scholarly journals Development of Environmentally Friendly Cellulose Derivative-Based Hydrogels for Contact Lenses Using a Radiation Crosslinking Technique

2021 ◽  
Vol 11 (19) ◽  
pp. 9168
Author(s):  
Akihiro Hiroki ◽  
Mitsumasa Taguchi
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Aqueous Solutions ◽  
Contact Lenses ◽  
Value Added ◽  
Environmentally Friendly ◽  
Soft Contact ◽  
Elongation At Break ◽  
Soft Contact Lenses ◽  
Polyethylene Glycol 1000

Although they have potential environmental pollution issues, soft contact lenses are value-added biodevices for medical use. Thus, it is important to reconsider starting materials and production methods to achieve sustainable development. In this study, hydrogels composed of hydroxypropyl cellulose (HPC) as an environmentally friendly material were produced by radiation and investigated for use in disposable soft contact lenses. HPC-based hydrogels with good mechanical properties and transparency were prepared by irradiation of electron beams on highly concentrated aqueous solutions containing HPC, polyethylene glycol #1000 dimethacrylate (23G), and 2-hydroxyethyl methacrylate (HEMA). The addition of 23G to HPC aqueous solutions resulted in an increase in the gel fraction as well as improved mechanical properties, such as tensile strength and elongation at break. The tensile strength and the elongation at break of HPC/HEMA/23G hydrogel obtained by the further addition of HEMA with HPC/23G aqueous solutions exhibited 0.2 MPa and 124%, which were approximately 2.0 and 1.8 times larger than these of the pure HPC hydrogel, respectively. The evaluation of the properties of the HPC/HEMA/23G hydrogel demonstrated its potential as a soft contact material with improved mechanical properties.

Development, Validation and Parametric Analysis of a Finite Element Model to Simulate the Behavior of Low-Friction Cartilage Replacements

2013 ◽  
Author(s):  
Manuel E. Santana ◽  
Michelle M. Blum
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Parametric Analysis ◽  
Biomedical Applications ◽  
Contact Lenses ◽  
Element Model ◽  
Low Friction ◽  
Soft Contact ◽  
Soft Contact Lenses ◽  
Research Areas

Hydrogels have many interesting biomedical applications which have led to a significant body of research in several areas including simulation [1], mechanical properties [2], and modifications to increase biocompatibility [3]. The behavior of these materials is an important mechanism to simulate because of their current and potential medical uses. In particular, soft contact lenses [4] and artificial cartilage [5] replacements are two of the research areas that will benefit from this study.

scholarly journals Environmentally Friendly Melt-Processed Chitosan/Starch Composites Modified with PVA and Lignin

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2685
Author(s):  
Weronika Janik ◽  
Anna Wojtala ◽  
Anna Pietruszka ◽  
Gabriela Dudek ◽  
Ewa Sabura
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Smooth Surface ◽  
Solution Method ◽  
Thermomechanical Processing ◽  
Environmentally Friendly ◽  
Poly Vinyl Alcohol ◽  
Elongation At Break ◽  
Selection Of ◽  
Scanning Electron

Chitosan/starch-based composites were prepared by thermomechanical processing as an alternative to the traditional solution method, with the aim of fabricating environmentally friendly materials on a larger scale. Different contents and types of lignin and poly(vinyl alcohol), PVA were incorporated into chitosan/starch compositions to improve their mechanical properties. It was demonstrated that the presence of both lignin and PVA increases the values of tensile strength and elongation at break of the composites. Moreover, it was observed that by the selection of a type of lignin and PVA, it was possible to tailor the internal microstructure of the samples. As observed in scanning electron microscope (SEM) micrographs, the introduction of lignin and PVA resulted in the formation of a smooth surface and homogeneous samples.

Peculiarities of cultivation of the monolayer of fetal fibroblasts on the soft contact lenses, with contain the collagen

2009 ◽  
Vol 21 (5) ◽  
pp. 46-50
Author(s):  
N. Pasechnikova ◽  
◽  
G. Drozhzhina ◽  
O. Ivanova ◽  
I. Nasinnik ◽  
...  
Keyword(s):  
Contact Lenses ◽  
Soft Contact ◽  
Soft Contact Lenses ◽  
Fetal Fibroblasts

Modification of therapeutic silicone-hydrogel soft contact lenses

2016 ◽  
Vol 16 (3) ◽  
pp. 117-120 ◽  
Author(s):  
T.N. Safonova ◽  
◽  
I.A. Novikov ◽  
V.I. Boev ◽  
O.V. Gladkova ◽  
...  
Keyword(s):  
Contact Lenses ◽  
Soft Contact ◽  
Silicone Hydrogel ◽  
Soft Contact Lenses

scholarly journals Myopia Control with Combination Low-Dose Atropine and Peripheral Defocus Soft Contact Lenses: A Case Series

