Evaluation of the Sorption Properties of a Self-Adhesive Hydrogel Wound Dressing

2019 ◽  
Vol 821 ◽  
pp. 10-16
Author(s):  
Javier Kristina Mutya ◽  
Nadura Riscia ◽  
Jim Clarence Rengel ◽  
Terence Tumolva
Keyword(s):  
Layer Thickness ◽  
Diffusion Coefficients ◽  
Wound Dressing ◽  
Adhesive Layer ◽  
Sorption Properties ◽  
Hydroxyethyl Cellulose ◽  
Swelling Kinetics ◽  
Hydrogel Formulation ◽  
Through Diffusion

A novel self-adhesive wound dressing product was developed using a hydroxyethyl cellulose (HEC) hydrogel layered with a TAPE-gelatin bioadhesive. This wound dressing was then evaluated for its sorption properties through diffusion and swelling tests, and the parameters analyzed were hydrogel formulation, wound dressing thickness and adhesive layer thickness. Results showed that the wound dressing produced using 6% NaOH/5% thiourea in the crosslinking solution, with 2.5 mm hydrogel thickness, and 0.2 mm TAPE-gelatin thickness had the highest water absorbed. Lastly, analysis on swelling kinetics based on a previous study was conducted to determine the diffusion coefficients for the composite wound dressing.

Development of a Self-Adhesive Cellulosic Hydrogel Wound Dressing

2019 ◽  
Vol 801 ◽  
pp. 15-20
Author(s):  
Terence Tumolva ◽  
Sweet Hazel Aquino ◽  
Kryzsa Mae Cabeguin ◽  
John Frederick Imperial
Keyword(s):  
Wound Dressing ◽  
Human Lymphocytes ◽  
Peel Test ◽  
Adhesive Layer ◽  
Inhibition Zone ◽  
Adhesive Contact ◽  
Hydroxyethyl Cellulose ◽  
Cross Linking ◽  
Test Analysis ◽  
Mixing Ratios

In this study, a self-adhesive hydrogel wound dressing was developed by combining hydroxyethyl cellulose (HEC) hydrogel with a tannic acid-polyethylene glycol (TAPE) adhesive bioadhesive with gelatin. Test samples of the cellulosic wound dressing were prepared with three (3) different mixing ratios of the crosslinking solution, three (3) different adhesive formulation, and two different hydrogel/adhesive contact area (flat, ridged). Adhesion performances of these samples on porcine skin were evaluated by performing a T-peel test. Analysis of the HEC/TAPE-gelatin interface showed that the HEC cross-linking agent formulation, adhesive thickness, and presence of surface ridges showed significant three-way interaction effects, and these parameters were modeled using orthogonal polynomials and optimized via response surface methodology (RSM). The adhesion on the HEC-TAPE-gelatin interface was also investigated further using scanning electron microscopy (SEM), where it had been observed that greater adhesion occurred with a decrease in cross-linking density, thinner adhesive layer, and the presence of ridges. Lastly, disk diffusion testing indicated greater antimicrobial activity (mean inhibition zone = 12 mm) against S. aureus and P. aeruginosa in contrast to commercial hydrogel dressings (mean inhibition zone = 7.5 mm), while MTT assay on human lymphocytes resulted to a 98% cell survival rate. Based on these results, it was concluded that it is feasible to use HEC hydrogel with TAPE-gelatin adhesive for manufacturing self-adhesive wound dressing products.

scholarly journals Measurement on Diffusion Coefficients and Isotope Fractionation Factors by a Through-Diffusion Experiment

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 208
Author(s):  
Takuma Hasegawa ◽  
Kotaro Nakata ◽  
Rhys Gwynne
Keyword(s):  
Groundwater Flow ◽  
Diffusion Coefficients ◽  
Isotope Fractionation ◽  
Free Water ◽  
Effective Porosity ◽  
Diffusion Experiment ◽  
Fractionation Factor ◽  
Through Diffusion ◽  
Geological Formations ◽  
Fractionation Factors

