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Polycarbonate is commonly used in eye protection, as well as in other projectile-resistant viewing and lighting applications that would normally indicate the use of glass, but require much higher impact-resistance. Polycarbonate lenses also protect the eye from UV light.
A polycarbonate is an oxocarbon dianion consisting of a chain of carbonate units, where successive carbonyl groups are directly linked to each other by shared additional oxygen atoms. That is, they are the conjugate bases of polycarbonic acids , the conceptual anhydrides of carbonic acid , or polymers of carbon dioxide .
Polycarbonate polyols are more expensive than other polyols and are thus used in more demanding applications. [31] [32] They have been used to make an isophorone diisocyanate based prepolymer which is then used in glass coatings. [33] They may be used in reactive hotmelt adhesives. [34] All polyols may be used to produce polyurethane prepolymers.
Portion of backbone of nylon 6,6.. Polymer chemistry is a sub-discipline of chemistry that focuses on the structures of chemicals, chemical synthesis, and chemical and physical properties of polymers and macromolecules.
The word plastic derives from the Greek πλαστικός (plastikos), meaning "capable of being shaped or molded;" in turn, it is from πλαστός (plastos) meaning "molded." [ 8 ] As a noun , the word most commonly refers to the solid products of petrochemical-derived manufacturing.
BPA is the monomer precursor for polycarbonate; Terephthalic acid is a comonomer that, with ethylene glycol, forms polyethylene terephthalate. Dimethylsilicon dichloride is a monomer that, upon hydrolysis, gives polydimethylsiloxane.
IUPAC definition A polymer is a substance composed of macromolecules. [ 2 ] A macromolecule is a molecule of high relative molecular mass, the structure of which essentially comprises the multiple repetition of units derived, actually or conceptually, from molecules of low relative molecular mass.
EPSs are mostly composed of polysaccharides (exopolysaccharides) and proteins, but include other macromolecules such as DNA, lipids and humic substances. EPSs are the construction material of bacterial settlements and either remain attached to the cell's outer surface, or are secreted into its growth medium.