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The main polycarbonate material is produced by the reaction of bisphenol A (BPA) and phosgene COCl 2. The overall reaction can be written as follows: The first step of the synthesis involves treatment of bisphenol A with sodium hydroxide, which deprotonates the hydroxyl groups of the bisphenol A. [6] (HOC 6 H 4) 2 CMe 2 + 2 NaOH → Na 2 (OC 6 ...
The orienting process serves to improve gas and moisture barrier properties and impact strength. This material is not resistant at high temperature. Its maximum temperature is 200 °F (93 °C). Polycarbonate (PC) PC is a clear plastic used to make bottles for milk and water. Five-gallon water bottles are a common application of PC ...
A suitably chosen material coating can reduce the effects of mechanical stress and vibrations on the circuit and its ability to perform in extreme temperatures. For example, in a chip-on-board assembly process, a silicon die is mounted on the board with an adhesive or soldering process, and then it is electrically connected by wire bonding ...
Recycling codes on products. Recycling codes are used to identify the materials out of which the item is made, to facilitate easier recycling process.The presence on an item of a recycling code, a chasing arrows logo, or a resin code, is not an automatic indicator that a material is recyclable; it is an explanation of what the item is made of.
Mixing these together can give a material with inconsistent properties, which can be unappealing to industry. For example, mixing different colored plastics with different plastic colorants together can produce a discolored or brown material and for this reason plastic is usually sorted both by polymer type and color prior to recycling. [5]
made of soft, flexible plastics that allow oxygen to pass through to the cornea. Soft contact lenses may be easier to adjust to and are more comfortable than rigid gas permeable lenses. Newer soft lens materials include silicone-hydrogels to provide more oxygen to your eye while you wear your lenses. [4]
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Materials that allow the transmission of light waves through them are called optically transparent. Chemically pure (undoped) window glass and clean river or spring water are prime examples of this. Materials that do not allow the transmission of any light wave frequencies are called opaque. Such substances may have a chemical composition which ...