Swelling behavior of poly (N-hydroxymethylacrylamide-co-acrylic acid) hydrogels and release of potassium nitrate as fertilizer

2018 ◽  
Vol 38 (5) ◽  
pp. 437-447 ◽  
Author(s):  
Fatma Louzri ◽  
Sadjia Bennour
Keyword(s):  
Ionic Strength ◽  
Acrylic Acid ◽  
Release Kinetics ◽  
Potassium Nitrate ◽  
Swelling Behavior ◽  
Scanning Calorimetry ◽  
Ph Values ◽  
Dynamic Swelling ◽  
Kinetics Of ◽  
And Diffusion

Abstract Poly (N-hydroxymethylacrylamide-co-acrylic acid) [P(NHMA-AAx)] hydrogels were prepared by free-radical polymerization in aqueous solution at 56°C, using N,N′-methylenebisacrylamide as the cross-linking agent. The synthesized hydrogels were subsequently investigated by a series of characterization techniques including Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis and differential scanning calorimetry analysis. The effects of comonomer composition in the feed, pH, temperature and ionic strength on the swelling behavior were studied. Results indicated that the swelling capabilities of P(NHMA-AAx) hydrogels decreased with the increase in N-hydroxymethylacrylamide (NHMA) content in the polymeric matrix and ionic strength of the medium. Additionally, the hydrogels showed both temperature and pH responses. The dynamic swelling behaviors of hydrogels at different pH values followed a non-Fickian type. The P(NHMA-AAx) hydrogels were also loaded with potassium nitrate (KNO3) as a model agrochemical, and the release kinetics of fertilizer from the hydrogels was studied as a function of KNO3 and NHMA concentrations. Moreover, various kinetic parameters, such as release exponents and diffusion coefficients, were calculated.

Investigation of pH-dependent swelling behavior and kinetic parameters of novel poly(acrylamide-co-acrylic acid) hydrogels with spirulina

e-Polymers ◽  
2015 ◽  
Vol 15 (2) ◽  
pp. 81-93 ◽  
Author(s):  
Demet Aydınoğlu
Keyword(s):  
Acrylic Acid ◽  
Swelling Behavior ◽  
Swelling Kinetics ◽  
Mechanical Behaviors ◽  
Ph Values ◽  
Diffusion Parameters ◽  
Ph Dependent ◽  
And Diffusion ◽  
Radical Solution ◽  
Poly Acrylamide

AbstractPoly(acrylamide-co-acrylic acid)-spirulina (AAm-AAc-Sp) hydrogels were prepared by free radical solution polymerization of the monomer acrylamide (AAm) and the comonomer acrylic acid (AAc) with N,N-methylene bisacrylamide (BAAm) as the crosslinker in the presence of spirulina (Sp), which is a microalga species. The swelling ratios of the hydrogels were followed by gravimetric measurements. Hence, swelling kinetics and diffusion parameters were determined. Furthermore, the morphological structures and mechanical behaviors of the hydrogels were investigated by scanning electron microscopy and by using a uniaxial compression machine, respectively. All the results showed that spirulina had strong influence in the pH-dependent swelling behavior, as well as on the kinetic and diffusion parameters due to its interaction with the acrylic acid units. These interactions were attributed to spirulina, which caused a change in pore size and its distribution. The present novel hydrogels showed high swelling at neutral pH, but collapsed slowly at low and high pH values. Thus, these AAm-AAc-Sp hydrogels can be good candidates for pH-sensitive drug delivery systems.

scholarly journals Hydroxypropyl Methylcellulose-Based Hydrogel Copolymeric for Controlled Delivery of Galantamine Hydrobromide in Dementia

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1350
Author(s):  
Sidra Bashir ◽  
Nadiah Zafar ◽  
Noureddine Lebaz ◽  
Asif Mahmood ◽  
Abdelhamid Elaissari
Keyword(s):  
Acrylic Acid ◽  
Release Kinetics ◽  
Drug Loading ◽  
Hydroxypropyl Methylcellulose ◽  
Controlled Delivery ◽  
Release Mechanism ◽  
Release Kinetic ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Gel Fraction

