swelling behavior
Recently Published Documents


TOTAL DOCUMENTS

1190
(FIVE YEARS 179)

H-INDEX

64
(FIVE YEARS 8)

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4402
Author(s):  
Klara Loos ◽  
Vivianne Marie Bruère ◽  
Benedikt Demmel ◽  
Yvonne Ilmberger ◽  
Alexander Lion ◽  
...  

The present study investigates different elastomers with regard to their behavior towards liquids such as moisture, fuels, or fuel components. First, four additively manufactured materials are examined in detail with respect to their swelling in the fuel component toluene as well as in water. The chemical nature of the materials is elucidated by means of infrared spectroscopy. The experimentally derived absorption curves of the materials in the liquids are described mathematically using Fick’s diffusion law. The mechanical behavior is determined by uniaxial tensile tests, which are evaluated on the basis of stress and strain at break. The results of the study allow for deriving valuable recommendations regarding the printing process and postprocessing. Second, this article investigates the swelling behavior of new as well as thermo-oxidatively aged elastomers in synthetic fuels. For this purpose, an analysis routine is presented using sorption experiments combined with gas chromatography and mass spectrometry and is thus capable of analyzing the swelling behavior multifacetted. The transition of elastomer constituents into the surrounding fuel at different aging and sorption times is determined precisely. The change in mechanical properties is quantified using density measurements, micro Shore A hardness measurements, and the parameters stress and strain at break from uniaxial tensile tests.


2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Shuxin Zhang ◽  
Yangyang Peng ◽  
Ran Jiang ◽  
Wenqiang Liu ◽  
Huanlei Yang ◽  
...  

Acrylic polymer is a superabsorbent for water and widely used in diapers, in which its swelling behavior can be significantly affected by several factors, i.e., the time, temperature, pH, and salt concentration, and thus the product performance in the applications. In this work, the water absorption behavior of acrylic superabsorbent polymers by each of these individual factors was investigated. The results showed that the water absorbency increases with the pH in the range of 2 to ~7 and decreases when the pH continues to increase. However, it decreases with the increases in NaCl concentration in the solution. Moreover, more water can be absorbed by the acrylic polymers at the higher temperature. Based on a previously developed kinetic swelling model and the information from the above investigations, a semiempirical model for predicting the swelling behavior of superabsorbent polymers (SAPs) under different conditions has been developed. Data showed that the model can predict (with a relative error of <4.5%) the amount of water absorbed by acrylic SAPs under different swelling conditions. The model would be very helpful to the practical application in both product design and its performance evaluation.


2021 ◽  
Vol 14 (23) ◽  
Author(s):  
Peddireddy Sreekanth Reddy ◽  
Bijayananda Mohanty ◽  
Bendadi Hanumantha Rao

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 237
Author(s):  
Kasula Nagaraja ◽  
Kummari S. V. Krishna Rao ◽  
Sunmi Zo ◽  
Sung Soo Han ◽  
Kummara Madhususdana Rao

In this paper, novel pH-responsive, semi-interpenetrating polymer hydrogels based on tamarind gum-co-poly(acrylamidoglycolic acid) (TMGA) polymers were synthesized using simple free radical polymerization in the presence of bis[2-(methacryloyloxy)ethyl] phosphate as a crosslinker and potassium persulfate as a initiator. In addition, these hydrogels were used as templates for the green synthesis of silver nanoparticles (13.4 ± 3.6 nm in diameter, TMGA-Ag) by using leaf extract of Teminalia bellirica as a reducing agent. Swelling kinetics and the equilibrium swelling behavior of the TMGA hydrogels were investigated in various pH environments, and the maximum % of equilibrium swelling behavior observed was 2882 ± 1.2. The synthesized hydrogels and silver nanocomposites were characterized via UV, FTIR, XRD, SEM and TEM. TMGA and TMGA-Ag hydrogels were investigated to study the characteristics of drug delivery and antimicrobial study. Doxorubicin hydrochloride, a chemotherapeutic agent successfully encapsulated with maximum encapsulation efficiency, i.e., 69.20 ± 1.2, was used in in vitro release studies in pH physiological and gastric environments at 37 °C. The drug release behavior was examined with kinetic models such as zero-order, first-order, Higuchi, Hixson Crowell and Korsmeyer–Peppas. These release data were best fitted with the Korsemeyer–Peppas transport mechanism, with n = 0.91. The effects of treatment on HCT116 human colon cancer cells were assessed via cell viability and cell cycle analysis. The antimicrobial activity of TMGA-Ag hydrogels was studied against Staphylococcus aureus and Klebsiella pneumonia. Finally, the results demonstrate that TMGA and TMGA-Ag are promising candidates for anti-cancer drug delivery and the inactivation of pathogenic bacteria, respectively.


