Ad
related to: polycarbonate density properties of matter
Search results
Results from the WOW.Com Content Network
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 .
If the s in a material exceeds the yield point, the strain caused in the material by the application of load does not disappear totally on the removal of load. The plastic deformation caused to the material is known as creep. At high temperatures, the strain due to creep is quite appreciable. [2] Density: Mass per unit volume (kg/m^3)
Although single layer polycarbonate sheeting is more flexible than polycarbonate in twinwall configuration, it still retains significant advantages over alternative materials, including glass. A typical 6mm sheet has a density of 0.72 g/cm^2 [6] and a thermal insulation R value of 0.3 m^2°C/W, while allowing 80% of visible light pass through. [7]
They can also be classified by their physical properties, including hardness, density, tensile strength, thermal resistance, and glass transition temperature. Plastics can additionally be classified by their resistance and reactions to various substances and processes, such as exposure to organic solvents, oxidation , and ionizing radiation ...
HDPE is known for its high strength-to-density ratio. [4] The density of HDPE ranges from 930 to 970 kg/m 3. [5] Although the density of HDPE is only marginally higher than that of low-density polyethylene, HDPE has little branching, giving it stronger intermolecular forces and tensile strength (38 MPa versus 21 MPa) than LDPE. [6]
Plastic crystals were discovered in 1938 by Belgian chemist Jean Timmermans [4] by their anomalously low entropy of fusion.He found that organic substances having an entropy of fusion lower than approximately 17 J·K −1 ·mol −1 (~2R, where R is the molar gas constant) had peculiar properties.
In this state, the distinction between liquid and gas disappears. A supercritical fluid has the physical properties of a gas, but its high density confers solvent properties in some cases, which leads to useful applications. For example, supercritical carbon dioxide is used to extract caffeine in the manufacture of decaffeinated coffee. [3]
Ad
related to: polycarbonate density properties of matter