For radioactive waste disposal, it is important that local groundwater flow is slow as groundwater flow is the main transport medium for radioactive nuclides in geological formations. When the groundwater flow is very slow, diffusion is the dominant transport mechanism (diffusion-dominant domain). Key pieces of evidence indicating a diffusion-dominant domain are the separation of components and the fractionation of isotopes by diffusion. To prove this, it is necessary to investigate the different diffusion coefficients for each component and the related stable isotope fractionation factors. Thus, in this study, through-diffusion and effective-porosity experiments were conducted on selected artificial materials and natural rocks. We also undertook measurements relating to the isotope fractionation factors of Cl and Br isotopes for natural samples. For natural rock samples, the diffusion coefficients of water isotopes (HDO and H218O) were three to four times higher than those of monovalent anions (Cl−, Br- and NO3−), and the isotope fractionation factor of 37Cl (1.0017–1.0021) was slightly higher than that of free water. It was experimentally confirmed that the isotope fractionation factor of 81Br was approximately 1.0007–1.0010, which is equivalent to that of free water. The enrichment factor of 81Br was almost half that of 37Cl. The effective porosity ratios of HDO and Cl were slightly different, but the difference was not significant compared to the ratio of their diffusion coefficients. As a result, component separation was dominated by diffusion. For artificial samples, the diffusion coefficients and effective porosities of HDO and Cl were almost the same; it was thus difficult to assess the component separation by diffusion. However, isotope fractionation of Cl and Br was confirmed using a through-diffusion experiment. The results show that HDO and Cl separation and isotope fractionation of Cl and Br can be expected in diffusion-dominant domains in geological formations.

Experimental determination of impact tensile properties of adhesive butt joints with the split Hopkinson bar

2003 ◽  
Vol 38 (3) ◽  
pp. 233-245 ◽  
Author(s):  
T Yokoyama
Keyword(s):  
Tensile Strength ◽  
Layer Thickness ◽  
Energy Absorption ◽  
Loading Rate ◽  
Adhesive Layer ◽  
Hopkinson Bar ◽  
Butt Joints ◽  
Cyanoacrylate Adhesive ◽  
Split Hopkinson ◽  
The Impact

The tensile strength and energy absorption of adhesive butt joints at high rates of loading are determined with a tensile split Hopkinson bar using a cylindrical specimen. A commercially available single-component cyanoacrylate adhesive (instantaneous adhesive) and two different adherend materials are used in the adhesion tests. The impact tensile strength of the cyanoacrylate adhesive butt joints is determined from the applied tensile stress history at failure initiation. The impact absorbed energy is obtained by numerical integration of dynamic tensile load-adhesive deformation data. Comparative tension tests at low and intermediate rates of loading are performed on an Instron testing machine. An axisymmetric finite element analysis is carried out to investigate the stress distributions in the adhesive layer of the cyanoacrylate adhesive butt joints. The effects of loading rate, adherend material and adhesive layer thickness on the tensile strength and energy absorption of the cyanoacrylate adhesive butt joints are examined in detail. It is shown that the joint tensile strength increases significantly with increasing loading rate and is greatly affected by both the adhesive layer thickness and the adherend materials. The limitations of the technique are discussed.

Experimental Studies on Strengthening and Failure Mechanism for the Metal/Silicone Rubber/Metal Bonding System

2018 ◽  
Vol 10 (03) ◽  
pp. 1850029 ◽  
Author(s):  
Jingchuan Li ◽  
Lihong Liang ◽  
Xiaoming Liu ◽  
Hansong Ma ◽  
Jingru Song ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Failure Mechanism ◽  
Layer Thickness ◽  
Silicone Rubber ◽  
Adhesive Layer ◽  
Normal Strain ◽  
Failure Strength ◽  
Metal Bonding ◽  
Bonding System ◽  
Average Shear

In the present research, we carry out a systematical experimental investigation on the strength, toughness and failure mechanism of the metal/silicone rubber/metal bonding system. For the case of the aluminum alloy cylinder/silicone rubber/aluminum alloy cylinder bonding system, we measure the tensile deformation and failure behaviors, including the dependence of the failure loading on the adhesive layer thickness and scarf angle. Through introducing a series of definitions, such as average normal stress, average shear stress, average normal strain and average shear strain, along the bonding interface, we realize the measurements on interfacial failure strength, and obtain the relationship between the interfacial strength and the interfacial scarf angle as well as adhesive layer thickness, and we further obtain the failure strength surface, interfacial fracture energy, as well as the energy release rate for the bonding system. The obtained results can provide a scientific basis for deeply understanding the strength and toughness properties as well as the failure mechanism of the metal-adhesive bonding system, and have an important guidance on optimization design and property evolution of the bonding system.

scholarly journals Possibilities and limits of adhesive layer thickness optical evaluation

2010 ◽  
Vol 10 (1) ◽  
pp. 45-49 ◽  
Author(s):  
Miroslav Müller ◽  
Nataša Náprstková
Keyword(s):  
Layer Thickness ◽  
Adhesive Layer
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