cross-linking agent concentration from 3.3 to 5.3% and adding 2% salt did not markedly affect the thermal stability of the immobilized R-amylase.

    Get Price
  • Experimental analyses and molecular simulation of the ...

    In the current study, two diverse cellulose models (water only; water, dicyandiamide, melamine and polyacrylamide) are developed and analyzed. Numerous model variables, including the diffusion coefficient of water and cellulose chain distance, are collated, in order to examine the effects of amines on the thermal stability of cellulose.

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  • Polymers | Free Full-Text | Polyacrylamide

    Chronic wounds are severe breaks in the skin barrier that fail to heal in an acceptable time-frame, thus preventing the complete restoration of the tissue’s anatomical and functional integrity, increasing the likelihood of infections and apoptosis. Hydrogels are known as a drug delivery system and have the potential to cover wounds and burns on the skin. Aloe barbadensis contains over 75 ...

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  • Molecular dynamics simulations as a tool for

    2013-4-26 · Keratinases are proteolytic enzymes capable of degrading insoluble keratins. The importance of these enzymes is being increasingly recognized in fields as diverse as animal feed production, textile processing, detergent formulation, leather manufacture, and medicine. To enhance the thermostability of Bacillus licheniformis BBE11-1 keratinase, the PoPMuSiC algorithm was applied to …

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  • Thermal Stability of Immobilized Glucoamylase

    2014-9-9 · Glucoamylase[α-1,4: 1,6-glucan-4: 6-glucohydroease, EC 3.2.1.3] from Rhizopus niveus was entrapped in polyacrylamide gels and adsorbed onto SP-Sephadex C–50 to elucidate the thermostability mechanism of immobilized enzymes. The thermal stability of immobilized glucoamylase entrapped in polyacrylamide gels was enhanced slightly compared with glucoamylase in free solution, and was …

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  • INTRODUCTIONS

    2020-8-20 · Introductions A clear and concise introduction serves as a roadmap for your reader. It should state your primary argument or position on a topic, and then outline the main points you will discuss as you justify your position throughout the main body. Take your time when deciding how to word your introduction, and remember that your introduction

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  • Mechanical and thermal stability of polyacrylamide

    The exceptional mechanical and thermal stability of the polyacrylamide-based microgels and their easiness to be tailored for the required application make these chemicals excellent candidates as future sweep improvers under harsh reservoir conditions in which other conventional polymers might fail.

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  • Writing Effective Introductions - Valencia College

    2019-5-17 · Writing Effective Introductions Great writers know that effective and impacting essays begin with an interesting and engaging introduction that reveals their thesis and purpose, while capturing the reader’s attention. Introductions help writers… – Reveal their essay’s central idea or thesis

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  • Introductions | Caddying Community

    Molly Stewart. 19 days ago. Hello everyone, as a newly joined member of this space I thought I would introduce myself. My name is Molly Stewart, I live in Scotland and have caddied 5 seasons at four different golf courses in Scotland and New Zealand. I love the lifestyle that caddying brings and although I have not looped in the past year (a ...

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  • Preparation and properties of amphiphilic

    2020-5-20 · Hu et al. synthesized β-cyclodextrin-functionalized polyacrylamide/MMT nanocomposites, which exhibited better temperature resistance, salts tolerance, rheological properties, thermal stability and higher viscosity than pure polymer . However, research on properties of aqueous solution of water-soluble amphiphilic hydrophobically associative ...

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  • A KINETIC ANAYSIS OF THE DEGRADATION OF GRAFTED

    2010-3-26 · Grafted anionic polyacrylamide gel has been synthesised in the laboratory following radical polymerisation process. Kinetics of thermal degradation of synthesised gel was evaluated under nonisthothermal condition by integral approximation method to determine the thermal stability of the material from thermogavometric study.

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  • Thermal and rheological properties of cellulose-graft ...

