Processing/Structure Relationships of Mica-Filled PE-Films with Low Oxygen Permeability

1998 ◽  
Vol 13 (1) ◽  
pp. 58-66 ◽  
Author(s):  
M. Xanthos ◽  
N. Faridi ◽  
Y. Li
Keyword(s):  
Oxygen Permeability ◽  
Low Oxygen

scholarly journals HYDROGELS FROM POLYACRYLIC ACID FOR REDUCTION OF BIOADHESION ON SILICONE CONTACT LENSES

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Zahida Ademović ◽  
Snježana Marić ◽  
Peter Kingshott ◽  
Zoran Iličković
Keyword(s):  
Surface Modification ◽  
Oxygen Permeability ◽  
Contact Lenses ◽  
Low Oxygen ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Angle Measurements ◽  
Contact Angle Measurements ◽  
Lysozyme Adsorption ◽  
Tof Ms

Contact lenses suffer from two limitations: low oxygen permeability and deposition of protein and lipids. In order to prevent bioadhesion, surface must be completely inert to all biological reactions. To achieve this, surface properties must be tailored. Also, to improve comfort, surface must be highly wettable and lubricous. In this paper the surface of silicone contact lenses was modified by plasma induced copolymerization of acrylic acid. A wettable surface was generated and in addition carboxyl groups that were created on the surface provided an ideal reactive platform for subsequent grafting of polyethylene glycol. Each surface modification step was analysed by XPS and contact angle measurements. Lysozyme adsorption on modified silicone contact lenses was analysed by surface-MALDI-ToF-MS and XPS. After incubation with lysozyme, surface-MALDI-TOF-MS and XPS analysis showed a reduction of adsorbed lysozyme on hydrogel modified contact lenses. Surface modification of silicone with PEG is a method for reduction of protein adsorption on contact lenses.

Fe/Mn-based Perovskite-Type Oxides with Excellent Oxygen Permeability and Reduction Tolerance

2004 ◽  
Vol 835 ◽  
Author(s):  
Yasutake Teraoka ◽  
Hironobu Shimokawa ◽  
Hajime Kusaba ◽  
Kazunari Sasaki
Keyword(s):  
Partial Oxidation ◽  
Synthesis Gas ◽  
Oxygen Permeability ◽  
Membrane Reactors ◽  
Permeation Flux ◽  
Low Oxygen ◽  
Reducing Atmosphere ◽  
A Site ◽  
Perovskite Type ◽  
Perovskite Type Structure

ABSTRACTA family of Co-free, Fe/Mn-based perovskite-type oxides, (Sr, A')(Fe, Mn)O3-δ (A'=La, Ba, Ca), was synthesized, and their oxygen permeability and phase stability in reducing atmosphere were investigated. The substitution of Mn at B site caused the decrease in oxygen permeability. As for the effect of A-site substitution, prominent promotion was observed by the substitution of Ba for 30% of Sr, and Ba0.3Sr0.7FeO3-δ was found to be one of most excellent oxygen permeable materials with the permeation flux of 3.0 cm3(STP) cm−2 min−1 at 900 °C. Reduction tolerance was evaluated by TG measurements in a 5%H2/N2 stream up to 1000 °C. After the TG measurements, crystal structures of La-Sr-Co-Fe-O and Sr-Fe-(Mn)-O perovskites were decomposed or transformed into low oxygen permeable phases, but the perovskite-type structure of Ba-Sr-Fe-(Mn)-O survived. The Fe/Mn-based perovskites with high oxygen permeability and exceeding reduction tolerance could be used as stable membrane materials for membrane reactors catalyzing NO-CH4 reaction and the partial oxidation of CH4 into synthesis gas.

scholarly journals Refractive behavior changes with six months daily wear of high and low oxygen permeability hydrogel contact lenses

2006 ◽  
Vol 65 (2) ◽  
Author(s):  
W.D.H. Gillan
Keyword(s):  
Oxygen Permeability ◽  
Contact Lenses ◽  
The Other ◽  
Behavior Changes ◽  
Low Oxygen ◽  
Soft Contact ◽  
Silicone Hydrogel ◽  
Refractive State ◽  
Soft Contact Lenses ◽  
Silicone Hydrogels

