Effect of temperature and pH on swelling behavior of hydroxyethyl cellullose-acrylamide hydrogel

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Gabriel J. Alonso ◽  
José Luis A. Rivera ◽  
Ana María M. Mendoza ◽  
Maria Leonor H. Mendez
Keyword(s):  
Infrared Spectroscopy ◽  
Crosslinking Agent ◽  
Ph Sensitive ◽  
Swelling Behavior ◽  
Hydroxyethyl Cellulose ◽  
Effect Of Temperature ◽  
Swelling Capacity ◽  
Different Levels

AbstractThe swelling behavior of hydroxyethyl cellulose-acrylamide hydrogels at different pH and temperatures was studied. The absorption increased for the first 12 hours and then decreased. Several hydroxyethyl cellulose-acrylamide ratios were studied. Increasing hydroxyethyl cellulose amount decreased swelling, indicating that swelling was affected by increase in crosslinking. Three different levels of crosslinking agent were studied. Hydrogels exhibited a thermal and pH sensitive behaviour. Highest swelling capacity was found at pH 7.0 and 30 °C. All samples were characterized by means of infrared spectroscopy (FTIR). Characteristic absorbance peaks for both materials were found, showing the presence of hydroxyethyl cellulose and acrylamide on hydrogel.

scholarly journals pH-Sensitive Starch-Based Hydrogels: Synthesis and Effect of Molecular Components on Drug Release Behavior

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1974
Author(s):  
Juan Carlos Quintanilla de Stéfano ◽  
Vanessa Abundis-Correa ◽  
Sergio Daniel Herrera-Flores ◽  
Alejandro J. Alvarez
Keyword(s):  
Drug Delivery ◽  
Drug Release ◽  
Release Rate ◽  
Crosslinking Agent ◽  
Ph Sensitive ◽  
Fickian Diffusion ◽  
Butyl Methacrylate ◽  
Release Behavior ◽  
Drug Release Behavior ◽  
Swelling Capacity

The drug release behavior of pH-sensitive starch-based hydrogels was systematically studied. Hydrogels were synthesized by copolymerization of acrylic acid (AA) and other acrylate comonomers onto the starch backbone. The hydrophilic agents 2-hydroxy ethyl methacrylate (HEMA), and acrylamide (AAm), as well as the hydrophobic butyl-methacrylate (BMA), were utilized as comonomers. Methylene-bisacrylamide (MBA) was employed as a crosslinking agent. The synthesized hydrogels were loaded with caffeine as a model drug. The effects of the hydrophobic/hydrophilic character of the comonomers and chemical crosslinking on the swelling capacity and the release rate of caffeine were investigated. The use of the crosslinking agent and hydrophobic monomers decreased the swelling capacity of the hydrogels. The release rate of caffeine increased with the presence of a hydrophobic monomer. The fastest release was obtained with the AA/BMA/AAm formulation, and the slowest release was observed with the AA/HEMA/AAm formulation. The transport mechanism was controlled by Fickian diffusion in formulations containing AAm, and controlled by the polymer-relaxation mechanism in formulations containing MBA. Overall, our results showed that the swelling and drug delivery behavior can be tuned by varying the chemical composition of the copolymer formulations. These starch-based hydrogels can be useful as drug delivery devices in many biomedical applications.

pH-Sensitive graphene oxide/sodium alginate/polyacrylamide nanocomposite semi-IPN hydrogel with improved mechanical strength

RSC Advances ◽  
2015 ◽  
Vol 5 (108) ◽  
pp. 89083-89091 ◽  
Author(s):  
Huijuan Zhang ◽  
Xianjuan Pang ◽  
Yuan Qi
Keyword(s):  
Graphene Oxide ◽  
Mechanical Strength ◽  
Sodium Alginate ◽  
Ph Sensitive ◽  
Swelling Behavior ◽  
Ph Dependent

A pH-sensitive and mechanically strong graphene oxide/sodium alginate/polyacrylamide nanocomposite semi-IPN hydrogel was designed and prepared. The composite semi-IPN hydrogel showed superior mechanical strength and pH-dependent swelling behavior.

scholarly journals The effect of temperature on the physiological condition and growth performance of freshwater eel elver Anguilla bicolor bicolor McClelland, 1844

2018 ◽  
Vol 17 (2) ◽  
pp. 181
Author(s):  
Latifa Fekri ◽  
Ridwan Affandi ◽  
Muhammad Fajar Rahardjo ◽  
Tatag Budiardi ◽  
Charles Parningotan Haratua Simanjuntak ◽  
...  
Keyword(s):  
Growth Performance ◽  
Physiological Condition ◽  
Effect Of Temperature ◽  
Aquatic Animal ◽  
Metabolism Rate ◽  
Randomized Design ◽  
Freshwater Eel ◽  
Survival And Growth ◽  
Physiology Laboratory ◽  
Different Levels