Author(s):  
Shaine Mohammadali Lalji ◽  
Syed Imran Ali ◽  
Rafiq Ahmed ◽  
Saud Hashmi ◽  
Zahoor Ul Hussain Awan

AbstractSwelling of shale potentially occurs when it is exposed to water-based drilling fluid. The migration of hydrogen ions (H+) in the nano-interlayered platelets of the shale rock is utterly responsible for the swelling behavior in the shale. Conventionally, swelling behavior of any shale formation can be experimentally determined by linear dynamic swell meter. However, it is extremely important to validate these experimental results; hence, this research study aims in conducting a comparative performance analysis for different kinetic models, namely Peleg’s model, first-order exponential association equation and pseudo-second-order kinetic model, and a newly developed scaling swelling model in estimating the experimental results of three different shale samples, namely Talhar, Ranikot and Murree, obtained from different regions of Pakistan. It was found that the performance of the scaling swelling model was the most accurate in predicting the experimental swelling results with accuracy greater than 95% in all the three samples. Peleg’s model is found to be the most inaccurate with $$p \mathrm{values}< \alpha (0.05)$$ p values < α ( 0.05 ) in all the three formations. The equilibrium state in all the three samples was unable to attain by the use of this model. This clearly shows that the transient states continue throughout the course of experimentation, thus demonstrating a higher water activity in the shale samples. Moreover, when comparison was made between the two remaining kinetic adsorption models, it was perceived that pseudo-second-order kinetic was far superior to first-order exponential association equation with $${\mathrm{mean}}_{\mathrm{model}}\simeq {\mathrm{mean}}_{\mathrm{experiment}}$$ mean model ≃ mean experiment and less dispersion in the dataset. Nevertheless, the performance of this model also suffers with the increase in clay content. Furthermore, all these analyses were further validated by different statistical error analysis that includes MAE, APRE% and ANOVA.


Author(s):  
Kasula Nagaraja ◽  
Kummari S.V. Krishna Rao ◽  
Sunmi Zo ◽  
Sung Soo Han ◽  
Madhusudana Rao Kummara

Novel pH responsive semi-interpenetrating polymer hydrogels based on tamarind gum-co-poly(acrylamidoglycolic acid) (TMGA) polymers have been synthesized using simple free radical polymerization in the presence of bis[2-(methacryloyloxy)ethyl] phosphate as a crosslinker and potassium persulfate as a initiator. In addition, these hydrogels have been used as templates for green synthesis of silver nanoparticles (13.4&plusmn;3.6 nm in diameter, TMGA-Ag) by using leaf extract of Teminalia bellirica as reducing agent. Swelling kinetics and equilibrium swelling behavior of the TMGA hydrogels have been investigated in various pH environment the maxium % equilibrium swelling behavior observed i.e., 2882&plusmn;1.2. The synthesized hydrogels and silver nanocomposites have been characterized by the UV, FTIR, XRD, SEM and TEM. TMGA and TMGA-Ag hydrogels have been investigated to study the characteristics of drug delivery and antimicrobial study. Doxorubicin hydrochloride, a chemotherapeutic agent successfully encapsulated with maximum encapulstaion efficiency i.e., 69.20&plusmn;1.2 and performed in vitro release studies in pH physiological and gastric environment at 37 ℃. The drug release behavior is examined with kinetic models such as zero order, first order, Higuchi, Hixson Crowell, Korsmeyer-Peppas. These release data was the best fitted with the Korsemeyer-Peppas transport mechanism with n=0.91. Treatment effect on HCT116 Cell, human colon cancer cells were assessed with cell viability and cell cycle analysis. Antimicrobial activity of TMGA-Ag hydrogels is studied against to Staphylococcus aureus and Klebsiella pneumonia. Finally, the results demonstrate that TMGA and TMGA-Ag are promising candidates for anti-cancer drug delivery and inactivation of pathogenic bacteria, respectively.


Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3904
Author(s):  
Muhammad Abdullah Akram ◽  
Barkat Ali Khan ◽  
Muhammad Khalid Khan ◽  
Ali Alqahtani ◽  
Sultan M. Alshahrani ◽  
...  

Trichophyton rubrum (T. rubrum) is the main cause of chronic dermatophytosis which is highly prevalent worldwide. This study was aimed to fabricate and characterize polymeric emulgel of eugenol and linalool for the treatment of T. rubrum infections. Using the slow emulsification method, the emulgel was prepared and characterized for thermodynamic stability, pH analysis, viscosity, spreadability, swelling behavior, %drug content, surface morphology, globules size, polydispersity index, surface charge (mV), thermal behavior, in vitro drug release and XRD studies. Biological activities of emulgel were conducted against T. rubrum in vitro and in vivo. Results indicated that emulgel formulations were thermodynamically stable. The pH of the formulations was within an acceptable range for skin. The viscosity and spreadability were optimum for the better patient compliance. The swelling behavior was 111.10 ± 1.25% after 90 min. The drug content was within the official pharmacopeia limit i.e., 100 ± 10%. The surface morphology revealed by scanning electron microscopy showed a spherical-shaped structure with characteristic larger cracks and wrinkles. The droplet size, PDI, and surface charge of the optimized emulgel were 888.45 ± 8.78 nm, 0.44 and −20.30 mV, respectively. The emulgel released 84.32% of eugenol and 76.93% of linalool after 12 hr. There was complete disappearance of the diffraction peaks corresponding to the drugs after XRD analysis. In rabbits, the infection was safely and completely recovered after 12 days and the emulgel produced significant effects (p < 0.05) similar to the standard product Clotrim®. It is concluded that the eugenol–linalool emulgel best described all its physical properties and can be applied topically for the treatment of T. rubrum infections.


Sign in / Sign up

Export Citation Format

Share Document