    In order to prepare a cellulose-based water absorbent material in an environmentally-friendly way, a cellulose-graft-polyacrylamide (cellulose-g-PAM) copolymer is synthesized by in situ graft copolymerization through a co-rotating twin-screw extruder.An ionic liquid, namely 1-N-butyl-3-methylimidazolium chloride, is used as the reaction medium and ceric ammonium nitrate is used as …

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  • SOY PROTEIN HYDROLYSATE; SOLUBILITY, THERMAL

    2016-5-18 · thermal stability, solutions (5% w/v) of hydrolysates and SPI were subjected to heat treatment at 95°C for 60 min followed by centrifugation and determination of protein content in the supernatant using a nitrogen analyzer. Solubility and thermal stability at different protein concentrations (1%, 2.5%, 5%, and 7%) in a black tea beverage

    Get Price
  • Mechanical and thermal stability of polyacrylamide

    The exceptional mechanical and thermal stability of the polyacrylamide-based microgels and their easiness to be tailored for the required application make these chemicals excellent candidates as future sweep improvers under harsh reservoir conditions in which other conventional polymers might fail.

    Get Price
  • Hydrolysis and Precipitation of Polyacrylamides in

    Sample Preparations. Because thermal stability of polyacrylamides isimpaired in the presence of dissolved polyacrylamides is impaired in thepresence of dissolved oxygen, precautions were taken to exclude oxygen frompolymer solutions. A glove box maintained under an polymer solutions.

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  • Synthesis and evaluation of partially hydrolysed ...

    2016-7-20 · 35 .SA. The thermal stability of PHPA solution was evaluatged in a Parr pressure reactor at ap-propriate temperature. The completely formulated muds were pre-pared using the synthesized PHPA as viscosifier, polyanionic cellulose (PAC) or carboxy methyl cellulose (CMC) as fluid loss controlling agent, and sodium salt of sulphonated asphaltene as

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  • A KINETIC ANAYSIS OF THE DEGRADATION OF GRAFTED

    2010-3-26 · Grafted anionic polyacrylamide gel has been synthesised in the laboratory following radical polymerisation process. Kinetics of thermal degradation of synthesised gel was evaluated under nonisthothermal condition by integral approximation method to determine the thermal stability of the material from thermogavometric study.

    Get Price
  • Fast DNA Extraction with Polyacrylamide

    2020-6-3 · The chem. structure, thermal stability, crystallinity, pore size and distribution, surface area, surface morphol. and energy dispersive spectrum of PAM/SA microspheres were detd. by FTIR, TGA, XRD, BET, SEM and EDS. In addn., the effects of pH, temp. and adsorbent dosage on the adsorption capacity of Methylene blue (MB) were evaluated.

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  • Immobilization of acrylamide-modified

    1999-1-1 · To test the thermal stability of the gel attachment, polyacrylamide beads (25 µl volume) containing 5′-acrylamide oligonucleotides or unmodified oligonucleotides of identical sequence were prepared (Materials and Methods) and subjected to a standard …

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  • Shear Stability of EOR Polymers | SPE Journal | OnePetro

    2012-4-16 · The highly flexible polyacrylamide homopolymer is the most sensitive to shear degradation. Introduction of acrylate groups in the polymer chain induces some stability because of the rigidity provided by charge repulsion, which vanishes in the presence of high salinity because of the screening of acrylate negative charges.

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  • Isolation and Thermal Stabilization of Bacteriocin Nisin ...

    Testing of Thermal Long-Term Stability It is known that proteins are sensitive to heat treatment, especially in relation to long-term stability and activity [ 29 ]. In this study, thermal stability of nisin products was observed during storage (up to 165 days) at four different temperatures representing conditions of production (−18°C ...

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  • SOY PROTEIN HYDROLYSATE; SOLUBILITY, THERMAL

    2016-5-18 · thermal stability, solutions (5% w/v) of hydrolysates and SPI were subjected to heat treatment at 95°C for 60 min followed by centrifugation and determination of protein content in the supernatant using a nitrogen analyzer. Solubility and thermal stability at different protein concentrations (1%, 2.5%, 5%, and 7%) in a black tea beverage

    Get Price