The study aims to prepare a smart copolymeric for controlled delivery of Galantamine hydrobromide. The synthesis of the hydrogel was executed through free radical polymerization using HPMC (Hydroxypropyl methylcellulose) and pectin as polymers and acrylic acid as monomer. Cross-linking was performed by methylene bisacrylamide (MBA). HPMC-pectin-co-acrylic acid hydrogel was loaded with Galantamine hydrobromide (antidementia drug) as a model drug for treatment of Alzheimer based dementia. Formulated hydrogels (SN1–SN9) were characterized for Fourier transform-infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction, and energy dispersive X-ray. Drug loading efficiency, gel fraction, measurements of porosity, and tensile strength were reported. Swelling and release studies were performed at pH 1.2 and 7.4. Drug liberation mechanism was evaluated by applying different release kinetic models. Galantamine hydrobromide was released from prepared hydrogels by Fickian release mechanism. Swelling, gel fraction, porosity, and drug release percentages were found to be dependent on hydroxypropyl methylcellulose, pectin, acrylic acid, and methylene bisacrylamide concentrations. By increasing HPMC amount, swelling was increased from 76.7% to 95.9%. Toxicity studies were conducted on albino male rabbits for a period of 14 days. Hematological and histopathological studies were carried out to evaluate safety level of hydrogel. Successfully prepared HPMC-pectin-co-acrylic acid hydrogel showed good swelling and release kinetics, which may help greatly in providing controlled release drug effect leading to enhanced patient compliance for dementia patients.

Mathematical Modeling of Drug Release from Spherical Drug Particles: Analysis of the Effect of Absorption Rate on Drug Release Rate

2009 ◽  
Vol 4 (5) ◽  
Author(s):  
Norman W Loney ◽  
Ramana Susarla
Keyword(s):  
Drug Release ◽  
Absorption Rate ◽  
Release Kinetics ◽  
Closed Form Solution ◽  
Form Solution ◽  
Proposed Model ◽  
Significant Difference ◽  
Rate Of Absorption ◽  
Kinetics Of ◽  
And Diffusion

A closed form solution has been obtained for the release kinetics of a solute from a spherical drug matrix into a finite volume of liquid, taking into account the effect of rate of absorption. The proposed model results clearly show the effect of the absorption rate constant on the rate of drug release. The obtained results are compared with the experimental data and diffusion-only model results. There is a significant difference in the release profile when the rate of absorption of drug is slow. The most important feature of the mathematical relationship between the liquid concentration verses time is its ability to predict change in the performance of the drug by manipulating the parameters of the equation. These parameters include the initial concentration of the drug, the radius of the drug and diffusivity of the drug in the solid to name a few. Therefore, a substantial number of experiments can be eliminated when the optimal performance of a drug is sought after.

scholarly journals Influence of Acrylic Acid on Kinetics of UV-Induced Cotelomerization Process and Properties of Obtained Pressure-Sensitive Adhesives

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5661
Author(s):  
Agnieszka Kowalczyk ◽  
Mateusz Weisbrodt ◽  
Beata Schmidt ◽  
Konrad Gziut
Keyword(s):  
Acrylic Acid ◽  
Crosslinking Agent ◽  
Solid Content ◽  
Scanning Calorimetry ◽  
Adhesive Properties ◽  
Pressure Sensitive Adhesives ◽  
Molecular Weights ◽  
Pressure Sensitive ◽  
Physicochemical Features ◽  
Kinetics Of

A new environmentally friendly method of photoreactive pressure-sensitive adhesives (PSAs) preparation was demonstrated. PSAs based on n-butyl acrylate (BA), acrylic acid (AA) and 4-acryloyloxy benxophenone (ABP) were prepared via the UV-induced cotelomerization process in the presence of a radical photoinitiator (acylphosphine oxide) and telogen (tetrabromomethane). Hydroxyterminated polybutadiene was used as a crosslinking agent. Influence of AA concentration (0–10 wt %) on kinetics of the cotelomerization process was investigated using a photodifferential scanning calorimetry method, selected physicochemical features of obtained photoreactive BA/AA/ABP cotelomers (molecular masses, polydispersity, monomers conversion and dynamic viscosity) and self-adhesive properties of obtained PSAs (adhesion, tack and cohesion) were studied, as well. It turned out that AA content is the important factor that influences monomers conversion (thereby the volatile parts content in prepolymer) and PSAs’ properties. As the acrylic acid content increases, the reaction rate increases, but the total monomers conversion and the solid content of the prepolymer decreases. Additionally, the adhesion and cohesion of PSAs were grown up, and their tackiness decreased. However, the AA content has no effect on molecular weights (Mw and Mn) and polydispersity (c.a. 1.5) of photoreactive cotelomers. The optimal AA content necessary to obtain a prepolymer with low volatile parts content and good PSA properties was determined.

Investigation of Curing Kinetics of Azo-Containing Twin Liquid Crystalline Epoxy Resins with Anhydride

2013 ◽  
Vol 702 ◽  
pp. 115-118
Author(s):  
Teng Fei Shen ◽  
Chun Feng Sun ◽  
Ying Juan Sun
Keyword(s):  
Epoxy Resins ◽  
Liquid Crystalline ◽  
Curing Kinetics ◽  
Chemical Kinetic ◽  
Diffusion Control ◽  
Kinetic Control ◽  
Control Mechanisms ◽  
Scanning Calorimetry ◽  
Kinetics Of ◽  
And Diffusion

A series of novel azo-containing twin liquid crystalline (LC) epoxy monomers were cured with anhydrides without extra catalyst and the curing kinetics was investigated by non-isothermal differential scanning calorimetry (DSC) technique. The results showed that the effect of phase behavior on activation energy (Ea) was very great. The chemical kinetic control and diffusion control mechanisms dominant the curing together, which gives a larger value of Ea. Azo group also served as a catalyst to accelerate the curing reaction.