<p align="center"><strong>ABSTRACT</strong></p><p align="center"> </p><p>This study aimed to analyze the effect of water temperature on the physiological condition and growth performance of freshwater eel elver<em> Anguilla bicolor bicolor </em>(McClelland, 1844). This study was conducted in March 2017 at the Physiology Laboratory of Aquatic Animal, Faculty of Fisheries and Marine Sciences, Bogor Agricultural University. The study used a completely randomized design with five different levels of temperature (22<sup>°</sup>C, 24<sup>°</sup>C, 26<sup>°</sup>C, 28<sup>°</sup>C, and 30<sup>°</sup>C) as treatments with two replications. The size of elver was 2‒3 g. Fish were fed with 1 mm pellet containing 45% of protein. The feeding level was 7 % of fish biomass and the feeding frequency was two times a day. The results showed that temperatures range from 24‒30<sup>°</sup>C could be used for freshwater eel elver rearing and 28‒30<sup>°</sup>Cwere the best temperatures to support survival and growth performance of eel elver. A temperature of 24<sup>°</sup>C was the best temperature that could reduce the metabolism rate and did not cause stress on the elver.</p><p> </p><p>Keywords: elver, physiological conditions, growth performance, metabolism, temperature</p><p> </p><p> </p><p align="center"><strong>ABSTRAK</strong></p><p align="center"><strong> </strong></p><p>Penelitian dengan tujuan menganalisis pengaruh suhu terhadap kondisi fisiologis dan kinerja pertumbuhan <em>elver</em> ikan sidat (<em>Anguilla bicolor bicolor</em> McClelland, 1844) telah dilakukan pada bulan Maret 2017 di Laboratorium Fisiologi Hewan Air FPIK IPB. Penelitian menggunakan rancangan acak lengkap dengan lima perlakuan suhu berbeda (22<sup>°</sup>C, 24<sup>°</sup>C, 26<sup>°</sup>C, 28<sup>°</sup>C, dan 30<sup>°</sup>C) dengan masing-masing dua ulangan. Ukuran benih yang digunakan 2‒3 g. Pakan yang diberikan berupa pellet berukuran 1 mm dengan kadar protein 45%. Jumlah pakan yang diberikan (FR) adalah 7% dari biomassa ikan dan diberikan dua kali sehari. Hasil penelitian menunjukkan bahwa kisaran suhu 24‒30<sup>°</sup>C dapat digunakan dalam pemeliharaan <em>elver</em> ikan sidat, dan suhu 28‒30<sup>°</sup>C merupakan suhu yang sangat baik untuk mendukung kelangsungan hidup dan pertumbuhan <em>elver</em> ikan sidat. Suhu media 24<sup>°</sup>C adalah suhu terbaik yang dapat menekan laju metabolisme dengan tidak menyebabkan stres pada <em>elver </em>ikan sidat.</p><p> </p><p>Kata kunci: <em>elver</em>, kondisi fisiologis, kinerja pertumbuhan, metabolisme, suhu</p><p> </p><p> </p>

Rheological and textural analysis as tools for investigation of drug-polymer and polymer–polymer interactions on the example of low-acyl gellan gum and mesalazine

2022 ◽  
pp. 088532822110527
Author(s):  
Piotr Gadziński ◽  
Tomasz Zbigniew Osmałek ◽  
Anna Froelich ◽  
Oliwia Wilmańska ◽  
Agata Nowak ◽  
...  
Keyword(s):  
Profile Analysis ◽  
Polymer Network ◽  
Crosslinking Agent ◽  
Gellan Gum ◽  
Hydroxyethyl Cellulose ◽  
Rheological Analysis ◽  
Gelling Agents ◽  
Texture Profile ◽  
Ionic Crosslinking ◽  
Model Drug

Purpose. In the performed study, the rheological and textural parameters of gellan-based hydrogels were investigated and their dependence on three factors was taken into consideration: ( i) The presence of the model drug, ( ii) The presence and type of the ionic crosslinking agent, and ( iii) the composition of the polymer network. The objective was to compare two analytical methods, regarded as complementary, and define to what extent the obtained results correlate with each other. Methods. The hydrogels contained low-acyl gellan gum or its mixtures with hydroxyethyl cellulose or κ-carrageenan. CaCl2 and MgCl2 were used as gelling agents. Mesalazine was used as a model drug. The rheological analysis included oscillatory stress and frequency sweeping. The texture profile analysis was performed to calculate texture parameters. Results. Placebo gels without the addition of gelling agents had the weakest structure. The drug had the strongest ability to increase the stiffness of the polymer network. The weakest structure revealed the placebo samples without the addition of gelling agents. Texture analysis revealed no significant influence of the drug on the strength of the gels, while rheological measurements indicated clear differences. Conclusions. It can be concluded that in the case of some parameters methods correlate, that is, the effect related to gelling ions. However, the rheological analysis seems to be more precise and sensitive to some changes in the mechanical properties of the gels.