Introduction: The investigation of myopia and soft contact lenses is not new. Many reports show  that  the  wearing  of  silicone  hydrogel lenses as opposed to conventional disposable hydrogel lenses results in little progression of myopia in the eyes wearing silicone hydrogels. Method: Six subjects wore a silicone hydro-gel lens on one eye while the other eye wore a habitual disposable hydrogel lens for six months of daily wear. Fifty measurements of refractive state in each eye were taken prior to the subjects wearing a silicone lens in one eye and a conven-tional hydrogel lens in the other eye. After six months of daily wear another fifty measurements of refractive state were taken for each subject. Results:  Although  there  is  no  statisti-cal  support  for  the  findings  of  this  study, comet stereo-pairs are used to show the chang-es in refractive state for each subject. Four of  the  six  subjects  showed  an  increase  in myopia in the eye wearing the silicone lens. Discussion:  The  increase  in  myopia in eyes wearing a silicone hydrogel lens is contrary  to  the  findings  of  other  studies.

scholarly journals REGIONAL VARIATION IN FLUID RESERVOIR THICKNESS, OXYGEN TRANSMISSIBILITY AND CORNEAL OEDEMA DURING SCLERAL LENS WEAR

2021 ◽  
Vol 5 (1) ◽  
pp. e32-e43
Author(s):  
Obinwanne Junior Chukwuemeka ◽  
Damian C. Echendu ◽  
Isaura Ilorena D'Alva Brito dos Santos ◽  
Sharon Onwuka ◽  
Osazee Agbonlahor
Keyword(s):  
Regional Variation ◽  
Oxygen Permeability ◽  
Anterior Segment ◽  
Corneal Edema ◽  
Peripheral Region ◽  
Low Oxygen ◽  
Lens Thickness ◽  
Before And After ◽  
Lens Wear ◽  
Fluid Reservoir

Purpose: To determine if regional variation in post lens fluid reservoir thickness (PLFT) during scleral lens wear leads to regional variation in oxygen transmissibility and corneal edema during 4 hours of non-fenestrated scleral lens wear.Methods: About 20 healthy subjects (mean age, 28.8 ± 4.2 years) were fitted with nonfenestrated rotationally symmetric scleral lenses. Anterior segment optical coherence tomography was used to measure cornea thickness before and after lens wear, PLFT 10 minutes and 4 hours after lens application, and scleral lens thickness (with the scleral lens in situ) 4 hours after scleral lens application. These measurements were limited to the central 6 mm and divided into three zones (central, mid-peripheral, and peripheral zones). In the mid-peripheral and peripheral zones, eight principal meridians were measured, generating 17 measurement points in total. Scleral lens thickness and PLFT measurements were corrected for optical distortions by a series of equations. Oxygen transmissibility was calculated by dividing the scleral lens oxygen permeability by the optically-corrected scleral lens thickness, taking into account the oxygen permeability of saline and fluid reservoir thickness.Results: A significant regional variation in PLFT (F = 12.860, P = 0. 012) was observed after 10 minutes of the lens application, PLFT was thickest and thinnest in the inferotemporal and the superonasal region of the peripheral zones( 322.6 ± 161.8 µm and 153.8 ± 96.4 µm, respectively); however, this variation was not statistically significant at 4 hours of scleral lens wear (F = 4.692; P = 0.073). Despite significant regional variation in oxygen transmissibility (F = 48.472; P = 0.001) and relatively low oxygen transmissibility through the scleral lens, induced corneal edema did not vary significantly in different regions (F = 3.346; P = 0.126). In the central corneal region, the induced corneal edema correlated moderately with PLFT (r = 0.468; P = 0.037) and oxygen transmissibility (r = -0.528; P = 0.017). This relationship was insignificant in the peripheral cornea.Conclusion: The inferotemporal peripheral region had the thickest PLFT and least oxygen transmissibility, and the superonasal region had the vice versa. Despite significant variation in PLFT and oxygen transmissibility initially, in healthy corneas, this variation does not seem to induce statistically significant regional variation in corneal edema. Increased central PLFT and decreased oxygen transmissibility moderately correlate with central corneal edema.

scholarly journals Addition of Al(OH)3 versus AlO(OH) nanoparticles on the optical, thermo-mechanical and heat/oxygen transmission properties of microfibrillated cellulose films