2021 ◽  
pp. 548-554
Author(s):  
Nir Erdinest ◽  
Naomi London ◽  
Nadav Levinger ◽  
Yair Morad
Keyword(s):  
Low Dose ◽  
Contact Lenses ◽  
Case Series ◽  
Concentric Circle ◽  
Retrospective Case ◽  
Soft Contact ◽  
Myopia Progression ◽  
Soft Contact Lenses ◽  
Center Distance ◽  
Myopia Control

The goal of this retrospective case series is to demonstrate the effectivity of combination low-dose atropine therapy with peripheral defocus, double concentric circle design with a center distance soft contact lenses at controlling myopia progression over 1 year of treatment. Included in this series are 3 female children aged 8–10 years with progressing myopia averaging −4.37 ± 0.88 D at the beginning of treatment. Their average annual myopic progression during the 3 years prior to therapy was 1.12 ± 0.75 D. They had not attempted any myopia control treatments prior to this therapy. The children were treated with a combination of 0.01% atropine therapy with spherical peripheral defocus daily replacement soft lenses MiSight<sup>®</sup> 1 day (Cooper Vision, Phoenix, AZ, USA). They underwent cycloplegic refraction, and a slit-lamp evaluation every 6 months which confirmed no adverse reactions or staining was present. Each of the 3 children exhibited an average of 0.25 ± 0.25 D of myopia progression at the end of 1 year of treatment. To the best of the authors’ knowledge, this is the first published study exhibiting that combining low-dose atropine and peripheral defocus soft contact lenses is effective at controlling children’s moderate to severe myopia progression during 1 year of therapy.

scholarly journals The Structure and Mechanical Properties of Hemp Fibers-Reinforced Poly(ε-Caprolactone) Composites Modified by Electron Beam Irradiation

2021 ◽  
Vol 11 (12) ◽  
pp. 5317
Author(s):  
Rafał Malinowski ◽  
Aneta Raszkowska-Kaczor ◽  
Krzysztof Moraczewski ◽  
Wojciech Głuszewski ◽  
Volodymyr Krasinskyi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Electron Beam ◽  
Impact Strength ◽  
Flexural Modulus ◽  
Natural Fibers ◽  
High Energy ◽  
Electron Radiation ◽  
Elongation At Break ◽  
Hemp Fibers

The need for the development of new biodegradable materials and modification of the properties the current ones possess has essentially increased in recent years. The aim of this study was the comparison of changes occurring in poly(ε-caprolactone) (PCL) due to its modification by high-energy electron beam derived from a linear electron accelerator, as well as the addition of natural fibers in the form of cut hemp fibers. Changes to the fibers structure in the obtained composites and the geometrical surface structure of sample fractures with the use of scanning electron microscopy were investigated. Moreover, the mechanical properties were examined, including tensile strength, elongation at break, flexural modulus and impact strength of the modified PCL. It was found that PCL, modified with hemp fibers and/or electron radiation, exhibited enhanced flexural modulus but the elongation at break and impact strength decreased. Depending on the electron radiation dose and the hemp fibers content, tensile strength decreased or increased. It was also found that hemp fibers caused greater changes to the mechanical properties of PCL than electron radiation. The prepared composites exhibited uniform distribution of the dispersed phase in the polymer matrix and adequate adhesion at the interface between the two components.

scholarly journals Effect of Moisture Content on the Processing and Mechanical Properties of a Biodegradable Polyester

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1616
Author(s):  
Vincenzo Titone ◽  
Antonio Correnti ◽  
Francesco Paolo La Mantia
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Moisture Content ◽  
Mechanical Testing ◽  
Hydrolytic Degradation ◽  
Slight Reduction ◽  
Biodegradable Polyester ◽  
Molding Process ◽  
Elongation At Break ◽  
Effect Of Moisture

This work is focused on the influence of moisture content on the processing and mechanical properties of a biodegradable polyester used for applications in injection molding. The pellets of the biodegradable polyester were exposed under different relative humidity conditions at a constant temperature before being compression molded. The compression-molded specimens were again placed under the above conditions before the mechanical testing. With all these samples, it is possible to determine the effect of moisture content on the processing and mechanical properties separately, as well as the combined effect of moisture content on the mechanical properties. The results obtained showed that the amount of absorbed water—both before processing and before mechanical testing—causes an increase in elongation at break and a slight reduction of the elastic modulus and tensile strength. These changes have been associated with possible hydrolytic degradation during the compression molding process and, in particular, with the plasticizing action of the moisture absorbed by the specimens.

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