Effect of temperature, time and glycerol concentration on the dehydration and rehydration process of Steinernema carpocapsae and S. feltiae in alginate granule formulation

Nematology ◽  
2017 ◽  
Vol 19 (2) ◽  
pp. 225-235 ◽  
Author(s):  
Naser Eivazian Kary ◽  
Samira Chahardoli ◽  
Davoud Mohammadi ◽  
Aoife B. Dillon
Keyword(s):  
Survival Rates ◽  
Steinernema Carpocapsae ◽  
Effect Of Temperature ◽  
Glycerol Solution ◽  
Glycerol Concentration ◽  
Granule Formulation ◽  
Osmotic Solution ◽  
Temperature Time ◽  
Rehydration Process ◽  
Different Levels

The osmotic responses ofSteinernema carpocapsaeandS. feltiaein terms of dehydration and rehydration in the presence of calcium alginate and formaldehyde were studied. Infective juveniles (IJ) were exposed to different levels of osmotic concentrations, temperatures and dehydration periods and survival of immobilised IJ was quantified. Osmotic responses showed significant differences and the highest numbers of osmotically dehydratedS. feltiaeandS. carpocapsaeIJ were recorded at 14 and 12% glycerol solution, respectively. Mean percentage of rehydrated IJ was significantly higher when dehydration was processed in 22% glycerol solution. Alginate-formulated IJ showed significantly different survival rates depending on the IJ state (dehydrated or non-dehydrated) and the presence of antimicrobial agent. In addition to optimising alginate formulation, the results demonstrate that the concentration of osmotic solution not only determines the percentage of dehydrated IJ, but also their recovery rate during rehydration. By adding formaldehyde, considerable increases were observed in IJ survival.

Effect of Temperature on the Material Properties and the Results of Thermal Stress Analysis

2017 ◽  
Vol 729 ◽  
pp. 8-12
Author(s):  
Tae Kyung Kim ◽  
Dong Kwon Oh ◽  
Kwang Ju Lee
Keyword(s):  
Thermal Stress ◽  
Elastic Modulus ◽  
Stress Analysis ◽  
Material Properties ◽  
Room Temperature ◽  
Test System ◽  
Effect Of Temperature ◽  
Air Conditioning System ◽  
Thermal Stress Analysis ◽  
Different Levels

Use of correct values of material properties is important in structural analysis. When incorrect values are used in the analysis, engineers may end up with misleading conclusions. The magnitudes of elastic modulus and strength are usually measured from experiments at room temperature. When these values are used in the thermal stress analysis of structures, the results may not be reliable because the magnitudes of elastic modulus and strength depend on temperature. The temperature distribution of HVAC (Heating, Ventilation and Air Conditioning) system was analyzed. The material properties were measured using MTS810 material test system and MTS 651 environmental chamber at different levels of temperature. They were used in the thermal stress analysis of HVAC system. It was found that the results of thermal stress analysis were significantly different from the results using material properties which were measured from experiments at room temperature.

scholarly journals Skin and bubble formation in films made of methyl nanocellulose, hydrophobically modified ethyl(hydroxyethyl)cellulose and microfibrillated cellulose

Cellulose ◽  
2020 ◽  
Author(s):  
Johanna Lyytikäinen ◽  
Maria Morits ◽  
Monika Österberg ◽  
Isto Heiskanen ◽  
Kaj Backfolk
Keyword(s):  
Methyl Cellulose ◽  
Microfibrillated Cellulose ◽  
Hydroxyethyl Cellulose ◽  
Effect Of Temperature ◽  
Cellulose Derivatives ◽  
Air Bubbles ◽  
Oxygen Transmission Rate ◽  
Hydrophobically Modified ◽  
Film Forming ◽  
Ethyl Hydroxyethyl Cellulose

