Radical annihilation of γ-ray-irradiated contact lens blanks made of a 2-hydroxyethyl methacrylate copolymer at elevated temperatures

2010 ◽  
pp. n/a-n/a ◽  
Author(s):  
Young-Shang Lin ◽  
Li-June Ming ◽  
J. S. Peng ◽  
Ying-Kai Fu ◽  
Sanboh Lee
Keyword(s):  
Contact Lens ◽  
Elevated Temperatures ◽  
Hydroxyethyl Methacrylate ◽  
Γ Ray ◽  
Methacrylate Copolymer

Effect of Buffer on the Optical Properties of Irradiated Hydroxyethyl Methacrylate Copolymer

2002 ◽  
Vol 17 (5) ◽  
pp. 1199-1207
Author(s):  
K. F. Chou ◽  
C. C. Han ◽  
Sanboh Lee
Keyword(s):  
Optical Properties ◽  
Irradiation Dose ◽  
Ph Value ◽  
Bathochromic Shift ◽  
Cutoff Wavelength ◽  
Hydroxyethyl Methacrylate ◽  
Γ Irradiation ◽  
Incident Wavelength ◽  
Γ Ray ◽  
Methacrylate Copolymer

The effect of buffer and γ irradiation on the optical properties of hydroxyethyl methacrylate (HEMA) copolymer was investigated. The transmission of HEMA copolymer decreased with the increase of irradiation dose and/or pH value of the buffer. The cutoff wavelength of HEMA copolymer exhibits a bathochromic shift as the γ-ray dose and/or pH value of buffer increases. The influence of atmosphere during γ-ray irradiation on the optical properties of HEMA copolymer was investigated. The change of optical properties of HEMA copolymer irradiated in air was more pronounced than that irradiated in vacuum. Light was scattered by holes in the polymer. The relationship between scattering intensity (Is) and incident wavelength (λ) can be described by the formula Is ∝ λ−n. The span of holes increases with the irradiation dose regardless of radiation atmosphere and pH value in the range of 4.1–6.5. A boundary between the inner and outer layers of HEMA copolymer irradiated in air was observed, separating two differential morphologies of holes.

Transmission in irradiated hydroxyethyl methacrylate copolymer at elevated temperatures

2002 ◽  
Vol 17 (9) ◽  
pp. 2260-2265 ◽  
Author(s):  
K-P. Lu ◽  
Sanboh Lee ◽  
C. C. Han
Keyword(s):  
Elevated Temperatures ◽  
Wave Length ◽  
Color Centers ◽  
Order Kinetic ◽  
Hydroxyethyl Methacrylate ◽  
Absorption Data ◽  
Visible Spectra ◽  
Transmission Data ◽  
Methacrylate Copolymer ◽  
Good Agreement

Transmission losses were monitored in the ultraviolet-visible spectra of irradiated hydroxyethyl methacrylate (HEMA) copolymer at elevated temperatures. The transmission in irradiated HEMA in the ultraviolet and visible wave length range was almost the same for doses 400 kGy ≤ Φ ≤ 1000 kGy, but was smaller than that of the nonirradiated HEMA copolymer. The reduction in transmission in the irradiated specimens was attributed to the presence of color centers. The concentration of color centers was enhanced by thermal annealing. The transmission data (or absorption data) at 467 nm was found in good agreement with the theoretical model in which the color center production followed a first-order kinetic process. The rate constant satisfies the Arrhenius equation, and the corresponding activation energy is 17.37 kJ/mol and is independent of the dosage. The results were compared with those reported in the literature.

scholarly journals Deposition of styrene/2-hydroxyethyl methacrylate copolymer latex onto grafted nylon 6 fiber.

1989 ◽  
Vol 45 (12) ◽  
pp. 523-528
Author(s):  
Masahiko Sasaki ◽  
Nobuaki Matsumoto ◽  
Toshiro Suzawa
Keyword(s):  
Nylon 6 ◽  
Hydroxyethyl Methacrylate ◽  
Methacrylate Copolymer
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