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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.
This kind of plastic is a good option for substituting conventional plastic produced from petrochemicals because of low emission of carbon dioxide. The commonly used process in producing lactic acid is via fermentation ; to obtain the polylactic acid, the polymerization process follows.
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 .
The key advantage of this type of ceramic material is the versatility afforded by the use of polymeric precursors in terms of processing and shaping. Polymer derived ceramics can be additively manufactured (3D printed) by means of fused filament fabrication , [ 4 ] stereolithography that uses photopolymerization of preceramic polymers . [ 5 ]
Marine plastic pollution, for example, creates garbage patches. Of all the plastic discarded so far, some 14% has been incinerated and less than 10% has been recycled. [5] In developed economies, about a third of plastic is used in packaging and roughly the same in buildings in applications such as piping, plumbing or vinyl siding. [6]
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.
Polycarbonate drink containers are also a source of exposure, although most disposable drinks bottles are actually made of PET, which contains no BPA. Among the non-food sources, exposure routes include through dust, [ 10 ] thermal paper, [ 20 ] clothing, [ 19 ] dental materials, [ 71 ] and medical devices. [ 17 ]
Flax seeds and sesame seeds contain high levels of lignans. [1] [8] The principal lignan precursor found in flaxseeds is secoisolariciresinol diglucoside.[1] [8] Other foods containing lignans include cereals (rye, wheat, oat and barley), soybeans, tofu, cruciferous vegetables, such as broccoli and cabbage, and some fruits, particularly apricots and strawberries. [1]