Cellulose ◽  
2021 ◽  
Author(s):  
Tjaša Kolar ◽  
Branka Mušič ◽  
Romana Cerc Korošec ◽  
Vanja Kokol
Keyword(s):  
Thermal Management ◽  
Oxygen Permeability ◽  
Hydrophobic Surface ◽  
Exothermic Peak ◽  
Microfibrillated Cellulose ◽  
Low Oxygen ◽  
Cellulose Films ◽  
One Step ◽  
Thermal Stability Of ◽  
Oxygen Transmission

AbstractDifferently structured aluminum (tri/mono) hydroxide (Al(OH)3 /AlO(OH)) nanoparticles were prepared and used as thermal-management additives to microfibrillated cellulose (MFC), cast-dried in thin-layer films. Both particles increased the thermal stability of the MFC film, yielding 20–23% residue at 600 °C, and up to 57% lowered enthalpy (to 5.5–7.5 kJ/g) at 0.15 wt% of loading, while transforming to alumina (Al2O3). However, the film containing 40 nm large Al(OH)3 particles decomposed in a one-step process, and released up to 20% more energy between 300 and 400 °C as compared to the films prepared from smaller (21 nm) and meta-stable AlO(OH), which decomposed gradually with an exothermic peak shifted to 480 °C. The latter resulted in a highly flexible, optically transparent (95%), and mechanically stronger (5.7 GPa) film with a much lower specific heat capacity (0.31–0.28 J/gK compared to 0.68–0.89 J/gK for MFC-Al(OH)3 and 0.87–1.26 for MFC films), which rendered it as an effective heat-dissipating material to be used in flexible opto-electronics. Low oxygen permeability (2192.8 cm3/m2day) and a hydrophobic surface (> 60°) also rendered such a film useful in ecologically-benign and thermosensitive packaging.

scholarly journals Addition of Al(OH)3 vs. AlO(OH) nanoparticles on the optical, thermo-mechanical and heat/oxygen transmission properties of microfibrillated cellulose films

2021 ◽  
Author(s):  
Tjaša Kolar ◽  
Branka Mušič ◽  
Romana Cerc Korošec ◽  
Vanja Kokol
Keyword(s):  
Thermal Management ◽  
Oxygen Permeability ◽  
Hydrophobic Surface ◽  
Exothermic Peak ◽  
Microfibrillated Cellulose ◽  
Low Oxygen ◽  
Cellulose Films ◽  
One Step ◽  
Thermal Stability Of ◽  
Oxygen Transmission

Abstract Differently structured aluminum (tri/mono) hydroxide (Al(OH)3 / AlO(OH)) nanoparticles were prepared and used as thermal-management additives to microfibrillated cellulose (MFC), cast-dried in thin-layer films. Both particles increased the thermal stability of the MFC film, yielding 20–23% residue at 600 °C, and up to 57% lowered enthalpy (to 5.5–7.5 kJ/g) at 0.15 wt% of loading, while transforming to Al2O3. However, the film containing 40 nm large Al(OH)3 particles decomposed in a one-step process, and released up to 20 % more energy between 300–400°C as compared to the films prepared from smaller (21 nm) and meta-stable AlO(OH), which decomposed gradually with an exothermic peak shifted to 480 °C. The latter resulted in a highly flexible, optically transparent (95%), and mechanically stronger (5.7 GPa) film with a much lower specific heat capacity (0.31 − 0.28 J/gK compared to 0.68–0.89 J/gK for MFC-Al(OH)3 and 0.87–1.26 for MFC films), which render it as an effective heat-dissipating material to be used in flexible opto-electronics. Low oxygen permeability (2192.8 cm3/m2day) and a hydrophobic surface (>60°) rendered such a film also useful in ecologically-benign and thermosensitive packaging.

Vascular Response to Extended Wear of Hydrogel Lenses with High and Low Oxygen Permeability

2001 ◽  
Vol 78 (3) ◽  
pp. 147-151 ◽  
Author(s):  
Kathryn A. Dumbleton ◽  
Robin L. Chalmers ◽  
Doris B. Richter ◽  
Desmond Fonn
Keyword(s):  
Oxygen Permeability ◽  
Vascular Response ◽  
Low Oxygen
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