AbstractThe use of nanomaterials and polymers from renewable resources is important in the search for sustainable alternatives to plastic-based packaging materials and films. In this work, self-supporting thin films prepared from derivatized and non-derivatized nanocellulose and cellulose derivatives were studied. The effect of drying temperature on the film-forming behavior of compositions comprising hydrophobically modified ethyl(hydroxyethyl)cellulose (EHEC), native microfibrillated cellulose (MFC) and nanocellulose made from methyl cellulose was determined. The interaction between the components was assessed from viscosity measurements made at different temperatures, the result being linked to a thermal-dependent association during liquid evaporation, and the subsequent barrier and film-forming properties. The effect of temperature on suspensions was clearly different between the materials, confirming that there were differences in interaction and association between EHEC–MFC and methyl nanocellulose–MFC compositions. The amphiphilic EHEC affected both the suspension homogeneity and the film properties. Air bubbles were formed under certain conditions and composition particularly in MFC films, dependent on the drying procedure. The presence of air bubbles did not affect the oxygen transmission rate or the oil and grease resistance. An increasing amount of MFC improved the oxygen barrier properties of the films.

scholarly journals ENZYMATICALLY SYNTHESIZED pH-RESPONSIVE IPN FOR IN-SITU RELEASE OF PANTOPRAZOLE SODIUM

2019 ◽  
pp. 98-103
Author(s):  
Saruchi Sharma ◽  
VANEET KUMAR
Keyword(s):  
Drug Release ◽  
Polymer Network ◽  
Lateral Diffusion ◽  
Ph Sensitive ◽  
Interpenetrating Polymer Network ◽  
Release Behavior ◽  
Ph Responsive ◽  
Gum Tragacanth ◽  
Swelling Capacity

Objective: This study involves the synthesis of Gum tragacanth (gt) based interpenetrating polymer network (ipn) and its utilization for sustained release of anti-ulcerative drug i.e. pantoprazole sodium. Methods: IPN was synthesized from Gum tragacanth, polyacrylic acid (gt-cl-paa) hydrogel. gt-cl-paa was kept in distilled water. Further, acryamide (aam) and methylmethacrylate (mma) was added and then kept for overnight. Later on, lipase and glutaraldehyde were added. Homopolymers and the unreacted monomers were removed using acetone. Synthesized IPN was dried at 50 °C for further study. Synthesized ipn was swelled in water and the drug was added to it. The drug was entrapped in the pores of the synthesized ipn and then drug release behavior was studied using uv-vis spectrophotometer. Results: Gt, paa and mma based crosslinked IPN were synthesized using lipase-glutaraldehyde as initiator-crosslinker system. The synthesized IPN was pH sensitive and possessed the desired swelling capacity required for the controlled and systematic liberation of pantoprazole sodium at 37 °C. The kinetic of drug release was studied and found that lateral diffusion (DL) of drug was higher as compared to the initial diffusion (DI). The prepared IPN can be used as prospective carrier for prolonged drug delivery. Conclusion: A novel pH sensitive and colon targeted IPN was synthesized. It acts as an effective device for the controlled release of drug pantoprazole sodium.

The Effects of Acrylamide Loading on the Swelling Capacity of Superabsorbent Polymer in Different Aqueous Medium

2013 ◽  
Vol 812 ◽  
pp. 20-29 ◽  
Author(s):  
Mohamed Nur Raihan ◽  
Nadras Othman ◽  
Ahmad Zulkifli ◽  
Fauzi Roslinda
Keyword(s):  
Aqueous Medium ◽  
Crosslinking Agent ◽  
Dry Weight ◽  
Urea Solution ◽  
Distilled Water ◽  
Superabsorbent Polymer ◽  
Potassium Persulphate ◽  
Superabsorbent Hydrogel ◽  
Waste Polystyrene ◽  
Swelling Capacity

Superabsorbent polymer from waste polystyrene-graft-polyacrylamide was synthesized through emulsion polymerization technique using acrylamide as a monomer and potassium persulphate as an initiator in the presence of N,N-methylenebisacrylamide (NMBA) as a crosslinking agent. The effects of acrylamide loading was investigated to obtain the optimum condition that shows the best swelling capacity in three different aqueous medium; distilled water, saline solution and urea solution. Superabsorbent hydrogel were characterized by Fourier Transform Infrared (FTIR), thermogravimetric analysis (TGA) and electron scanning microscopy (SEM). Swelling test showed optimum absorbencies for distilled water, saline and urea solution were 1230 wt%, 1160 wt% and 440 wt% from their dry weight, respectively, recorded at ratio 1:10 of waste polystyrene to acrylamide. Meanwhile, the IR Spectroscopy proves that the grafting process between acrylamide and waste polystyrene was occurred in the hydrogel. Thermal degradation of the hydrogel started at 350 °C and the existence of porous unit can be observed in SEM micrographs.

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