polycarbonate


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polycarbonate

(pŏl″ē-kăr′bĭ-nāt, -nĭt) [″ + ″]
A transparent polymer used to manufacture eye protectors, shields, and other medical devices.

Polycarbonate

A very strong type of plastic often used in safety glasses, sport glasses, and children's eyeglasses. Polycarbonate lenses have approximately 50 times the impact resistance of glass lenses.

index of refraction

The ratio of the speed of light in a vacuum or in air, c, to the speed of light in a given medium, v. Symbol: n. Hence,
n = c/v
The speed of light in a given medium depends upon its wavelength. Consequently, the index of refraction varies accordingly, being greater for short wavelengths (blue) than for longer wavelengths (red). The index of refraction forms the basis of Snell's law, which quantitatively determines the deviation of light rays traversing a surface separating two media of different refractive indices. Syn. refractive index. Plural: indices. See dispersion; law of refraction; gradient-index lens; high index lens; speed of light; refractometer.
Table I3 Refractive indices of some transparent media at selected wavelengths
spectral lineGFDCA
OriginCalciumHydrogenSodiumHydrogenOxygen
wavelength (nm)430.8486.1589.3656.3759.4
aqueous or vitreous humour1.34401.34041.33601.33411.3317
crystalline lens1.43071.42591.42001.41751.4144
spectacle crown1.53481.52931.52301.52041.5163
dense flint1.63971.62901.61701.61221.6062

Table I4 Index of refraction n of various media for sodium light (λ = 589.3)
air1.00
water (at 20ºC)1.333
spectacle crown glass1.523
flint glass (dense)1.62
flint glass (extra dense)1.65-1.70
titanium oxide glass1.701
calcite crystal
ordinary ray1.658
extraordinary ray1.486
quartz crystal
ordinary ray1.544
extraordinary ray1.553
diamond2.42
Canada balsam1.53-1.54
CR-391.498
polycarbonate1.586
silicone rubber1.44
CAB1.47
PMMA1.49
HEMA1.43
hydrogel polymer
20% water content1.46-1.48
75% water content1.37-1.38
eye
tears1.336
cornea1.376
aqueous humour1.336
crystalline lens (average effect)1.42
vitreous humour1.336

plastic 

Various organic or synthetic materials (e.g. CR-39, HEMA, polymethyl methacrylate, polycarbonate, etc.) that can be transformed into solid shapes to make spectacle frames, contact lenses, ophthalmic lenses, etc. and can be made to have good optical surfaces, high light transmission and refractive indices and dispersions similar to that of crown or flint glass. See acetone; index of refraction; plastic spectacle frame.
References in periodicals archive ?
KBR globally licenses and designs polycarbonate synthesis and compounding plants as well as complementary phenolic technologies, including phenol/acetone, and bisphenol-A (BPA).
On the contrary, the surfaces of the polyurethanes prepared with polycarbonate diol and 50wt% polycarbonate diol + 50wt% polyether obtained after abrasion show similar and lower roughness.
SORPLAS achieves even better durability and heat resistance (+42degC) than conventional flame retardant polycarbonate plastic(3) that has been created using entirely new materials.
Polycarbonate enclosures are capable of dealing with this constant stress and protecting the electronic equipment they contain, perhaps more so than fiberglass or stainless steel enclosures.
The latest examples for the company's development expertise are polycarbonates with particularly high thermal conductivity for cooling elements used for the thermal management of LEDs and a film that joins the points of light from individual LEDs to form a homogenous band of light.
The project uses the world's leading non-phosgene polycarbonate manufacturing technology, which complies with China's national energy saving and carbon emission policy.
The new polycarbonate production plant will be located in SSTPC and is
As is routine with any new patent application, he carried out a patent search and discovered much to his amazement that the German chemical company Bayer had applied for a polycarbonate patent the same year!
In this article, we proposed a novel polycarbonate that has high optical transparence at the communication wavelengths.
Not all polycarbonate plastics contain BPA, but nearly three-quarters of the BPA used in the United States in 2003 went into the manufacture of this one material.
This is the first time that any study has shown that drinking from polycarbonate bottles increases the level of urinary BPA, and that drinking containers made with BPA release the chemical into the liquid that people drink in sufficient amounts, BBC reported.
Named Holofuse [TM], the product is a polycarbonate film incorporating a clear holographic pattern into the surface without the use of adhesives.