Swelling Properties and Kinetics of Starch-g-Poly(acrylic acid) Hydrogels

2012 ◽  
Vol 550-553 ◽  
pp. 1316-1320
Author(s):  
Ji Yan Shi ◽  
Li Ren Fan ◽  
Ji Qing Song ◽  
Wen Bo Bai
Keyword(s):  
Relative Humidity ◽  
Acrylic Acid ◽  
Moisture Absorption ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Swelling Properties ◽  
X Ray ◽  
Hygroscopic Swelling ◽  
Kinetics Of ◽  
Poly Acrylic Acid

Starch-g-poly(acrylic acid) (CSt-g-PAA) hydrogels were prepared from cassava starch and acrylic acid by graft polymerization. The hydrogels were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermogravimetric-differential scanning calorimetry (TG-DSC). Additionally, the water absorbency and hygroscopic swelling properties of the hydrogels were investigated respectively. The two processes were simulated using mathematical modes. The results revealed that the crystal structure of starch was destroyed. At 40°C and relative humidity 90% (90% RH), the samples (starch mass15%, 50%) have a better performance of the moisture absorption. Hygroscopic rate declined with the increase of relative humidity.

scholarly journals Fast Swelling Superabsorbent Hydrogels Starch Based Prepared by Gamma Radiation Techniques

2014 ◽  
Vol 14 (3) ◽  
pp. 246-252 ◽  
Author(s):  
Erizal Erizal ◽  
Dian Pribadi Perkasa ◽  
Basril Abbas ◽  
Sudirman Sudirman ◽  
Sulistioso G.S.
Keyword(s):  
Differential Scanning Calorimetry ◽  
Fourier Transform ◽  
Ionic Strength ◽  
Acrylic Acid ◽  
Irradiation Dose ◽  
Room Temperature ◽  
Scanning Calorimetry ◽  
Radiation Crosslinking ◽  
Infra Red ◽  
Short Time

Fast swelling hydrogels were synthesized from the mixture of acrylamide (AAM)-acrylic acid (AA)-starch (15:5:1 w/v) solution by radiation crosslinking with varying irradiation doses (7.5-12.5 kGy) at room temperature. The copolymers were characterizated by Fourier transform infra red spectroscopy (FTIR) and Differential scanning calorimetry (DSC). It was found that hydrogels showed superabsorbent properties with higher swelling capacities (~400 g/g) and reached at a very short time (3 min). There was no significance difference between the effect irradiation dose on swelling of hydrogels. The hydrogels were also found to sensitive to the ionic strength of medium. The FTIR spectra and thermogram DSC of hydrogels were confirmed the crosslinking occurs in the hydrogels.

scholarly journals Effect of Carbon Chain Length, Ionic Strength, and pH on the In Vitro Release Kinetics of Cationic Drugs from Fatty-Acid-Loaded Contact Lenses

Pharmaceutics ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1060
Author(s):  
Cesar Torres-Luna ◽  
Naiping Hu ◽  
Roman Domszy ◽  
Xin Fan ◽  
Jeff Yang ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Ionic Strength ◽  
Chain Length ◽  
Contact Lenses ◽  
Release Kinetics ◽  
Carbon Chain ◽  
Carbon Chain Length ◽  
Cationic Drugs ◽  
Kinetics Of

This paper explores the use of fatty acids in silicone hydrogel contact lenses for extending the release duration of cationic drugs. Drug release kinetics was dependent on the carbon chain length of the fatty acid loaded in the lens, with 12-, 14- and 18-carbon chain length fatty acids increasing the uptake and the release duration of ketotifen fumarate (KTF) and tetracaine hydrochloride (THCL). Drug release kinetics from oleic acid-loaded lenses was evaluated in phosphate buffer saline (PBS) at different ionic strengths (I = 167, 500, 1665 mM); the release duration of KTF and THCL was decreased with increasing ionic strength of the release medium. Furthermore, the release of KTF and THCL in deionized water did not show a burst and was significantly slower compared to that in PBS. The release kinetics of KTF and THCL was significantly faster when the pH of the release medium was decreased from 7.4 towards 5.5 because of the decrease in the relative amounts of oleate anions in the lens mostly populated at the polymer–pore interfaces. The use of boundary charges at the polymer–pore interfaces of a contact lens to enhance drug partition and extend its release is further confirmed by loading cationic phytosphingosine in contact lenses to attract an anionic drug.

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