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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.
EPS are mostly composed of polysaccharides (exopolysaccharides) and proteins, but include other macromolecules such as DNA, lipids and humic substances. EPS are the construction material of bacterial settlements and either remain attached to the cell's outer surface, or are secreted into its growth medium.
The study of polymer thermodynamics helps improve the material properties of various polymer-based materials such as polystyrene (styrofoam) and polycarbonate. Common improvements include toughening , improving impact resistance , improving biodegradability , and altering a material's solubility .
The chemical composition of a mixture can be defined as the distribution of the individual substances that constitute the mixture, called "components". In other words, it is equivalent to quantifying the concentration of each component. Because there are different ways to define the concentration of a component, there are also different ways to ...
Polymer degradation is the reduction in the physical properties of a polymer, such as strength, caused by changes in its chemical composition.Polymers and particularly plastics are subject to degradation at all stages of their product life cycle, including during their initial processing, use, disposal into the environment and recycling. [1]
The ASTM D6866 method has been developed to certify the biologically derived content of bioplastics. Cosmic rays colliding with the atmosphere mean that some of the carbon is the radioactive isotope carbon-14. CO 2 from the atmosphere is used by plants in photosynthesis, so new plant material will contain both carbon-14 and carbon-12.